Support conversion between integer types. (#6856)

Add an `IntFitsIn` interface with a custom witness, such that `T impls IntFitsIn(U)` if `T` is an integer type all of whose values fit losslessly into the integer type `U`. Use it to constrain implicit conversions between integer types. So far, this has not been extended to the `CppCompat.[U]{Long32,LongLong64}` types, only to `Core.Int(N)` and `Core.UInt(N)`. Assisted-by: Gemini 3 Pro via Antigravity
2026-09-24 15:10:12 +01:00 · 2026-03-10 01:40:16 +00:00
parent 18cfeb7476
commit c297344937
27 changed files with 1281 additions and 349 deletions
@@ -49,3 +49,5 @@ impl forall [T:! type, U:! ImplicitAs(T)] const U as ImplicitAs(T) {
 impl forall [T:! type, U:! type] T* as UnsafeAs(U*) {
  fn Convert[self: T*]() -> U* = "pointer.unsafe_convert";
 }
+
+interface IntFitsIn(Dest:! type) {}
@@ -97,8 +97,8 @@ impl u32 as ImplicitAs(CppCompat.ULong32) {
 }

 // TODO: ImplicitAs from ULong32 to UInt(N) if N > 32.
-final impl CppCompat.ULong32 as ImplicitAs(u32) {
-  fn Convert[self: Self]() -> u32 = "int.convert";
+final impl CppCompat.ULong32 as ImplicitAs(u64) {
+  fn Convert[self: Self]() -> u64 = "int.convert";
 }

 impl IntLiteral() as ImplicitAs(CppCompat.LongLong64) {
@@ -146,8 +146,8 @@ impl u64 as ImplicitAs(CppCompat.ULongLong64) {
 }

 // TODO: ImplicitAs from ULongLong64 to UInt(N) if N > 64.
-final impl CppCompat.ULongLong64 as ImplicitAs(u64) {
-  fn Convert[self: Self]() -> u64 = "int.convert";
+final impl CppCompat.ULongLong64 as ImplicitAs(u128) {
+  fn Convert[self: Self]() -> u128 = "int.convert";
 }

 // TODO: As from Long32 to Int(N) if N < 32.
@@ -42,7 +42,26 @@ final impl forall [From:! IntLiteral()] Int(From) as As(IntLiteral()) {
  fn Convert[self: Self]() -> IntLiteral() = "int.convert_checked";
 }

-// TODO: Allow as an implicit conversion if N > M.
+// Work around the inability to put a `where` clause on a generic parameter of
+// type `IntLiteral`.
+// TODO: Remove this once possible.
+private interface AnyInt {
+  let Width:! IntLiteral();
+  fn AsInt[self: Self]() -> Int(Width);
+}
+
+impl forall [N:! IntLiteral()] Int(N) as AnyInt where .Width = N {
+  fn AsInt[self: Self]() -> Self { return self; }
+}
+
+impl forall [To:! IntLiteral(), From:! AnyInt & IntFitsIn(Int(To))]
+    From as ImplicitAs(Int(To)) {
+  fn Convert[self: Self]() -> Int(To) {
+    fn Impl(src: Int(From.Width)) -> Int(To) = "int.convert";
+    return Impl(self.AsInt());
+  }
+}
+
 final impl forall [From:! IntLiteral(), To:! IntLiteral()] Int(From) as As(Int(To)) {
  fn Convert[self: Self]() -> Int(To) = "int.convert";
 }
@@ -43,12 +43,52 @@ final impl forall [From:! IntLiteral()] UInt(From) as As(IntLiteral()) {
  fn Convert[self: Self]() -> IntLiteral() = "int.convert_checked";
 }

-// TODO: Allow as an implicit conversion if To > From.
+// Work around the inability to put a `where` clause on a generic parameter of
+// type `IntLiteral`.
+// TODO: Remove this once possible.
+private interface AnyUInt {
+  let Width:! IntLiteral();
+  fn AsUInt[self: Self]() -> UInt(Width);
+}
+
+impl forall [N:! IntLiteral()] UInt(N) as AnyUInt where .Width = N {
+  fn AsUInt[self: Self]() -> Self { return self; }
+}
+
+// Work around the inability to constrain types other than `.Self` by reversing
+// the Self and argument type of `ImplicitAs`.
+// TODO: Remove this once possible.
+private interface FromUInt(From:! type) {
+  fn Convert(from: From) -> Self;
+}
+
+impl forall [To:! IntLiteral(), From:! AnyUInt & IntFitsIn(UInt(To))]
+    UInt(To) as FromUInt(From) {
+  fn Convert(from: From) -> Self {
+    fn Impl(src: UInt(From.Width)) -> Self = "int.convert";
+    return Impl(from.AsUInt());
+  }
+}
+
+impl forall [To:! IntLiteral(), From:! AnyUInt & IntFitsIn(Int(To))]
+    Int(To) as FromUInt(From) {
+  fn Convert(from: From) -> Self {
+    fn Impl(src: UInt(From.Width)) -> Self = "int.convert";
+    return Impl(from.AsUInt());
+  }
+}
+
+impl forall [From:! IntLiteral(), To:! FromUInt(UInt(From))]
+    UInt(From) as ImplicitAs(To) {
+  fn Convert[self: Self]() -> To {
+    return To.Convert(self);
+  }
+}
+
 final impl forall [From:! IntLiteral(), To:! IntLiteral()] UInt(From) as As(UInt(To)) {
  fn Convert[self: Self]() -> UInt(To) = "int.convert";
 }

-// TODO: Allow as an implicit conversion if To > From.
 final impl forall [From:! IntLiteral(), To:! IntLiteral()] UInt(From) as As(Int(To)) {
  fn Convert[self: Self]() -> Int(To) = "int.convert";
 }
@@ -48,6 +48,7 @@ CARBON_CORE_IDENTIFIER(ImplicitAs)
 CARBON_CORE_IDENTIFIER(Inc)
 CARBON_CORE_IDENTIFIER(IndexWith)
 CARBON_CORE_IDENTIFIER(Int)
+CARBON_CORE_IDENTIFIER(IntFitsIn)
 CARBON_CORE_IDENTIFIER(Iterate)
 CARBON_CORE_IDENTIFIER(LeftShiftAssignWith)
 CARBON_CORE_IDENTIFIER(LeftShiftWith)
@@ -77,8 +77,8 @@ static auto GetCppAssociatedFunctions(const CoreInterface core_interface)
    case CoreInterface::Destroy:
      return {llvm::to_underlying(AssociatedFunction::Destructor)};
    case CoreInterface::Unknown:
-      CARBON_FATAL(
-          "`CoreInterface::Unknown` doesn't have a `CppCoreFunction` mapping");
+    case CoreInterface::IntFitsIn:
+      CARBON_FATAL("No AssociatedFunction mapping for this interface");
  }
 }

@@ -131,6 +131,7 @@ static auto FindCppAssociatedFunction(Context& context, SemIR::LocId loc_id,

  return fn_id;
 }
+
 auto LookupCppImpl(Context& context, SemIR::LocId loc_id,
                   CoreInterface core_interface,
                   SemIR::ConstantId query_self_const_id,
@@ -142,18 +143,20 @@ auto LookupCppImpl(Context& context, SemIR::LocId loc_id,
    return SemIR::InstId::None;
  }

-  auto associated_functions = GetCppAssociatedFunctions(core_interface);
  auto witness_id = SemIR::ErrorInst::InstId;

  switch (core_interface) {
    case CoreInterface::Copy:
    case CoreInterface::Destroy: {
+      auto associated_functions = GetCppAssociatedFunctions(core_interface);
      CARBON_CHECK(associated_functions.count() == 1);
      witness_id = FindCppAssociatedFunction(
          context, loc_id,
          static_cast<AssociatedFunction>(associated_functions.to_ullong()),
          class_decl);
    } break;
+    case CoreInterface::IntFitsIn:
+      return SemIR::InstId::None;
    case CoreInterface::Unknown:
      CARBON_FATAL("shouldn't be called with `Unknown`");
  }
@@ -14,6 +14,7 @@
 #include "toolchain/check/inst.h"
 #include "toolchain/check/name_lookup.h"
 #include "toolchain/check/type.h"
+#include "toolchain/check/type_completion.h"
 #include "toolchain/sem_ir/builtin_function_kind.h"
 #include "toolchain/sem_ir/ids.h"
 #include "toolchain/sem_ir/typed_insts.h"
@@ -283,7 +284,8 @@ auto GetCoreInterface(Context& context, SemIR::InterfaceId interface_id)

  for (auto [core_identifier, core_interface] :
       {std::pair{CoreIdentifier::Copy, CoreInterface::Copy},
-        std::pair{CoreIdentifier::Destroy, CoreInterface::Destroy}}) {
+        std::pair{CoreIdentifier::Destroy, CoreInterface::Destroy},
+        std::pair{CoreIdentifier::IntFitsIn, CoreInterface::IntFitsIn}}) {
    if (interface.name_id ==
        context.core_identifiers().AddNameId(core_identifier)) {
      return core_interface;
@@ -348,16 +350,11 @@ static auto TypeCanDestroy(Context& context,
  }
 }

-auto LookupCustomWitness(Context& context, SemIR::LocId loc_id,
-                         CoreInterface core_interface,
-                         SemIR::ConstantId query_self_const_id,
-                         SemIR::SpecificInterfaceId query_specific_interface_id)
+static auto MakeDestroyWitness(
+    Context& context, SemIR::LocId loc_id,
+    SemIR::ConstantId query_self_const_id,
+    SemIR::SpecificInterfaceId query_specific_interface_id)
    -> std::optional<SemIR::InstId> {
-  // TODO: Handle more interfaces, particularly copy, move, and conversion.
-  if (core_interface != CoreInterface::Destroy) {
-    return std::nullopt;
-  }
-
  auto query_specific_interface =
      context.specific_interfaces().Get(query_specific_interface_id);

@@ -383,4 +380,93 @@ auto LookupCustomWitness(Context& context, SemIR::LocId loc_id,
                            query_specific_interface_id, {op_id});
 }

+static auto MakeIntFitsInWitness(
+    Context& context, SemIR::LocId loc_id,
+    SemIR::ConstantId query_self_const_id,
+    SemIR::SpecificInterfaceId query_specific_interface_id)
+    -> std::optional<SemIR::InstId> {
+  auto query_specific_interface =
+      context.specific_interfaces().Get(query_specific_interface_id);
+
+  auto args_id = query_specific_interface.specific_id;
+  if (!args_id.has_value()) {
+    return std::nullopt;
+  }
+  auto args_block_id = context.specifics().Get(args_id).args_id;
+  auto args_block = context.inst_blocks().Get(args_block_id);
+  if (args_block.size() != 1) {
+    return std::nullopt;
+  }
+
+  auto dest_const_id = context.constant_values().Get(args_block[0]);
+  if (!dest_const_id.is_constant()) {
+    return std::nullopt;
+  }
+
+  auto src_type_id = GetFacetAsType(context, query_self_const_id);
+  auto dest_type_id = GetFacetAsType(context, dest_const_id);
+
+  auto context_fn = [](DiagnosticContextBuilder& /*builder*/) -> void {};
+  if (!RequireCompleteType(context, src_type_id, loc_id, context_fn) ||
+      !RequireCompleteType(context, dest_type_id, loc_id, context_fn)) {
+    return std::nullopt;
+  }
+
+  auto src_info = context.types().TryGetIntTypeInfo(src_type_id);
+  auto dest_info = context.types().TryGetIntTypeInfo(dest_type_id);
+
+  if (!src_info || !dest_info) {
+    return std::nullopt;
+  }
+
+  // If the bit width is unknown (e.g., due to symbolic evaluation), we cannot
+  // determine whether it fits yet.
+  if (src_info->bit_width == IntId::None ||
+      dest_info->bit_width == IntId::None) {
+    return std::nullopt;
+  }
+
+  const auto& src_width = context.ints().Get(src_info->bit_width);
+  const auto& dest_width = context.ints().Get(dest_info->bit_width);
+
+  bool fits = false;
+  if (src_info->is_signed && !dest_info->is_signed) {
+    // Signed -> unsigned: would truncate the sign bit.
+    fits = false;
+  } else if (src_info->is_signed == dest_info->is_signed) {
+    // Signed -> signed or unsigned -> unsigned: allow widening or preserving
+    // width.
+    fits = src_width.sle(dest_width);
+  } else {
+    // Unsigned -> signed: strict widening required.
+    fits = src_width.slt(dest_width);
+  }
+
+  if (!fits) {
+    return std::nullopt;
+  }
+
+  return BuildCustomWitness(context, loc_id, query_self_const_id,
+                            query_specific_interface_id, {});
+}
+
+auto LookupCustomWitness(Context& context, SemIR::LocId loc_id,
+                         CoreInterface core_interface,
+                         SemIR::ConstantId query_self_const_id,
+                         SemIR::SpecificInterfaceId query_specific_interface_id)
+    -> std::optional<SemIR::InstId> {
+  switch (core_interface) {
+    case CoreInterface::Destroy:
+      return MakeDestroyWitness(context, loc_id, query_self_const_id,
+                                query_specific_interface_id);
+    case CoreInterface::IntFitsIn:
+      return MakeIntFitsInWitness(context, loc_id, query_self_const_id,
+                                  query_specific_interface_id);
+    case CoreInterface::Copy:
+    case CoreInterface::Unknown:
+      // TODO: Handle more interfaces, particularly copy, move, and conversion.
+      return std::nullopt;
+  }
+}
+
 }  // namespace Carbon::Check
@@ -24,6 +24,7 @@ auto BuildCustomWitness(Context& context, SemIR::LocId loc_id,
 enum class CoreInterface : std::int8_t {
  Copy = 1 << 0,
  Destroy = 1 << 1,
+  IntFitsIn = 1 << 2,

  Unknown = -1,
 };
@@ -120,7 +120,7 @@ var b: array(1, 39999999999999999993);
 // CHECK:STDOUT:   %To.fe9: Core.IntLiteral = symbolic_binding To, 0 [symbolic]
 // CHECK:STDOUT:   %Core.IntLiteral.as.As.impl.Convert.type.2b1: type = fn_type @Core.IntLiteral.as.As.impl.Convert, @Core.IntLiteral.as.As.impl(%To.fe9) [symbolic]
 // CHECK:STDOUT:   %Core.IntLiteral.as.As.impl.Convert.979: %Core.IntLiteral.as.As.impl.Convert.type.2b1 = struct_value () [symbolic]
-// CHECK:STDOUT:   %From: Core.IntLiteral = symbolic_binding From, 0 [symbolic]
+// CHECK:STDOUT:   %From.fe9: Core.IntLiteral = symbolic_binding From, 0 [symbolic]
 // CHECK:STDOUT:   %As.impl_witness.e1d: <witness> = impl_witness imports.%As.impl_witness_table.7eb, @Core.IntLiteral.as.As.impl(%int_32) [concrete]
 // CHECK:STDOUT:   %Core.IntLiteral.as.As.impl.Convert.type.3e7: type = fn_type @Core.IntLiteral.as.As.impl.Convert, @Core.IntLiteral.as.As.impl(%int_32) [concrete]
 // CHECK:STDOUT:   %Core.IntLiteral.as.As.impl.Convert.bbd: %Core.IntLiteral.as.As.impl.Convert.type.3e7 = struct_value () [concrete]
@@ -132,16 +132,16 @@ var b: array(1, 39999999999999999993);
 // CHECK:STDOUT:   %bound_method.d64: <bound method> = bound_method %int_3.1ba, %Core.IntLiteral.as.As.impl.Convert.specific_fn [concrete]
 // CHECK:STDOUT:   %int_3.d14: %u32 = int_value 3 [concrete]
 // CHECK:STDOUT:   %ImplicitAs.type.139: type = facet_type <@ImplicitAs, @ImplicitAs(Core.IntLiteral)> [concrete]
-// CHECK:STDOUT:   %UInt.as.ImplicitAs.impl.Convert.type.7f8: type = fn_type @UInt.as.ImplicitAs.impl.Convert, @UInt.as.ImplicitAs.impl(%From) [symbolic]
+// CHECK:STDOUT:   %UInt.as.ImplicitAs.impl.Convert.type.7f8: type = fn_type @UInt.as.ImplicitAs.impl.Convert.1, @UInt.as.ImplicitAs.impl.607(%From.fe9) [symbolic]
 // CHECK:STDOUT:   %UInt.as.ImplicitAs.impl.Convert.0ea: %UInt.as.ImplicitAs.impl.Convert.type.7f8 = struct_value () [symbolic]
-// CHECK:STDOUT:   %ImplicitAs.impl_witness.895: <witness> = impl_witness imports.%ImplicitAs.impl_witness_table.493, @UInt.as.ImplicitAs.impl(%int_32) [concrete]
-// CHECK:STDOUT:   %UInt.as.ImplicitAs.impl.Convert.type.543: type = fn_type @UInt.as.ImplicitAs.impl.Convert, @UInt.as.ImplicitAs.impl(%int_32) [concrete]
+// CHECK:STDOUT:   %ImplicitAs.impl_witness.895: <witness> = impl_witness imports.%ImplicitAs.impl_witness_table.493, @UInt.as.ImplicitAs.impl.607(%int_32) [concrete]
+// CHECK:STDOUT:   %UInt.as.ImplicitAs.impl.Convert.type.543: type = fn_type @UInt.as.ImplicitAs.impl.Convert.1, @UInt.as.ImplicitAs.impl.607(%int_32) [concrete]
 // CHECK:STDOUT:   %UInt.as.ImplicitAs.impl.Convert.342: %UInt.as.ImplicitAs.impl.Convert.type.543 = struct_value () [concrete]
 // CHECK:STDOUT:   %ImplicitAs.facet.2c6: %ImplicitAs.type.139 = facet_value %u32, (%ImplicitAs.impl_witness.895) [concrete]
 // CHECK:STDOUT:   %ImplicitAs.WithSelf.Convert.type.70d: type = fn_type @ImplicitAs.WithSelf.Convert, @ImplicitAs.WithSelf(Core.IntLiteral, %ImplicitAs.facet.2c6) [concrete]
 // CHECK:STDOUT:   %.044: type = fn_type_with_self_type %ImplicitAs.WithSelf.Convert.type.70d, %ImplicitAs.facet.2c6 [concrete]
 // CHECK:STDOUT:   %UInt.as.ImplicitAs.impl.Convert.bound: <bound method> = bound_method %int_3.d14, %UInt.as.ImplicitAs.impl.Convert.342 [concrete]
-// CHECK:STDOUT:   %UInt.as.ImplicitAs.impl.Convert.specific_fn: <specific function> = specific_function %UInt.as.ImplicitAs.impl.Convert.342, @UInt.as.ImplicitAs.impl.Convert(%int_32) [concrete]
+// CHECK:STDOUT:   %UInt.as.ImplicitAs.impl.Convert.specific_fn: <specific function> = specific_function %UInt.as.ImplicitAs.impl.Convert.342, @UInt.as.ImplicitAs.impl.Convert.1(%int_32) [concrete]
 // CHECK:STDOUT:   %bound_method.c86: <bound method> = bound_method %int_3.d14, %UInt.as.ImplicitAs.impl.Convert.specific_fn [concrete]
 // CHECK:STDOUT:   %array_type: type = array_type %int_3.1ba, %i32 [concrete]
 // CHECK:STDOUT: }
@@ -149,8 +149,8 @@ var b: array(1, 39999999999999999993);
 // CHECK:STDOUT: imports {
 // CHECK:STDOUT:   %Core.import_ref.600: @Core.IntLiteral.as.As.impl.%Core.IntLiteral.as.As.impl.Convert.type (%Core.IntLiteral.as.As.impl.Convert.type.2b1) = import_ref Core//prelude/types/uint, loc{{\d+_\d+}}, loaded [symbolic = @Core.IntLiteral.as.As.impl.%Core.IntLiteral.as.As.impl.Convert (constants.%Core.IntLiteral.as.As.impl.Convert.979)]
 // CHECK:STDOUT:   %As.impl_witness_table.7eb = impl_witness_table (%Core.import_ref.600), @Core.IntLiteral.as.As.impl [concrete]
-// CHECK:STDOUT:   %Core.import_ref.483: @UInt.as.ImplicitAs.impl.%UInt.as.ImplicitAs.impl.Convert.type (%UInt.as.ImplicitAs.impl.Convert.type.7f8) = import_ref Core//prelude/types/uint, loc{{\d+_\d+}}, loaded [symbolic = @UInt.as.ImplicitAs.impl.%UInt.as.ImplicitAs.impl.Convert (constants.%UInt.as.ImplicitAs.impl.Convert.0ea)]
-// CHECK:STDOUT:   %ImplicitAs.impl_witness_table.493 = impl_witness_table (%Core.import_ref.483), @UInt.as.ImplicitAs.impl [concrete]
+// CHECK:STDOUT:   %Core.import_ref.483: @UInt.as.ImplicitAs.impl.607.%UInt.as.ImplicitAs.impl.Convert.type (%UInt.as.ImplicitAs.impl.Convert.type.7f8) = import_ref Core//prelude/types/uint, loc{{\d+_\d+}}, loaded [symbolic = @UInt.as.ImplicitAs.impl.607.%UInt.as.ImplicitAs.impl.Convert (constants.%UInt.as.ImplicitAs.impl.Convert.0ea)]
+// CHECK:STDOUT:   %ImplicitAs.impl_witness_table.493 = impl_witness_table (%Core.import_ref.483), @UInt.as.ImplicitAs.impl.607 [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {
@@ -167,7 +167,7 @@ var b: array(1, 39999999999999999993);
 // CHECK:STDOUT:     %.loc6_18.2: %u32 = converted %int_3.loc6, %.loc6_18.1 [concrete = constants.%int_3.d14]
 // CHECK:STDOUT:     %impl.elem0.loc6_18.2: %.044 = impl_witness_access constants.%ImplicitAs.impl_witness.895, element0 [concrete = constants.%UInt.as.ImplicitAs.impl.Convert.342]
 // CHECK:STDOUT:     %bound_method.loc6_18.3: <bound method> = bound_method %.loc6_18.2, %impl.elem0.loc6_18.2 [concrete = constants.%UInt.as.ImplicitAs.impl.Convert.bound]
-// CHECK:STDOUT:     %specific_fn.loc6_18.2: <specific function> = specific_function %impl.elem0.loc6_18.2, @UInt.as.ImplicitAs.impl.Convert(constants.%int_32) [concrete = constants.%UInt.as.ImplicitAs.impl.Convert.specific_fn]
+// CHECK:STDOUT:     %specific_fn.loc6_18.2: <specific function> = specific_function %impl.elem0.loc6_18.2, @UInt.as.ImplicitAs.impl.Convert.1(constants.%int_32) [concrete = constants.%UInt.as.ImplicitAs.impl.Convert.specific_fn]
 // CHECK:STDOUT:     %bound_method.loc6_18.4: <bound method> = bound_method %.loc6_18.2, %specific_fn.loc6_18.2 [concrete = constants.%bound_method.c86]
 // CHECK:STDOUT:     %UInt.as.ImplicitAs.impl.Convert.call: init Core.IntLiteral = call %bound_method.loc6_18.4(%.loc6_18.2) [concrete = constants.%int_3.1ba]
 // CHECK:STDOUT:     %.loc6_18.3: Core.IntLiteral = value_of_initializer %UInt.as.ImplicitAs.impl.Convert.call [concrete = constants.%int_3.1ba]
@@ -74,7 +74,7 @@ fn Read(y:! Core.IntLiteral()) {
 // CHECK:STDOUT:   %OptionalStorage.type: type = facet_type <@OptionalStorage> [concrete]
 // CHECK:STDOUT:   %Destroy.type: type = facet_type <@Destroy> [concrete]
 // CHECK:STDOUT:   %Copy.type: type = facet_type <@Copy> [concrete]
-// CHECK:STDOUT:   %facet_type: type = facet_type <@Destroy & @Copy> [concrete]
+// CHECK:STDOUT:   %facet_type.7e2: type = facet_type <@Destroy & @Copy> [concrete]
 // CHECK:STDOUT:   %Optional.type: type = generic_class_type @Optional [concrete]
 // CHECK:STDOUT:   %Optional.generic: %Optional.type = struct_value () [concrete]
 // CHECK:STDOUT:   %T.542: %OptionalStorage.type = symbolic_binding T, 0 [symbolic]
@@ -84,7 +84,7 @@ fn Read(y:! Core.IntLiteral()) {
 // CHECK:STDOUT:   %Optional.None.fcb: %Optional.None.type.fc5 = struct_value () [symbolic]
 // CHECK:STDOUT:   %.Self.2b2: %Iterate.type = symbolic_binding .Self [symbolic_self]
 // CHECK:STDOUT:   %Iterate.lookup_impl_witness.53f: <witness> = lookup_impl_witness %.Self.2b2, @Iterate [symbolic_self]
-// CHECK:STDOUT:   %impl.elem0.3b1: %facet_type = impl_witness_access %Iterate.lookup_impl_witness.53f, element0 [symbolic_self]
+// CHECK:STDOUT:   %impl.elem0.3b1: %facet_type.7e2 = impl_witness_access %Iterate.lookup_impl_witness.53f, element0 [symbolic_self]
 // CHECK:STDOUT:   %.Self.binding.as_type: type = symbolic_binding_type .Self, %.Self.2b2 [symbolic_self]
 // CHECK:STDOUT:   %Iterate.assoc_type: type = assoc_entity_type @Iterate [concrete]
 // CHECK:STDOUT:   %assoc1.a27: %Iterate.assoc_type = assoc_entity element1, imports.%Core.import_ref.cd6 [concrete]
@@ -97,7 +97,7 @@ fn Read(y:! Core.IntLiteral()) {
 // CHECK:STDOUT:   %.83cba3.1: Core.Form = init_form %Int.fc6021.1 [symbolic]
 // CHECK:STDOUT:   %.4f8: require_specific_def_type = require_specific_def @Int.as.Copy.impl(%N) [symbolic]
 // CHECK:STDOUT:   %Copy.lookup_impl_witness.7a8: <witness> = lookup_impl_witness %Int.fc6021.1, @Copy [symbolic]
-// CHECK:STDOUT:   %facet_value: %facet_type = facet_value %Int.fc6021.1, (%Destroy.lookup_impl_witness.93c, %Copy.lookup_impl_witness.7a8) [symbolic]
+// CHECK:STDOUT:   %facet_value: %facet_type.7e2 = facet_value %Int.fc6021.1, (%Destroy.lookup_impl_witness.93c, %Copy.lookup_impl_witness.7a8) [symbolic]
 // CHECK:STDOUT:   %Iterate_where.type: type = facet_type <@Iterate where %impl.elem0.3b1 = %facet_value and %impl.elem1.49e = %Int.fc6021.1> [symbolic]
 // CHECK:STDOUT:   %Iterate.impl_witness: <witness> = impl_witness @IntRange.as.Iterate.impl.%Iterate.impl_witness_table, @IntRange.as.Iterate.impl(%N) [symbolic]
 // CHECK:STDOUT:   %require_complete.234: <witness> = require_complete_type %Iterate_where.type [symbolic]
@@ -233,8 +233,8 @@ fn Read(y:! Core.IntLiteral()) {
 // CHECK:STDOUT:   %Core.import_ref.aeb: @Optional.%Optional.Some.type (%Optional.Some.type.eaa) = import_ref Core//prelude/iterate, inst{{[0-9A-F]+}} [indirect], loaded [symbolic = @Optional.%Optional.Some (constants.%Optional.Some.6ca)]
 // CHECK:STDOUT:   %Core.import_ref.cd6: type = import_ref Core//prelude/iterate, loc{{\d+_\d+}}, loaded [concrete = %CursorType]
 // CHECK:STDOUT:   %CursorType: type = assoc_const_decl @CursorType [concrete] {}
-// CHECK:STDOUT:   %Core.import_ref.f74: %facet_type = import_ref Core//prelude/iterate, loc{{\d+_\d+}}, loaded [concrete = %ElementType]
-// CHECK:STDOUT:   %ElementType: %facet_type = assoc_const_decl @ElementType [concrete] {}
+// CHECK:STDOUT:   %Core.import_ref.f74: %facet_type.7e2 = import_ref Core//prelude/iterate, loc{{\d+_\d+}}, loaded [concrete = %ElementType]
+// CHECK:STDOUT:   %ElementType: %facet_type.7e2 = assoc_const_decl @ElementType [concrete] {}
 // CHECK:STDOUT:   %Core.import_ref.18d: @Int.as.Copy.impl.%Int.as.Copy.impl.Op.type (%Int.as.Copy.impl.Op.type.824) = import_ref Core//prelude/types/int, loc{{\d+_\d+}}, loaded [symbolic = @Int.as.Copy.impl.%Int.as.Copy.impl.Op (constants.%Int.as.Copy.impl.Op.9b9)]
 // CHECK:STDOUT:   %Copy.impl_witness_table.e76 = impl_witness_table (%Core.import_ref.18d), @Int.as.Copy.impl [concrete]
 // CHECK:STDOUT:   %Core.Optional: %Optional.type = import_ref Core//prelude/types/optional, Optional, loaded [concrete = constants.%Optional.generic]
@@ -300,7 +300,7 @@ fn Read(y:! Core.IntLiteral()) {
 // CHECK:STDOUT:   %Destroy.lookup_impl_witness: <witness> = lookup_impl_witness %Int.loc9_54.1, @Destroy [symbolic = %Destroy.lookup_impl_witness (constants.%Destroy.lookup_impl_witness.93c)]
 // CHECK:STDOUT:   %.loc9_85.1: require_specific_def_type = require_specific_def @Int.as.Copy.impl(%N) [symbolic = %.loc9_85.1 (constants.%.4f8)]
 // CHECK:STDOUT:   %Copy.lookup_impl_witness: <witness> = lookup_impl_witness %Int.loc9_54.1, @Copy [symbolic = %Copy.lookup_impl_witness (constants.%Copy.lookup_impl_witness.7a8)]
-// CHECK:STDOUT:   %facet_value.loc9_85.1: %facet_type = facet_value %Int.loc9_54.1, (%Destroy.lookup_impl_witness, %Copy.lookup_impl_witness) [symbolic = %facet_value.loc9_85.1 (constants.%facet_value)]
+// CHECK:STDOUT:   %facet_value.loc9_85.1: %facet_type.7e2 = facet_value %Int.loc9_54.1, (%Destroy.lookup_impl_witness, %Copy.lookup_impl_witness) [symbolic = %facet_value.loc9_85.1 (constants.%facet_value)]
 // CHECK:STDOUT:   %Iterate_where.type: type = facet_type <@Iterate where constants.%impl.elem0.3b1 = %facet_value.loc9_85.1 and constants.%impl.elem1.49e = %Int.loc9_54.1> [symbolic = %Iterate_where.type (constants.%Iterate_where.type)]
 // CHECK:STDOUT:   %Iterate.impl_witness.loc9_87.2: <witness> = impl_witness %Iterate.impl_witness_table, @IntRange.as.Iterate.impl(%N) [symbolic = %Iterate.impl_witness.loc9_87.2 (constants.%Iterate.impl_witness)]
 // CHECK:STDOUT:
@@ -371,7 +371,7 @@ fn Read(y:! Core.IntLiteral()) {
 // CHECK:STDOUT:     }
 // CHECK:STDOUT:     %Iterate.impl_witness_table = impl_witness_table (%impl_witness_assoc_constant.loc9_87.1, %impl_witness_assoc_constant.loc9_87.2, %IntRange.as.Iterate.impl.NewCursor.decl, %IntRange.as.Iterate.impl.Next.decl), @IntRange.as.Iterate.impl [concrete]
 // CHECK:STDOUT:     %Iterate.impl_witness.loc9_87.1: <witness> = impl_witness %Iterate.impl_witness_table, @IntRange.as.Iterate.impl(constants.%N) [symbolic = %Iterate.impl_witness.loc9_87.2 (constants.%Iterate.impl_witness)]
-// CHECK:STDOUT:     %impl_witness_assoc_constant.loc9_87.1: %facet_type = impl_witness_assoc_constant constants.%facet_value [symbolic = %facet_value.loc9_85.1 (constants.%facet_value)]
+// CHECK:STDOUT:     %impl_witness_assoc_constant.loc9_87.1: %facet_type.7e2 = impl_witness_assoc_constant constants.%facet_value [symbolic = %facet_value.loc9_85.1 (constants.%facet_value)]
 // CHECK:STDOUT:     %impl_witness_assoc_constant.loc9_87.2: type = impl_witness_assoc_constant constants.%Int.fc6021.1 [symbolic = %Int.loc9_54.1 (constants.%Int.fc6021.1)]
 // CHECK:STDOUT:
 // CHECK:STDOUT:   !members:
@@ -445,13 +445,13 @@ fn Read(y:! Core.IntLiteral()) {
 // CHECK:STDOUT:       %.Self.as_type.loc9_60: type = facet_access_type %.Self.ref.loc9_60 [symbolic_self = constants.%.Self.binding.as_type]
 // CHECK:STDOUT:       %.loc9_60: type = converted %.Self.ref.loc9_60, %.Self.as_type.loc9_60 [symbolic_self = constants.%.Self.binding.as_type]
 // CHECK:STDOUT:       %ElementType.ref: %Iterate.assoc_type = name_ref ElementType, imports.%Core.import_ref.39b [concrete = constants.%assoc0.4bd]
-// CHECK:STDOUT:       %impl.elem0: %facet_type = impl_witness_access constants.%Iterate.lookup_impl_witness.53f, element0 [symbolic_self = constants.%impl.elem0.3b1]
+// CHECK:STDOUT:       %impl.elem0: %facet_type.7e2 = impl_witness_access constants.%Iterate.lookup_impl_witness.53f, element0 [symbolic_self = constants.%impl.elem0.3b1]
 // CHECK:STDOUT:       %Core.ref.loc9_75: <namespace> = name_ref Core, imports.%Core [concrete = imports.%Core]
 // CHECK:STDOUT:       %Int.ref.loc9_79: %Int.type = name_ref Int, imports.%Core.Int [concrete = constants.%Int.generic]
 // CHECK:STDOUT:       %N.ref.loc9_84: Core.IntLiteral = name_ref N, @IntRange.%N.loc4_16.2 [symbolic = %N (constants.%N)]
 // CHECK:STDOUT:       %Int.loc9_85: type = class_type @Int, @Int(constants.%N) [symbolic = %Int.loc9_54.1 (constants.%Int.fc6021.1)]
-// CHECK:STDOUT:       %facet_value.loc9_85.2: %facet_type = facet_value %Int.loc9_85, (constants.%Destroy.lookup_impl_witness.93c, constants.%Copy.lookup_impl_witness.7a8) [symbolic = %facet_value.loc9_85.1 (constants.%facet_value)]
-// CHECK:STDOUT:       %.loc9_85.2: %facet_type = converted %Int.loc9_85, %facet_value.loc9_85.2 [symbolic = %facet_value.loc9_85.1 (constants.%facet_value)]
+// CHECK:STDOUT:       %facet_value.loc9_85.2: %facet_type.7e2 = facet_value %Int.loc9_85, (constants.%Destroy.lookup_impl_witness.93c, constants.%Copy.lookup_impl_witness.7a8) [symbolic = %facet_value.loc9_85.1 (constants.%facet_value)]
+// CHECK:STDOUT:       %.loc9_85.2: %facet_type.7e2 = converted %Int.loc9_85, %facet_value.loc9_85.2 [symbolic = %facet_value.loc9_85.1 (constants.%facet_value)]
 // CHECK:STDOUT:       %.loc9_24: type = where_expr %.Self [symbolic = %Iterate_where.type (constants.%Iterate_where.type)] {
 // CHECK:STDOUT:         requirement_base_facet_type constants.%Iterate.type
 // CHECK:STDOUT:         requirement_rewrite %impl.elem1, %Int.loc9_54.2
@@ -569,7 +569,7 @@ fn Read(y:! Core.IntLiteral()) {
 // CHECK:STDOUT:   %pattern_type.loc11_25: type = pattern_type %ptr.loc11_44.1 [symbolic = %pattern_type.loc11_25 (constants.%pattern_type.bda)]
 // CHECK:STDOUT:   %Destroy.lookup_impl_witness: <witness> = lookup_impl_witness %Int.loc11_43.1, @Destroy [symbolic = %Destroy.lookup_impl_witness (constants.%Destroy.lookup_impl_witness.93c)]
 // CHECK:STDOUT:   %Copy.lookup_impl_witness: <witness> = lookup_impl_witness %Int.loc11_43.1, @Copy [symbolic = %Copy.lookup_impl_witness (constants.%Copy.lookup_impl_witness.7a8)]
-// CHECK:STDOUT:   %facet_value: %facet_type = facet_value %Int.loc11_43.1, (%Destroy.lookup_impl_witness, %Copy.lookup_impl_witness) [symbolic = %facet_value (constants.%facet_value)]
+// CHECK:STDOUT:   %facet_value: %facet_type.7e2 = facet_value %Int.loc11_43.1, (%Destroy.lookup_impl_witness, %Copy.lookup_impl_witness) [symbolic = %facet_value (constants.%facet_value)]
 // CHECK:STDOUT:   %.loc11_75.3: require_specific_def_type = require_specific_def @T.binding.as_type.as.OptionalStorage.impl(%facet_value) [symbolic = %.loc11_75.3 (constants.%.63c)]
 // CHECK:STDOUT:   %OptionalStorage.lookup_impl_witness: <witness> = lookup_impl_witness %Int.loc11_43.1, @OptionalStorage [symbolic = %OptionalStorage.lookup_impl_witness (constants.%OptionalStorage.lookup_impl_witness.b62)]
 // CHECK:STDOUT:   %OptionalStorage.facet.loc11_75.1: %OptionalStorage.type = facet_value %Int.loc11_43.1, (%OptionalStorage.lookup_impl_witness) [symbolic = %OptionalStorage.facet.loc11_75.1 (constants.%OptionalStorage.facet.01e)]
@@ -0,0 +1,114 @@
+// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+// INCLUDE-FILE: toolchain/testing/testdata/min_prelude/primitives.carbon
+//
+// AUTOUPDATE
+// TIP: To test this file alone, run:
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/impl/custom_witness/int_fits_in.carbon
+// TIP: To dump output, run:
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/impl/custom_witness/int_fits_in.carbon
+
+// --- core.carbon
+
+package Core;
+
+interface IntFitsIn(Dest:! type) {}
+
+fn CheckFitsIn[U:! type, T:! IntFitsIn(U)](unused t: T, unused u: U) {}
+
+// --- valid.carbon
+
+library "[[@TEST_NAME]]";
+
+import Core;
+
+fn CheckOk() {
+  Core.CheckFitsIn(1 as i32, 2 as i64);
+  Core.CheckFitsIn(1 as u32, 2 as u64);
+  Core.CheckFitsIn(1 as u32, 2 as i64);
+}
+
+// --- fail_narrowing.carbon
+
+library "[[@TEST_NAME]]";
+
+import Core;
+
+fn CheckFail() {
+  // CHECK:STDERR: fail_narrowing.carbon:[[@LINE+7]]:3: error: cannot convert type `i64` into type implementing `Core.IntFitsIn(i32)` [ConversionFailureTypeToFacet]
+  // CHECK:STDERR:   Core.CheckFitsIn(1 as i64, 2 as i32);
+  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+  // CHECK:STDERR: core.carbon:6:1: note: while deducing parameters of generic declared here [DeductionGenericHere]
+  // CHECK:STDERR: fn CheckFitsIn[U:! type, T:! IntFitsIn(U)](unused t: T, unused u: U) {}
+  // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+  // CHECK:STDERR:
+  Core.CheckFitsIn(1 as i64, 2 as i32);
+  // CHECK:STDERR: fail_narrowing.carbon:[[@LINE+7]]:3: error: cannot convert type `i64` into type implementing `Core.IntFitsIn(u32)` [ConversionFailureTypeToFacet]
+  // CHECK:STDERR:   Core.CheckFitsIn(1 as i64, 2 as u32);
+  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+  // CHECK:STDERR: core.carbon:6:1: note: while deducing parameters of generic declared here [DeductionGenericHere]
+  // CHECK:STDERR: fn CheckFitsIn[U:! type, T:! IntFitsIn(U)](unused t: T, unused u: U) {}
+  // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+  // CHECK:STDERR:
+  Core.CheckFitsIn(1 as i64, 2 as u32);
+  // CHECK:STDERR: fail_narrowing.carbon:[[@LINE+7]]:3: error: cannot convert type `u64` into type implementing `Core.IntFitsIn(i32)` [ConversionFailureTypeToFacet]
+  // CHECK:STDERR:   Core.CheckFitsIn(1 as u64, 2 as i32);
+  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+  // CHECK:STDERR: core.carbon:6:1: note: while deducing parameters of generic declared here [DeductionGenericHere]
+  // CHECK:STDERR: fn CheckFitsIn[U:! type, T:! IntFitsIn(U)](unused t: T, unused u: U) {}
+  // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+  // CHECK:STDERR:
+  Core.CheckFitsIn(1 as u64, 2 as i32);
+  // CHECK:STDERR: fail_narrowing.carbon:[[@LINE+7]]:3: error: cannot convert type `u64` into type implementing `Core.IntFitsIn(u32)` [ConversionFailureTypeToFacet]
+  // CHECK:STDERR:   Core.CheckFitsIn(1 as u64, 2 as u32);
+  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+  // CHECK:STDERR: core.carbon:6:1: note: while deducing parameters of generic declared here [DeductionGenericHere]
+  // CHECK:STDERR: fn CheckFitsIn[U:! type, T:! IntFitsIn(U)](unused t: T, unused u: U) {}
+  // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+  // CHECK:STDERR:
+  Core.CheckFitsIn(1 as u64, 2 as u32);
+}
+
+// --- fail_same_size_sign_change.carbon
+
+library "[[@TEST_NAME]]";
+
+import Core;
+
+fn CheckFail() {
+  // CHECK:STDERR: fail_same_size_sign_change.carbon:[[@LINE+7]]:3: error: cannot convert type `u32` into type implementing `Core.IntFitsIn(i32)` [ConversionFailureTypeToFacet]
+  // CHECK:STDERR:   Core.CheckFitsIn(1 as u32, 2 as i32);
+  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+  // CHECK:STDERR: core.carbon:6:1: note: while deducing parameters of generic declared here [DeductionGenericHere]
+  // CHECK:STDERR: fn CheckFitsIn[U:! type, T:! IntFitsIn(U)](unused t: T, unused u: U) {}
+  // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+  // CHECK:STDERR:
+  Core.CheckFitsIn(1 as u32, 2 as i32);
+  // CHECK:STDERR: fail_same_size_sign_change.carbon:[[@LINE+7]]:3: error: cannot convert type `i32` into type implementing `Core.IntFitsIn(u32)` [ConversionFailureTypeToFacet]
+  // CHECK:STDERR:   Core.CheckFitsIn(1 as i32, 2 as u32);
+  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+  // CHECK:STDERR: core.carbon:6:1: note: while deducing parameters of generic declared here [DeductionGenericHere]
+  // CHECK:STDERR: fn CheckFitsIn[U:! type, T:! IntFitsIn(U)](unused t: T, unused u: U) {}
+  // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+  // CHECK:STDERR:
+  Core.CheckFitsIn(1 as i32, 2 as u32);
+}
+
+// --- fail_signed_to_wider_unsigned.carbon
+
+library "[[@TEST_NAME]]";
+
+import Core;
+
+fn CheckFail() {
+  // CHECK:STDERR: fail_signed_to_wider_unsigned.carbon:[[@LINE+7]]:3: error: cannot convert type `i32` into type implementing `Core.IntFitsIn(u32)` [ConversionFailureTypeToFacet]
+  // CHECK:STDERR:   Core.CheckFitsIn(1 as i32, 2 as u32);
+  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+  // CHECK:STDERR: core.carbon:6:1: note: while deducing parameters of generic declared here [DeductionGenericHere]
+  // CHECK:STDERR: fn CheckFitsIn[U:! type, T:! IntFitsIn(U)](unused t: T, unused u: U) {}
+  // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+  // CHECK:STDERR:
+  Core.CheckFitsIn(1 as i32, 2 as u32);
+}
@@ -638,13 +638,38 @@ fn F() {
  let cpp_compat_ulong: Core.CppCompat.ULong32 = cpp_unsigned_long;
  let unused cpp_compat_ulong_result: Cpp.ULongResult = Cpp.PassULong(cpp_compat_ulong);

-  let carbon_u32: u32 = cpp_unsigned_long;
+  let carbon_u32: u32 = 1;
  let unused carbon_u32_result: Cpp.UIntResult = Cpp.PassULong(carbon_u32);

  var unused a: array(f32, 1 as Cpp.unsigned_long) = (1.0,);
  //@dump-sem-ir-end
 }

+// --- fail_no_ulong_to_u32.carbon
+
+library "[[@TEST_NAME]]";
+
+import Cpp;
+
+fn F() {
+  let cpp_unsigned_long: Cpp.unsigned_long = 1;
+
+  // For portability reasons, this is not allowed even though `unsigned long`
+  // happens to fit in `u32` on this target.
+  // CHECK:STDERR: fail_no_ulong_to_u32.carbon:[[@LINE+11]]:25: error: cannot implicitly convert expression of type `Cpp.unsigned_long` to `u32` [ConversionFailure]
+  // CHECK:STDERR:   let carbon_u32: u32 = cpp_unsigned_long;
+  // CHECK:STDERR:                         ^~~~~~~~~~~~~~~~~
+  // CHECK:STDERR: fail_no_ulong_to_u32.carbon:[[@LINE+8]]:25: note: type `Cpp.unsigned_long` does not implement interface `Core.ImplicitAs(u32)` [MissingImplInMemberAccessInContext]
+  // CHECK:STDERR:   let carbon_u32: u32 = cpp_unsigned_long;
+  // CHECK:STDERR:                         ^~~~~~~~~~~~~~~~~
+  // CHECK:STDERR:
+  // CHECK:STDERR: fail_no_ulong_to_u32.carbon:[[@LINE+4]]:7: warning: binding `carbon_u32` unused [UnusedBinding]
+  // CHECK:STDERR:   let carbon_u32: u32 = cpp_unsigned_long;
+  // CHECK:STDERR:       ^~~~~~~~~~
+  // CHECK:STDERR:
+  let carbon_u32: u32 = cpp_unsigned_long;
+}
+
 // --- copy_unsigned_long.carbon

 library "[[@TEST_NAME]]";
@@ -672,8 +697,8 @@ fn CopyUnsignedLong() {
 // CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.type.4e6: type = fn_type @Core.IntLiteral.as.ImplicitAs.impl.Convert, @Core.IntLiteral.as.ImplicitAs.impl(%To.fe9) [symbolic]
 // CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.3c2: %Core.IntLiteral.as.ImplicitAs.impl.Convert.type.4e6 = struct_value () [symbolic]
 // CHECK:STDOUT:   %ImplicitAs.type.139: type = facet_type <@ImplicitAs, @ImplicitAs(Core.IntLiteral)> [concrete]
-// CHECK:STDOUT:   %From: Core.IntLiteral = symbolic_binding From, 0 [symbolic]
-// CHECK:STDOUT:   %Int.as.ImplicitAs.impl.Convert.type.2ed: type = fn_type @Int.as.ImplicitAs.impl.Convert, @Int.as.ImplicitAs.impl(%From) [symbolic]
+// CHECK:STDOUT:   %From.fe9: Core.IntLiteral = symbolic_binding From, 0 [symbolic]
+// CHECK:STDOUT:   %Int.as.ImplicitAs.impl.Convert.type.2ed: type = fn_type @Int.as.ImplicitAs.impl.Convert, @Int.as.ImplicitAs.impl(%From.fe9) [symbolic]
 // CHECK:STDOUT:   %Int.as.ImplicitAs.impl.Convert.d29: %Int.as.ImplicitAs.impl.Convert.type.2ed = struct_value () [symbolic]
 // CHECK:STDOUT:   %ImplicitAs.impl_witness.556: <witness> = impl_witness imports.%ImplicitAs.impl_witness_table.74f, @Core.IntLiteral.as.ImplicitAs.impl(%int_64) [concrete]
 // CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.type.b78: type = fn_type @Core.IntLiteral.as.ImplicitAs.impl.Convert, @Core.IntLiteral.as.ImplicitAs.impl(%int_64) [concrete]
@@ -834,8 +859,8 @@ fn CopyUnsignedLong() {
 // CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.type.6a6: type = fn_type @Core.IntLiteral.as.ImplicitAs.impl.Convert, @Core.IntLiteral.as.ImplicitAs.impl(%To.fe9) [symbolic]
 // CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.46e: %Core.IntLiteral.as.ImplicitAs.impl.Convert.type.6a6 = struct_value () [symbolic]
 // CHECK:STDOUT:   %ImplicitAs.type.139: type = facet_type <@ImplicitAs, @ImplicitAs(Core.IntLiteral)> [concrete]
-// CHECK:STDOUT:   %From: Core.IntLiteral = symbolic_binding From, 0 [symbolic]
-// CHECK:STDOUT:   %UInt.as.ImplicitAs.impl.Convert.type.7f8: type = fn_type @UInt.as.ImplicitAs.impl.Convert, @UInt.as.ImplicitAs.impl(%From) [symbolic]
+// CHECK:STDOUT:   %From.fe9: Core.IntLiteral = symbolic_binding From, 0 [symbolic]
+// CHECK:STDOUT:   %UInt.as.ImplicitAs.impl.Convert.type.7f8: type = fn_type @UInt.as.ImplicitAs.impl.Convert.1, @UInt.as.ImplicitAs.impl.607(%From.fe9) [symbolic]
 // CHECK:STDOUT:   %UInt.as.ImplicitAs.impl.Convert.0ea: %UInt.as.ImplicitAs.impl.Convert.type.7f8 = struct_value () [symbolic]
 // CHECK:STDOUT:   %ImplicitAs.impl_witness.bb3: <witness> = impl_witness imports.%ImplicitAs.impl_witness_table.899, @Core.IntLiteral.as.ImplicitAs.impl(%int_64) [concrete]
 // CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.type.fb8: type = fn_type @Core.IntLiteral.as.ImplicitAs.impl.Convert, @Core.IntLiteral.as.ImplicitAs.impl(%int_64) [concrete]
@@ -861,14 +886,14 @@ fn CopyUnsignedLong() {
 // CHECK:STDOUT:   %Core.IntLiteral.as.As.impl.Convert.bound: <bound method> = bound_method %int_1.5b8, %Core.IntLiteral.as.As.impl.Convert.715 [concrete]
 // CHECK:STDOUT:   %Core.IntLiteral.as.As.impl.Convert.specific_fn: <specific function> = specific_function %Core.IntLiteral.as.As.impl.Convert.715, @Core.IntLiteral.as.As.impl.Convert(%int_64) [concrete]
 // CHECK:STDOUT:   %bound_method.9cf: <bound method> = bound_method %int_1.5b8, %Core.IntLiteral.as.As.impl.Convert.specific_fn [concrete]
-// CHECK:STDOUT:   %ImplicitAs.impl_witness.2cc: <witness> = impl_witness imports.%ImplicitAs.impl_witness_table.493, @UInt.as.ImplicitAs.impl(%int_64) [concrete]
-// CHECK:STDOUT:   %UInt.as.ImplicitAs.impl.Convert.type.812: type = fn_type @UInt.as.ImplicitAs.impl.Convert, @UInt.as.ImplicitAs.impl(%int_64) [concrete]
+// CHECK:STDOUT:   %ImplicitAs.impl_witness.2cc: <witness> = impl_witness imports.%ImplicitAs.impl_witness_table.493, @UInt.as.ImplicitAs.impl.607(%int_64) [concrete]
+// CHECK:STDOUT:   %UInt.as.ImplicitAs.impl.Convert.type.812: type = fn_type @UInt.as.ImplicitAs.impl.Convert.1, @UInt.as.ImplicitAs.impl.607(%int_64) [concrete]
 // CHECK:STDOUT:   %UInt.as.ImplicitAs.impl.Convert.309: %UInt.as.ImplicitAs.impl.Convert.type.812 = struct_value () [concrete]
 // CHECK:STDOUT:   %ImplicitAs.facet.02d: %ImplicitAs.type.139 = facet_value %u64, (%ImplicitAs.impl_witness.2cc) [concrete]
 // CHECK:STDOUT:   %ImplicitAs.WithSelf.Convert.type.79a: type = fn_type @ImplicitAs.WithSelf.Convert, @ImplicitAs.WithSelf(Core.IntLiteral, %ImplicitAs.facet.02d) [concrete]
 // CHECK:STDOUT:   %.74a: type = fn_type_with_self_type %ImplicitAs.WithSelf.Convert.type.79a, %ImplicitAs.facet.02d [concrete]
 // CHECK:STDOUT:   %UInt.as.ImplicitAs.impl.Convert.bound: <bound method> = bound_method %int_1.f23, %UInt.as.ImplicitAs.impl.Convert.309 [concrete]
-// CHECK:STDOUT:   %UInt.as.ImplicitAs.impl.Convert.specific_fn: <specific function> = specific_function %UInt.as.ImplicitAs.impl.Convert.309, @UInt.as.ImplicitAs.impl.Convert(%int_64) [concrete]
+// CHECK:STDOUT:   %UInt.as.ImplicitAs.impl.Convert.specific_fn: <specific function> = specific_function %UInt.as.ImplicitAs.impl.Convert.309, @UInt.as.ImplicitAs.impl.Convert.1(%int_64) [concrete]
 // CHECK:STDOUT:   %bound_method.f18: <bound method> = bound_method %int_1.f23, %UInt.as.ImplicitAs.impl.Convert.specific_fn [concrete]
 // CHECK:STDOUT:   %array_type: type = array_type %int_1.5b8, %f32.97e [concrete]
 // CHECK:STDOUT:   %pattern_type.b36: type = pattern_type %array_type [concrete]
@@ -901,8 +926,8 @@ fn CopyUnsignedLong() {
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %Core.import_ref.741: @Core.IntLiteral.as.ImplicitAs.impl.%Core.IntLiteral.as.ImplicitAs.impl.Convert.type (%Core.IntLiteral.as.ImplicitAs.impl.Convert.type.6a6) = import_ref Core//prelude/types/uint, loc{{\d+_\d+}}, loaded [symbolic = @Core.IntLiteral.as.ImplicitAs.impl.%Core.IntLiteral.as.ImplicitAs.impl.Convert (constants.%Core.IntLiteral.as.ImplicitAs.impl.Convert.46e)]
 // CHECK:STDOUT:   %ImplicitAs.impl_witness_table.899 = impl_witness_table (%Core.import_ref.741), @Core.IntLiteral.as.ImplicitAs.impl [concrete]
-// CHECK:STDOUT:   %Core.import_ref.483: @UInt.as.ImplicitAs.impl.%UInt.as.ImplicitAs.impl.Convert.type (%UInt.as.ImplicitAs.impl.Convert.type.7f8) = import_ref Core//prelude/types/uint, loc{{\d+_\d+}}, loaded [symbolic = @UInt.as.ImplicitAs.impl.%UInt.as.ImplicitAs.impl.Convert (constants.%UInt.as.ImplicitAs.impl.Convert.0ea)]
-// CHECK:STDOUT:   %ImplicitAs.impl_witness_table.493 = impl_witness_table (%Core.import_ref.483), @UInt.as.ImplicitAs.impl [concrete]
+// CHECK:STDOUT:   %Core.import_ref.483: @UInt.as.ImplicitAs.impl.607.%UInt.as.ImplicitAs.impl.Convert.type (%UInt.as.ImplicitAs.impl.Convert.type.7f8) = import_ref Core//prelude/types/uint, loc{{\d+_\d+}}, loaded [symbolic = @UInt.as.ImplicitAs.impl.607.%UInt.as.ImplicitAs.impl.Convert (constants.%UInt.as.ImplicitAs.impl.Convert.0ea)]
+// CHECK:STDOUT:   %ImplicitAs.impl_witness_table.493 = impl_witness_table (%Core.import_ref.483), @UInt.as.ImplicitAs.impl.607 [concrete]
 // CHECK:STDOUT:   %Core.import_ref.600: @Core.IntLiteral.as.As.impl.%Core.IntLiteral.as.As.impl.Convert.type (%Core.IntLiteral.as.As.impl.Convert.type.2b1) = import_ref Core//prelude/types/uint, loc{{\d+_\d+}}, loaded [symbolic = @Core.IntLiteral.as.As.impl.%Core.IntLiteral.as.As.impl.Convert (constants.%Core.IntLiteral.as.As.impl.Convert.979)]
 // CHECK:STDOUT:   %As.impl_witness_table.7eb = impl_witness_table (%Core.import_ref.600), @Core.IntLiteral.as.As.impl [concrete]
 // CHECK:STDOUT:   %Core.import_ref.38a: @Core.FloatLiteral.as.ImplicitAs.impl.%Core.FloatLiteral.as.ImplicitAs.impl.Convert.type (%Core.FloatLiteral.as.ImplicitAs.impl.Convert.type.02f) = import_ref Core//prelude/types/float, loc{{\d+_\d+}}, loaded [symbolic = @Core.FloatLiteral.as.ImplicitAs.impl.%Core.FloatLiteral.as.ImplicitAs.impl.Convert (constants.%Core.FloatLiteral.as.ImplicitAs.impl.Convert.1f0)]
@@ -967,7 +992,7 @@ fn CopyUnsignedLong() {
 // CHECK:STDOUT:     %.loc11_30.2: %u64 = converted %int_1.loc11, %.loc11_30.1 [concrete = constants.%int_1.f23]
 // CHECK:STDOUT:     %impl.elem0.loc11_30.2: %.74a = impl_witness_access constants.%ImplicitAs.impl_witness.2cc, element0 [concrete = constants.%UInt.as.ImplicitAs.impl.Convert.309]
 // CHECK:STDOUT:     %bound_method.loc11_30.3: <bound method> = bound_method %.loc11_30.2, %impl.elem0.loc11_30.2 [concrete = constants.%UInt.as.ImplicitAs.impl.Convert.bound]
-// CHECK:STDOUT:     %specific_fn.loc11_30.2: <specific function> = specific_function %impl.elem0.loc11_30.2, @UInt.as.ImplicitAs.impl.Convert(constants.%int_64) [concrete = constants.%UInt.as.ImplicitAs.impl.Convert.specific_fn]
+// CHECK:STDOUT:     %specific_fn.loc11_30.2: <specific function> = specific_function %impl.elem0.loc11_30.2, @UInt.as.ImplicitAs.impl.Convert.1(constants.%int_64) [concrete = constants.%UInt.as.ImplicitAs.impl.Convert.specific_fn]
 // CHECK:STDOUT:     %bound_method.loc11_30.4: <bound method> = bound_method %.loc11_30.2, %specific_fn.loc11_30.2 [concrete = constants.%bound_method.f18]
 // CHECK:STDOUT:     %UInt.as.ImplicitAs.impl.Convert.call: init Core.IntLiteral = call %bound_method.loc11_30.4(%.loc11_30.2) [concrete = constants.%int_1.5b8]
 // CHECK:STDOUT:     %.loc11_30.3: Core.IntLiteral = value_of_initializer %UInt.as.ImplicitAs.impl.Convert.call [concrete = constants.%int_1.5b8]
@@ -3917,14 +3942,13 @@ fn CopyUnsignedLong() {
 // CHECK:STDOUT:   %ImplicitAs.generic: %ImplicitAs.type.cc7 = struct_value () [concrete]
 // CHECK:STDOUT:   %ImplicitAs.type.3c3: type = facet_type <@ImplicitAs, @ImplicitAs(%Cpp.unsigned_long)> [concrete]
 // CHECK:STDOUT:   %ImplicitAs.type.139: type = facet_type <@ImplicitAs, @ImplicitAs(Core.IntLiteral)> [concrete]
-// CHECK:STDOUT:   %ImplicitAs.type.146: type = facet_type <@ImplicitAs, @ImplicitAs(%u32)> [concrete]
 // CHECK:STDOUT:   %ImplicitAs.impl_witness.a19: <witness> = impl_witness imports.%ImplicitAs.impl_witness_table.5b5 [concrete]
 // CHECK:STDOUT:   %ImplicitAs.facet.66c: %ImplicitAs.type.3c3 = facet_value Core.IntLiteral, (%ImplicitAs.impl_witness.a19) [concrete]
 // CHECK:STDOUT:   %ImplicitAs.WithSelf.Convert.type.b7d: type = fn_type @ImplicitAs.WithSelf.Convert, @ImplicitAs.WithSelf(%Cpp.unsigned_long, %ImplicitAs.facet.66c) [concrete]
 // CHECK:STDOUT:   %.541: type = fn_type_with_self_type %ImplicitAs.WithSelf.Convert.type.b7d, %ImplicitAs.facet.66c [concrete]
 // CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.type.71f: type = fn_type @Core.IntLiteral.as.ImplicitAs.impl.Convert.1 [concrete]
 // CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.14b: %Core.IntLiteral.as.ImplicitAs.impl.Convert.type.71f = struct_value () [concrete]
-// CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.bound: <bound method> = bound_method %int_1.5b8, %Core.IntLiteral.as.ImplicitAs.impl.Convert.14b [concrete]
+// CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.bound.92f: <bound method> = bound_method %int_1.5b8, %Core.IntLiteral.as.ImplicitAs.impl.Convert.14b [concrete]
 // CHECK:STDOUT:   %int_1.0ab: %Cpp.unsigned_long = int_value 1 [concrete]
 // CHECK:STDOUT:   %ULongResult: type = class_type @ULongResult [concrete]
 // CHECK:STDOUT:   %pattern_type.6f2: type = pattern_type %ULongResult [concrete]
@@ -3934,12 +3958,20 @@ fn CopyUnsignedLong() {
 // CHECK:STDOUT:   %PassULong__carbon_thunk.type.3fc2d8.1: type = fn_type @PassULong__carbon_thunk.1 [concrete]
 // CHECK:STDOUT:   %PassULong__carbon_thunk.ff747d.1: %PassULong__carbon_thunk.type.3fc2d8.1 = struct_value () [concrete]
 // CHECK:STDOUT:   %pattern_type.4a9: type = pattern_type %u32 [concrete]
-// CHECK:STDOUT:   %ImplicitAs.impl_witness.e61: <witness> = impl_witness imports.%ImplicitAs.impl_witness_table.af7 [concrete]
-// CHECK:STDOUT:   %ImplicitAs.facet.3c4: %ImplicitAs.type.146 = facet_value %Cpp.unsigned_long, (%ImplicitAs.impl_witness.e61) [concrete]
-// CHECK:STDOUT:   %ImplicitAs.WithSelf.Convert.type.4ad: type = fn_type @ImplicitAs.WithSelf.Convert, @ImplicitAs.WithSelf(%u32, %ImplicitAs.facet.3c4) [concrete]
-// CHECK:STDOUT:   %.5ab: type = fn_type_with_self_type %ImplicitAs.WithSelf.Convert.type.4ad, %ImplicitAs.facet.3c4 [concrete]
-// CHECK:STDOUT:   %Cpp.unsigned_long.as.ImplicitAs.impl.Convert.type.bef: type = fn_type @Cpp.unsigned_long.as.ImplicitAs.impl.Convert.1 [concrete]
-// CHECK:STDOUT:   %Cpp.unsigned_long.as.ImplicitAs.impl.Convert.19d: %Cpp.unsigned_long.as.ImplicitAs.impl.Convert.type.bef = struct_value () [concrete]
+// CHECK:STDOUT:   %ImplicitAs.type.146: type = facet_type <@ImplicitAs, @ImplicitAs(%u32)> [concrete]
+// CHECK:STDOUT:   %To.fe9: Core.IntLiteral = symbolic_binding To, 0 [symbolic]
+// CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.type.6a6: type = fn_type @Core.IntLiteral.as.ImplicitAs.impl.Convert.2, @Core.IntLiteral.as.ImplicitAs.impl.c85(%To.fe9) [symbolic]
+// CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.46e: %Core.IntLiteral.as.ImplicitAs.impl.Convert.type.6a6 = struct_value () [symbolic]
+// CHECK:STDOUT:   %ImplicitAs.impl_witness.29e: <witness> = impl_witness imports.%ImplicitAs.impl_witness_table.899, @Core.IntLiteral.as.ImplicitAs.impl.c85(%int_32) [concrete]
+// CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.type.b07: type = fn_type @Core.IntLiteral.as.ImplicitAs.impl.Convert.2, @Core.IntLiteral.as.ImplicitAs.impl.c85(%int_32) [concrete]
+// CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.90e: %Core.IntLiteral.as.ImplicitAs.impl.Convert.type.b07 = struct_value () [concrete]
+// CHECK:STDOUT:   %ImplicitAs.facet.309: %ImplicitAs.type.146 = facet_value Core.IntLiteral, (%ImplicitAs.impl_witness.29e) [concrete]
+// CHECK:STDOUT:   %ImplicitAs.WithSelf.Convert.type.a88: type = fn_type @ImplicitAs.WithSelf.Convert, @ImplicitAs.WithSelf(%u32, %ImplicitAs.facet.309) [concrete]
+// CHECK:STDOUT:   %.b47: type = fn_type_with_self_type %ImplicitAs.WithSelf.Convert.type.a88, %ImplicitAs.facet.309 [concrete]
+// CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.bound.412: <bound method> = bound_method %int_1.5b8, %Core.IntLiteral.as.ImplicitAs.impl.Convert.90e [concrete]
+// CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.specific_fn: <specific function> = specific_function %Core.IntLiteral.as.ImplicitAs.impl.Convert.90e, @Core.IntLiteral.as.ImplicitAs.impl.Convert.2(%int_32) [concrete]
+// CHECK:STDOUT:   %bound_method.21d: <bound method> = bound_method %int_1.5b8, %Core.IntLiteral.as.ImplicitAs.impl.Convert.specific_fn [concrete]
+// CHECK:STDOUT:   %int_1.c1d: %u32 = int_value 1 [concrete]
 // CHECK:STDOUT:   %UIntResult: type = class_type @UIntResult [concrete]
 // CHECK:STDOUT:   %pattern_type.dc7: type = pattern_type %UIntResult [concrete]
 // CHECK:STDOUT:   %ptr.059: type = ptr_type %UIntResult [concrete]
@@ -3962,9 +3994,9 @@ fn CopyUnsignedLong() {
 // CHECK:STDOUT:   %ImplicitAs.facet.2f7: %ImplicitAs.type.139 = facet_value %Cpp.unsigned_long, (%ImplicitAs.impl_witness.a13) [concrete]
 // CHECK:STDOUT:   %ImplicitAs.WithSelf.Convert.type.328: type = fn_type @ImplicitAs.WithSelf.Convert, @ImplicitAs.WithSelf(Core.IntLiteral, %ImplicitAs.facet.2f7) [concrete]
 // CHECK:STDOUT:   %.0db: type = fn_type_with_self_type %ImplicitAs.WithSelf.Convert.type.328, %ImplicitAs.facet.2f7 [concrete]
-// CHECK:STDOUT:   %Cpp.unsigned_long.as.ImplicitAs.impl.Convert.type.a9d: type = fn_type @Cpp.unsigned_long.as.ImplicitAs.impl.Convert.2 [concrete]
-// CHECK:STDOUT:   %Cpp.unsigned_long.as.ImplicitAs.impl.Convert.e53: %Cpp.unsigned_long.as.ImplicitAs.impl.Convert.type.a9d = struct_value () [concrete]
-// CHECK:STDOUT:   %Cpp.unsigned_long.as.ImplicitAs.impl.Convert.bound: <bound method> = bound_method %int_1.0ab, %Cpp.unsigned_long.as.ImplicitAs.impl.Convert.e53 [concrete]
+// CHECK:STDOUT:   %Cpp.unsigned_long.as.ImplicitAs.impl.Convert.type: type = fn_type @Cpp.unsigned_long.as.ImplicitAs.impl.Convert [concrete]
+// CHECK:STDOUT:   %Cpp.unsigned_long.as.ImplicitAs.impl.Convert: %Cpp.unsigned_long.as.ImplicitAs.impl.Convert.type = struct_value () [concrete]
+// CHECK:STDOUT:   %Cpp.unsigned_long.as.ImplicitAs.impl.Convert.bound: <bound method> = bound_method %int_1.0ab, %Cpp.unsigned_long.as.ImplicitAs.impl.Convert [concrete]
 // CHECK:STDOUT:   %array_type: type = array_type %int_1.5b8, %f32.97e [concrete]
 // CHECK:STDOUT:   %pattern_type.b36: type = pattern_type %array_type [concrete]
 // CHECK:STDOUT:   %float.674: Core.FloatLiteral = float_literal_value 10e-1 [concrete]
@@ -3982,7 +4014,7 @@ fn CopyUnsignedLong() {
 // CHECK:STDOUT:   %.98d: type = fn_type_with_self_type %ImplicitAs.WithSelf.Convert.type.e4d, %ImplicitAs.facet.945 [concrete]
 // CHECK:STDOUT:   %Core.FloatLiteral.as.ImplicitAs.impl.Convert.bound: <bound method> = bound_method %float.674, %Core.FloatLiteral.as.ImplicitAs.impl.Convert.e55 [concrete]
 // CHECK:STDOUT:   %Core.FloatLiteral.as.ImplicitAs.impl.Convert.specific_fn: <specific function> = specific_function %Core.FloatLiteral.as.ImplicitAs.impl.Convert.e55, @Core.FloatLiteral.as.ImplicitAs.impl.Convert(%int_32) [concrete]
-// CHECK:STDOUT:   %bound_method: <bound method> = bound_method %float.674, %Core.FloatLiteral.as.ImplicitAs.impl.Convert.specific_fn [concrete]
+// CHECK:STDOUT:   %bound_method.1e4: <bound method> = bound_method %float.674, %Core.FloatLiteral.as.ImplicitAs.impl.Convert.specific_fn [concrete]
 // CHECK:STDOUT:   %float.e3b: %f32.97e = float_value 1 [concrete]
 // CHECK:STDOUT:   %array: %array_type = tuple_value (%float.e3b) [concrete]
 // CHECK:STDOUT:   %Destroy.type: type = facet_type <@Destroy> [concrete]
@@ -4030,8 +4062,8 @@ fn CopyUnsignedLong() {
 // CHECK:STDOUT:     <elided>
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %Core.UInt: %UInt.type = import_ref Core//prelude/types/uint, UInt, loaded [concrete = constants.%UInt.generic]
-// CHECK:STDOUT:   %Core.import_ref.d88: %Cpp.unsigned_long.as.ImplicitAs.impl.Convert.type.bef = import_ref Core//prelude/types/cpp/int, loc{{\d+_\d+}}, loaded [concrete = constants.%Cpp.unsigned_long.as.ImplicitAs.impl.Convert.19d]
-// CHECK:STDOUT:   %ImplicitAs.impl_witness_table.af7 = impl_witness_table (%Core.import_ref.d88), @Cpp.unsigned_long.as.ImplicitAs.impl.66a [concrete]
+// CHECK:STDOUT:   %Core.import_ref.741: @Core.IntLiteral.as.ImplicitAs.impl.c85.%Core.IntLiteral.as.ImplicitAs.impl.Convert.type (%Core.IntLiteral.as.ImplicitAs.impl.Convert.type.6a6) = import_ref Core//prelude/types/uint, loc{{\d+_\d+}}, loaded [symbolic = @Core.IntLiteral.as.ImplicitAs.impl.c85.%Core.IntLiteral.as.ImplicitAs.impl.Convert (constants.%Core.IntLiteral.as.ImplicitAs.impl.Convert.46e)]
+// CHECK:STDOUT:   %ImplicitAs.impl_witness_table.899 = impl_witness_table (%Core.import_ref.741), @Core.IntLiteral.as.ImplicitAs.impl.c85 [concrete]
 // CHECK:STDOUT:   %UIntResult.decl: type = class_decl @UIntResult [concrete = constants.%UIntResult] {} {}
 // CHECK:STDOUT:   %PassULong__carbon_thunk.decl.108234.2: %PassULong__carbon_thunk.type.3fc2d8.2 = fn_decl @PassULong__carbon_thunk.2 [concrete = constants.%PassULong__carbon_thunk.ff747d.2] {
 // CHECK:STDOUT:     <elided>
@@ -4042,7 +4074,7 @@ fn CopyUnsignedLong() {
 // CHECK:STDOUT:   %Core.As: %As.type.90f = import_ref Core//prelude/operators/as, As, loaded [concrete = constants.%As.generic]
 // CHECK:STDOUT:   %Core.import_ref.190: %Core.IntLiteral.as.As.impl.Convert.type = import_ref Core//prelude/types/cpp/int, loc{{\d+_\d+}}, loaded [concrete = constants.%Core.IntLiteral.as.As.impl.Convert]
 // CHECK:STDOUT:   %As.impl_witness_table.f58 = impl_witness_table (%Core.import_ref.190), @Core.IntLiteral.as.As.impl.8c9 [concrete]
-// CHECK:STDOUT:   %Core.import_ref.f5e: %Cpp.unsigned_long.as.ImplicitAs.impl.Convert.type.a9d = import_ref Core//prelude/types/cpp/int, loc{{\d+_\d+}}, loaded [concrete = constants.%Cpp.unsigned_long.as.ImplicitAs.impl.Convert.e53]
+// CHECK:STDOUT:   %Core.import_ref.f5e: %Cpp.unsigned_long.as.ImplicitAs.impl.Convert.type = import_ref Core//prelude/types/cpp/int, loc{{\d+_\d+}}, loaded [concrete = constants.%Cpp.unsigned_long.as.ImplicitAs.impl.Convert]
 // CHECK:STDOUT:   %ImplicitAs.impl_witness_table.50d = impl_witness_table (%Core.import_ref.f5e), @Cpp.unsigned_long.as.ImplicitAs.impl.78e [concrete]
 // CHECK:STDOUT:   %Core.import_ref.38a: @Core.FloatLiteral.as.ImplicitAs.impl.%Core.FloatLiteral.as.ImplicitAs.impl.Convert.type (%Core.FloatLiteral.as.ImplicitAs.impl.Convert.type.02f) = import_ref Core//prelude/types/float, loc{{\d+_\d+}}, loaded [symbolic = @Core.FloatLiteral.as.ImplicitAs.impl.%Core.FloatLiteral.as.ImplicitAs.impl.Convert (constants.%Core.FloatLiteral.as.ImplicitAs.impl.Convert.1f0)]
 // CHECK:STDOUT:   %ImplicitAs.impl_witness_table.31a = impl_witness_table (%Core.import_ref.38a), @Core.FloatLiteral.as.ImplicitAs.impl [concrete]
@@ -4060,9 +4092,9 @@ fn CopyUnsignedLong() {
 // CHECK:STDOUT:     %unsigned_long.ref.loc15: type = name_ref unsigned_long, constants.%Cpp.unsigned_long [concrete = constants.%Cpp.unsigned_long]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %impl.elem0.loc15: %.541 = impl_witness_access constants.%ImplicitAs.impl_witness.a19, element0 [concrete = constants.%Core.IntLiteral.as.ImplicitAs.impl.Convert.14b]
-// CHECK:STDOUT:   %bound_method.loc15: <bound method> = bound_method %int_1.loc15, %impl.elem0.loc15 [concrete = constants.%Core.IntLiteral.as.ImplicitAs.impl.Convert.bound]
-// CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.call: init %Cpp.unsigned_long = call %bound_method.loc15(%int_1.loc15) [concrete = constants.%int_1.0ab]
-// CHECK:STDOUT:   %.loc15_46.1: %Cpp.unsigned_long = value_of_initializer %Core.IntLiteral.as.ImplicitAs.impl.Convert.call [concrete = constants.%int_1.0ab]
+// CHECK:STDOUT:   %bound_method.loc15: <bound method> = bound_method %int_1.loc15, %impl.elem0.loc15 [concrete = constants.%Core.IntLiteral.as.ImplicitAs.impl.Convert.bound.92f]
+// CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.call.loc15: init %Cpp.unsigned_long = call %bound_method.loc15(%int_1.loc15) [concrete = constants.%int_1.0ab]
+// CHECK:STDOUT:   %.loc15_46.1: %Cpp.unsigned_long = value_of_initializer %Core.IntLiteral.as.ImplicitAs.impl.Convert.call.loc15 [concrete = constants.%int_1.0ab]
 // CHECK:STDOUT:   %.loc15_46.2: %Cpp.unsigned_long = converted %int_1.loc15, %.loc15_46.1 [concrete = constants.%int_1.0ab]
 // CHECK:STDOUT:   %cpp_unsigned_long: %Cpp.unsigned_long = value_binding cpp_unsigned_long, %.loc15_46.2
 // CHECK:STDOUT:   name_binding_decl {
@@ -4112,13 +4144,15 @@ fn CopyUnsignedLong() {
 // CHECK:STDOUT:   name_binding_decl {
 // CHECK:STDOUT:     %carbon_u32.patt: %pattern_type.4a9 = value_binding_pattern carbon_u32 [concrete]
 // CHECK:STDOUT:   }
-// CHECK:STDOUT:   %cpp_unsigned_long.ref.loc21: %Cpp.unsigned_long = name_ref cpp_unsigned_long, %cpp_unsigned_long
+// CHECK:STDOUT:   %int_1.loc21: Core.IntLiteral = int_value 1 [concrete = constants.%int_1.5b8]
 // CHECK:STDOUT:   %u32: type = type_literal constants.%u32 [concrete = constants.%u32]
-// CHECK:STDOUT:   %impl.elem0.loc21: %.5ab = impl_witness_access constants.%ImplicitAs.impl_witness.e61, element0 [concrete = constants.%Cpp.unsigned_long.as.ImplicitAs.impl.Convert.19d]
-// CHECK:STDOUT:   %bound_method.loc21: <bound method> = bound_method %cpp_unsigned_long.ref.loc21, %impl.elem0.loc21
-// CHECK:STDOUT:   %Cpp.unsigned_long.as.ImplicitAs.impl.Convert.call.loc21: init %u32 = call %bound_method.loc21(%cpp_unsigned_long.ref.loc21)
-// CHECK:STDOUT:   %.loc21_25.1: %u32 = value_of_initializer %Cpp.unsigned_long.as.ImplicitAs.impl.Convert.call.loc21
-// CHECK:STDOUT:   %.loc21_25.2: %u32 = converted %cpp_unsigned_long.ref.loc21, %.loc21_25.1
+// CHECK:STDOUT:   %impl.elem0.loc21: %.b47 = impl_witness_access constants.%ImplicitAs.impl_witness.29e, element0 [concrete = constants.%Core.IntLiteral.as.ImplicitAs.impl.Convert.90e]
+// CHECK:STDOUT:   %bound_method.loc21_25.1: <bound method> = bound_method %int_1.loc21, %impl.elem0.loc21 [concrete = constants.%Core.IntLiteral.as.ImplicitAs.impl.Convert.bound.412]
+// CHECK:STDOUT:   %specific_fn.loc21: <specific function> = specific_function %impl.elem0.loc21, @Core.IntLiteral.as.ImplicitAs.impl.Convert.2(constants.%int_32) [concrete = constants.%Core.IntLiteral.as.ImplicitAs.impl.Convert.specific_fn]
+// CHECK:STDOUT:   %bound_method.loc21_25.2: <bound method> = bound_method %int_1.loc21, %specific_fn.loc21 [concrete = constants.%bound_method.21d]
+// CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.call.loc21: init %u32 = call %bound_method.loc21_25.2(%int_1.loc21) [concrete = constants.%int_1.c1d]
+// CHECK:STDOUT:   %.loc21_25.1: %u32 = value_of_initializer %Core.IntLiteral.as.ImplicitAs.impl.Convert.call.loc21 [concrete = constants.%int_1.c1d]
+// CHECK:STDOUT:   %.loc21_25.2: %u32 = converted %int_1.loc21, %.loc21_25.1 [concrete = constants.%int_1.c1d]
 // CHECK:STDOUT:   %carbon_u32: %u32 = value_binding carbon_u32, %.loc21_25.2
 // CHECK:STDOUT:   name_binding_decl {
 // CHECK:STDOUT:     %carbon_u32_result.patt: %pattern_type.dc7 = value_binding_pattern carbon_u32_result [concrete]
@@ -4146,8 +4180,8 @@ fn CopyUnsignedLong() {
 // CHECK:STDOUT:   %.loc24_59.1: %tuple.type = tuple_literal (%float) [concrete = constants.%tuple]
 // CHECK:STDOUT:   %impl.elem0.loc24_59: %.98d = impl_witness_access constants.%ImplicitAs.impl_witness.bc6, element0 [concrete = constants.%Core.FloatLiteral.as.ImplicitAs.impl.Convert.e55]
 // CHECK:STDOUT:   %bound_method.loc24_59.1: <bound method> = bound_method %float, %impl.elem0.loc24_59 [concrete = constants.%Core.FloatLiteral.as.ImplicitAs.impl.Convert.bound]
-// CHECK:STDOUT:   %specific_fn: <specific function> = specific_function %impl.elem0.loc24_59, @Core.FloatLiteral.as.ImplicitAs.impl.Convert(constants.%int_32) [concrete = constants.%Core.FloatLiteral.as.ImplicitAs.impl.Convert.specific_fn]
-// CHECK:STDOUT:   %bound_method.loc24_59.2: <bound method> = bound_method %float, %specific_fn [concrete = constants.%bound_method]
+// CHECK:STDOUT:   %specific_fn.loc24: <specific function> = specific_function %impl.elem0.loc24_59, @Core.FloatLiteral.as.ImplicitAs.impl.Convert(constants.%int_32) [concrete = constants.%Core.FloatLiteral.as.ImplicitAs.impl.Convert.specific_fn]
+// CHECK:STDOUT:   %bound_method.loc24_59.2: <bound method> = bound_method %float, %specific_fn.loc24 [concrete = constants.%bound_method.1e4]
 // CHECK:STDOUT:   %Core.FloatLiteral.as.ImplicitAs.impl.Convert.call: init %f32.97e = call %bound_method.loc24_59.2(%float) [concrete = constants.%float.e3b]
 // CHECK:STDOUT:   %.loc24_59.2: init %f32.97e = converted %float, %Core.FloatLiteral.as.ImplicitAs.impl.Convert.call [concrete = constants.%float.e3b]
 // CHECK:STDOUT:   %int_0: Core.IntLiteral = int_value 0 [concrete = constants.%int_0]
@@ -4166,10 +4200,10 @@ fn CopyUnsignedLong() {
 // CHECK:STDOUT:     %Core.IntLiteral.as.As.impl.Convert.call: init %Cpp.unsigned_long = call %bound_method.loc24_30.1(%int_1.loc24) [concrete = constants.%int_1.0ab]
 // CHECK:STDOUT:     %.loc24_30.1: %Cpp.unsigned_long = value_of_initializer %Core.IntLiteral.as.As.impl.Convert.call [concrete = constants.%int_1.0ab]
 // CHECK:STDOUT:     %.loc24_30.2: %Cpp.unsigned_long = converted %int_1.loc24, %.loc24_30.1 [concrete = constants.%int_1.0ab]
-// CHECK:STDOUT:     %impl.elem0.loc24_30.2: %.0db = impl_witness_access constants.%ImplicitAs.impl_witness.a13, element0 [concrete = constants.%Cpp.unsigned_long.as.ImplicitAs.impl.Convert.e53]
+// CHECK:STDOUT:     %impl.elem0.loc24_30.2: %.0db = impl_witness_access constants.%ImplicitAs.impl_witness.a13, element0 [concrete = constants.%Cpp.unsigned_long.as.ImplicitAs.impl.Convert]
 // CHECK:STDOUT:     %bound_method.loc24_30.2: <bound method> = bound_method %.loc24_30.2, %impl.elem0.loc24_30.2 [concrete = constants.%Cpp.unsigned_long.as.ImplicitAs.impl.Convert.bound]
-// CHECK:STDOUT:     %Cpp.unsigned_long.as.ImplicitAs.impl.Convert.call.loc24: init Core.IntLiteral = call %bound_method.loc24_30.2(%.loc24_30.2) [concrete = constants.%int_1.5b8]
-// CHECK:STDOUT:     %.loc24_30.3: Core.IntLiteral = value_of_initializer %Cpp.unsigned_long.as.ImplicitAs.impl.Convert.call.loc24 [concrete = constants.%int_1.5b8]
+// CHECK:STDOUT:     %Cpp.unsigned_long.as.ImplicitAs.impl.Convert.call: init Core.IntLiteral = call %bound_method.loc24_30.2(%.loc24_30.2) [concrete = constants.%int_1.5b8]
+// CHECK:STDOUT:     %.loc24_30.3: Core.IntLiteral = value_of_initializer %Cpp.unsigned_long.as.ImplicitAs.impl.Convert.call [concrete = constants.%int_1.5b8]
 // CHECK:STDOUT:     %.loc24_30.4: Core.IntLiteral = converted %.loc24_30.2, %.loc24_30.3 [concrete = constants.%int_1.5b8]
 // CHECK:STDOUT:     %array_type: type = array_type %.loc24_30.4, %f32 [concrete = constants.%array_type]
 // CHECK:STDOUT:   }
@@ -586,13 +586,38 @@ fn F() {
  let cpp_compat_ulong_long: Core.CppCompat.ULongLong64 = cpp_unsigned_long_long;
  let unused cpp_compat_ulong_long_result: Cpp.ULongLongResult = Cpp.PassULongLong(cpp_compat_ulong_long);

-  let carbon_u64: u64 = cpp_unsigned_long_long;
+  let carbon_u64: u64 = 1;
  let unused carbon_u64_result: Cpp.ULongResult = Cpp.PassULongLong(carbon_u64);

  var unused a: array(f32, 1 as Cpp.unsigned_long_long) = (1.0,);
  //@dump-sem-ir-end
 }

+// --- fail_pass_ulonglong_to_u64.carbon
+
+library "[[@TEST_NAME]]";
+
+import Cpp;
+
+fn F() {
+  let cpp_unsigned_long_long: Cpp.unsigned_long_long = 1;
+
+  // For portability reasons, this is not allowed even though `unsigned long
+  // long` happens to fit in `u64` on this target.
+  // CHECK:STDERR: fail_pass_ulonglong_to_u64.carbon:[[@LINE+11]]:25: error: cannot implicitly convert expression of type `Cpp.unsigned_long_long` to `u64` [ConversionFailure]
+  // CHECK:STDERR:   let carbon_u64: u64 = cpp_unsigned_long_long;
+  // CHECK:STDERR:                         ^~~~~~~~~~~~~~~~~~~~~~
+  // CHECK:STDERR: fail_pass_ulonglong_to_u64.carbon:[[@LINE+8]]:25: note: type `Cpp.unsigned_long_long` does not implement interface `Core.ImplicitAs(u64)` [MissingImplInMemberAccessInContext]
+  // CHECK:STDERR:   let carbon_u64: u64 = cpp_unsigned_long_long;
+  // CHECK:STDERR:                         ^~~~~~~~~~~~~~~~~~~~~~
+  // CHECK:STDERR:
+  // CHECK:STDERR: fail_pass_ulonglong_to_u64.carbon:[[@LINE+4]]:7: warning: binding `carbon_u64` unused [UnusedBinding]
+  // CHECK:STDERR:   let carbon_u64: u64 = cpp_unsigned_long_long;
+  // CHECK:STDERR:       ^~~~~~~~~~
+  // CHECK:STDERR:
+  let carbon_u64: u64 = cpp_unsigned_long_long;
+}
+
 // --- copy_unsigned_long_long.carbon

 library "[[@TEST_NAME]]";
@@ -620,8 +645,8 @@ fn CopyUnsignedLongLong() {
 // CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.type.4e6: type = fn_type @Core.IntLiteral.as.ImplicitAs.impl.Convert, @Core.IntLiteral.as.ImplicitAs.impl(%To.fe9) [symbolic]
 // CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.3c2: %Core.IntLiteral.as.ImplicitAs.impl.Convert.type.4e6 = struct_value () [symbolic]
 // CHECK:STDOUT:   %ImplicitAs.type.139: type = facet_type <@ImplicitAs, @ImplicitAs(Core.IntLiteral)> [concrete]
-// CHECK:STDOUT:   %From: Core.IntLiteral = symbolic_binding From, 0 [symbolic]
-// CHECK:STDOUT:   %Int.as.ImplicitAs.impl.Convert.type.2ed: type = fn_type @Int.as.ImplicitAs.impl.Convert, @Int.as.ImplicitAs.impl(%From) [symbolic]
+// CHECK:STDOUT:   %From.fe9: Core.IntLiteral = symbolic_binding From, 0 [symbolic]
+// CHECK:STDOUT:   %Int.as.ImplicitAs.impl.Convert.type.2ed: type = fn_type @Int.as.ImplicitAs.impl.Convert, @Int.as.ImplicitAs.impl(%From.fe9) [symbolic]
 // CHECK:STDOUT:   %Int.as.ImplicitAs.impl.Convert.d29: %Int.as.ImplicitAs.impl.Convert.type.2ed = struct_value () [symbolic]
 // CHECK:STDOUT:   %ImplicitAs.impl_witness.556: <witness> = impl_witness imports.%ImplicitAs.impl_witness_table.74f, @Core.IntLiteral.as.ImplicitAs.impl(%int_64) [concrete]
 // CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.type.b78: type = fn_type @Core.IntLiteral.as.ImplicitAs.impl.Convert, @Core.IntLiteral.as.ImplicitAs.impl(%int_64) [concrete]
@@ -782,8 +807,8 @@ fn CopyUnsignedLongLong() {
 // CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.type.6a6: type = fn_type @Core.IntLiteral.as.ImplicitAs.impl.Convert, @Core.IntLiteral.as.ImplicitAs.impl(%To.fe9) [symbolic]
 // CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.46e: %Core.IntLiteral.as.ImplicitAs.impl.Convert.type.6a6 = struct_value () [symbolic]
 // CHECK:STDOUT:   %ImplicitAs.type.139: type = facet_type <@ImplicitAs, @ImplicitAs(Core.IntLiteral)> [concrete]
-// CHECK:STDOUT:   %From: Core.IntLiteral = symbolic_binding From, 0 [symbolic]
-// CHECK:STDOUT:   %UInt.as.ImplicitAs.impl.Convert.type.7f8: type = fn_type @UInt.as.ImplicitAs.impl.Convert, @UInt.as.ImplicitAs.impl(%From) [symbolic]
+// CHECK:STDOUT:   %From.fe9: Core.IntLiteral = symbolic_binding From, 0 [symbolic]
+// CHECK:STDOUT:   %UInt.as.ImplicitAs.impl.Convert.type.7f8: type = fn_type @UInt.as.ImplicitAs.impl.Convert.1, @UInt.as.ImplicitAs.impl.607(%From.fe9) [symbolic]
 // CHECK:STDOUT:   %UInt.as.ImplicitAs.impl.Convert.0ea: %UInt.as.ImplicitAs.impl.Convert.type.7f8 = struct_value () [symbolic]
 // CHECK:STDOUT:   %ImplicitAs.impl_witness.bb3: <witness> = impl_witness imports.%ImplicitAs.impl_witness_table.899, @Core.IntLiteral.as.ImplicitAs.impl(%int_64) [concrete]
 // CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.type.fb8: type = fn_type @Core.IntLiteral.as.ImplicitAs.impl.Convert, @Core.IntLiteral.as.ImplicitAs.impl(%int_64) [concrete]
@@ -809,14 +834,14 @@ fn CopyUnsignedLongLong() {
 // CHECK:STDOUT:   %Core.IntLiteral.as.As.impl.Convert.bound: <bound method> = bound_method %int_1.5b8, %Core.IntLiteral.as.As.impl.Convert.715 [concrete]
 // CHECK:STDOUT:   %Core.IntLiteral.as.As.impl.Convert.specific_fn: <specific function> = specific_function %Core.IntLiteral.as.As.impl.Convert.715, @Core.IntLiteral.as.As.impl.Convert(%int_64) [concrete]
 // CHECK:STDOUT:   %bound_method.9cf: <bound method> = bound_method %int_1.5b8, %Core.IntLiteral.as.As.impl.Convert.specific_fn [concrete]
-// CHECK:STDOUT:   %ImplicitAs.impl_witness.2cc: <witness> = impl_witness imports.%ImplicitAs.impl_witness_table.493, @UInt.as.ImplicitAs.impl(%int_64) [concrete]
-// CHECK:STDOUT:   %UInt.as.ImplicitAs.impl.Convert.type.812: type = fn_type @UInt.as.ImplicitAs.impl.Convert, @UInt.as.ImplicitAs.impl(%int_64) [concrete]
+// CHECK:STDOUT:   %ImplicitAs.impl_witness.2cc: <witness> = impl_witness imports.%ImplicitAs.impl_witness_table.493, @UInt.as.ImplicitAs.impl.607(%int_64) [concrete]
+// CHECK:STDOUT:   %UInt.as.ImplicitAs.impl.Convert.type.812: type = fn_type @UInt.as.ImplicitAs.impl.Convert.1, @UInt.as.ImplicitAs.impl.607(%int_64) [concrete]
 // CHECK:STDOUT:   %UInt.as.ImplicitAs.impl.Convert.309: %UInt.as.ImplicitAs.impl.Convert.type.812 = struct_value () [concrete]
 // CHECK:STDOUT:   %ImplicitAs.facet.02d: %ImplicitAs.type.139 = facet_value %u64, (%ImplicitAs.impl_witness.2cc) [concrete]
 // CHECK:STDOUT:   %ImplicitAs.WithSelf.Convert.type.79a: type = fn_type @ImplicitAs.WithSelf.Convert, @ImplicitAs.WithSelf(Core.IntLiteral, %ImplicitAs.facet.02d) [concrete]
 // CHECK:STDOUT:   %.74a: type = fn_type_with_self_type %ImplicitAs.WithSelf.Convert.type.79a, %ImplicitAs.facet.02d [concrete]
 // CHECK:STDOUT:   %UInt.as.ImplicitAs.impl.Convert.bound: <bound method> = bound_method %int_1.f23, %UInt.as.ImplicitAs.impl.Convert.309 [concrete]
-// CHECK:STDOUT:   %UInt.as.ImplicitAs.impl.Convert.specific_fn: <specific function> = specific_function %UInt.as.ImplicitAs.impl.Convert.309, @UInt.as.ImplicitAs.impl.Convert(%int_64) [concrete]
+// CHECK:STDOUT:   %UInt.as.ImplicitAs.impl.Convert.specific_fn: <specific function> = specific_function %UInt.as.ImplicitAs.impl.Convert.309, @UInt.as.ImplicitAs.impl.Convert.1(%int_64) [concrete]
 // CHECK:STDOUT:   %bound_method.f18: <bound method> = bound_method %int_1.f23, %UInt.as.ImplicitAs.impl.Convert.specific_fn [concrete]
 // CHECK:STDOUT:   %array_type: type = array_type %int_1.5b8, %f32.97e [concrete]
 // CHECK:STDOUT:   %pattern_type.b36: type = pattern_type %array_type [concrete]
@@ -849,8 +874,8 @@ fn CopyUnsignedLongLong() {
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %Core.import_ref.741: @Core.IntLiteral.as.ImplicitAs.impl.%Core.IntLiteral.as.ImplicitAs.impl.Convert.type (%Core.IntLiteral.as.ImplicitAs.impl.Convert.type.6a6) = import_ref Core//prelude/types/uint, loc{{\d+_\d+}}, loaded [symbolic = @Core.IntLiteral.as.ImplicitAs.impl.%Core.IntLiteral.as.ImplicitAs.impl.Convert (constants.%Core.IntLiteral.as.ImplicitAs.impl.Convert.46e)]
 // CHECK:STDOUT:   %ImplicitAs.impl_witness_table.899 = impl_witness_table (%Core.import_ref.741), @Core.IntLiteral.as.ImplicitAs.impl [concrete]
-// CHECK:STDOUT:   %Core.import_ref.483: @UInt.as.ImplicitAs.impl.%UInt.as.ImplicitAs.impl.Convert.type (%UInt.as.ImplicitAs.impl.Convert.type.7f8) = import_ref Core//prelude/types/uint, loc{{\d+_\d+}}, loaded [symbolic = @UInt.as.ImplicitAs.impl.%UInt.as.ImplicitAs.impl.Convert (constants.%UInt.as.ImplicitAs.impl.Convert.0ea)]
-// CHECK:STDOUT:   %ImplicitAs.impl_witness_table.493 = impl_witness_table (%Core.import_ref.483), @UInt.as.ImplicitAs.impl [concrete]
+// CHECK:STDOUT:   %Core.import_ref.483: @UInt.as.ImplicitAs.impl.607.%UInt.as.ImplicitAs.impl.Convert.type (%UInt.as.ImplicitAs.impl.Convert.type.7f8) = import_ref Core//prelude/types/uint, loc{{\d+_\d+}}, loaded [symbolic = @UInt.as.ImplicitAs.impl.607.%UInt.as.ImplicitAs.impl.Convert (constants.%UInt.as.ImplicitAs.impl.Convert.0ea)]
+// CHECK:STDOUT:   %ImplicitAs.impl_witness_table.493 = impl_witness_table (%Core.import_ref.483), @UInt.as.ImplicitAs.impl.607 [concrete]
 // CHECK:STDOUT:   %Core.import_ref.600: @Core.IntLiteral.as.As.impl.%Core.IntLiteral.as.As.impl.Convert.type (%Core.IntLiteral.as.As.impl.Convert.type.2b1) = import_ref Core//prelude/types/uint, loc{{\d+_\d+}}, loaded [symbolic = @Core.IntLiteral.as.As.impl.%Core.IntLiteral.as.As.impl.Convert (constants.%Core.IntLiteral.as.As.impl.Convert.979)]
 // CHECK:STDOUT:   %As.impl_witness_table.7eb = impl_witness_table (%Core.import_ref.600), @Core.IntLiteral.as.As.impl [concrete]
 // CHECK:STDOUT:   %Core.import_ref.38a: @Core.FloatLiteral.as.ImplicitAs.impl.%Core.FloatLiteral.as.ImplicitAs.impl.Convert.type (%Core.FloatLiteral.as.ImplicitAs.impl.Convert.type.02f) = import_ref Core//prelude/types/float, loc{{\d+_\d+}}, loaded [symbolic = @Core.FloatLiteral.as.ImplicitAs.impl.%Core.FloatLiteral.as.ImplicitAs.impl.Convert (constants.%Core.FloatLiteral.as.ImplicitAs.impl.Convert.1f0)]
@@ -915,7 +940,7 @@ fn CopyUnsignedLongLong() {
 // CHECK:STDOUT:     %.loc11_30.2: %u64 = converted %int_1.loc11, %.loc11_30.1 [concrete = constants.%int_1.f23]
 // CHECK:STDOUT:     %impl.elem0.loc11_30.2: %.74a = impl_witness_access constants.%ImplicitAs.impl_witness.2cc, element0 [concrete = constants.%UInt.as.ImplicitAs.impl.Convert.309]
 // CHECK:STDOUT:     %bound_method.loc11_30.3: <bound method> = bound_method %.loc11_30.2, %impl.elem0.loc11_30.2 [concrete = constants.%UInt.as.ImplicitAs.impl.Convert.bound]
-// CHECK:STDOUT:     %specific_fn.loc11_30.2: <specific function> = specific_function %impl.elem0.loc11_30.2, @UInt.as.ImplicitAs.impl.Convert(constants.%int_64) [concrete = constants.%UInt.as.ImplicitAs.impl.Convert.specific_fn]
+// CHECK:STDOUT:     %specific_fn.loc11_30.2: <specific function> = specific_function %impl.elem0.loc11_30.2, @UInt.as.ImplicitAs.impl.Convert.1(constants.%int_64) [concrete = constants.%UInt.as.ImplicitAs.impl.Convert.specific_fn]
 // CHECK:STDOUT:     %bound_method.loc11_30.4: <bound method> = bound_method %.loc11_30.2, %specific_fn.loc11_30.2 [concrete = constants.%bound_method.f18]
 // CHECK:STDOUT:     %UInt.as.ImplicitAs.impl.Convert.call: init Core.IntLiteral = call %bound_method.loc11_30.4(%.loc11_30.2) [concrete = constants.%int_1.5b8]
 // CHECK:STDOUT:     %.loc11_30.3: Core.IntLiteral = value_of_initializer %UInt.as.ImplicitAs.impl.Convert.call [concrete = constants.%int_1.5b8]
@@ -3643,7 +3668,7 @@ fn CopyUnsignedLongLong() {
 // CHECK:STDOUT:   %.30f: type = fn_type_with_self_type %ImplicitAs.WithSelf.Convert.type.3d9, %ImplicitAs.facet.195 [concrete]
 // CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.type.bcb: type = fn_type @Core.IntLiteral.as.ImplicitAs.impl.Convert.1 [concrete]
 // CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.f87: %Core.IntLiteral.as.ImplicitAs.impl.Convert.type.bcb = struct_value () [concrete]
-// CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.bound: <bound method> = bound_method %int_1.5b8, %Core.IntLiteral.as.ImplicitAs.impl.Convert.f87 [concrete]
+// CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.bound.4b8: <bound method> = bound_method %int_1.5b8, %Core.IntLiteral.as.ImplicitAs.impl.Convert.f87 [concrete]
 // CHECK:STDOUT:   %int_1.79a: %Cpp.unsigned_long_long = int_value 1 [concrete]
 // CHECK:STDOUT:   %ULongLongResult: type = class_type @ULongLongResult [concrete]
 // CHECK:STDOUT:   %pattern_type.633: type = pattern_type %ULongLongResult [concrete]
@@ -3653,12 +3678,19 @@ fn CopyUnsignedLongLong() {
 // CHECK:STDOUT:   %PassULongLong__carbon_thunk.type.88c6c2.1: type = fn_type @PassULongLong__carbon_thunk.1 [concrete]
 // CHECK:STDOUT:   %PassULongLong__carbon_thunk.887181.1: %PassULongLong__carbon_thunk.type.88c6c2.1 = struct_value () [concrete]
 // CHECK:STDOUT:   %pattern_type.157: type = pattern_type %u64 [concrete]
-// CHECK:STDOUT:   %ImplicitAs.impl_witness.905: <witness> = impl_witness imports.%ImplicitAs.impl_witness_table.182 [concrete]
-// CHECK:STDOUT:   %ImplicitAs.facet.fb4: %ImplicitAs.type.584 = facet_value %Cpp.unsigned_long_long, (%ImplicitAs.impl_witness.905) [concrete]
-// CHECK:STDOUT:   %ImplicitAs.WithSelf.Convert.type.f8a: type = fn_type @ImplicitAs.WithSelf.Convert, @ImplicitAs.WithSelf(%u64, %ImplicitAs.facet.fb4) [concrete]
-// CHECK:STDOUT:   %.c93: type = fn_type_with_self_type %ImplicitAs.WithSelf.Convert.type.f8a, %ImplicitAs.facet.fb4 [concrete]
-// CHECK:STDOUT:   %Cpp.unsigned_long_long.as.ImplicitAs.impl.Convert.type.03b: type = fn_type @Cpp.unsigned_long_long.as.ImplicitAs.impl.Convert.1 [concrete]
-// CHECK:STDOUT:   %Cpp.unsigned_long_long.as.ImplicitAs.impl.Convert.d3c: %Cpp.unsigned_long_long.as.ImplicitAs.impl.Convert.type.03b = struct_value () [concrete]
+// CHECK:STDOUT:   %To.fe9: Core.IntLiteral = symbolic_binding To, 0 [symbolic]
+// CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.type.6a6: type = fn_type @Core.IntLiteral.as.ImplicitAs.impl.Convert.2, @Core.IntLiteral.as.ImplicitAs.impl.c85(%To.fe9) [symbolic]
+// CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.46e: %Core.IntLiteral.as.ImplicitAs.impl.Convert.type.6a6 = struct_value () [symbolic]
+// CHECK:STDOUT:   %ImplicitAs.impl_witness.bb3: <witness> = impl_witness imports.%ImplicitAs.impl_witness_table.899, @Core.IntLiteral.as.ImplicitAs.impl.c85(%int_64) [concrete]
+// CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.type.fb8: type = fn_type @Core.IntLiteral.as.ImplicitAs.impl.Convert.2, @Core.IntLiteral.as.ImplicitAs.impl.c85(%int_64) [concrete]
+// CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.042: %Core.IntLiteral.as.ImplicitAs.impl.Convert.type.fb8 = struct_value () [concrete]
+// CHECK:STDOUT:   %ImplicitAs.facet.dfe: %ImplicitAs.type.584 = facet_value Core.IntLiteral, (%ImplicitAs.impl_witness.bb3) [concrete]
+// CHECK:STDOUT:   %ImplicitAs.WithSelf.Convert.type.408: type = fn_type @ImplicitAs.WithSelf.Convert, @ImplicitAs.WithSelf(%u64, %ImplicitAs.facet.dfe) [concrete]
+// CHECK:STDOUT:   %.f17: type = fn_type_with_self_type %ImplicitAs.WithSelf.Convert.type.408, %ImplicitAs.facet.dfe [concrete]
+// CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.bound.141: <bound method> = bound_method %int_1.5b8, %Core.IntLiteral.as.ImplicitAs.impl.Convert.042 [concrete]
+// CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.specific_fn: <specific function> = specific_function %Core.IntLiteral.as.ImplicitAs.impl.Convert.042, @Core.IntLiteral.as.ImplicitAs.impl.Convert.2(%int_64) [concrete]
+// CHECK:STDOUT:   %bound_method.fec: <bound method> = bound_method %int_1.5b8, %Core.IntLiteral.as.ImplicitAs.impl.Convert.specific_fn [concrete]
+// CHECK:STDOUT:   %int_1.f23: %u64 = int_value 1 [concrete]
 // CHECK:STDOUT:   %ULongResult: type = class_type @ULongResult [concrete]
 // CHECK:STDOUT:   %pattern_type.6f2: type = pattern_type %ULongResult [concrete]
 // CHECK:STDOUT:   %ptr.f5e: type = ptr_type %ULongResult [concrete]
@@ -3681,9 +3713,9 @@ fn CopyUnsignedLongLong() {
 // CHECK:STDOUT:   %ImplicitAs.facet.29a: %ImplicitAs.type.139 = facet_value %Cpp.unsigned_long_long, (%ImplicitAs.impl_witness.7c3) [concrete]
 // CHECK:STDOUT:   %ImplicitAs.WithSelf.Convert.type.314: type = fn_type @ImplicitAs.WithSelf.Convert, @ImplicitAs.WithSelf(Core.IntLiteral, %ImplicitAs.facet.29a) [concrete]
 // CHECK:STDOUT:   %.66f: type = fn_type_with_self_type %ImplicitAs.WithSelf.Convert.type.314, %ImplicitAs.facet.29a [concrete]
-// CHECK:STDOUT:   %Cpp.unsigned_long_long.as.ImplicitAs.impl.Convert.type.109: type = fn_type @Cpp.unsigned_long_long.as.ImplicitAs.impl.Convert.2 [concrete]
-// CHECK:STDOUT:   %Cpp.unsigned_long_long.as.ImplicitAs.impl.Convert.ffb: %Cpp.unsigned_long_long.as.ImplicitAs.impl.Convert.type.109 = struct_value () [concrete]
-// CHECK:STDOUT:   %Cpp.unsigned_long_long.as.ImplicitAs.impl.Convert.bound: <bound method> = bound_method %int_1.79a, %Cpp.unsigned_long_long.as.ImplicitAs.impl.Convert.ffb [concrete]
+// CHECK:STDOUT:   %Cpp.unsigned_long_long.as.ImplicitAs.impl.Convert.type: type = fn_type @Cpp.unsigned_long_long.as.ImplicitAs.impl.Convert [concrete]
+// CHECK:STDOUT:   %Cpp.unsigned_long_long.as.ImplicitAs.impl.Convert: %Cpp.unsigned_long_long.as.ImplicitAs.impl.Convert.type = struct_value () [concrete]
+// CHECK:STDOUT:   %Cpp.unsigned_long_long.as.ImplicitAs.impl.Convert.bound: <bound method> = bound_method %int_1.79a, %Cpp.unsigned_long_long.as.ImplicitAs.impl.Convert [concrete]
 // CHECK:STDOUT:   %array_type: type = array_type %int_1.5b8, %f32.97e [concrete]
 // CHECK:STDOUT:   %pattern_type.b36: type = pattern_type %array_type [concrete]
 // CHECK:STDOUT:   %float.674: Core.FloatLiteral = float_literal_value 10e-1 [concrete]
@@ -3701,7 +3733,7 @@ fn CopyUnsignedLongLong() {
 // CHECK:STDOUT:   %.98d: type = fn_type_with_self_type %ImplicitAs.WithSelf.Convert.type.e4d, %ImplicitAs.facet.945 [concrete]
 // CHECK:STDOUT:   %Core.FloatLiteral.as.ImplicitAs.impl.Convert.bound: <bound method> = bound_method %float.674, %Core.FloatLiteral.as.ImplicitAs.impl.Convert.e55 [concrete]
 // CHECK:STDOUT:   %Core.FloatLiteral.as.ImplicitAs.impl.Convert.specific_fn: <specific function> = specific_function %Core.FloatLiteral.as.ImplicitAs.impl.Convert.e55, @Core.FloatLiteral.as.ImplicitAs.impl.Convert(%int_32) [concrete]
-// CHECK:STDOUT:   %bound_method: <bound method> = bound_method %float.674, %Core.FloatLiteral.as.ImplicitAs.impl.Convert.specific_fn [concrete]
+// CHECK:STDOUT:   %bound_method.1e4: <bound method> = bound_method %float.674, %Core.FloatLiteral.as.ImplicitAs.impl.Convert.specific_fn [concrete]
 // CHECK:STDOUT:   %float.e3b: %f32.97e = float_value 1 [concrete]
 // CHECK:STDOUT:   %array: %array_type = tuple_value (%float.e3b) [concrete]
 // CHECK:STDOUT:   %Destroy.type: type = facet_type <@Destroy> [concrete]
@@ -3749,8 +3781,8 @@ fn CopyUnsignedLongLong() {
 // CHECK:STDOUT:     <elided>
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %Core.UInt: %UInt.type = import_ref Core//prelude/types/uint, UInt, loaded [concrete = constants.%UInt.generic]
-// CHECK:STDOUT:   %Core.import_ref.506: %Cpp.unsigned_long_long.as.ImplicitAs.impl.Convert.type.03b = import_ref Core//prelude/types/cpp/int, loc{{\d+_\d+}}, loaded [concrete = constants.%Cpp.unsigned_long_long.as.ImplicitAs.impl.Convert.d3c]
-// CHECK:STDOUT:   %ImplicitAs.impl_witness_table.182 = impl_witness_table (%Core.import_ref.506), @Cpp.unsigned_long_long.as.ImplicitAs.impl.7c6 [concrete]
+// CHECK:STDOUT:   %Core.import_ref.741: @Core.IntLiteral.as.ImplicitAs.impl.c85.%Core.IntLiteral.as.ImplicitAs.impl.Convert.type (%Core.IntLiteral.as.ImplicitAs.impl.Convert.type.6a6) = import_ref Core//prelude/types/uint, loc{{\d+_\d+}}, loaded [symbolic = @Core.IntLiteral.as.ImplicitAs.impl.c85.%Core.IntLiteral.as.ImplicitAs.impl.Convert (constants.%Core.IntLiteral.as.ImplicitAs.impl.Convert.46e)]
+// CHECK:STDOUT:   %ImplicitAs.impl_witness_table.899 = impl_witness_table (%Core.import_ref.741), @Core.IntLiteral.as.ImplicitAs.impl.c85 [concrete]
 // CHECK:STDOUT:   %ULongResult.decl: type = class_decl @ULongResult [concrete = constants.%ULongResult] {} {}
 // CHECK:STDOUT:   %PassULongLong__carbon_thunk.decl.f0c073.2: %PassULongLong__carbon_thunk.type.88c6c2.2 = fn_decl @PassULongLong__carbon_thunk.2 [concrete = constants.%PassULongLong__carbon_thunk.887181.2] {
 // CHECK:STDOUT:     <elided>
@@ -3761,7 +3793,7 @@ fn CopyUnsignedLongLong() {
 // CHECK:STDOUT:   %Core.As: %As.type.90f = import_ref Core//prelude/operators/as, As, loaded [concrete = constants.%As.generic]
 // CHECK:STDOUT:   %Core.import_ref.7e9: %Core.IntLiteral.as.As.impl.Convert.type = import_ref Core//prelude/types/cpp/int, loc{{\d+_\d+}}, loaded [concrete = constants.%Core.IntLiteral.as.As.impl.Convert]
 // CHECK:STDOUT:   %As.impl_witness_table.002 = impl_witness_table (%Core.import_ref.7e9), @Core.IntLiteral.as.As.impl.b6f [concrete]
-// CHECK:STDOUT:   %Core.import_ref.5ac: %Cpp.unsigned_long_long.as.ImplicitAs.impl.Convert.type.109 = import_ref Core//prelude/types/cpp/int, loc{{\d+_\d+}}, loaded [concrete = constants.%Cpp.unsigned_long_long.as.ImplicitAs.impl.Convert.ffb]
+// CHECK:STDOUT:   %Core.import_ref.5ac: %Cpp.unsigned_long_long.as.ImplicitAs.impl.Convert.type = import_ref Core//prelude/types/cpp/int, loc{{\d+_\d+}}, loaded [concrete = constants.%Cpp.unsigned_long_long.as.ImplicitAs.impl.Convert]
 // CHECK:STDOUT:   %ImplicitAs.impl_witness_table.d12 = impl_witness_table (%Core.import_ref.5ac), @Cpp.unsigned_long_long.as.ImplicitAs.impl.fca [concrete]
 // CHECK:STDOUT:   %Core.import_ref.38a: @Core.FloatLiteral.as.ImplicitAs.impl.%Core.FloatLiteral.as.ImplicitAs.impl.Convert.type (%Core.FloatLiteral.as.ImplicitAs.impl.Convert.type.02f) = import_ref Core//prelude/types/float, loc{{\d+_\d+}}, loaded [symbolic = @Core.FloatLiteral.as.ImplicitAs.impl.%Core.FloatLiteral.as.ImplicitAs.impl.Convert (constants.%Core.FloatLiteral.as.ImplicitAs.impl.Convert.1f0)]
 // CHECK:STDOUT:   %ImplicitAs.impl_witness_table.31a = impl_witness_table (%Core.import_ref.38a), @Core.FloatLiteral.as.ImplicitAs.impl [concrete]
@@ -3779,9 +3811,9 @@ fn CopyUnsignedLongLong() {
 // CHECK:STDOUT:     %unsigned_long_long.ref.loc15: type = name_ref unsigned_long_long, constants.%Cpp.unsigned_long_long [concrete = constants.%Cpp.unsigned_long_long]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %impl.elem0.loc15: %.30f = impl_witness_access constants.%ImplicitAs.impl_witness.4384, element0 [concrete = constants.%Core.IntLiteral.as.ImplicitAs.impl.Convert.f87]
-// CHECK:STDOUT:   %bound_method.loc15: <bound method> = bound_method %int_1.loc15, %impl.elem0.loc15 [concrete = constants.%Core.IntLiteral.as.ImplicitAs.impl.Convert.bound]
-// CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.call: init %Cpp.unsigned_long_long = call %bound_method.loc15(%int_1.loc15) [concrete = constants.%int_1.79a]
-// CHECK:STDOUT:   %.loc15_56.1: %Cpp.unsigned_long_long = value_of_initializer %Core.IntLiteral.as.ImplicitAs.impl.Convert.call [concrete = constants.%int_1.79a]
+// CHECK:STDOUT:   %bound_method.loc15: <bound method> = bound_method %int_1.loc15, %impl.elem0.loc15 [concrete = constants.%Core.IntLiteral.as.ImplicitAs.impl.Convert.bound.4b8]
+// CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.call.loc15: init %Cpp.unsigned_long_long = call %bound_method.loc15(%int_1.loc15) [concrete = constants.%int_1.79a]
+// CHECK:STDOUT:   %.loc15_56.1: %Cpp.unsigned_long_long = value_of_initializer %Core.IntLiteral.as.ImplicitAs.impl.Convert.call.loc15 [concrete = constants.%int_1.79a]
 // CHECK:STDOUT:   %.loc15_56.2: %Cpp.unsigned_long_long = converted %int_1.loc15, %.loc15_56.1 [concrete = constants.%int_1.79a]
 // CHECK:STDOUT:   %cpp_unsigned_long_long: %Cpp.unsigned_long_long = value_binding cpp_unsigned_long_long, %.loc15_56.2
 // CHECK:STDOUT:   name_binding_decl {
@@ -3831,13 +3863,15 @@ fn CopyUnsignedLongLong() {
 // CHECK:STDOUT:   name_binding_decl {
 // CHECK:STDOUT:     %carbon_u64.patt: %pattern_type.157 = value_binding_pattern carbon_u64 [concrete]
 // CHECK:STDOUT:   }
-// CHECK:STDOUT:   %cpp_unsigned_long_long.ref.loc21: %Cpp.unsigned_long_long = name_ref cpp_unsigned_long_long, %cpp_unsigned_long_long
+// CHECK:STDOUT:   %int_1.loc21: Core.IntLiteral = int_value 1 [concrete = constants.%int_1.5b8]
 // CHECK:STDOUT:   %u64: type = type_literal constants.%u64 [concrete = constants.%u64]
-// CHECK:STDOUT:   %impl.elem0.loc21: %.c93 = impl_witness_access constants.%ImplicitAs.impl_witness.905, element0 [concrete = constants.%Cpp.unsigned_long_long.as.ImplicitAs.impl.Convert.d3c]
-// CHECK:STDOUT:   %bound_method.loc21: <bound method> = bound_method %cpp_unsigned_long_long.ref.loc21, %impl.elem0.loc21
-// CHECK:STDOUT:   %Cpp.unsigned_long_long.as.ImplicitAs.impl.Convert.call.loc21: init %u64 = call %bound_method.loc21(%cpp_unsigned_long_long.ref.loc21)
-// CHECK:STDOUT:   %.loc21_25.1: %u64 = value_of_initializer %Cpp.unsigned_long_long.as.ImplicitAs.impl.Convert.call.loc21
-// CHECK:STDOUT:   %.loc21_25.2: %u64 = converted %cpp_unsigned_long_long.ref.loc21, %.loc21_25.1
+// CHECK:STDOUT:   %impl.elem0.loc21: %.f17 = impl_witness_access constants.%ImplicitAs.impl_witness.bb3, element0 [concrete = constants.%Core.IntLiteral.as.ImplicitAs.impl.Convert.042]
+// CHECK:STDOUT:   %bound_method.loc21_25.1: <bound method> = bound_method %int_1.loc21, %impl.elem0.loc21 [concrete = constants.%Core.IntLiteral.as.ImplicitAs.impl.Convert.bound.141]
+// CHECK:STDOUT:   %specific_fn.loc21: <specific function> = specific_function %impl.elem0.loc21, @Core.IntLiteral.as.ImplicitAs.impl.Convert.2(constants.%int_64) [concrete = constants.%Core.IntLiteral.as.ImplicitAs.impl.Convert.specific_fn]
+// CHECK:STDOUT:   %bound_method.loc21_25.2: <bound method> = bound_method %int_1.loc21, %specific_fn.loc21 [concrete = constants.%bound_method.fec]
+// CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.call.loc21: init %u64 = call %bound_method.loc21_25.2(%int_1.loc21) [concrete = constants.%int_1.f23]
+// CHECK:STDOUT:   %.loc21_25.1: %u64 = value_of_initializer %Core.IntLiteral.as.ImplicitAs.impl.Convert.call.loc21 [concrete = constants.%int_1.f23]
+// CHECK:STDOUT:   %.loc21_25.2: %u64 = converted %int_1.loc21, %.loc21_25.1 [concrete = constants.%int_1.f23]
 // CHECK:STDOUT:   %carbon_u64: %u64 = value_binding carbon_u64, %.loc21_25.2
 // CHECK:STDOUT:   name_binding_decl {
 // CHECK:STDOUT:     %carbon_u64_result.patt: %pattern_type.6f2 = value_binding_pattern carbon_u64_result [concrete]
@@ -3865,8 +3899,8 @@ fn CopyUnsignedLongLong() {
 // CHECK:STDOUT:   %.loc24_64.1: %tuple.type = tuple_literal (%float) [concrete = constants.%tuple]
 // CHECK:STDOUT:   %impl.elem0.loc24_64: %.98d = impl_witness_access constants.%ImplicitAs.impl_witness.bc6, element0 [concrete = constants.%Core.FloatLiteral.as.ImplicitAs.impl.Convert.e55]
 // CHECK:STDOUT:   %bound_method.loc24_64.1: <bound method> = bound_method %float, %impl.elem0.loc24_64 [concrete = constants.%Core.FloatLiteral.as.ImplicitAs.impl.Convert.bound]
-// CHECK:STDOUT:   %specific_fn: <specific function> = specific_function %impl.elem0.loc24_64, @Core.FloatLiteral.as.ImplicitAs.impl.Convert(constants.%int_32) [concrete = constants.%Core.FloatLiteral.as.ImplicitAs.impl.Convert.specific_fn]
-// CHECK:STDOUT:   %bound_method.loc24_64.2: <bound method> = bound_method %float, %specific_fn [concrete = constants.%bound_method]
+// CHECK:STDOUT:   %specific_fn.loc24: <specific function> = specific_function %impl.elem0.loc24_64, @Core.FloatLiteral.as.ImplicitAs.impl.Convert(constants.%int_32) [concrete = constants.%Core.FloatLiteral.as.ImplicitAs.impl.Convert.specific_fn]
+// CHECK:STDOUT:   %bound_method.loc24_64.2: <bound method> = bound_method %float, %specific_fn.loc24 [concrete = constants.%bound_method.1e4]
 // CHECK:STDOUT:   %Core.FloatLiteral.as.ImplicitAs.impl.Convert.call: init %f32.97e = call %bound_method.loc24_64.2(%float) [concrete = constants.%float.e3b]
 // CHECK:STDOUT:   %.loc24_64.2: init %f32.97e = converted %float, %Core.FloatLiteral.as.ImplicitAs.impl.Convert.call [concrete = constants.%float.e3b]
 // CHECK:STDOUT:   %int_0: Core.IntLiteral = int_value 0 [concrete = constants.%int_0]
@@ -3885,10 +3919,10 @@ fn CopyUnsignedLongLong() {
 // CHECK:STDOUT:     %Core.IntLiteral.as.As.impl.Convert.call: init %Cpp.unsigned_long_long = call %bound_method.loc24_30.1(%int_1.loc24) [concrete = constants.%int_1.79a]
 // CHECK:STDOUT:     %.loc24_30.1: %Cpp.unsigned_long_long = value_of_initializer %Core.IntLiteral.as.As.impl.Convert.call [concrete = constants.%int_1.79a]
 // CHECK:STDOUT:     %.loc24_30.2: %Cpp.unsigned_long_long = converted %int_1.loc24, %.loc24_30.1 [concrete = constants.%int_1.79a]
-// CHECK:STDOUT:     %impl.elem0.loc24_30.2: %.66f = impl_witness_access constants.%ImplicitAs.impl_witness.7c3, element0 [concrete = constants.%Cpp.unsigned_long_long.as.ImplicitAs.impl.Convert.ffb]
+// CHECK:STDOUT:     %impl.elem0.loc24_30.2: %.66f = impl_witness_access constants.%ImplicitAs.impl_witness.7c3, element0 [concrete = constants.%Cpp.unsigned_long_long.as.ImplicitAs.impl.Convert]
 // CHECK:STDOUT:     %bound_method.loc24_30.2: <bound method> = bound_method %.loc24_30.2, %impl.elem0.loc24_30.2 [concrete = constants.%Cpp.unsigned_long_long.as.ImplicitAs.impl.Convert.bound]
-// CHECK:STDOUT:     %Cpp.unsigned_long_long.as.ImplicitAs.impl.Convert.call.loc24: init Core.IntLiteral = call %bound_method.loc24_30.2(%.loc24_30.2) [concrete = constants.%int_1.5b8]
-// CHECK:STDOUT:     %.loc24_30.3: Core.IntLiteral = value_of_initializer %Cpp.unsigned_long_long.as.ImplicitAs.impl.Convert.call.loc24 [concrete = constants.%int_1.5b8]
+// CHECK:STDOUT:     %Cpp.unsigned_long_long.as.ImplicitAs.impl.Convert.call: init Core.IntLiteral = call %bound_method.loc24_30.2(%.loc24_30.2) [concrete = constants.%int_1.5b8]
+// CHECK:STDOUT:     %.loc24_30.3: Core.IntLiteral = value_of_initializer %Cpp.unsigned_long_long.as.ImplicitAs.impl.Convert.call [concrete = constants.%int_1.5b8]
 // CHECK:STDOUT:     %.loc24_30.4: Core.IntLiteral = converted %.loc24_30.2, %.loc24_30.3 [concrete = constants.%int_1.5b8]
 // CHECK:STDOUT:     %array_type: type = array_type %.loc24_30.4, %f32 [concrete = constants.%array_type]
 // CHECK:STDOUT:   }
@@ -786,8 +786,8 @@ fn F() {
 // CHECK:STDOUT:   %foo__carbon_thunk.type: type = fn_type @foo__carbon_thunk [concrete]
 // CHECK:STDOUT:   %foo__carbon_thunk: %foo__carbon_thunk.type = struct_value () [concrete]
 // CHECK:STDOUT:   %ImplicitAs.type.8ae: type = facet_type <@ImplicitAs, @ImplicitAs(%u8)> [concrete]
-// CHECK:STDOUT:   %To: Core.IntLiteral = symbolic_binding To, 0 [symbolic]
-// CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.type.6a6: type = fn_type @Core.IntLiteral.as.ImplicitAs.impl.Convert, @Core.IntLiteral.as.ImplicitAs.impl(%To) [symbolic]
+// CHECK:STDOUT:   %To.fe9: Core.IntLiteral = symbolic_binding To, 0 [symbolic]
+// CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.type.6a6: type = fn_type @Core.IntLiteral.as.ImplicitAs.impl.Convert, @Core.IntLiteral.as.ImplicitAs.impl(%To.fe9) [symbolic]
 // CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.46e: %Core.IntLiteral.as.ImplicitAs.impl.Convert.type.6a6 = struct_value () [symbolic]
 // CHECK:STDOUT:   %Copy.type: type = facet_type <@Copy> [concrete]
 // CHECK:STDOUT:   %ImplicitAs.impl_witness.7d6: <witness> = impl_witness imports.%ImplicitAs.impl_witness_table.899, @Core.IntLiteral.as.ImplicitAs.impl(%int_8) [concrete]
@@ -1067,8 +1067,8 @@ fn F() {
 // CHECK:STDOUT:   %i32: type = class_type @Int, @Int(%int_32) [concrete]
 // CHECK:STDOUT:   %int_1.5d2: %i32 = int_value 1 [concrete]
 // CHECK:STDOUT:   %ImplicitAs.type.139: type = facet_type <@ImplicitAs, @ImplicitAs(Core.IntLiteral)> [concrete]
-// CHECK:STDOUT:   %From: Core.IntLiteral = symbolic_binding From, 0 [symbolic]
-// CHECK:STDOUT:   %Int.as.ImplicitAs.impl.Convert.type.2ed: type = fn_type @Int.as.ImplicitAs.impl.Convert, @Int.as.ImplicitAs.impl(%From) [symbolic]
+// CHECK:STDOUT:   %From.fe9: Core.IntLiteral = symbolic_binding From, 0 [symbolic]
+// CHECK:STDOUT:   %Int.as.ImplicitAs.impl.Convert.type.2ed: type = fn_type @Int.as.ImplicitAs.impl.Convert, @Int.as.ImplicitAs.impl(%From.fe9) [symbolic]
 // CHECK:STDOUT:   %Int.as.ImplicitAs.impl.Convert.d29: %Int.as.ImplicitAs.impl.Convert.type.2ed = struct_value () [symbolic]
 // CHECK:STDOUT:   %ImplicitAs.impl_witness.640: <witness> = impl_witness imports.%ImplicitAs.impl_witness_table.ea2, @Int.as.ImplicitAs.impl(%int_32) [concrete]
 // CHECK:STDOUT:   %Int.as.ImplicitAs.impl.Convert.type.240: type = fn_type @Int.as.ImplicitAs.impl.Convert, @Int.as.ImplicitAs.impl(%int_32) [concrete]
@@ -0,0 +1,264 @@
+// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+// INCLUDE-FILE: toolchain/testing/testdata/min_prelude/full.carbon
+//
+// AUTOUPDATE
+// TIP: To test this file alone, run:
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/primitives/int_conversions.carbon
+// TIP: To dump output, run:
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/primitives/int_conversions.carbon
+
+// --- valid.carbon
+
+library "[[@TEST_NAME]]";
+
+fn TestFits() {
+  var a: i32 = 1;
+  var unused b: i64 = a;
+
+  var w: u32 = 1;
+  var unused x: u64 = w;
+}
+
+// --- fail_narrow.carbon
+
+library "[[@TEST_NAME]]";
+
+fn TestFailures() {
+  var a: i64 = 1;
+  // CHECK:STDERR: fail_narrow.carbon:[[@LINE+7]]:3: error: cannot implicitly convert expression of type `i64` to `i32` [ConversionFailure]
+  // CHECK:STDERR:   var unused b: i32 = a;
+  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~
+  // CHECK:STDERR: fail_narrow.carbon:[[@LINE+4]]:3: note: type `i64` does not implement interface `Core.ImplicitAs(i32)` [MissingImplInMemberAccessInContext]
+  // CHECK:STDERR:   var unused b: i32 = a;
+  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~
+  // CHECK:STDERR:
+  var unused b: i32 = a;
+
+  var w: u64 = 1;
+  // CHECK:STDERR: fail_narrow.carbon:[[@LINE+7]]:3: error: cannot implicitly convert expression of type `u64` to `u32` [ConversionFailure]
+  // CHECK:STDERR:   var unused x: u32 = w;
+  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~
+  // CHECK:STDERR: fail_narrow.carbon:[[@LINE+4]]:3: note: type `u64` does not implement interface `Core.ImplicitAs(u32)` [MissingImplInMemberAccessInContext]
+  // CHECK:STDERR:   var unused x: u32 = w;
+  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~
+  // CHECK:STDERR:
+  var unused x: u32 = w;
+}
+
+// --- cpp_compat.carbon
+
+library "[[@TEST_NAME]]";
+
+fn TestCppCompat() {
+  var c: i32 = 1;
+  var unused d: Core.CppCompat.Long32 = c;
+}
+
+// --- fail_todo_cpp_compat_widen.carbon
+
+library "[[@TEST_NAME]]";
+
+fn TestCppCompat() {
+  var a: Core.CppCompat.Long32 = 1;
+  // CHECK:STDERR: fail_todo_cpp_compat_widen.carbon:[[@LINE+11]]:17: error: bit width of integer type literal must be a multiple of 8; use `Core.Int(33)` instead [IntWidthNotMultipleOf8]
+  // CHECK:STDERR:   var unused b: i33 = a;
+  // CHECK:STDERR:                 ^~~
+  // CHECK:STDERR:
+  // CHECK:STDERR: fail_todo_cpp_compat_widen.carbon:[[@LINE+7]]:3: error: cannot implicitly convert expression of type `Core.CppCompat.Long32` to `i33` [ConversionFailure]
+  // CHECK:STDERR:   var unused b: i33 = a;
+  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~
+  // CHECK:STDERR: fail_todo_cpp_compat_widen.carbon:[[@LINE+4]]:3: note: type `Core.CppCompat.Long32` does not implement interface `Core.ImplicitAs(i33)` [MissingImplInMemberAccessInContext]
+  // CHECK:STDERR:   var unused b: i33 = a;
+  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~
+  // CHECK:STDERR:
+  var unused b: i33 = a;
+
+  var c: Core.CppCompat.LongLong64 = 1;
+  // CHECK:STDERR: fail_todo_cpp_compat_widen.carbon:[[@LINE+11]]:17: error: bit width of integer type literal must be a multiple of 8; use `Core.Int(65)` instead [IntWidthNotMultipleOf8]
+  // CHECK:STDERR:   var unused d: i65 = c;
+  // CHECK:STDERR:                 ^~~
+  // CHECK:STDERR:
+  // CHECK:STDERR: fail_todo_cpp_compat_widen.carbon:[[@LINE+7]]:3: error: cannot implicitly convert expression of type `Core.CppCompat.LongLong64` to `i65` [ConversionFailure]
+  // CHECK:STDERR:   var unused d: i65 = c;
+  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~
+  // CHECK:STDERR: fail_todo_cpp_compat_widen.carbon:[[@LINE+4]]:3: note: type `Core.CppCompat.LongLong64` does not implement interface `Core.ImplicitAs(i65)` [MissingImplInMemberAccessInContext]
+  // CHECK:STDERR:   var unused d: i65 = c;
+  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~
+  // CHECK:STDERR:
+  var unused d: i65 = c;
+
+  var e: Core.CppCompat.ULong32 = 1;
+  // CHECK:STDERR: fail_todo_cpp_compat_widen.carbon:[[@LINE+11]]:17: error: bit width of integer type literal must be a multiple of 8; use `Core.UInt(33)` instead [IntWidthNotMultipleOf8]
+  // CHECK:STDERR:   var unused f: u33 = e;
+  // CHECK:STDERR:                 ^~~
+  // CHECK:STDERR:
+  // CHECK:STDERR: fail_todo_cpp_compat_widen.carbon:[[@LINE+7]]:3: error: cannot implicitly convert expression of type `Core.CppCompat.ULong32` to `u33` [ConversionFailure]
+  // CHECK:STDERR:   var unused f: u33 = e;
+  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~
+  // CHECK:STDERR: fail_todo_cpp_compat_widen.carbon:[[@LINE+4]]:3: note: type `Core.CppCompat.ULong32` does not implement interface `Core.ImplicitAs(u33)` [MissingImplInMemberAccessInContext]
+  // CHECK:STDERR:   var unused f: u33 = e;
+  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~
+  // CHECK:STDERR:
+  var unused f: u33 = e;
+
+  var g: Core.CppCompat.ULongLong64 = 1;
+  // CHECK:STDERR: fail_todo_cpp_compat_widen.carbon:[[@LINE+11]]:17: error: bit width of integer type literal must be a multiple of 8; use `Core.UInt(65)` instead [IntWidthNotMultipleOf8]
+  // CHECK:STDERR:   var unused h: u65 = g;
+  // CHECK:STDERR:                 ^~~
+  // CHECK:STDERR:
+  // CHECK:STDERR: fail_todo_cpp_compat_widen.carbon:[[@LINE+7]]:3: error: cannot implicitly convert expression of type `Core.CppCompat.ULongLong64` to `u65` [ConversionFailure]
+  // CHECK:STDERR:   var unused h: u65 = g;
+  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~
+  // CHECK:STDERR: fail_todo_cpp_compat_widen.carbon:[[@LINE+4]]:3: note: type `Core.CppCompat.ULongLong64` does not implement interface `Core.ImplicitAs(u65)` [MissingImplInMemberAccessInContext]
+  // CHECK:STDERR:   var unused h: u65 = g;
+  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~
+  // CHECK:STDERR:
+  var unused h: u65 = g;
+}
+
+// --- fail_cpp_compat_narrow.carbon
+
+library "[[@TEST_NAME]]";
+
+fn TestCppCompat() {
+  // Long32 is slightly wider than i32.
+  var a: Core.CppCompat.Long32 = 1;
+  // CHECK:STDERR: fail_cpp_compat_narrow.carbon:[[@LINE+7]]:3: error: cannot implicitly convert expression of type `Core.CppCompat.Long32` to `i32` [ConversionFailure]
+  // CHECK:STDERR:   var unused b: i32 = a;
+  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~
+  // CHECK:STDERR: fail_cpp_compat_narrow.carbon:[[@LINE+4]]:3: note: type `Core.CppCompat.Long32` does not implement interface `Core.ImplicitAs(i32)` [MissingImplInMemberAccessInContext]
+  // CHECK:STDERR:   var unused b: i32 = a;
+  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~
+  // CHECK:STDERR:
+  var unused b: i32 = a;
+
+  // LongLong64 is slightly wider than i64.
+  var c: Core.CppCompat.LongLong64 = 1;
+  // CHECK:STDERR: fail_cpp_compat_narrow.carbon:[[@LINE+7]]:3: error: cannot implicitly convert expression of type `Core.CppCompat.LongLong64` to `i64` [ConversionFailure]
+  // CHECK:STDERR:   var unused d: i64 = c;
+  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~
+  // CHECK:STDERR: fail_cpp_compat_narrow.carbon:[[@LINE+4]]:3: note: type `Core.CppCompat.LongLong64` does not implement interface `Core.ImplicitAs(i64)` [MissingImplInMemberAccessInContext]
+  // CHECK:STDERR:   var unused d: i64 = c;
+  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~
+  // CHECK:STDERR:
+  var unused d: i64 = c;
+
+  // ULong32 is slightly wider than u32.
+  var e: Core.CppCompat.ULong32 = 1;
+  // CHECK:STDERR: fail_cpp_compat_narrow.carbon:[[@LINE+7]]:3: error: cannot implicitly convert expression of type `Core.CppCompat.ULong32` to `u32` [ConversionFailure]
+  // CHECK:STDERR:   var unused f: u32 = e;
+  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~
+  // CHECK:STDERR: fail_cpp_compat_narrow.carbon:[[@LINE+4]]:3: note: type `Core.CppCompat.ULong32` does not implement interface `Core.ImplicitAs(u32)` [MissingImplInMemberAccessInContext]
+  // CHECK:STDERR:   var unused f: u32 = e;
+  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~
+  // CHECK:STDERR:
+  var unused f: u32 = e;
+
+  // ULongLong64 is slightly wider than u64.
+  var g: Core.CppCompat.ULongLong64 = 1;
+  // CHECK:STDERR: fail_cpp_compat_narrow.carbon:[[@LINE+7]]:3: error: cannot implicitly convert expression of type `Core.CppCompat.ULongLong64` to `u64` [ConversionFailure]
+  // CHECK:STDERR:   var unused h: u64 = g;
+  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~
+  // CHECK:STDERR: fail_cpp_compat_narrow.carbon:[[@LINE+4]]:3: note: type `Core.CppCompat.ULongLong64` does not implement interface `Core.ImplicitAs(u64)` [MissingImplInMemberAccessInContext]
+  // CHECK:STDERR:   var unused h: u64 = g;
+  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~
+  // CHECK:STDERR:
+  var unused h: u64 = g;
+}
+
+// --- widen_sign_change.carbon
+
+library "[[@TEST_NAME]]";
+
+fn TestWidenSign() {
+  var e: u32 = 1;
+  var unused f: i64 = e;
+}
+
+// --- fail_narrow_sign_change.carbon
+
+library "[[@TEST_NAME]]";
+
+fn TestMixedSign() {
+  var a: i32 = 1;
+  // CHECK:STDERR: fail_narrow_sign_change.carbon:[[@LINE+7]]:3: error: cannot implicitly convert expression of type `i32` to `u32` [ConversionFailure]
+  // CHECK:STDERR:   var unused b: u32 = a;
+  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~
+  // CHECK:STDERR: fail_narrow_sign_change.carbon:[[@LINE+4]]:3: note: type `i32` does not implement interface `Core.ImplicitAs(u32)` [MissingImplInMemberAccessInContext]
+  // CHECK:STDERR:   var unused b: u32 = a;
+  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~
+  // CHECK:STDERR:
+  var unused b: u32 = a;
+
+  var c: u32 = 1;
+  // CHECK:STDERR: fail_narrow_sign_change.carbon:[[@LINE+7]]:3: error: cannot implicitly convert expression of type `u32` to `i32` [ConversionFailure]
+  // CHECK:STDERR:   var unused d: i32 = c;
+  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~
+  // CHECK:STDERR: fail_narrow_sign_change.carbon:[[@LINE+4]]:3: note: type `u32` does not implement interface `Core.ImplicitAs(i32)` [MissingImplInMemberAccessInContext]
+  // CHECK:STDERR:   var unused d: i32 = c;
+  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~
+  // CHECK:STDERR:
+  var unused d: i32 = c;
+
+  var g: i32 = 1;
+  // CHECK:STDERR: fail_narrow_sign_change.carbon:[[@LINE+7]]:3: error: cannot implicitly convert expression of type `i32` to `u64` [ConversionFailure]
+  // CHECK:STDERR:   var unused h: u64 = g;
+  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~
+  // CHECK:STDERR: fail_narrow_sign_change.carbon:[[@LINE+4]]:3: note: type `i32` does not implement interface `Core.ImplicitAs(u64)` [MissingImplInMemberAccessInContext]
+  // CHECK:STDERR:   var unused h: u64 = g;
+  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~
+  // CHECK:STDERR:
+  var unused h: u64 = g;
+}
+
+// --- arbitrary_width.carbon
+
+library "[[@TEST_NAME]]";
+
+fn TestArbitraryWidth() {
+  var a: Core.Int(33) = 1;
+  var unused c: Core.Int(34) = a;
+
+  var d: Core.UInt(33) = 1;
+  var unused f: Core.UInt(34) = d;
+
+  var unused h: Core.Int(34) = d;
+}
+
+// --- fail_narrow_arbitrary_width.carbon
+
+library "[[@TEST_NAME]]";
+
+fn TestArbitraryWidth() {
+  var a: Core.Int(33) = 1;
+  // CHECK:STDERR: fail_narrow_arbitrary_width.carbon:[[@LINE+7]]:3: error: cannot implicitly convert expression of type `i33` to `i32` [ConversionFailure]
+  // CHECK:STDERR:   var unused b: Core.Int(32) = a;
+  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~~~~~~~~~~
+  // CHECK:STDERR: fail_narrow_arbitrary_width.carbon:[[@LINE+4]]:3: note: type `i33` does not implement interface `Core.ImplicitAs(i32)` [MissingImplInMemberAccessInContext]
+  // CHECK:STDERR:   var unused b: Core.Int(32) = a;
+  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~~~~~~~~~~
+  // CHECK:STDERR:
+  var unused b: Core.Int(32) = a;
+
+  var d: Core.UInt(33) = 1;
+  // CHECK:STDERR: fail_narrow_arbitrary_width.carbon:[[@LINE+7]]:3: error: cannot implicitly convert expression of type `u33` to `u32` [ConversionFailure]
+  // CHECK:STDERR:   var unused e: Core.UInt(32) = d;
+  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~~~~~~~~~~~
+  // CHECK:STDERR: fail_narrow_arbitrary_width.carbon:[[@LINE+4]]:3: note: type `u33` does not implement interface `Core.ImplicitAs(u32)` [MissingImplInMemberAccessInContext]
+  // CHECK:STDERR:   var unused e: Core.UInt(32) = d;
+  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~~~~~~~~~~~
+  // CHECK:STDERR:
+  var unused e: Core.UInt(32) = d;
+
+  // CHECK:STDERR: fail_narrow_arbitrary_width.carbon:[[@LINE+7]]:3: error: cannot implicitly convert expression of type `i33` to `u34` [ConversionFailure]
+  // CHECK:STDERR:   var unused g: Core.UInt(34) = a;
+  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~~~~~~~~~~~
+  // CHECK:STDERR: fail_narrow_arbitrary_width.carbon:[[@LINE+4]]:3: note: type `i33` does not implement interface `Core.ImplicitAs(u34)` [MissingImplInMemberAccessInContext]
+  // CHECK:STDERR:   var unused g: Core.UInt(34) = a;
+  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~~~~~~~~~~~
+  // CHECK:STDERR:
+  var unused g: Core.UInt(34) = a;
+}
@@ -113,16 +113,16 @@ fn VectorizedWithOptSpeed(a: array(i32, 65536)*) {
 // CHECK:STDOUT: !21 = !DILocalVariable(arg: 1, scope: !16, type: !19)
 // CHECK:STDOUT: !22 = !DILocation(line: 18, column: 9, scope: !16)
 // CHECK:STDOUT: !23 = !DILocation(line: 19, column: 5, scope: !16)
-// CHECK:STDOUT: !24 = !DILocation(line: 277, column: 3, scope: !25, inlinedAt: !32)
-// CHECK:STDOUT: !25 = distinct !DISubprogram(name: "Op", linkageName: "_COp:thunk.Int.9452f4c51951679b.Core:AddAssignWith.5375cfcbca6d9e35.Core.75bec4d236c9daa5", scope: null, file: !26, line: 277, type: !27, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !29)
+// CHECK:STDOUT: !24 = !DILocation(line: 296, column: 3, scope: !25, inlinedAt: !32)
+// CHECK:STDOUT: !25 = distinct !DISubprogram(name: "Op", linkageName: "_COp:thunk.Int.9452f4c51951679b.Core:AddAssignWith.5375cfcbca6d9e35.Core.57ee91777b6354a8", scope: null, file: !26, line: 296, type: !27, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !29)
 // CHECK:STDOUT: !26 = !DIFile(filename: "{{.*}}/prelude/types/int.carbon", directory: "")
 // CHECK:STDOUT: !27 = !DISubroutineType(types: !28)
 // CHECK:STDOUT: !28 = !{null, !7, !7}
 // CHECK:STDOUT: !29 = !{!30, !31}
 // CHECK:STDOUT: !30 = !DILocalVariable(arg: 1, scope: !25, type: !7)
 // CHECK:STDOUT: !31 = !DILocalVariable(arg: 2, scope: !25, type: !7)
-// CHECK:STDOUT: !32 = distinct !DILocation(line: 343, column: 5, scope: !33, inlinedAt: !38)
-// CHECK:STDOUT: !33 = distinct !DISubprogram(name: "Op", linkageName: "_COp.Int.9452f4c51951679b.Core:Inc.Core.be1e879c1ad406d8", scope: null, file: !26, line: 341, type: !34, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !36)
+// CHECK:STDOUT: !32 = distinct !DILocation(line: 362, column: 5, scope: !33, inlinedAt: !38)
+// CHECK:STDOUT: !33 = distinct !DISubprogram(name: "Op", linkageName: "_COp.Int.9452f4c51951679b.Core:Inc.Core.be1e879c1ad406d8", scope: null, file: !26, line: 360, type: !34, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !36)
 // CHECK:STDOUT: !34 = !DISubroutineType(types: !35)
 // CHECK:STDOUT: !35 = !{null, !7}
 // CHECK:STDOUT: !36 = !{!37}
@@ -113,16 +113,16 @@ fn VectorizedWithOptSpeed(a: array(i32, 65536)*) {
 // CHECK:STDOUT: !21 = !DILocalVariable(arg: 1, scope: !16, type: !19)
 // CHECK:STDOUT: !22 = !DILocation(line: 18, column: 9, scope: !16)
 // CHECK:STDOUT: !23 = !DILocation(line: 19, column: 5, scope: !16)
-// CHECK:STDOUT: !24 = !DILocation(line: 277, column: 3, scope: !25, inlinedAt: !32)
-// CHECK:STDOUT: !25 = distinct !DISubprogram(name: "Op", linkageName: "_COp:thunk.Int.9452f4c51951679b.Core:AddAssignWith.5375cfcbca6d9e35.Core.75bec4d236c9daa5", scope: null, file: !26, line: 277, type: !27, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !29)
+// CHECK:STDOUT: !24 = !DILocation(line: 296, column: 3, scope: !25, inlinedAt: !32)
+// CHECK:STDOUT: !25 = distinct !DISubprogram(name: "Op", linkageName: "_COp:thunk.Int.9452f4c51951679b.Core:AddAssignWith.5375cfcbca6d9e35.Core.57ee91777b6354a8", scope: null, file: !26, line: 296, type: !27, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !29)
 // CHECK:STDOUT: !26 = !DIFile(filename: "{{.*}}/prelude/types/int.carbon", directory: "")
 // CHECK:STDOUT: !27 = !DISubroutineType(types: !28)
 // CHECK:STDOUT: !28 = !{null, !7, !7}
 // CHECK:STDOUT: !29 = !{!30, !31}
 // CHECK:STDOUT: !30 = !DILocalVariable(arg: 1, scope: !25, type: !7)
 // CHECK:STDOUT: !31 = !DILocalVariable(arg: 2, scope: !25, type: !7)
-// CHECK:STDOUT: !32 = distinct !DILocation(line: 343, column: 5, scope: !33, inlinedAt: !38)
-// CHECK:STDOUT: !33 = distinct !DISubprogram(name: "Op", linkageName: "_COp.Int.9452f4c51951679b.Core:Inc.Core.be1e879c1ad406d8", scope: null, file: !26, line: 341, type: !34, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !36)
+// CHECK:STDOUT: !32 = distinct !DILocation(line: 362, column: 5, scope: !33, inlinedAt: !38)
+// CHECK:STDOUT: !33 = distinct !DISubprogram(name: "Op", linkageName: "_COp.Int.9452f4c51951679b.Core:Inc.Core.be1e879c1ad406d8", scope: null, file: !26, line: 360, type: !34, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !36)
 // CHECK:STDOUT: !34 = !DISubroutineType(types: !35)
 // CHECK:STDOUT: !35 = !{null, !7}
 // CHECK:STDOUT: !36 = !{!37}
@@ -87,13 +87,13 @@ fn VectorizedWithOptSpeed(a: array(i32, 65536)*) {
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: noinline nounwind optnone
 // CHECK:STDOUT: define linkonce_odr void @"_COp.Int.9452f4c51951679b.Core:Inc.Core.be1e879c1ad406d8"(ptr %self) #0 !dbg !28 {
-// CHECK:STDOUT:   call void @"_COp:thunk.Int.9452f4c51951679b.Core:AddAssignWith.5375cfcbca6d9e35.Core.75bec4d236c9daa5"(ptr %self, i32 1), !dbg !34
+// CHECK:STDOUT:   call void @"_COp:thunk.Int.9452f4c51951679b.Core:AddAssignWith.5375cfcbca6d9e35.Core.57ee91777b6354a8"(ptr %self, i32 1), !dbg !34
 // CHECK:STDOUT:   ret void, !dbg !35
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: noinline nounwind optnone
-// CHECK:STDOUT: define linkonce_odr void @"_COp:thunk.Int.9452f4c51951679b.Core:AddAssignWith.5375cfcbca6d9e35.Core.75bec4d236c9daa5"(ptr %self, i32 %other) #0 !dbg !36 {
-// CHECK:STDOUT:   %1 = call i32 @"_CConvert.14b8745117b2bc54:ImplicitAs.a9271c1e04015f9c.Core.64ccbb8e5d9a0b8e"(i32 %other), !dbg !42
+// CHECK:STDOUT: define linkonce_odr void @"_COp:thunk.Int.9452f4c51951679b.Core:AddAssignWith.5375cfcbca6d9e35.Core.57ee91777b6354a8"(ptr %self, i32 %other) #0 !dbg !36 {
+// CHECK:STDOUT:   %1 = call i32 @"_CConvert.272fc3e88346d0d9:ImplicitAs.d993a5132e000405.Core.628184612c80324d"(i32 %other), !dbg !42
 // CHECK:STDOUT:   %2 = load i32, ptr %self, align 4, !dbg !43
 // CHECK:STDOUT:   %3 = add i32 %2, %1, !dbg !43
 // CHECK:STDOUT:   store i32 %3, ptr %self, align 4, !dbg !43
@@ -101,8 +101,14 @@ fn VectorizedWithOptSpeed(a: array(i32, 65536)*) {
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: noinline nounwind optnone
-// CHECK:STDOUT: define linkonce_odr i32 @"_CConvert.14b8745117b2bc54:ImplicitAs.a9271c1e04015f9c.Core.64ccbb8e5d9a0b8e"(i32 %self) #0 !dbg !44 {
-// CHECK:STDOUT:   ret i32 %self, !dbg !50
+// CHECK:STDOUT: define linkonce_odr i32 @"_CConvert.272fc3e88346d0d9:ImplicitAs.d993a5132e000405.Core.628184612c80324d"(i32 %self) #0 !dbg !44 {
+// CHECK:STDOUT:   %1 = call i32 @"_CAsInt.Int.9452f4c51951679b.Core:AnyInt.Core.be1e879c1ad406d8"(i32 %self), !dbg !49
+// CHECK:STDOUT:   ret i32 %1, !dbg !50
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: noinline nounwind optnone
+// CHECK:STDOUT: define linkonce_odr i32 @"_CAsInt.Int.9452f4c51951679b.Core:AnyInt.Core.be1e879c1ad406d8"(i32 %self) #0 !dbg !51 {
+// CHECK:STDOUT:   ret i32 %self, !dbg !54
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: attributes #0 = { noinline nounwind optnone }
@@ -139,26 +145,30 @@ fn VectorizedWithOptSpeed(a: array(i32, 65536)*) {
 // CHECK:STDOUT: !25 = !DILocation(line: 20, column: 5, scope: !14)
 // CHECK:STDOUT: !26 = !DILocation(line: 18, column: 3, scope: !14)
 // CHECK:STDOUT: !27 = !DILocation(line: 15, column: 1, scope: !14)
-// CHECK:STDOUT: !28 = distinct !DISubprogram(name: "Op", linkageName: "_COp.Int.9452f4c51951679b.Core:Inc.Core.be1e879c1ad406d8", scope: null, file: !29, line: 341, type: !30, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !32)
+// CHECK:STDOUT: !28 = distinct !DISubprogram(name: "Op", linkageName: "_COp.Int.9452f4c51951679b.Core:Inc.Core.be1e879c1ad406d8", scope: null, file: !29, line: 360, type: !30, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !32)
 // CHECK:STDOUT: !29 = !DIFile(filename: "{{.*}}/prelude/types/int.carbon", directory: "")
 // CHECK:STDOUT: !30 = !DISubroutineType(types: !31)
 // CHECK:STDOUT: !31 = !{null, !7}
 // CHECK:STDOUT: !32 = !{!33}
 // CHECK:STDOUT: !33 = !DILocalVariable(arg: 1, scope: !28, type: !7)
-// CHECK:STDOUT: !34 = !DILocation(line: 343, column: 5, scope: !28)
-// CHECK:STDOUT: !35 = !DILocation(line: 341, column: 3, scope: !28)
-// CHECK:STDOUT: !36 = distinct !DISubprogram(name: "Op", linkageName: "_COp:thunk.Int.9452f4c51951679b.Core:AddAssignWith.5375cfcbca6d9e35.Core.75bec4d236c9daa5", scope: null, file: !29, line: 277, type: !37, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !39)
+// CHECK:STDOUT: !34 = !DILocation(line: 362, column: 5, scope: !28)
+// CHECK:STDOUT: !35 = !DILocation(line: 360, column: 3, scope: !28)
+// CHECK:STDOUT: !36 = distinct !DISubprogram(name: "Op", linkageName: "_COp:thunk.Int.9452f4c51951679b.Core:AddAssignWith.5375cfcbca6d9e35.Core.57ee91777b6354a8", scope: null, file: !29, line: 296, type: !37, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !39)
 // CHECK:STDOUT: !37 = !DISubroutineType(types: !38)
 // CHECK:STDOUT: !38 = !{null, !7, !7}
 // CHECK:STDOUT: !39 = !{!40, !41}
 // CHECK:STDOUT: !40 = !DILocalVariable(arg: 1, scope: !36, type: !7)
 // CHECK:STDOUT: !41 = !DILocalVariable(arg: 2, scope: !36, type: !7)
 // CHECK:STDOUT: !42 = !DILocation(line: 4294967295, scope: !36)
-// CHECK:STDOUT: !43 = !DILocation(line: 277, column: 3, scope: !36)
-// CHECK:STDOUT: !44 = distinct !DISubprogram(name: "Convert", linkageName: "_CConvert.14b8745117b2bc54:ImplicitAs.a9271c1e04015f9c.Core.64ccbb8e5d9a0b8e", scope: null, file: !45, line: 35, type: !46, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !48)
-// CHECK:STDOUT: !45 = !DIFile(filename: "{{.*}}/prelude/operators/as.carbon", directory: "")
-// CHECK:STDOUT: !46 = !DISubroutineType(types: !47)
-// CHECK:STDOUT: !47 = !{!7, !7}
-// CHECK:STDOUT: !48 = !{!49}
-// CHECK:STDOUT: !49 = !DILocalVariable(arg: 1, scope: !44, type: !7)
-// CHECK:STDOUT: !50 = !DILocation(line: 35, column: 38, scope: !44)
+// CHECK:STDOUT: !43 = !DILocation(line: 296, column: 3, scope: !36)
+// CHECK:STDOUT: !44 = distinct !DISubprogram(name: "Convert", linkageName: "_CConvert.272fc3e88346d0d9:ImplicitAs.d993a5132e000405.Core.628184612c80324d", scope: null, file: !29, line: 59, type: !45, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !47)
+// CHECK:STDOUT: !45 = !DISubroutineType(types: !46)
+// CHECK:STDOUT: !46 = !{!7, !7}
+// CHECK:STDOUT: !47 = !{!48}
+// CHECK:STDOUT: !48 = !DILocalVariable(arg: 1, scope: !44, type: !7)
+// CHECK:STDOUT: !49 = !DILocation(line: 61, column: 17, scope: !44)
+// CHECK:STDOUT: !50 = !DILocation(line: 61, column: 5, scope: !44)
+// CHECK:STDOUT: !51 = distinct !DISubprogram(name: "AsInt", linkageName: "_CAsInt.Int.9452f4c51951679b.Core:AnyInt.Core.be1e879c1ad406d8", scope: null, file: !29, line: 54, type: !45, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !52)
+// CHECK:STDOUT: !52 = !{!53}
+// CHECK:STDOUT: !53 = !DILocalVariable(arg: 1, scope: !51, type: !7)
+// CHECK:STDOUT: !54 = !DILocation(line: 54, column: 36, scope: !51)
@@ -86,13 +86,13 @@ fn VectorizedWithOptSpeed(a: array(i32, 65536)*) {
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: minsize nounwind optsize
 // CHECK:STDOUT: define linkonce_odr void @"_COp.Int.9452f4c51951679b.Core:Inc.Core.be1e879c1ad406d8"(ptr %self) #0 !dbg !28 {
-// CHECK:STDOUT:   call void @"_COp:thunk.Int.9452f4c51951679b.Core:AddAssignWith.5375cfcbca6d9e35.Core.75bec4d236c9daa5"(ptr %self, i32 1), !dbg !34
+// CHECK:STDOUT:   call void @"_COp:thunk.Int.9452f4c51951679b.Core:AddAssignWith.5375cfcbca6d9e35.Core.57ee91777b6354a8"(ptr %self, i32 1), !dbg !34
 // CHECK:STDOUT:   ret void, !dbg !35
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline minsize nounwind optsize
-// CHECK:STDOUT: define linkonce_odr void @"_COp:thunk.Int.9452f4c51951679b.Core:AddAssignWith.5375cfcbca6d9e35.Core.75bec4d236c9daa5"(ptr %self, i32 %other) #2 !dbg !36 {
-// CHECK:STDOUT:   %1 = call i32 @"_CConvert.14b8745117b2bc54:ImplicitAs.a9271c1e04015f9c.Core.64ccbb8e5d9a0b8e"(i32 %other), !dbg !42
+// CHECK:STDOUT: define linkonce_odr void @"_COp:thunk.Int.9452f4c51951679b.Core:AddAssignWith.5375cfcbca6d9e35.Core.57ee91777b6354a8"(ptr %self, i32 %other) #2 !dbg !36 {
+// CHECK:STDOUT:   %1 = call i32 @"_CConvert.272fc3e88346d0d9:ImplicitAs.d993a5132e000405.Core.628184612c80324d"(i32 %other), !dbg !42
 // CHECK:STDOUT:   %2 = load i32, ptr %self, align 4, !dbg !43
 // CHECK:STDOUT:   %3 = add i32 %2, %1, !dbg !43
 // CHECK:STDOUT:   store i32 %3, ptr %self, align 4, !dbg !43
@@ -100,8 +100,14 @@ fn VectorizedWithOptSpeed(a: array(i32, 65536)*) {
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: minsize nounwind optsize
-// CHECK:STDOUT: define linkonce_odr i32 @"_CConvert.14b8745117b2bc54:ImplicitAs.a9271c1e04015f9c.Core.64ccbb8e5d9a0b8e"(i32 %self) #0 !dbg !44 {
-// CHECK:STDOUT:   ret i32 %self, !dbg !50
+// CHECK:STDOUT: define linkonce_odr i32 @"_CConvert.272fc3e88346d0d9:ImplicitAs.d993a5132e000405.Core.628184612c80324d"(i32 %self) #0 !dbg !44 {
+// CHECK:STDOUT:   %1 = call i32 @"_CAsInt.Int.9452f4c51951679b.Core:AnyInt.Core.be1e879c1ad406d8"(i32 %self), !dbg !49
+// CHECK:STDOUT:   ret i32 %1, !dbg !50
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: minsize nounwind optsize
+// CHECK:STDOUT: define linkonce_odr i32 @"_CAsInt.Int.9452f4c51951679b.Core:AnyInt.Core.be1e879c1ad406d8"(i32 %self) #0 !dbg !51 {
+// CHECK:STDOUT:   ret i32 %self, !dbg !54
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: attributes #0 = { minsize nounwind optsize }
@@ -139,26 +145,30 @@ fn VectorizedWithOptSpeed(a: array(i32, 65536)*) {
 // CHECK:STDOUT: !25 = !DILocation(line: 20, column: 5, scope: !14)
 // CHECK:STDOUT: !26 = !DILocation(line: 18, column: 3, scope: !14)
 // CHECK:STDOUT: !27 = !DILocation(line: 15, column: 1, scope: !14)
-// CHECK:STDOUT: !28 = distinct !DISubprogram(name: "Op", linkageName: "_COp.Int.9452f4c51951679b.Core:Inc.Core.be1e879c1ad406d8", scope: null, file: !29, line: 341, type: !30, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !32)
+// CHECK:STDOUT: !28 = distinct !DISubprogram(name: "Op", linkageName: "_COp.Int.9452f4c51951679b.Core:Inc.Core.be1e879c1ad406d8", scope: null, file: !29, line: 360, type: !30, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !32)
 // CHECK:STDOUT: !29 = !DIFile(filename: "{{.*}}/prelude/types/int.carbon", directory: "")
 // CHECK:STDOUT: !30 = !DISubroutineType(types: !31)
 // CHECK:STDOUT: !31 = !{null, !7}
 // CHECK:STDOUT: !32 = !{!33}
 // CHECK:STDOUT: !33 = !DILocalVariable(arg: 1, scope: !28, type: !7)
-// CHECK:STDOUT: !34 = !DILocation(line: 343, column: 5, scope: !28)
-// CHECK:STDOUT: !35 = !DILocation(line: 341, column: 3, scope: !28)
-// CHECK:STDOUT: !36 = distinct !DISubprogram(name: "Op", linkageName: "_COp:thunk.Int.9452f4c51951679b.Core:AddAssignWith.5375cfcbca6d9e35.Core.75bec4d236c9daa5", scope: null, file: !29, line: 277, type: !37, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !39)
+// CHECK:STDOUT: !34 = !DILocation(line: 362, column: 5, scope: !28)
+// CHECK:STDOUT: !35 = !DILocation(line: 360, column: 3, scope: !28)
+// CHECK:STDOUT: !36 = distinct !DISubprogram(name: "Op", linkageName: "_COp:thunk.Int.9452f4c51951679b.Core:AddAssignWith.5375cfcbca6d9e35.Core.57ee91777b6354a8", scope: null, file: !29, line: 296, type: !37, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !39)
 // CHECK:STDOUT: !37 = !DISubroutineType(types: !38)
 // CHECK:STDOUT: !38 = !{null, !7, !7}
 // CHECK:STDOUT: !39 = !{!40, !41}
 // CHECK:STDOUT: !40 = !DILocalVariable(arg: 1, scope: !36, type: !7)
 // CHECK:STDOUT: !41 = !DILocalVariable(arg: 2, scope: !36, type: !7)
 // CHECK:STDOUT: !42 = !DILocation(line: 4294967295, scope: !36)
-// CHECK:STDOUT: !43 = !DILocation(line: 277, column: 3, scope: !36)
-// CHECK:STDOUT: !44 = distinct !DISubprogram(name: "Convert", linkageName: "_CConvert.14b8745117b2bc54:ImplicitAs.a9271c1e04015f9c.Core.64ccbb8e5d9a0b8e", scope: null, file: !45, line: 35, type: !46, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !48)
-// CHECK:STDOUT: !45 = !DIFile(filename: "{{.*}}/prelude/operators/as.carbon", directory: "")
-// CHECK:STDOUT: !46 = !DISubroutineType(types: !47)
-// CHECK:STDOUT: !47 = !{!7, !7}
-// CHECK:STDOUT: !48 = !{!49}
-// CHECK:STDOUT: !49 = !DILocalVariable(arg: 1, scope: !44, type: !7)
-// CHECK:STDOUT: !50 = !DILocation(line: 35, column: 38, scope: !44)
+// CHECK:STDOUT: !43 = !DILocation(line: 296, column: 3, scope: !36)
+// CHECK:STDOUT: !44 = distinct !DISubprogram(name: "Convert", linkageName: "_CConvert.272fc3e88346d0d9:ImplicitAs.d993a5132e000405.Core.628184612c80324d", scope: null, file: !29, line: 59, type: !45, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !47)
+// CHECK:STDOUT: !45 = !DISubroutineType(types: !46)
+// CHECK:STDOUT: !46 = !{!7, !7}
+// CHECK:STDOUT: !47 = !{!48}
+// CHECK:STDOUT: !48 = !DILocalVariable(arg: 1, scope: !44, type: !7)
+// CHECK:STDOUT: !49 = !DILocation(line: 61, column: 17, scope: !44)
+// CHECK:STDOUT: !50 = !DILocation(line: 61, column: 5, scope: !44)
+// CHECK:STDOUT: !51 = distinct !DISubprogram(name: "AsInt", linkageName: "_CAsInt.Int.9452f4c51951679b.Core:AnyInt.Core.be1e879c1ad406d8", scope: null, file: !29, line: 54, type: !45, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !52)
+// CHECK:STDOUT: !52 = !{!53}
+// CHECK:STDOUT: !53 = !DILocalVariable(arg: 1, scope: !51, type: !7)
+// CHECK:STDOUT: !54 = !DILocation(line: 54, column: 36, scope: !51)
@@ -128,16 +128,16 @@ fn VectorizedWithOptSpeed(a: array(i32, 65536)*) {
 // CHECK:STDOUT: !20 = !{!21}
 // CHECK:STDOUT: !21 = !DILocalVariable(arg: 1, scope: !16, type: !19)
 // CHECK:STDOUT: !22 = !DILocation(line: 18, column: 9, scope: !16)
-// CHECK:STDOUT: !23 = !DILocation(line: 277, column: 3, scope: !24, inlinedAt: !31)
-// CHECK:STDOUT: !24 = distinct !DISubprogram(name: "Op", linkageName: "_COp:thunk.Int.9452f4c51951679b.Core:AddAssignWith.5375cfcbca6d9e35.Core.75bec4d236c9daa5", scope: null, file: !25, line: 277, type: !26, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !28)
+// CHECK:STDOUT: !23 = !DILocation(line: 296, column: 3, scope: !24, inlinedAt: !31)
+// CHECK:STDOUT: !24 = distinct !DISubprogram(name: "Op", linkageName: "_COp:thunk.Int.9452f4c51951679b.Core:AddAssignWith.5375cfcbca6d9e35.Core.57ee91777b6354a8", scope: null, file: !25, line: 296, type: !26, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !28)
 // CHECK:STDOUT: !25 = !DIFile(filename: "{{.*}}/prelude/types/int.carbon", directory: "")
 // CHECK:STDOUT: !26 = !DISubroutineType(types: !27)
 // CHECK:STDOUT: !27 = !{null, !7, !7}
 // CHECK:STDOUT: !28 = !{!29, !30}
 // CHECK:STDOUT: !29 = !DILocalVariable(arg: 1, scope: !24, type: !7)
 // CHECK:STDOUT: !30 = !DILocalVariable(arg: 2, scope: !24, type: !7)
-// CHECK:STDOUT: !31 = distinct !DILocation(line: 343, column: 5, scope: !32, inlinedAt: !37)
-// CHECK:STDOUT: !32 = distinct !DISubprogram(name: "Op", linkageName: "_COp.Int.9452f4c51951679b.Core:Inc.Core.be1e879c1ad406d8", scope: null, file: !25, line: 341, type: !33, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !35)
+// CHECK:STDOUT: !31 = distinct !DILocation(line: 362, column: 5, scope: !32, inlinedAt: !37)
+// CHECK:STDOUT: !32 = distinct !DISubprogram(name: "Op", linkageName: "_COp.Int.9452f4c51951679b.Core:Inc.Core.be1e879c1ad406d8", scope: null, file: !25, line: 360, type: !33, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !35)
 // CHECK:STDOUT: !33 = !DISubroutineType(types: !34)
 // CHECK:STDOUT: !34 = !{null, !7}
 // CHECK:STDOUT: !35 = !{!36}
@@ -105,7 +105,7 @@ fn F() {
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
 // CHECK:STDOUT: define linkonce_odr void @"_COp.Int.9452f4c51951679b.Core:Inc.Core.be1e879c1ad406d8"(ptr %self) #0 !dbg !49 {
-// CHECK:STDOUT:   call void @"_COp:thunk.Int.9452f4c51951679b.Core:AddAssignWith.e2da7149b7fcf782.Core.dcdd24268af36579"(ptr %self, i32 1), !dbg !55
+// CHECK:STDOUT:   call void @"_COp:thunk.Int.9452f4c51951679b.Core:AddAssignWith.e2da7149b7fcf782.Core.23ea0ff7335d4fdc"(ptr %self, i32 1), !dbg !55
 // CHECK:STDOUT:   ret void, !dbg !56
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -137,8 +137,8 @@ fn F() {
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline nounwind
-// CHECK:STDOUT: define linkonce_odr void @"_COp:thunk.Int.9452f4c51951679b.Core:AddAssignWith.e2da7149b7fcf782.Core.dcdd24268af36579"(ptr %self, i32 %other) #3 !dbg !79 {
-// CHECK:STDOUT:   %1 = call i32 @"_CConvert.1e58d10da180d7d9:ImplicitAs.39e2e54f50ee65cc.Core.255ef555a3d2f793"(i32 %other), !dbg !85
+// CHECK:STDOUT: define linkonce_odr void @"_COp:thunk.Int.9452f4c51951679b.Core:AddAssignWith.e2da7149b7fcf782.Core.23ea0ff7335d4fdc"(ptr %self, i32 %other) #3 !dbg !79 {
+// CHECK:STDOUT:   %1 = call i32 @"_CConvert.93210ed0b06d6c25:ImplicitAs.11da3bb3c3dce533.Core.5da21217b3d19eab"(i32 %other), !dbg !85
 // CHECK:STDOUT:   %2 = load i32, ptr %self, align 4, !dbg !86
 // CHECK:STDOUT:   %3 = add i32 %2, %1, !dbg !86
 // CHECK:STDOUT:   store i32 %3, ptr %self, align 4, !dbg !86
@@ -162,8 +162,14 @@ fn F() {
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define linkonce_odr i32 @"_CConvert.1e58d10da180d7d9:ImplicitAs.39e2e54f50ee65cc.Core.255ef555a3d2f793"(i32 %self) #0 !dbg !96 {
-// CHECK:STDOUT:   ret i32 %self, !dbg !102
+// CHECK:STDOUT: define linkonce_odr i32 @"_CConvert.93210ed0b06d6c25:ImplicitAs.11da3bb3c3dce533.Core.5da21217b3d19eab"(i32 %self) #0 !dbg !96 {
+// CHECK:STDOUT:   %1 = call i32 @"_CAsInt.Int.9452f4c51951679b.Core:AnyInt.Core.be1e879c1ad406d8"(i32 %self), !dbg !101
+// CHECK:STDOUT:   ret i32 %1, !dbg !102
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define linkonce_odr i32 @"_CAsInt.Int.9452f4c51951679b.Core:AnyInt.Core.be1e879c1ad406d8"(i32 %self) #0 !dbg !103 {
+// CHECK:STDOUT:   ret i32 %self, !dbg !106
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; uselistorder directives
@@ -226,14 +232,14 @@ fn F() {
 // CHECK:STDOUT: !46 = !DILocalVariable(arg: 1, scope: !44, type: !17)
 // CHECK:STDOUT: !47 = !DILocation(line: 36, column: 12, scope: !44)
 // CHECK:STDOUT: !48 = !DILocation(line: 36, column: 5, scope: !44)
-// CHECK:STDOUT: !49 = distinct !DISubprogram(name: "Op", linkageName: "_COp.Int.9452f4c51951679b.Core:Inc.Core.be1e879c1ad406d8", scope: null, file: !50, line: 341, type: !51, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !53)
+// CHECK:STDOUT: !49 = distinct !DISubprogram(name: "Op", linkageName: "_COp.Int.9452f4c51951679b.Core:Inc.Core.be1e879c1ad406d8", scope: null, file: !50, line: 360, type: !51, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !53)
 // CHECK:STDOUT: !50 = !DIFile(filename: "{{.*}}/prelude/types/int.carbon", directory: "")
 // CHECK:STDOUT: !51 = !DISubroutineType(types: !52)
 // CHECK:STDOUT: !52 = !{null, !16}
 // CHECK:STDOUT: !53 = !{!54}
 // CHECK:STDOUT: !54 = !DILocalVariable(arg: 1, scope: !49, type: !16)
-// CHECK:STDOUT: !55 = !DILocation(line: 343, column: 5, scope: !49)
-// CHECK:STDOUT: !56 = !DILocation(line: 341, column: 3, scope: !49)
+// CHECK:STDOUT: !55 = !DILocation(line: 362, column: 5, scope: !49)
+// CHECK:STDOUT: !56 = !DILocation(line: 360, column: 3, scope: !49)
 // CHECK:STDOUT: !57 = distinct !DISubprogram(name: "Some", linkageName: "_CSome.Optional.Core.b5e6acce74484d77", scope: null, file: !37, line: 29, type: !58, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !60)
 // CHECK:STDOUT: !58 = !DISubroutineType(types: !59)
 // CHECK:STDOUT: !59 = !{!17, !16}
@@ -256,14 +262,14 @@ fn F() {
 // CHECK:STDOUT: !76 = !DILocalVariable(arg: 1, scope: !74, type: !17)
 // CHECK:STDOUT: !77 = !DILocation(line: 127, column: 12, scope: !74)
 // CHECK:STDOUT: !78 = !DILocation(line: 127, column: 5, scope: !74)
-// CHECK:STDOUT: !79 = distinct !DISubprogram(name: "Op", linkageName: "_COp:thunk.Int.9452f4c51951679b.Core:AddAssignWith.e2da7149b7fcf782.Core.dcdd24268af36579", scope: null, file: !50, line: 277, type: !80, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !82)
+// CHECK:STDOUT: !79 = distinct !DISubprogram(name: "Op", linkageName: "_COp:thunk.Int.9452f4c51951679b.Core:AddAssignWith.e2da7149b7fcf782.Core.23ea0ff7335d4fdc", scope: null, file: !50, line: 296, type: !80, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !82)
 // CHECK:STDOUT: !80 = !DISubroutineType(types: !81)
 // CHECK:STDOUT: !81 = !{null, !16, !16}
 // CHECK:STDOUT: !82 = !{!83, !84}
 // CHECK:STDOUT: !83 = !DILocalVariable(arg: 1, scope: !79, type: !16)
 // CHECK:STDOUT: !84 = !DILocalVariable(arg: 2, scope: !79, type: !16)
 // CHECK:STDOUT: !85 = !DILocation(line: 4294967295, scope: !79)
-// CHECK:STDOUT: !86 = !DILocation(line: 277, column: 3, scope: !79)
+// CHECK:STDOUT: !86 = !DILocation(line: 296, column: 3, scope: !79)
 // CHECK:STDOUT: !87 = distinct !DISubprogram(name: "Some", linkageName: "_CSome.3e8267224c5dc9c2:OptionalStorage.Core.bfb441135f07cbe1", scope: null, file: !37, line: 115, type: !58, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !88)
 // CHECK:STDOUT: !88 = !{!89}
 // CHECK:STDOUT: !89 = !DILocalVariable(arg: 1, scope: !87, type: !16)
@@ -273,10 +279,14 @@ fn F() {
 // CHECK:STDOUT: !93 = distinct !DISubprogram(name: "None", linkageName: "_CNone.3e8267224c5dc9c2:OptionalStorage.Core.bfb441135f07cbe1", scope: null, file: !37, line: 110, type: !65, spFlags: DISPFlagDefinition, unit: !2)
 // CHECK:STDOUT: !94 = !DILocation(line: 112, column: 5, scope: !93)
 // CHECK:STDOUT: !95 = !DILocation(line: 113, column: 5, scope: !93)
-// CHECK:STDOUT: !96 = distinct !DISubprogram(name: "Convert", linkageName: "_CConvert.1e58d10da180d7d9:ImplicitAs.39e2e54f50ee65cc.Core.255ef555a3d2f793", scope: null, file: !97, line: 35, type: !98, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !100)
-// CHECK:STDOUT: !97 = !DIFile(filename: "{{.*}}/prelude/operators/as.carbon", directory: "")
-// CHECK:STDOUT: !98 = !DISubroutineType(types: !99)
-// CHECK:STDOUT: !99 = !{!16, !16}
-// CHECK:STDOUT: !100 = !{!101}
-// CHECK:STDOUT: !101 = !DILocalVariable(arg: 1, scope: !96, type: !16)
-// CHECK:STDOUT: !102 = !DILocation(line: 35, column: 38, scope: !96)
+// CHECK:STDOUT: !96 = distinct !DISubprogram(name: "Convert", linkageName: "_CConvert.93210ed0b06d6c25:ImplicitAs.11da3bb3c3dce533.Core.5da21217b3d19eab", scope: null, file: !50, line: 59, type: !97, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !99)
+// CHECK:STDOUT: !97 = !DISubroutineType(types: !98)
+// CHECK:STDOUT: !98 = !{!16, !16}
+// CHECK:STDOUT: !99 = !{!100}
+// CHECK:STDOUT: !100 = !DILocalVariable(arg: 1, scope: !96, type: !16)
+// CHECK:STDOUT: !101 = !DILocation(line: 61, column: 17, scope: !96)
+// CHECK:STDOUT: !102 = !DILocation(line: 61, column: 5, scope: !96)
+// CHECK:STDOUT: !103 = distinct !DISubprogram(name: "AsInt", linkageName: "_CAsInt.Int.9452f4c51951679b.Core:AnyInt.Core.be1e879c1ad406d8", scope: null, file: !50, line: 54, type: !97, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !104)
+// CHECK:STDOUT: !104 = !{!105}
+// CHECK:STDOUT: !105 = !DILocalVariable(arg: 1, scope: !103, type: !16)
+// CHECK:STDOUT: !106 = !DILocation(line: 54, column: 36, scope: !103)
@@ -126,7 +126,7 @@ fn For() {
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
 // CHECK:STDOUT: define linkonce_odr void @"_COp.Int.9452f4c51951679b.Core:Inc.Core.be1e879c1ad406d8"(ptr %self) #0 !dbg !58 {
-// CHECK:STDOUT:   call void @"_COp:thunk.Int.9452f4c51951679b.Core:AddAssignWith.5375cfcbca6d9e35.Core.cfd8ddddc59ca787"(ptr %self, i32 1), !dbg !64
+// CHECK:STDOUT:   call void @"_COp:thunk.Int.9452f4c51951679b.Core:AddAssignWith.5375cfcbca6d9e35.Core.57ee91777b6354a8"(ptr %self, i32 1), !dbg !64
 // CHECK:STDOUT:   ret void, !dbg !65
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -158,8 +158,8 @@ fn For() {
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline nounwind
-// CHECK:STDOUT: define linkonce_odr void @"_COp:thunk.Int.9452f4c51951679b.Core:AddAssignWith.5375cfcbca6d9e35.Core.cfd8ddddc59ca787"(ptr %self, i32 %other) #2 !dbg !88 {
-// CHECK:STDOUT:   %1 = call i32 @"_CConvert.14b8745117b2bc54:ImplicitAs.a9271c1e04015f9c.Core.beca8a3ca33a86fb"(i32 %other), !dbg !94
+// CHECK:STDOUT: define linkonce_odr void @"_COp:thunk.Int.9452f4c51951679b.Core:AddAssignWith.5375cfcbca6d9e35.Core.57ee91777b6354a8"(ptr %self, i32 %other) #2 !dbg !88 {
+// CHECK:STDOUT:   %1 = call i32 @"_CConvert.272fc3e88346d0d9:ImplicitAs.d993a5132e000405.Core.628184612c80324d"(i32 %other), !dbg !94
 // CHECK:STDOUT:   %2 = load i32, ptr %self, align 4, !dbg !95
 // CHECK:STDOUT:   %3 = add i32 %2, %1, !dbg !95
 // CHECK:STDOUT:   store i32 %3, ptr %self, align 4, !dbg !95
@@ -183,8 +183,14 @@ fn For() {
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define linkonce_odr i32 @"_CConvert.14b8745117b2bc54:ImplicitAs.a9271c1e04015f9c.Core.beca8a3ca33a86fb"(i32 %self) #0 !dbg !105 {
-// CHECK:STDOUT:   ret i32 %self, !dbg !111
+// CHECK:STDOUT: define linkonce_odr i32 @"_CConvert.272fc3e88346d0d9:ImplicitAs.d993a5132e000405.Core.628184612c80324d"(i32 %self) #0 !dbg !105 {
+// CHECK:STDOUT:   %1 = call i32 @"_CAsInt.Int.9452f4c51951679b.Core:AnyInt.Core.be1e879c1ad406d8"(i32 %self), !dbg !110
+// CHECK:STDOUT:   ret i32 %1, !dbg !111
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define linkonce_odr i32 @"_CAsInt.Int.9452f4c51951679b.Core:AnyInt.Core.be1e879c1ad406d8"(i32 %self) #0 !dbg !112 {
+// CHECK:STDOUT:   ret i32 %self, !dbg !115
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; uselistorder directives
@@ -255,14 +261,14 @@ fn For() {
 // CHECK:STDOUT: !55 = !DILocalVariable(arg: 1, scope: !53, type: !23)
 // CHECK:STDOUT: !56 = !DILocation(line: 36, column: 12, scope: !53)
 // CHECK:STDOUT: !57 = !DILocation(line: 36, column: 5, scope: !53)
-// CHECK:STDOUT: !58 = distinct !DISubprogram(name: "Op", linkageName: "_COp.Int.9452f4c51951679b.Core:Inc.Core.be1e879c1ad406d8", scope: null, file: !59, line: 341, type: !60, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !62)
+// CHECK:STDOUT: !58 = distinct !DISubprogram(name: "Op", linkageName: "_COp.Int.9452f4c51951679b.Core:Inc.Core.be1e879c1ad406d8", scope: null, file: !59, line: 360, type: !60, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !62)
 // CHECK:STDOUT: !59 = !DIFile(filename: "{{.*}}/prelude/types/int.carbon", directory: "")
 // CHECK:STDOUT: !60 = !DISubroutineType(types: !61)
 // CHECK:STDOUT: !61 = !{null, !22}
 // CHECK:STDOUT: !62 = !{!63}
 // CHECK:STDOUT: !63 = !DILocalVariable(arg: 1, scope: !58, type: !22)
-// CHECK:STDOUT: !64 = !DILocation(line: 343, column: 5, scope: !58)
-// CHECK:STDOUT: !65 = !DILocation(line: 341, column: 3, scope: !58)
+// CHECK:STDOUT: !64 = !DILocation(line: 362, column: 5, scope: !58)
+// CHECK:STDOUT: !65 = !DILocation(line: 360, column: 3, scope: !58)
 // CHECK:STDOUT: !66 = distinct !DISubprogram(name: "Some", linkageName: "_CSome.Optional.Core.a0986cb4211ec3fb", scope: null, file: !46, line: 29, type: !67, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !69)
 // CHECK:STDOUT: !67 = !DISubroutineType(types: !68)
 // CHECK:STDOUT: !68 = !{!23, !22}
@@ -285,14 +291,14 @@ fn For() {
 // CHECK:STDOUT: !85 = !DILocalVariable(arg: 1, scope: !83, type: !23)
 // CHECK:STDOUT: !86 = !DILocation(line: 127, column: 12, scope: !83)
 // CHECK:STDOUT: !87 = !DILocation(line: 127, column: 5, scope: !83)
-// CHECK:STDOUT: !88 = distinct !DISubprogram(name: "Op", linkageName: "_COp:thunk.Int.9452f4c51951679b.Core:AddAssignWith.5375cfcbca6d9e35.Core.cfd8ddddc59ca787", scope: null, file: !59, line: 277, type: !89, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !91)
+// CHECK:STDOUT: !88 = distinct !DISubprogram(name: "Op", linkageName: "_COp:thunk.Int.9452f4c51951679b.Core:AddAssignWith.5375cfcbca6d9e35.Core.57ee91777b6354a8", scope: null, file: !59, line: 296, type: !89, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !91)
 // CHECK:STDOUT: !89 = !DISubroutineType(types: !90)
 // CHECK:STDOUT: !90 = !{null, !22, !22}
 // CHECK:STDOUT: !91 = !{!92, !93}
 // CHECK:STDOUT: !92 = !DILocalVariable(arg: 1, scope: !88, type: !22)
 // CHECK:STDOUT: !93 = !DILocalVariable(arg: 2, scope: !88, type: !22)
 // CHECK:STDOUT: !94 = !DILocation(line: 4294967295, scope: !88)
-// CHECK:STDOUT: !95 = !DILocation(line: 277, column: 3, scope: !88)
+// CHECK:STDOUT: !95 = !DILocation(line: 296, column: 3, scope: !88)
 // CHECK:STDOUT: !96 = distinct !DISubprogram(name: "Some", linkageName: "_CSome.3e8267224c5dc9c2:OptionalStorage.Core.0b1ea4541e2057b5", scope: null, file: !46, line: 115, type: !67, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !97)
 // CHECK:STDOUT: !97 = !{!98}
 // CHECK:STDOUT: !98 = !DILocalVariable(arg: 1, scope: !96, type: !22)
@@ -302,10 +308,14 @@ fn For() {
 // CHECK:STDOUT: !102 = distinct !DISubprogram(name: "None", linkageName: "_CNone.3e8267224c5dc9c2:OptionalStorage.Core.0b1ea4541e2057b5", scope: null, file: !46, line: 110, type: !74, spFlags: DISPFlagDefinition, unit: !2)
 // CHECK:STDOUT: !103 = !DILocation(line: 112, column: 5, scope: !102)
 // CHECK:STDOUT: !104 = !DILocation(line: 113, column: 5, scope: !102)
-// CHECK:STDOUT: !105 = distinct !DISubprogram(name: "Convert", linkageName: "_CConvert.14b8745117b2bc54:ImplicitAs.a9271c1e04015f9c.Core.beca8a3ca33a86fb", scope: null, file: !106, line: 35, type: !107, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !109)
-// CHECK:STDOUT: !106 = !DIFile(filename: "{{.*}}/prelude/operators/as.carbon", directory: "")
-// CHECK:STDOUT: !107 = !DISubroutineType(types: !108)
-// CHECK:STDOUT: !108 = !{!22, !22}
-// CHECK:STDOUT: !109 = !{!110}
-// CHECK:STDOUT: !110 = !DILocalVariable(arg: 1, scope: !105, type: !22)
-// CHECK:STDOUT: !111 = !DILocation(line: 35, column: 38, scope: !105)
+// CHECK:STDOUT: !105 = distinct !DISubprogram(name: "Convert", linkageName: "_CConvert.272fc3e88346d0d9:ImplicitAs.d993a5132e000405.Core.628184612c80324d", scope: null, file: !59, line: 59, type: !106, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !108)
+// CHECK:STDOUT: !106 = !DISubroutineType(types: !107)
+// CHECK:STDOUT: !107 = !{!22, !22}
+// CHECK:STDOUT: !108 = !{!109}
+// CHECK:STDOUT: !109 = !DILocalVariable(arg: 1, scope: !105, type: !22)
+// CHECK:STDOUT: !110 = !DILocation(line: 61, column: 17, scope: !105)
+// CHECK:STDOUT: !111 = !DILocation(line: 61, column: 5, scope: !105)
+// CHECK:STDOUT: !112 = distinct !DISubprogram(name: "AsInt", linkageName: "_CAsInt.Int.9452f4c51951679b.Core:AnyInt.Core.be1e879c1ad406d8", scope: null, file: !59, line: 54, type: !106, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !113)
+// CHECK:STDOUT: !113 = !{!114}
+// CHECK:STDOUT: !114 = !DILocalVariable(arg: 1, scope: !112, type: !22)
+// CHECK:STDOUT: !115 = !DILocation(line: 54, column: 36, scope: !112)
@@ -114,7 +114,7 @@ fn For() {
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
 // CHECK:STDOUT: define linkonce_odr void @"_COp.Int.9452f4c51951679b.Core:Inc.Core.be1e879c1ad406d8"(ptr %self) #0 !dbg !54 {
-// CHECK:STDOUT:   call void @"_COp:thunk.Int.9452f4c51951679b.Core:AddAssignWith.5375cfcbca6d9e35.Core.cfd8ddddc59ca787"(ptr %self, i32 1), !dbg !60
+// CHECK:STDOUT:   call void @"_COp:thunk.Int.9452f4c51951679b.Core:AddAssignWith.5375cfcbca6d9e35.Core.57ee91777b6354a8"(ptr %self, i32 1), !dbg !60
 // CHECK:STDOUT:   ret void, !dbg !61
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -146,8 +146,8 @@ fn For() {
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline nounwind
-// CHECK:STDOUT: define linkonce_odr void @"_COp:thunk.Int.9452f4c51951679b.Core:AddAssignWith.5375cfcbca6d9e35.Core.cfd8ddddc59ca787"(ptr %self, i32 %other) #2 !dbg !84 {
-// CHECK:STDOUT:   %1 = call i32 @"_CConvert.14b8745117b2bc54:ImplicitAs.a9271c1e04015f9c.Core.beca8a3ca33a86fb"(i32 %other), !dbg !90
+// CHECK:STDOUT: define linkonce_odr void @"_COp:thunk.Int.9452f4c51951679b.Core:AddAssignWith.5375cfcbca6d9e35.Core.57ee91777b6354a8"(ptr %self, i32 %other) #2 !dbg !84 {
+// CHECK:STDOUT:   %1 = call i32 @"_CConvert.272fc3e88346d0d9:ImplicitAs.d993a5132e000405.Core.628184612c80324d"(i32 %other), !dbg !90
 // CHECK:STDOUT:   %2 = load i32, ptr %self, align 4, !dbg !91
 // CHECK:STDOUT:   %3 = add i32 %2, %1, !dbg !91
 // CHECK:STDOUT:   store i32 %3, ptr %self, align 4, !dbg !91
@@ -171,8 +171,14 @@ fn For() {
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define linkonce_odr i32 @"_CConvert.14b8745117b2bc54:ImplicitAs.a9271c1e04015f9c.Core.beca8a3ca33a86fb"(i32 %self) #0 !dbg !101 {
-// CHECK:STDOUT:   ret i32 %self, !dbg !107
+// CHECK:STDOUT: define linkonce_odr i32 @"_CConvert.272fc3e88346d0d9:ImplicitAs.d993a5132e000405.Core.628184612c80324d"(i32 %self) #0 !dbg !101 {
+// CHECK:STDOUT:   %1 = call i32 @"_CAsInt.Int.9452f4c51951679b.Core:AnyInt.Core.be1e879c1ad406d8"(i32 %self), !dbg !106
+// CHECK:STDOUT:   ret i32 %1, !dbg !107
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define linkonce_odr i32 @"_CAsInt.Int.9452f4c51951679b.Core:AnyInt.Core.be1e879c1ad406d8"(i32 %self) #0 !dbg !108 {
+// CHECK:STDOUT:   ret i32 %self, !dbg !111
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; uselistorder directives
@@ -239,14 +245,14 @@ fn For() {
 // CHECK:STDOUT: !51 = !DILocalVariable(arg: 1, scope: !49, type: !19)
 // CHECK:STDOUT: !52 = !DILocation(line: 36, column: 12, scope: !49)
 // CHECK:STDOUT: !53 = !DILocation(line: 36, column: 5, scope: !49)
-// CHECK:STDOUT: !54 = distinct !DISubprogram(name: "Op", linkageName: "_COp.Int.9452f4c51951679b.Core:Inc.Core.be1e879c1ad406d8", scope: null, file: !55, line: 341, type: !56, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !58)
+// CHECK:STDOUT: !54 = distinct !DISubprogram(name: "Op", linkageName: "_COp.Int.9452f4c51951679b.Core:Inc.Core.be1e879c1ad406d8", scope: null, file: !55, line: 360, type: !56, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !58)
 // CHECK:STDOUT: !55 = !DIFile(filename: "{{.*}}/prelude/types/int.carbon", directory: "")
 // CHECK:STDOUT: !56 = !DISubroutineType(types: !57)
 // CHECK:STDOUT: !57 = !{null, !18}
 // CHECK:STDOUT: !58 = !{!59}
 // CHECK:STDOUT: !59 = !DILocalVariable(arg: 1, scope: !54, type: !18)
-// CHECK:STDOUT: !60 = !DILocation(line: 343, column: 5, scope: !54)
-// CHECK:STDOUT: !61 = !DILocation(line: 341, column: 3, scope: !54)
+// CHECK:STDOUT: !60 = !DILocation(line: 362, column: 5, scope: !54)
+// CHECK:STDOUT: !61 = !DILocation(line: 360, column: 3, scope: !54)
 // CHECK:STDOUT: !62 = distinct !DISubprogram(name: "Some", linkageName: "_CSome.Optional.Core.a0986cb4211ec3fb", scope: null, file: !42, line: 29, type: !63, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !65)
 // CHECK:STDOUT: !63 = !DISubroutineType(types: !64)
 // CHECK:STDOUT: !64 = !{!19, !18}
@@ -269,14 +275,14 @@ fn For() {
 // CHECK:STDOUT: !81 = !DILocalVariable(arg: 1, scope: !79, type: !19)
 // CHECK:STDOUT: !82 = !DILocation(line: 127, column: 12, scope: !79)
 // CHECK:STDOUT: !83 = !DILocation(line: 127, column: 5, scope: !79)
-// CHECK:STDOUT: !84 = distinct !DISubprogram(name: "Op", linkageName: "_COp:thunk.Int.9452f4c51951679b.Core:AddAssignWith.5375cfcbca6d9e35.Core.cfd8ddddc59ca787", scope: null, file: !55, line: 277, type: !85, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !87)
+// CHECK:STDOUT: !84 = distinct !DISubprogram(name: "Op", linkageName: "_COp:thunk.Int.9452f4c51951679b.Core:AddAssignWith.5375cfcbca6d9e35.Core.57ee91777b6354a8", scope: null, file: !55, line: 296, type: !85, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !87)
 // CHECK:STDOUT: !85 = !DISubroutineType(types: !86)
 // CHECK:STDOUT: !86 = !{null, !18, !18}
 // CHECK:STDOUT: !87 = !{!88, !89}
 // CHECK:STDOUT: !88 = !DILocalVariable(arg: 1, scope: !84, type: !18)
 // CHECK:STDOUT: !89 = !DILocalVariable(arg: 2, scope: !84, type: !18)
 // CHECK:STDOUT: !90 = !DILocation(line: 4294967295, scope: !84)
-// CHECK:STDOUT: !91 = !DILocation(line: 277, column: 3, scope: !84)
+// CHECK:STDOUT: !91 = !DILocation(line: 296, column: 3, scope: !84)
 // CHECK:STDOUT: !92 = distinct !DISubprogram(name: "Some", linkageName: "_CSome.3e8267224c5dc9c2:OptionalStorage.Core.0b1ea4541e2057b5", scope: null, file: !42, line: 115, type: !63, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !93)
 // CHECK:STDOUT: !93 = !{!94}
 // CHECK:STDOUT: !94 = !DILocalVariable(arg: 1, scope: !92, type: !18)
@@ -286,10 +292,14 @@ fn For() {
 // CHECK:STDOUT: !98 = distinct !DISubprogram(name: "None", linkageName: "_CNone.3e8267224c5dc9c2:OptionalStorage.Core.0b1ea4541e2057b5", scope: null, file: !42, line: 110, type: !70, spFlags: DISPFlagDefinition, unit: !2)
 // CHECK:STDOUT: !99 = !DILocation(line: 112, column: 5, scope: !98)
 // CHECK:STDOUT: !100 = !DILocation(line: 113, column: 5, scope: !98)
-// CHECK:STDOUT: !101 = distinct !DISubprogram(name: "Convert", linkageName: "_CConvert.14b8745117b2bc54:ImplicitAs.a9271c1e04015f9c.Core.beca8a3ca33a86fb", scope: null, file: !102, line: 35, type: !103, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !105)
-// CHECK:STDOUT: !102 = !DIFile(filename: "{{.*}}/prelude/operators/as.carbon", directory: "")
-// CHECK:STDOUT: !103 = !DISubroutineType(types: !104)
-// CHECK:STDOUT: !104 = !{!18, !18}
-// CHECK:STDOUT: !105 = !{!106}
-// CHECK:STDOUT: !106 = !DILocalVariable(arg: 1, scope: !101, type: !18)
-// CHECK:STDOUT: !107 = !DILocation(line: 35, column: 38, scope: !101)
+// CHECK:STDOUT: !101 = distinct !DISubprogram(name: "Convert", linkageName: "_CConvert.272fc3e88346d0d9:ImplicitAs.d993a5132e000405.Core.628184612c80324d", scope: null, file: !55, line: 59, type: !102, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !104)
+// CHECK:STDOUT: !102 = !DISubroutineType(types: !103)
+// CHECK:STDOUT: !103 = !{!18, !18}
+// CHECK:STDOUT: !104 = !{!105}
+// CHECK:STDOUT: !105 = !DILocalVariable(arg: 1, scope: !101, type: !18)
+// CHECK:STDOUT: !106 = !DILocation(line: 61, column: 17, scope: !101)
+// CHECK:STDOUT: !107 = !DILocation(line: 61, column: 5, scope: !101)
+// CHECK:STDOUT: !108 = distinct !DISubprogram(name: "AsInt", linkageName: "_CAsInt.Int.9452f4c51951679b.Core:AnyInt.Core.be1e879c1ad406d8", scope: null, file: !55, line: 54, type: !102, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !109)
+// CHECK:STDOUT: !109 = !{!110}
+// CHECK:STDOUT: !110 = !DILocalVariable(arg: 1, scope: !108, type: !18)
+// CHECK:STDOUT: !111 = !DILocation(line: 54, column: 36, scope: !108)
@@ -37,13 +37,13 @@ fn IncrSigned() {
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
 // CHECK:STDOUT: define linkonce_odr void @"_COp.Int.9452f4c51951679b.Core:Inc.Core.be1e879c1ad406d8"(ptr %self) #0 !dbg !10 {
-// CHECK:STDOUT:   call void @"_COp:thunk.Int.9452f4c51951679b.Core:AddAssignWith.5375cfcbca6d9e35.Core.75bec4d236c9daa5"(ptr %self, i32 1), !dbg !17
+// CHECK:STDOUT:   call void @"_COp:thunk.Int.9452f4c51951679b.Core:AddAssignWith.5375cfcbca6d9e35.Core.57ee91777b6354a8"(ptr %self, i32 1), !dbg !17
 // CHECK:STDOUT:   ret void, !dbg !18
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline nounwind
-// CHECK:STDOUT: define linkonce_odr void @"_COp:thunk.Int.9452f4c51951679b.Core:AddAssignWith.5375cfcbca6d9e35.Core.75bec4d236c9daa5"(ptr %self, i32 %other) #2 !dbg !19 {
-// CHECK:STDOUT:   %1 = call i32 @"_CConvert.14b8745117b2bc54:ImplicitAs.a9271c1e04015f9c.Core.64ccbb8e5d9a0b8e"(i32 %other), !dbg !25
+// CHECK:STDOUT: define linkonce_odr void @"_COp:thunk.Int.9452f4c51951679b.Core:AddAssignWith.5375cfcbca6d9e35.Core.57ee91777b6354a8"(ptr %self, i32 %other) #2 !dbg !19 {
+// CHECK:STDOUT:   %1 = call i32 @"_CConvert.272fc3e88346d0d9:ImplicitAs.d993a5132e000405.Core.628184612c80324d"(i32 %other), !dbg !25
 // CHECK:STDOUT:   %2 = load i32, ptr %self, align 4, !dbg !26
 // CHECK:STDOUT:   %3 = add i32 %2, %1, !dbg !26
 // CHECK:STDOUT:   store i32 %3, ptr %self, align 4, !dbg !26
@@ -51,8 +51,14 @@ fn IncrSigned() {
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define linkonce_odr i32 @"_CConvert.14b8745117b2bc54:ImplicitAs.a9271c1e04015f9c.Core.64ccbb8e5d9a0b8e"(i32 %self) #0 !dbg !27 {
-// CHECK:STDOUT:   ret i32 %self, !dbg !33
+// CHECK:STDOUT: define linkonce_odr i32 @"_CConvert.272fc3e88346d0d9:ImplicitAs.d993a5132e000405.Core.628184612c80324d"(i32 %self) #0 !dbg !27 {
+// CHECK:STDOUT:   %1 = call i32 @"_CAsInt.Int.9452f4c51951679b.Core:AnyInt.Core.be1e879c1ad406d8"(i32 %self), !dbg !32
+// CHECK:STDOUT:   ret i32 %1, !dbg !33
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define linkonce_odr i32 @"_CAsInt.Int.9452f4c51951679b.Core:AnyInt.Core.be1e879c1ad406d8"(i32 %self) #0 !dbg !34 {
+// CHECK:STDOUT:   ret i32 %self, !dbg !37
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: attributes #0 = { nounwind }
@@ -72,27 +78,31 @@ fn IncrSigned() {
 // CHECK:STDOUT: !7 = !DILocation(line: 5, column: 3, scope: !4)
 // CHECK:STDOUT: !8 = !DILocation(line: 6, column: 3, scope: !4)
 // CHECK:STDOUT: !9 = !DILocation(line: 4, column: 1, scope: !4)
-// CHECK:STDOUT: !10 = distinct !DISubprogram(name: "Op", linkageName: "_COp.Int.9452f4c51951679b.Core:Inc.Core.be1e879c1ad406d8", scope: null, file: !11, line: 341, type: !12, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !15)
+// CHECK:STDOUT: !10 = distinct !DISubprogram(name: "Op", linkageName: "_COp.Int.9452f4c51951679b.Core:Inc.Core.be1e879c1ad406d8", scope: null, file: !11, line: 360, type: !12, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !15)
 // CHECK:STDOUT: !11 = !DIFile(filename: "{{.*}}/prelude/types/int.carbon", directory: "")
 // CHECK:STDOUT: !12 = !DISubroutineType(types: !13)
 // CHECK:STDOUT: !13 = !{null, !14}
 // CHECK:STDOUT: !14 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
 // CHECK:STDOUT: !15 = !{!16}
 // CHECK:STDOUT: !16 = !DILocalVariable(arg: 1, scope: !10, type: !14)
-// CHECK:STDOUT: !17 = !DILocation(line: 343, column: 5, scope: !10)
-// CHECK:STDOUT: !18 = !DILocation(line: 341, column: 3, scope: !10)
-// CHECK:STDOUT: !19 = distinct !DISubprogram(name: "Op", linkageName: "_COp:thunk.Int.9452f4c51951679b.Core:AddAssignWith.5375cfcbca6d9e35.Core.75bec4d236c9daa5", scope: null, file: !11, line: 277, type: !20, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !22)
+// CHECK:STDOUT: !17 = !DILocation(line: 362, column: 5, scope: !10)
+// CHECK:STDOUT: !18 = !DILocation(line: 360, column: 3, scope: !10)
+// CHECK:STDOUT: !19 = distinct !DISubprogram(name: "Op", linkageName: "_COp:thunk.Int.9452f4c51951679b.Core:AddAssignWith.5375cfcbca6d9e35.Core.57ee91777b6354a8", scope: null, file: !11, line: 296, type: !20, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !22)
 // CHECK:STDOUT: !20 = !DISubroutineType(types: !21)
 // CHECK:STDOUT: !21 = !{null, !14, !14}
 // CHECK:STDOUT: !22 = !{!23, !24}
 // CHECK:STDOUT: !23 = !DILocalVariable(arg: 1, scope: !19, type: !14)
 // CHECK:STDOUT: !24 = !DILocalVariable(arg: 2, scope: !19, type: !14)
 // CHECK:STDOUT: !25 = !DILocation(line: 4294967295, scope: !19)
-// CHECK:STDOUT: !26 = !DILocation(line: 277, column: 3, scope: !19)
-// CHECK:STDOUT: !27 = distinct !DISubprogram(name: "Convert", linkageName: "_CConvert.14b8745117b2bc54:ImplicitAs.a9271c1e04015f9c.Core.64ccbb8e5d9a0b8e", scope: null, file: !28, line: 35, type: !29, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !31)
-// CHECK:STDOUT: !28 = !DIFile(filename: "{{.*}}/prelude/operators/as.carbon", directory: "")
-// CHECK:STDOUT: !29 = !DISubroutineType(types: !30)
-// CHECK:STDOUT: !30 = !{!14, !14}
-// CHECK:STDOUT: !31 = !{!32}
-// CHECK:STDOUT: !32 = !DILocalVariable(arg: 1, scope: !27, type: !14)
-// CHECK:STDOUT: !33 = !DILocation(line: 35, column: 38, scope: !27)
+// CHECK:STDOUT: !26 = !DILocation(line: 296, column: 3, scope: !19)
+// CHECK:STDOUT: !27 = distinct !DISubprogram(name: "Convert", linkageName: "_CConvert.272fc3e88346d0d9:ImplicitAs.d993a5132e000405.Core.628184612c80324d", scope: null, file: !11, line: 59, type: !28, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !30)
+// CHECK:STDOUT: !28 = !DISubroutineType(types: !29)
+// CHECK:STDOUT: !29 = !{!14, !14}
+// CHECK:STDOUT: !30 = !{!31}
+// CHECK:STDOUT: !31 = !DILocalVariable(arg: 1, scope: !27, type: !14)
+// CHECK:STDOUT: !32 = !DILocation(line: 61, column: 17, scope: !27)
+// CHECK:STDOUT: !33 = !DILocation(line: 61, column: 5, scope: !27)
+// CHECK:STDOUT: !34 = distinct !DISubprogram(name: "AsInt", linkageName: "_CAsInt.Int.9452f4c51951679b.Core:AnyInt.Core.be1e879c1ad406d8", scope: null, file: !11, line: 54, type: !28, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !35)
+// CHECK:STDOUT: !35 = !{!36}
+// CHECK:STDOUT: !36 = !DILocalVariable(arg: 1, scope: !34, type: !14)
+// CHECK:STDOUT: !37 = !DILocation(line: 54, column: 36, scope: !34)
@@ -2,7 +2,7 @@
 // Exceptions. See /LICENSE for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
-// INCLUDE-FILE: toolchain/testing/testdata/min_prelude/uint.carbon
+// INCLUDE-FILE: toolchain/testing/testdata/min_prelude/full.carbon
 //
 // AUTOUPDATE
 // TIP: To test this file alone, run:
@@ -10,11 +10,19 @@
 // TIP: To dump output, run:
 // TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/lower/testdata/primitives/int_types.carbon

+// --- pass_and_return.carbon
+
+library "[[@TEST_NAME]]";
+
 fn F_i8(a: i8) -> i8 { return a; }
 fn F_u16(a: u16) -> u16 { return a; }
 fn F_i64(a: i64) -> i64 { return a; }
 fn F_u65536(a: u65536) -> u65536 { return a; }

+// --- load_and_store.carbon
+
+library "[[@TEST_NAME]]";
+
 fn LoadStore_Bytes(p: Core.Int(24)*, n: Core.Int(24)) -> Core.Int(24) {
  let v: Core.Int(24) = *p;
  *p = n;
@@ -27,8 +35,18 @@ fn LoadStore_NotBytes(p: Core.Int(13)*, n: Core.Int(13)) -> Core.Int(13) {
  return v;
 }

-// CHECK:STDOUT: ; ModuleID = 'int_types.carbon'
-// CHECK:STDOUT: source_filename = "int_types.carbon"
+// --- convert.carbon
+
+library "[[@TEST_NAME]]";
+
+fn ImplicitWidenSigned(a: i8) -> i32 { return a; }
+fn ImplicitWidenUnsigned(a: u8) -> u32 { return a; }
+fn ImplicitWidenUnsignedToSigned(a: u8) -> i32 { return a; }
+fn ImplicitWidenCustom(a: Core.Int(4)) -> Core.Int(5) { return a; }
+fn ImplicitWidenUnsignedCustom(a: Core.UInt(4)) -> Core.UInt(5) { return a; }
+
+// CHECK:STDOUT: ; ModuleID = 'pass_and_return.carbon'
+// CHECK:STDOUT: source_filename = "pass_and_return.carbon"
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
 // CHECK:STDOUT: define i8 @_CF_i8.Main(i8 %a) #0 !dbg !4 {
@@ -54,22 +72,62 @@ fn LoadStore_NotBytes(p: Core.Int(13)*, n: Core.Int(13)) -> Core.Int(13) {
 // CHECK:STDOUT:   ret i65536 %a, !dbg !31
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: attributes #0 = { nounwind }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "pass_and_return.carbon", directory: "")
+// CHECK:STDOUT: !4 = distinct !DISubprogram(name: "F_i8", linkageName: "_CF_i8.Main", scope: null, file: !3, line: 4, type: !5, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !8)
+// CHECK:STDOUT: !5 = !DISubroutineType(types: !6)
+// CHECK:STDOUT: !6 = !{!7, !7}
+// CHECK:STDOUT: !7 = !DIBasicType(name: "int", size: 8, encoding: DW_ATE_signed)
+// CHECK:STDOUT: !8 = !{!9}
+// CHECK:STDOUT: !9 = !DILocalVariable(arg: 1, scope: !4, type: !7)
+// CHECK:STDOUT: !10 = !DILocation(line: 4, column: 24, scope: !4)
+// CHECK:STDOUT: !11 = distinct !DISubprogram(name: "F_u16", linkageName: "_CF_u16.Main", scope: null, file: !3, line: 5, type: !12, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !15)
+// CHECK:STDOUT: !12 = !DISubroutineType(types: !13)
+// CHECK:STDOUT: !13 = !{!14, !14}
+// CHECK:STDOUT: !14 = !DIBasicType(name: "int", size: 16, encoding: DW_ATE_unsigned)
+// CHECK:STDOUT: !15 = !{!16}
+// CHECK:STDOUT: !16 = !DILocalVariable(arg: 1, scope: !11, type: !14)
+// CHECK:STDOUT: !17 = !DILocation(line: 5, column: 27, scope: !11)
+// CHECK:STDOUT: !18 = distinct !DISubprogram(name: "F_i64", linkageName: "_CF_i64.Main", scope: null, file: !3, line: 6, type: !19, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !22)
+// CHECK:STDOUT: !19 = !DISubroutineType(types: !20)
+// CHECK:STDOUT: !20 = !{!21, !21}
+// CHECK:STDOUT: !21 = !DIBasicType(name: "int", size: 64, encoding: DW_ATE_signed)
+// CHECK:STDOUT: !22 = !{!23}
+// CHECK:STDOUT: !23 = !DILocalVariable(arg: 1, scope: !18, type: !21)
+// CHECK:STDOUT: !24 = !DILocation(line: 6, column: 27, scope: !18)
+// CHECK:STDOUT: !25 = distinct !DISubprogram(name: "F_u65536", linkageName: "_CF_u65536.Main", scope: null, file: !3, line: 7, type: !26, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !29)
+// CHECK:STDOUT: !26 = !DISubroutineType(types: !27)
+// CHECK:STDOUT: !27 = !{!28, !28}
+// CHECK:STDOUT: !28 = !DIBasicType(name: "int", size: 65536, encoding: DW_ATE_unsigned)
+// CHECK:STDOUT: !29 = !{!30}
+// CHECK:STDOUT: !30 = !DILocalVariable(arg: 1, scope: !25, type: !28)
+// CHECK:STDOUT: !31 = !DILocation(line: 7, column: 36, scope: !25)
+// CHECK:STDOUT: ; ModuleID = 'load_and_store.carbon'
+// CHECK:STDOUT: source_filename = "load_and_store.carbon"
+// CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define i24 @_CLoadStore_Bytes.Main(ptr %p, i24 %n) #0 !dbg !32 {
+// CHECK:STDOUT: define i24 @_CLoadStore_Bytes.Main(ptr %p, i24 %n) #0 !dbg !4 {
 // CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %.loc19_25.2 = load i24, ptr %p, align 4, !dbg !40
-// CHECK:STDOUT:   store i24 %n, ptr %p, align 4, !dbg !41
-// CHECK:STDOUT:   ret i24 %.loc19_25.2, !dbg !42
+// CHECK:STDOUT:   %.loc5_25.2 = load i24, ptr %p, align 4, !dbg !12
+// CHECK:STDOUT:   store i24 %n, ptr %p, align 4, !dbg !13
+// CHECK:STDOUT:   ret i24 %.loc5_25.2, !dbg !14
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define i13 @_CLoadStore_NotBytes.Main(ptr %p, i13 %n) #0 !dbg !43 {
+// CHECK:STDOUT: define i13 @_CLoadStore_NotBytes.Main(ptr %p, i13 %n) #0 !dbg !15 {
 // CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %.loc25_25.2 = load i16, ptr %p, align 2, !dbg !50
-// CHECK:STDOUT:   %.loc25_25.21 = trunc i16 %.loc25_25.2 to i13, !dbg !50
-// CHECK:STDOUT:   %0 = zext i13 %n to i16, !dbg !51
-// CHECK:STDOUT:   store i16 %0, ptr %p, align 2, !dbg !51
-// CHECK:STDOUT:   ret i13 %.loc25_25.21, !dbg !52
+// CHECK:STDOUT:   %.loc11_25.2 = load i16, ptr %p, align 2, !dbg !22
+// CHECK:STDOUT:   %.loc11_25.21 = trunc i16 %.loc11_25.2 to i13, !dbg !22
+// CHECK:STDOUT:   %0 = zext i13 %n to i16, !dbg !23
+// CHECK:STDOUT:   store i16 %0, ptr %p, align 2, !dbg !23
+// CHECK:STDOUT:   ret i13 %.loc11_25.21, !dbg !24
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: attributes #0 = { nounwind }
@@ -80,53 +138,257 @@ fn LoadStore_NotBytes(p: Core.Int(13)*, n: Core.Int(13)) -> Core.Int(13) {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
-// CHECK:STDOUT: !3 = !DIFile(filename: "int_types.carbon", directory: "")
-// CHECK:STDOUT: !4 = distinct !DISubprogram(name: "F_i8", linkageName: "_CF_i8.Main", scope: null, file: !3, line: 13, type: !5, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !8)
+// CHECK:STDOUT: !3 = !DIFile(filename: "load_and_store.carbon", directory: "")
+// CHECK:STDOUT: !4 = distinct !DISubprogram(name: "LoadStore_Bytes", linkageName: "_CLoadStore_Bytes.Main", scope: null, file: !3, line: 4, type: !5, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !9)
 // CHECK:STDOUT: !5 = !DISubroutineType(types: !6)
-// CHECK:STDOUT: !6 = !{!7, !7}
-// CHECK:STDOUT: !7 = !DIBasicType(name: "int", size: 8, encoding: DW_ATE_signed)
-// CHECK:STDOUT: !8 = !{!9}
-// CHECK:STDOUT: !9 = !DILocalVariable(arg: 1, scope: !4, type: !7)
-// CHECK:STDOUT: !10 = !DILocation(line: 13, column: 24, scope: !4)
-// CHECK:STDOUT: !11 = distinct !DISubprogram(name: "F_u16", linkageName: "_CF_u16.Main", scope: null, file: !3, line: 14, type: !12, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !15)
-// CHECK:STDOUT: !12 = !DISubroutineType(types: !13)
-// CHECK:STDOUT: !13 = !{!14, !14}
-// CHECK:STDOUT: !14 = !DIBasicType(name: "int", size: 16, encoding: DW_ATE_unsigned)
-// CHECK:STDOUT: !15 = !{!16}
-// CHECK:STDOUT: !16 = !DILocalVariable(arg: 1, scope: !11, type: !14)
-// CHECK:STDOUT: !17 = !DILocation(line: 14, column: 27, scope: !11)
-// CHECK:STDOUT: !18 = distinct !DISubprogram(name: "F_i64", linkageName: "_CF_i64.Main", scope: null, file: !3, line: 15, type: !19, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !22)
-// CHECK:STDOUT: !19 = !DISubroutineType(types: !20)
-// CHECK:STDOUT: !20 = !{!21, !21}
-// CHECK:STDOUT: !21 = !DIBasicType(name: "int", size: 64, encoding: DW_ATE_signed)
-// CHECK:STDOUT: !22 = !{!23}
-// CHECK:STDOUT: !23 = !DILocalVariable(arg: 1, scope: !18, type: !21)
-// CHECK:STDOUT: !24 = !DILocation(line: 15, column: 27, scope: !18)
-// CHECK:STDOUT: !25 = distinct !DISubprogram(name: "F_u65536", linkageName: "_CF_u65536.Main", scope: null, file: !3, line: 16, type: !26, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !29)
-// CHECK:STDOUT: !26 = !DISubroutineType(types: !27)
-// CHECK:STDOUT: !27 = !{!28, !28}
-// CHECK:STDOUT: !28 = !DIBasicType(name: "int", size: 65536, encoding: DW_ATE_unsigned)
-// CHECK:STDOUT: !29 = !{!30}
-// CHECK:STDOUT: !30 = !DILocalVariable(arg: 1, scope: !25, type: !28)
-// CHECK:STDOUT: !31 = !DILocation(line: 16, column: 36, scope: !25)
-// CHECK:STDOUT: !32 = distinct !DISubprogram(name: "LoadStore_Bytes", linkageName: "_CLoadStore_Bytes.Main", scope: null, file: !3, line: 18, type: !33, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !37)
-// CHECK:STDOUT: !33 = !DISubroutineType(types: !34)
-// CHECK:STDOUT: !34 = !{!35, !36, !35}
-// CHECK:STDOUT: !35 = !DIBasicType(name: "int", size: 24, encoding: DW_ATE_signed)
-// CHECK:STDOUT: !36 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 8)
-// CHECK:STDOUT: !37 = !{!38, !39}
-// CHECK:STDOUT: !38 = !DILocalVariable(arg: 1, scope: !32, type: !36)
-// CHECK:STDOUT: !39 = !DILocalVariable(arg: 2, scope: !32, type: !35)
-// CHECK:STDOUT: !40 = !DILocation(line: 19, column: 25, scope: !32)
-// CHECK:STDOUT: !41 = !DILocation(line: 20, column: 3, scope: !32)
-// CHECK:STDOUT: !42 = !DILocation(line: 21, column: 3, scope: !32)
-// CHECK:STDOUT: !43 = distinct !DISubprogram(name: "LoadStore_NotBytes", linkageName: "_CLoadStore_NotBytes.Main", scope: null, file: !3, line: 24, type: !44, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !47)
-// CHECK:STDOUT: !44 = !DISubroutineType(types: !45)
-// CHECK:STDOUT: !45 = !{!46, !36, !46}
-// CHECK:STDOUT: !46 = !DIBasicType(name: "int", size: 13, encoding: DW_ATE_signed)
-// CHECK:STDOUT: !47 = !{!48, !49}
-// CHECK:STDOUT: !48 = !DILocalVariable(arg: 1, scope: !43, type: !36)
-// CHECK:STDOUT: !49 = !DILocalVariable(arg: 2, scope: !43, type: !46)
-// CHECK:STDOUT: !50 = !DILocation(line: 25, column: 25, scope: !43)
-// CHECK:STDOUT: !51 = !DILocation(line: 26, column: 3, scope: !43)
-// CHECK:STDOUT: !52 = !DILocation(line: 27, column: 3, scope: !43)
+// CHECK:STDOUT: !6 = !{!7, !8, !7}
+// CHECK:STDOUT: !7 = !DIBasicType(name: "int", size: 24, encoding: DW_ATE_signed)
+// CHECK:STDOUT: !8 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 8)
+// CHECK:STDOUT: !9 = !{!10, !11}
+// CHECK:STDOUT: !10 = !DILocalVariable(arg: 1, scope: !4, type: !8)
+// CHECK:STDOUT: !11 = !DILocalVariable(arg: 2, scope: !4, type: !7)
+// CHECK:STDOUT: !12 = !DILocation(line: 5, column: 25, scope: !4)
+// CHECK:STDOUT: !13 = !DILocation(line: 6, column: 3, scope: !4)
+// CHECK:STDOUT: !14 = !DILocation(line: 7, column: 3, scope: !4)
+// CHECK:STDOUT: !15 = distinct !DISubprogram(name: "LoadStore_NotBytes", linkageName: "_CLoadStore_NotBytes.Main", scope: null, file: !3, line: 10, type: !16, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !19)
+// CHECK:STDOUT: !16 = !DISubroutineType(types: !17)
+// CHECK:STDOUT: !17 = !{!18, !8, !18}
+// CHECK:STDOUT: !18 = !DIBasicType(name: "int", size: 13, encoding: DW_ATE_signed)
+// CHECK:STDOUT: !19 = !{!20, !21}
+// CHECK:STDOUT: !20 = !DILocalVariable(arg: 1, scope: !15, type: !8)
+// CHECK:STDOUT: !21 = !DILocalVariable(arg: 2, scope: !15, type: !18)
+// CHECK:STDOUT: !22 = !DILocation(line: 11, column: 25, scope: !15)
+// CHECK:STDOUT: !23 = !DILocation(line: 12, column: 3, scope: !15)
+// CHECK:STDOUT: !24 = !DILocation(line: 13, column: 3, scope: !15)
+// CHECK:STDOUT: ; ModuleID = 'convert.carbon'
+// CHECK:STDOUT: source_filename = "convert.carbon"
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define i32 @_CImplicitWidenSigned.Main(i8 %a) #0 !dbg !4 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %From.binding.as_type.as.ImplicitAs.impl.Convert.call = call i32 @"_CConvert.272fc3e88346d0d9:ImplicitAs.d993a5132e000405.Core.aa7228341bdcca99"(i8 %a), !dbg !11
+// CHECK:STDOUT:   ret i32 %From.binding.as_type.as.ImplicitAs.impl.Convert.call, !dbg !11
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define i32 @_CImplicitWidenUnsigned.Main(i8 %a) #0 !dbg !12 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %UInt.as.ImplicitAs.impl.Convert.call = call i32 @"_CConvert.UInt.9452f4c51951679b.Core:ImplicitAs.952fa4f2c764f083.Core.0e306488ea9f63ef"(i8 %a), !dbg !19
+// CHECK:STDOUT:   ret i32 %UInt.as.ImplicitAs.impl.Convert.call, !dbg !19
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define i32 @_CImplicitWidenUnsignedToSigned.Main(i8 %a) #0 !dbg !20 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %UInt.as.ImplicitAs.impl.Convert.call = call i32 @"_CConvert.UInt.9452f4c51951679b.Core:ImplicitAs.952fa4f2c764f083.Core.0237a74cabc89c74"(i8 %a), !dbg !25
+// CHECK:STDOUT:   ret i32 %UInt.as.ImplicitAs.impl.Convert.call, !dbg !25
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define i5 @_CImplicitWidenCustom.Main(i4 %a) #0 !dbg !26 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %From.binding.as_type.as.ImplicitAs.impl.Convert.call = call i5 @"_CConvert.272fc3e88346d0d9:ImplicitAs.d993a5132e000405.Core.61459d64876d7c49"(i4 %a), !dbg !33
+// CHECK:STDOUT:   ret i5 %From.binding.as_type.as.ImplicitAs.impl.Convert.call, !dbg !33
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define i5 @_CImplicitWidenUnsignedCustom.Main(i4 %a) #0 !dbg !34 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %UInt.as.ImplicitAs.impl.Convert.call = call i5 @"_CConvert.UInt.9452f4c51951679b.Core:ImplicitAs.952fa4f2c764f083.Core.d1cbb2cbeb4d860b"(i4 %a), !dbg !41
+// CHECK:STDOUT:   ret i5 %UInt.as.ImplicitAs.impl.Convert.call, !dbg !41
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define linkonce_odr i32 @"_CConvert.272fc3e88346d0d9:ImplicitAs.d993a5132e000405.Core.aa7228341bdcca99"(i8 %self) #0 !dbg !42 {
+// CHECK:STDOUT:   %1 = call i8 @"_CAsInt.Int.9452f4c51951679b.Core:AnyInt.Core.ca1ac10d3fc7c1a8"(i8 %self), !dbg !46
+// CHECK:STDOUT:   %2 = sext i8 %1 to i32, !dbg !47
+// CHECK:STDOUT:   ret i32 %2, !dbg !48
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define linkonce_odr i32 @"_CConvert.UInt.9452f4c51951679b.Core:ImplicitAs.952fa4f2c764f083.Core.0e306488ea9f63ef"(i8 %self) #0 !dbg !49 {
+// CHECK:STDOUT:   %1 = call i32 @"_CConvert.UInt.9452f4c51951679b.Core:FromUInt.382a8acefd0525fe.Core.081daf9d9b61e05a"(i8 %self), !dbg !53
+// CHECK:STDOUT:   ret i32 %1, !dbg !54
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define linkonce_odr i32 @"_CConvert.UInt.9452f4c51951679b.Core:ImplicitAs.952fa4f2c764f083.Core.0237a74cabc89c74"(i8 %self) #0 !dbg !55 {
+// CHECK:STDOUT:   %1 = call i32 @"_CConvert.Int.9452f4c51951679b.Core:FromUInt.a15ed48781b6c2b7.Core.069b661f6a62a7bd"(i8 %self), !dbg !58
+// CHECK:STDOUT:   ret i32 %1, !dbg !59
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define linkonce_odr i5 @"_CConvert.272fc3e88346d0d9:ImplicitAs.d993a5132e000405.Core.61459d64876d7c49"(i4 %self) #0 !dbg !60 {
+// CHECK:STDOUT:   %1 = call i4 @"_CAsInt.Int.9452f4c51951679b.Core:AnyInt.Core.044c7d430ddd4fd6"(i4 %self), !dbg !63
+// CHECK:STDOUT:   %2 = sext i4 %1 to i5, !dbg !64
+// CHECK:STDOUT:   ret i5 %2, !dbg !65
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define linkonce_odr i5 @"_CConvert.UInt.9452f4c51951679b.Core:ImplicitAs.952fa4f2c764f083.Core.d1cbb2cbeb4d860b"(i4 %self) #0 !dbg !66 {
+// CHECK:STDOUT:   %1 = call i5 @"_CConvert.UInt.9452f4c51951679b.Core:FromUInt.382a8acefd0525fe.Core.b0c274f0050b1ce4"(i4 %self), !dbg !69
+// CHECK:STDOUT:   ret i5 %1, !dbg !70
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define linkonce_odr i8 @"_CAsInt.Int.9452f4c51951679b.Core:AnyInt.Core.ca1ac10d3fc7c1a8"(i8 %self) #0 !dbg !71 {
+// CHECK:STDOUT:   ret i8 %self, !dbg !76
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define linkonce_odr i32 @"_CConvert.UInt.9452f4c51951679b.Core:FromUInt.382a8acefd0525fe.Core.081daf9d9b61e05a"(i8 %from) #0 !dbg !77 {
+// CHECK:STDOUT:   %1 = call i8 @"_CAsUInt.UInt.9452f4c51951679b.Core:AnyUInt.Core.ca1ac10d3fc7c1a8"(i8 %from), !dbg !80
+// CHECK:STDOUT:   %2 = zext i8 %1 to i32, !dbg !81
+// CHECK:STDOUT:   ret i32 %2, !dbg !82
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define linkonce_odr i32 @"_CConvert.Int.9452f4c51951679b.Core:FromUInt.a15ed48781b6c2b7.Core.069b661f6a62a7bd"(i8 %from) #0 !dbg !83 {
+// CHECK:STDOUT:   %1 = call i8 @"_CAsUInt.UInt.9452f4c51951679b.Core:AnyUInt.Core.ca1ac10d3fc7c1a8"(i8 %from), !dbg !86
+// CHECK:STDOUT:   %2 = zext i8 %1 to i32, !dbg !87
+// CHECK:STDOUT:   ret i32 %2, !dbg !88
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define linkonce_odr i4 @"_CAsInt.Int.9452f4c51951679b.Core:AnyInt.Core.044c7d430ddd4fd6"(i4 %self) #0 !dbg !89 {
+// CHECK:STDOUT:   ret i4 %self, !dbg !94
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define linkonce_odr i5 @"_CConvert.UInt.9452f4c51951679b.Core:FromUInt.382a8acefd0525fe.Core.b0c274f0050b1ce4"(i4 %from) #0 !dbg !95 {
+// CHECK:STDOUT:   %1 = call i4 @"_CAsUInt.UInt.9452f4c51951679b.Core:AnyUInt.Core.044c7d430ddd4fd6"(i4 %from), !dbg !98
+// CHECK:STDOUT:   %2 = zext i4 %1 to i5, !dbg !99
+// CHECK:STDOUT:   ret i5 %2, !dbg !100
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define linkonce_odr i8 @"_CAsUInt.UInt.9452f4c51951679b.Core:AnyUInt.Core.ca1ac10d3fc7c1a8"(i8 %self) #0 !dbg !101 {
+// CHECK:STDOUT:   ret i8 %self, !dbg !106
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define linkonce_odr i4 @"_CAsUInt.UInt.9452f4c51951679b.Core:AnyUInt.Core.044c7d430ddd4fd6"(i4 %self) #0 !dbg !107 {
+// CHECK:STDOUT:   ret i4 %self, !dbg !112
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; uselistorder directives
+// CHECK:STDOUT: uselistorder ptr @"_CAsUInt.UInt.9452f4c51951679b.Core:AnyUInt.Core.ca1ac10d3fc7c1a8", { 1, 0 }
+// CHECK:STDOUT:
+// CHECK:STDOUT: attributes #0 = { nounwind }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !3 = !DIFile(filename: "convert.carbon", directory: "")
+// CHECK:STDOUT: !4 = distinct !DISubprogram(name: "ImplicitWidenSigned", linkageName: "_CImplicitWidenSigned.Main", scope: null, file: !3, line: 4, type: !5, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !9)
+// CHECK:STDOUT: !5 = !DISubroutineType(types: !6)
+// CHECK:STDOUT: !6 = !{!7, !8}
+// CHECK:STDOUT: !7 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+// CHECK:STDOUT: !8 = !DIBasicType(name: "int", size: 8, encoding: DW_ATE_signed)
+// CHECK:STDOUT: !9 = !{!10}
+// CHECK:STDOUT: !10 = !DILocalVariable(arg: 1, scope: !4, type: !8)
+// CHECK:STDOUT: !11 = !DILocation(line: 4, column: 40, scope: !4)
+// CHECK:STDOUT: !12 = distinct !DISubprogram(name: "ImplicitWidenUnsigned", linkageName: "_CImplicitWidenUnsigned.Main", scope: null, file: !3, line: 5, type: !13, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !17)
+// CHECK:STDOUT: !13 = !DISubroutineType(types: !14)
+// CHECK:STDOUT: !14 = !{!15, !16}
+// CHECK:STDOUT: !15 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_unsigned)
+// CHECK:STDOUT: !16 = !DIBasicType(name: "int", size: 8, encoding: DW_ATE_unsigned)
+// CHECK:STDOUT: !17 = !{!18}
+// CHECK:STDOUT: !18 = !DILocalVariable(arg: 1, scope: !12, type: !16)
+// CHECK:STDOUT: !19 = !DILocation(line: 5, column: 42, scope: !12)
+// CHECK:STDOUT: !20 = distinct !DISubprogram(name: "ImplicitWidenUnsignedToSigned", linkageName: "_CImplicitWidenUnsignedToSigned.Main", scope: null, file: !3, line: 6, type: !21, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !23)
+// CHECK:STDOUT: !21 = !DISubroutineType(types: !22)
+// CHECK:STDOUT: !22 = !{!7, !16}
+// CHECK:STDOUT: !23 = !{!24}
+// CHECK:STDOUT: !24 = !DILocalVariable(arg: 1, scope: !20, type: !16)
+// CHECK:STDOUT: !25 = !DILocation(line: 6, column: 50, scope: !20)
+// CHECK:STDOUT: !26 = distinct !DISubprogram(name: "ImplicitWidenCustom", linkageName: "_CImplicitWidenCustom.Main", scope: null, file: !3, line: 7, type: !27, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !31)
+// CHECK:STDOUT: !27 = !DISubroutineType(types: !28)
+// CHECK:STDOUT: !28 = !{!29, !30}
+// CHECK:STDOUT: !29 = !DIBasicType(name: "int", size: 5, encoding: DW_ATE_signed)
+// CHECK:STDOUT: !30 = !DIBasicType(name: "int", size: 4, encoding: DW_ATE_signed)
+// CHECK:STDOUT: !31 = !{!32}
+// CHECK:STDOUT: !32 = !DILocalVariable(arg: 1, scope: !26, type: !30)
+// CHECK:STDOUT: !33 = !DILocation(line: 7, column: 57, scope: !26)
+// CHECK:STDOUT: !34 = distinct !DISubprogram(name: "ImplicitWidenUnsignedCustom", linkageName: "_CImplicitWidenUnsignedCustom.Main", scope: null, file: !3, line: 8, type: !35, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !39)
+// CHECK:STDOUT: !35 = !DISubroutineType(types: !36)
+// CHECK:STDOUT: !36 = !{!37, !38}
+// CHECK:STDOUT: !37 = !DIBasicType(name: "int", size: 5, encoding: DW_ATE_unsigned)
+// CHECK:STDOUT: !38 = !DIBasicType(name: "int", size: 4, encoding: DW_ATE_unsigned)
+// CHECK:STDOUT: !39 = !{!40}
+// CHECK:STDOUT: !40 = !DILocalVariable(arg: 1, scope: !34, type: !38)
+// CHECK:STDOUT: !41 = !DILocation(line: 8, column: 67, scope: !34)
+// CHECK:STDOUT: !42 = distinct !DISubprogram(name: "Convert", linkageName: "_CConvert.272fc3e88346d0d9:ImplicitAs.d993a5132e000405.Core.aa7228341bdcca99", scope: null, file: !43, line: 59, type: !5, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !44)
+// CHECK:STDOUT: !43 = !DIFile(filename: "{{.*}}/prelude/types/int.carbon", directory: "")
+// CHECK:STDOUT: !44 = !{!45}
+// CHECK:STDOUT: !45 = !DILocalVariable(arg: 1, scope: !42, type: !8)
+// CHECK:STDOUT: !46 = !DILocation(line: 61, column: 17, scope: !42)
+// CHECK:STDOUT: !47 = !DILocation(line: 61, column: 12, scope: !42)
+// CHECK:STDOUT: !48 = !DILocation(line: 61, column: 5, scope: !42)
+// CHECK:STDOUT: !49 = distinct !DISubprogram(name: "Convert", linkageName: "_CConvert.UInt.9452f4c51951679b.Core:ImplicitAs.952fa4f2c764f083.Core.0e306488ea9f63ef", scope: null, file: !50, line: 83, type: !13, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !51)
+// CHECK:STDOUT: !50 = !DIFile(filename: "{{.*}}/prelude/types/uint.carbon", directory: "")
+// CHECK:STDOUT: !51 = !{!52}
+// CHECK:STDOUT: !52 = !DILocalVariable(arg: 1, scope: !49, type: !16)
+// CHECK:STDOUT: !53 = !DILocation(line: 84, column: 12, scope: !49)
+// CHECK:STDOUT: !54 = !DILocation(line: 84, column: 5, scope: !49)
+// CHECK:STDOUT: !55 = distinct !DISubprogram(name: "Convert", linkageName: "_CConvert.UInt.9452f4c51951679b.Core:ImplicitAs.952fa4f2c764f083.Core.0237a74cabc89c74", scope: null, file: !50, line: 83, type: !21, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !56)
+// CHECK:STDOUT: !56 = !{!57}
+// CHECK:STDOUT: !57 = !DILocalVariable(arg: 1, scope: !55, type: !16)
+// CHECK:STDOUT: !58 = !DILocation(line: 84, column: 12, scope: !55)
+// CHECK:STDOUT: !59 = !DILocation(line: 84, column: 5, scope: !55)
+// CHECK:STDOUT: !60 = distinct !DISubprogram(name: "Convert", linkageName: "_CConvert.272fc3e88346d0d9:ImplicitAs.d993a5132e000405.Core.61459d64876d7c49", scope: null, file: !43, line: 59, type: !27, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !61)
+// CHECK:STDOUT: !61 = !{!62}
+// CHECK:STDOUT: !62 = !DILocalVariable(arg: 1, scope: !60, type: !30)
+// CHECK:STDOUT: !63 = !DILocation(line: 61, column: 17, scope: !60)
+// CHECK:STDOUT: !64 = !DILocation(line: 61, column: 12, scope: !60)
+// CHECK:STDOUT: !65 = !DILocation(line: 61, column: 5, scope: !60)
+// CHECK:STDOUT: !66 = distinct !DISubprogram(name: "Convert", linkageName: "_CConvert.UInt.9452f4c51951679b.Core:ImplicitAs.952fa4f2c764f083.Core.d1cbb2cbeb4d860b", scope: null, file: !50, line: 83, type: !35, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !67)
+// CHECK:STDOUT: !67 = !{!68}
+// CHECK:STDOUT: !68 = !DILocalVariable(arg: 1, scope: !66, type: !38)
+// CHECK:STDOUT: !69 = !DILocation(line: 84, column: 12, scope: !66)
+// CHECK:STDOUT: !70 = !DILocation(line: 84, column: 5, scope: !66)
+// CHECK:STDOUT: !71 = distinct !DISubprogram(name: "AsInt", linkageName: "_CAsInt.Int.9452f4c51951679b.Core:AnyInt.Core.ca1ac10d3fc7c1a8", scope: null, file: !43, line: 54, type: !72, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !74)
+// CHECK:STDOUT: !72 = !DISubroutineType(types: !73)
+// CHECK:STDOUT: !73 = !{!8, !8}
+// CHECK:STDOUT: !74 = !{!75}
+// CHECK:STDOUT: !75 = !DILocalVariable(arg: 1, scope: !71, type: !8)
+// CHECK:STDOUT: !76 = !DILocation(line: 54, column: 36, scope: !71)
+// CHECK:STDOUT: !77 = distinct !DISubprogram(name: "Convert", linkageName: "_CConvert.UInt.9452f4c51951679b.Core:FromUInt.382a8acefd0525fe.Core.081daf9d9b61e05a", scope: null, file: !50, line: 67, type: !13, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !78)
+// CHECK:STDOUT: !78 = !{!79}
+// CHECK:STDOUT: !79 = !DILocalVariable(arg: 1, scope: !77, type: !16)
+// CHECK:STDOUT: !80 = !DILocation(line: 69, column: 17, scope: !77)
+// CHECK:STDOUT: !81 = !DILocation(line: 69, column: 12, scope: !77)
+// CHECK:STDOUT: !82 = !DILocation(line: 69, column: 5, scope: !77)
+// CHECK:STDOUT: !83 = distinct !DISubprogram(name: "Convert", linkageName: "_CConvert.Int.9452f4c51951679b.Core:FromUInt.a15ed48781b6c2b7.Core.069b661f6a62a7bd", scope: null, file: !50, line: 75, type: !21, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !84)
+// CHECK:STDOUT: !84 = !{!85}
+// CHECK:STDOUT: !85 = !DILocalVariable(arg: 1, scope: !83, type: !16)
+// CHECK:STDOUT: !86 = !DILocation(line: 77, column: 17, scope: !83)
+// CHECK:STDOUT: !87 = !DILocation(line: 77, column: 12, scope: !83)
+// CHECK:STDOUT: !88 = !DILocation(line: 77, column: 5, scope: !83)
+// CHECK:STDOUT: !89 = distinct !DISubprogram(name: "AsInt", linkageName: "_CAsInt.Int.9452f4c51951679b.Core:AnyInt.Core.044c7d430ddd4fd6", scope: null, file: !43, line: 54, type: !90, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !92)
+// CHECK:STDOUT: !90 = !DISubroutineType(types: !91)
+// CHECK:STDOUT: !91 = !{!30, !30}
+// CHECK:STDOUT: !92 = !{!93}
+// CHECK:STDOUT: !93 = !DILocalVariable(arg: 1, scope: !89, type: !30)
+// CHECK:STDOUT: !94 = !DILocation(line: 54, column: 36, scope: !89)
+// CHECK:STDOUT: !95 = distinct !DISubprogram(name: "Convert", linkageName: "_CConvert.UInt.9452f4c51951679b.Core:FromUInt.382a8acefd0525fe.Core.b0c274f0050b1ce4", scope: null, file: !50, line: 67, type: !35, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !96)
+// CHECK:STDOUT: !96 = !{!97}
+// CHECK:STDOUT: !97 = !DILocalVariable(arg: 1, scope: !95, type: !38)
+// CHECK:STDOUT: !98 = !DILocation(line: 69, column: 17, scope: !95)
+// CHECK:STDOUT: !99 = !DILocation(line: 69, column: 12, scope: !95)
+// CHECK:STDOUT: !100 = !DILocation(line: 69, column: 5, scope: !95)
+// CHECK:STDOUT: !101 = distinct !DISubprogram(name: "AsUInt", linkageName: "_CAsUInt.UInt.9452f4c51951679b.Core:AnyUInt.Core.ca1ac10d3fc7c1a8", scope: null, file: !50, line: 55, type: !102, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !104)
+// CHECK:STDOUT: !102 = !DISubroutineType(types: !103)
+// CHECK:STDOUT: !103 = !{!16, !16}
+// CHECK:STDOUT: !104 = !{!105}
+// CHECK:STDOUT: !105 = !DILocalVariable(arg: 1, scope: !101, type: !16)
+// CHECK:STDOUT: !106 = !DILocation(line: 55, column: 37, scope: !101)
+// CHECK:STDOUT: !107 = distinct !DISubprogram(name: "AsUInt", linkageName: "_CAsUInt.UInt.9452f4c51951679b.Core:AnyUInt.Core.044c7d430ddd4fd6", scope: null, file: !50, line: 55, type: !108, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !110)
+// CHECK:STDOUT: !108 = !DISubroutineType(types: !109)
+// CHECK:STDOUT: !109 = !{!38, !38}
+// CHECK:STDOUT: !110 = !{!111}
+// CHECK:STDOUT: !111 = !DILocalVariable(arg: 1, scope: !107, type: !38)
+// CHECK:STDOUT: !112 = !DILocation(line: 55, column: 37, scope: !107)
@@ -67,17 +67,17 @@ fn AddOrRemoveConst(a: i32, b: const i32) {
 // CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %_.var.loc25), !dbg !25
 // CHECK:STDOUT:   call void @"_CConvert.a44fce96e16342e7:ImplicitAs.ad22d1bbc0605210.Core.77b263a5fd240ddf"(ptr %_.var.loc25, i32 %a), !dbg !25
 // CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %_.var.loc26), !dbg !26
-// CHECK:STDOUT:   call void @"_CConvert.e5cf8fcbb4feaae2:ImplicitAs.0f95c9e18c91e00a.Core.acebdc79896e8fac"(ptr %_.var.loc26, i32 %a), !dbg !26
+// CHECK:STDOUT:   call void @"_CConvert.e5cf8fcbb4feaae2:ImplicitAs.0f95c9e18c91e00a.Core.787d589b54a95071"(ptr %_.var.loc26, i32 %a), !dbg !26
 // CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %_.var.loc27), !dbg !27
-// CHECK:STDOUT:   call void @"_CConvert.a44fce96e16342e7:ImplicitAs.ad22d1bbc0605210.Core.1a1590d9059e7de0"(ptr %_.var.loc27, i32 %a), !dbg !27
+// CHECK:STDOUT:   call void @"_CConvert.a44fce96e16342e7:ImplicitAs.ad22d1bbc0605210.Core.25fb32d66f981ccd"(ptr %_.var.loc27, i32 %a), !dbg !27
 // CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %_.var.loc28), !dbg !28
 // CHECK:STDOUT:   call void @"_CConvert.17f42c13d842b71d:ImplicitAs.eb057aa32837c84e.Core.77b263a5fd240ddf"(ptr %_.var.loc28, i32 %b), !dbg !28
 // CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %_.var.loc29), !dbg !29
 // CHECK:STDOUT:   call void @"_CConvert.17f42c13d842b71d:ImplicitAs.eb057aa32837c84e.Core.693532dcb04bf6dc"(ptr %_.var.loc29, i32 %b), !dbg !29
 // CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %_.var.loc30), !dbg !30
-// CHECK:STDOUT:   call void @"_CConvert.17f42c13d842b71d:ImplicitAs.eb057aa32837c84e.Core.1a1590d9059e7de0"(ptr %_.var.loc30, i32 %b), !dbg !30
+// CHECK:STDOUT:   call void @"_CConvert.17f42c13d842b71d:ImplicitAs.eb057aa32837c84e.Core.25fb32d66f981ccd"(ptr %_.var.loc30, i32 %b), !dbg !30
 // CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %_.var.loc31), !dbg !31
-// CHECK:STDOUT:   call void @"_CConvert.17f42c13d842b71d:ImplicitAs.eb057aa32837c84e.Core.2e7d01f168fff135"(ptr %_.var.loc31, i32 %b), !dbg !31
+// CHECK:STDOUT:   call void @"_CConvert.17f42c13d842b71d:ImplicitAs.eb057aa32837c84e.Core.1c991c9fdfba671f"(ptr %_.var.loc31, i32 %b), !dbg !31
 // CHECK:STDOUT:   ret void, !dbg !32
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -115,14 +115,14 @@ fn AddOrRemoveConst(a: i32, b: const i32) {
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define linkonce_odr void @"_CConvert.e5cf8fcbb4feaae2:ImplicitAs.0f95c9e18c91e00a.Core.acebdc79896e8fac"(ptr sret({ i32, i1 }) %return, i32 %self) #0 !dbg !62 {
-// CHECK:STDOUT:   call void @"_CConvert.3667eb502d1ddfa9:OptionalAs.c7a50af9bdd61b43.Core.d4040f3d74e112f2"(ptr %return, i32 %self), !dbg !65
+// CHECK:STDOUT: define linkonce_odr void @"_CConvert.e5cf8fcbb4feaae2:ImplicitAs.0f95c9e18c91e00a.Core.787d589b54a95071"(ptr sret({ i32, i1 }) %return, i32 %self) #0 !dbg !62 {
+// CHECK:STDOUT:   call void @"_CConvert.3667eb502d1ddfa9:OptionalAs.c7a50af9bdd61b43.Core.5d35ad54738af8e4"(ptr %return, i32 %self), !dbg !65
 // CHECK:STDOUT:   ret void, !dbg !66
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define linkonce_odr void @"_CConvert.a44fce96e16342e7:ImplicitAs.ad22d1bbc0605210.Core.1a1590d9059e7de0"(ptr sret({ i32, i1 }) %return, i32 %self) #0 !dbg !67 {
-// CHECK:STDOUT:   call void @"_CConvert.e5cf8fcbb4feaae2:ImplicitAs.0f95c9e18c91e00a.Core.acebdc79896e8fac"(ptr %return, i32 %self), !dbg !70
+// CHECK:STDOUT: define linkonce_odr void @"_CConvert.a44fce96e16342e7:ImplicitAs.ad22d1bbc0605210.Core.25fb32d66f981ccd"(ptr sret({ i32, i1 }) %return, i32 %self) #0 !dbg !67 {
+// CHECK:STDOUT:   call void @"_CConvert.e5cf8fcbb4feaae2:ImplicitAs.0f95c9e18c91e00a.Core.787d589b54a95071"(ptr %return, i32 %self), !dbg !70
 // CHECK:STDOUT:   ret void, !dbg !71
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -139,14 +139,14 @@ fn AddOrRemoveConst(a: i32, b: const i32) {
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define linkonce_odr void @"_CConvert.17f42c13d842b71d:ImplicitAs.eb057aa32837c84e.Core.1a1590d9059e7de0"(ptr sret({ i32, i1 }) %return, i32 %self) #0 !dbg !82 {
-// CHECK:STDOUT:   call void @"_CConvert.e5cf8fcbb4feaae2:ImplicitAs.0f95c9e18c91e00a.Core.acebdc79896e8fac"(ptr %return, i32 %self), !dbg !85
+// CHECK:STDOUT: define linkonce_odr void @"_CConvert.17f42c13d842b71d:ImplicitAs.eb057aa32837c84e.Core.25fb32d66f981ccd"(ptr sret({ i32, i1 }) %return, i32 %self) #0 !dbg !82 {
+// CHECK:STDOUT:   call void @"_CConvert.e5cf8fcbb4feaae2:ImplicitAs.0f95c9e18c91e00a.Core.787d589b54a95071"(ptr %return, i32 %self), !dbg !85
 // CHECK:STDOUT:   ret void, !dbg !86
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define linkonce_odr void @"_CConvert.17f42c13d842b71d:ImplicitAs.eb057aa32837c84e.Core.2e7d01f168fff135"(ptr sret({ i32, i1 }) %return, i32 %self) #0 !dbg !87 {
-// CHECK:STDOUT:   call void @"_CConvert.a44fce96e16342e7:ImplicitAs.ad22d1bbc0605210.Core.1a1590d9059e7de0"(ptr %return, i32 %self), !dbg !90
+// CHECK:STDOUT: define linkonce_odr void @"_CConvert.17f42c13d842b71d:ImplicitAs.eb057aa32837c84e.Core.1c991c9fdfba671f"(ptr sret({ i32, i1 }) %return, i32 %self) #0 !dbg !87 {
+// CHECK:STDOUT:   call void @"_CConvert.a44fce96e16342e7:ImplicitAs.ad22d1bbc0605210.Core.25fb32d66f981ccd"(ptr %return, i32 %self), !dbg !90
 // CHECK:STDOUT:   ret void, !dbg !91
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -176,10 +176,10 @@ fn AddOrRemoveConst(a: i32, b: const i32) {
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define linkonce_odr void @"_CConvert.3667eb502d1ddfa9:OptionalAs.c7a50af9bdd61b43.Core.d4040f3d74e112f2"(ptr sret({ i32, i1 }) %return, i32 %self) #0 !dbg !110 {
+// CHECK:STDOUT: define linkonce_odr void @"_CConvert.3667eb502d1ddfa9:OptionalAs.c7a50af9bdd61b43.Core.5d35ad54738af8e4"(ptr sret({ i32, i1 }) %return, i32 %self) #0 !dbg !110 {
 // CHECK:STDOUT:   %temp = alloca i32, align 4, !dbg !113
 // CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %temp), !dbg !113
-// CHECK:STDOUT:   %1 = call i32 @"_CConvert.a44fce96e16342e7:ImplicitAs.ad22d1bbc0605210.Core.b930bfdac0979466"(i32 %self), !dbg !113
+// CHECK:STDOUT:   %1 = call i32 @"_CConvert.a44fce96e16342e7:ImplicitAs.ad22d1bbc0605210.Core.90a4f5ca3e06badd"(i32 %self), !dbg !113
 // CHECK:STDOUT:   store i32 %1, ptr %temp, align 4, !dbg !113
 // CHECK:STDOUT:   %2 = load i32, ptr %temp, align 4, !dbg !113
 // CHECK:STDOUT:   call void @_CSome.Optional.Core.b0246d3dd29c9210(ptr %return, i32 %2), !dbg !114
@@ -193,8 +193,8 @@ fn AddOrRemoveConst(a: i32, b: const i32) {
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define linkonce_odr i32 @"_CConvert.a44fce96e16342e7:ImplicitAs.ad22d1bbc0605210.Core.b930bfdac0979466"(i32 %self) #0 !dbg !121 {
-// CHECK:STDOUT:   %1 = call i32 @"_CConvert.14b8745117b2bc54:ImplicitAs.a9271c1e04015f9c.Core.64ccbb8e5d9a0b8e"(i32 %self), !dbg !124
+// CHECK:STDOUT: define linkonce_odr i32 @"_CConvert.a44fce96e16342e7:ImplicitAs.ad22d1bbc0605210.Core.90a4f5ca3e06badd"(i32 %self) #0 !dbg !121 {
+// CHECK:STDOUT:   %1 = call i32 @"_CConvert.272fc3e88346d0d9:ImplicitAs.d993a5132e000405.Core.628184612c80324d"(i32 %self), !dbg !124
 // CHECK:STDOUT:   ret i32 %1, !dbg !125
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -214,23 +214,29 @@ fn AddOrRemoveConst(a: i32, b: const i32) {
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define linkonce_odr i32 @"_CConvert.14b8745117b2bc54:ImplicitAs.a9271c1e04015f9c.Core.64ccbb8e5d9a0b8e"(i32 %self) #0 !dbg !137 {
-// CHECK:STDOUT:   ret i32 %self, !dbg !142
+// CHECK:STDOUT: define linkonce_odr i32 @"_CConvert.272fc3e88346d0d9:ImplicitAs.d993a5132e000405.Core.628184612c80324d"(i32 %self) #0 !dbg !137 {
+// CHECK:STDOUT:   %1 = call i32 @"_CAsInt.Int.9452f4c51951679b.Core:AnyInt.Core.be1e879c1ad406d8"(i32 %self), !dbg !143
+// CHECK:STDOUT:   ret i32 %1, !dbg !144
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define linkonce_odr void @"_CSome.3e8267224c5dc9c2:OptionalStorage.Core.5325ffa2b57e13bd"(ptr sret({ i32, i1 }) %return, i32 %self) #0 !dbg !143 {
-// CHECK:STDOUT:   %value = getelementptr inbounds nuw { i32, i1 }, ptr %return, i32 0, i32 0, !dbg !146
-// CHECK:STDOUT:   %1 = call i32 @"_COp.34e7a685d3648824:Copy.Core.64ccbb8e5d9a0b8e"(i32 %self), !dbg !147
-// CHECK:STDOUT:   store i32 %1, ptr %value, align 4, !dbg !146
-// CHECK:STDOUT:   %has_value = getelementptr inbounds nuw { i32, i1 }, ptr %return, i32 0, i32 1, !dbg !148
-// CHECK:STDOUT:   store i8 1, ptr %has_value, align 1, !dbg !148
-// CHECK:STDOUT:   ret void, !dbg !149
+// CHECK:STDOUT: define linkonce_odr void @"_CSome.3e8267224c5dc9c2:OptionalStorage.Core.5325ffa2b57e13bd"(ptr sret({ i32, i1 }) %return, i32 %self) #0 !dbg !145 {
+// CHECK:STDOUT:   %value = getelementptr inbounds nuw { i32, i1 }, ptr %return, i32 0, i32 0, !dbg !148
+// CHECK:STDOUT:   %1 = call i32 @"_COp.34e7a685d3648824:Copy.Core.64ccbb8e5d9a0b8e"(i32 %self), !dbg !149
+// CHECK:STDOUT:   store i32 %1, ptr %value, align 4, !dbg !148
+// CHECK:STDOUT:   %has_value = getelementptr inbounds nuw { i32, i1 }, ptr %return, i32 0, i32 1, !dbg !150
+// CHECK:STDOUT:   store i8 1, ptr %has_value, align 1, !dbg !150
+// CHECK:STDOUT:   ret void, !dbg !151
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define linkonce_odr i32 @"_COp.34e7a685d3648824:Copy.Core.64ccbb8e5d9a0b8e"(i32 %self) #0 !dbg !150 {
-// CHECK:STDOUT:   ret i32 %self, !dbg !154
+// CHECK:STDOUT: define linkonce_odr i32 @"_CAsInt.Int.9452f4c51951679b.Core:AnyInt.Core.be1e879c1ad406d8"(i32 %self) #0 !dbg !152 {
+// CHECK:STDOUT:   ret i32 %self, !dbg !155
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define linkonce_odr i32 @"_COp.34e7a685d3648824:Copy.Core.64ccbb8e5d9a0b8e"(i32 %self) #0 !dbg !156 {
+// CHECK:STDOUT:   ret i32 %self, !dbg !160
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; uselistorder directives
@@ -305,12 +311,12 @@ fn AddOrRemoveConst(a: i32, b: const i32) {
 // CHECK:STDOUT: !59 = !DILocalVariable(arg: 1, scope: !56, type: !20)
 // CHECK:STDOUT: !60 = !DILocation(line: 40, column: 45, scope: !56)
 // CHECK:STDOUT: !61 = !DILocation(line: 40, column: 38, scope: !56)
-// CHECK:STDOUT: !62 = distinct !DISubprogram(name: "Convert", linkageName: "_CConvert.e5cf8fcbb4feaae2:ImplicitAs.0f95c9e18c91e00a.Core.acebdc79896e8fac", scope: null, file: !34, line: 93, type: !45, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !63)
+// CHECK:STDOUT: !62 = distinct !DISubprogram(name: "Convert", linkageName: "_CConvert.e5cf8fcbb4feaae2:ImplicitAs.0f95c9e18c91e00a.Core.787d589b54a95071", scope: null, file: !34, line: 93, type: !45, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !63)
 // CHECK:STDOUT: !63 = !{!64}
 // CHECK:STDOUT: !64 = !DILocalVariable(arg: 1, scope: !62, type: !20)
 // CHECK:STDOUT: !65 = !DILocation(line: 94, column: 12, scope: !62)
 // CHECK:STDOUT: !66 = !DILocation(line: 94, column: 5, scope: !62)
-// CHECK:STDOUT: !67 = distinct !DISubprogram(name: "Convert", linkageName: "_CConvert.a44fce96e16342e7:ImplicitAs.ad22d1bbc0605210.Core.1a1590d9059e7de0", scope: null, file: !57, line: 40, type: !45, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !68)
+// CHECK:STDOUT: !67 = distinct !DISubprogram(name: "Convert", linkageName: "_CConvert.a44fce96e16342e7:ImplicitAs.ad22d1bbc0605210.Core.25fb32d66f981ccd", scope: null, file: !57, line: 40, type: !45, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !68)
 // CHECK:STDOUT: !68 = !{!69}
 // CHECK:STDOUT: !69 = !DILocalVariable(arg: 1, scope: !67, type: !20)
 // CHECK:STDOUT: !70 = !DILocation(line: 40, column: 45, scope: !67)
@@ -325,12 +331,12 @@ fn AddOrRemoveConst(a: i32, b: const i32) {
 // CHECK:STDOUT: !79 = !DILocalVariable(arg: 1, scope: !77, type: !20)
 // CHECK:STDOUT: !80 = !DILocation(line: 44, column: 45, scope: !77)
 // CHECK:STDOUT: !81 = !DILocation(line: 44, column: 38, scope: !77)
-// CHECK:STDOUT: !82 = distinct !DISubprogram(name: "Convert", linkageName: "_CConvert.17f42c13d842b71d:ImplicitAs.eb057aa32837c84e.Core.1a1590d9059e7de0", scope: null, file: !57, line: 44, type: !45, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !83)
+// CHECK:STDOUT: !82 = distinct !DISubprogram(name: "Convert", linkageName: "_CConvert.17f42c13d842b71d:ImplicitAs.eb057aa32837c84e.Core.25fb32d66f981ccd", scope: null, file: !57, line: 44, type: !45, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !83)
 // CHECK:STDOUT: !83 = !{!84}
 // CHECK:STDOUT: !84 = !DILocalVariable(arg: 1, scope: !82, type: !20)
 // CHECK:STDOUT: !85 = !DILocation(line: 44, column: 45, scope: !82)
 // CHECK:STDOUT: !86 = !DILocation(line: 44, column: 38, scope: !82)
-// CHECK:STDOUT: !87 = distinct !DISubprogram(name: "Convert", linkageName: "_CConvert.17f42c13d842b71d:ImplicitAs.eb057aa32837c84e.Core.2e7d01f168fff135", scope: null, file: !57, line: 44, type: !45, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !88)
+// CHECK:STDOUT: !87 = distinct !DISubprogram(name: "Convert", linkageName: "_CConvert.17f42c13d842b71d:ImplicitAs.eb057aa32837c84e.Core.1c991c9fdfba671f", scope: null, file: !57, line: 44, type: !45, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !88)
 // CHECK:STDOUT: !88 = !{!89}
 // CHECK:STDOUT: !89 = !DILocalVariable(arg: 1, scope: !87, type: !20)
 // CHECK:STDOUT: !90 = !DILocation(line: 44, column: 45, scope: !87)
@@ -353,7 +359,7 @@ fn AddOrRemoveConst(a: i32, b: const i32) {
 // CHECK:STDOUT: !107 = distinct !DISubprogram(name: "None", linkageName: "_CNone.3e8267224c5dc9c2:OptionalStorage.Core.bfb441135f07cbe1", scope: null, file: !34, line: 110, type: !52, spFlags: DISPFlagDefinition, unit: !2)
 // CHECK:STDOUT: !108 = !DILocation(line: 112, column: 5, scope: !107)
 // CHECK:STDOUT: !109 = !DILocation(line: 113, column: 5, scope: !107)
-// CHECK:STDOUT: !110 = distinct !DISubprogram(name: "Convert", linkageName: "_CConvert.3667eb502d1ddfa9:OptionalAs.c7a50af9bdd61b43.Core.d4040f3d74e112f2", scope: null, file: !34, line: 75, type: !45, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !111)
+// CHECK:STDOUT: !110 = distinct !DISubprogram(name: "Convert", linkageName: "_CConvert.3667eb502d1ddfa9:OptionalAs.c7a50af9bdd61b43.Core.5d35ad54738af8e4", scope: null, file: !34, line: 75, type: !45, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !111)
 // CHECK:STDOUT: !111 = !{!112}
 // CHECK:STDOUT: !112 = !DILocalVariable(arg: 1, scope: !110, type: !20)
 // CHECK:STDOUT: !113 = !DILocation(line: 76, column: 29, scope: !110)
@@ -364,7 +370,7 @@ fn AddOrRemoveConst(a: i32, b: const i32) {
 // CHECK:STDOUT: !118 = !DILocalVariable(arg: 1, scope: !116, type: !20)
 // CHECK:STDOUT: !119 = !DILocation(line: 30, column: 12, scope: !116)
 // CHECK:STDOUT: !120 = !DILocation(line: 30, column: 5, scope: !116)
-// CHECK:STDOUT: !121 = distinct !DISubprogram(name: "Convert", linkageName: "_CConvert.a44fce96e16342e7:ImplicitAs.ad22d1bbc0605210.Core.b930bfdac0979466", scope: null, file: !57, line: 40, type: !45, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !122)
+// CHECK:STDOUT: !121 = distinct !DISubprogram(name: "Convert", linkageName: "_CConvert.a44fce96e16342e7:ImplicitAs.ad22d1bbc0605210.Core.90a4f5ca3e06badd", scope: null, file: !57, line: 40, type: !45, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !122)
 // CHECK:STDOUT: !122 = !{!123}
 // CHECK:STDOUT: !123 = !DILocalVariable(arg: 1, scope: !121, type: !20)
 // CHECK:STDOUT: !124 = !DILocation(line: 40, column: 45, scope: !121)
@@ -380,21 +386,27 @@ fn AddOrRemoveConst(a: i32, b: const i32) {
 // CHECK:STDOUT: !134 = !DILocation(line: 119, column: 5, scope: !131)
 // CHECK:STDOUT: !135 = !DILocation(line: 120, column: 5, scope: !131)
 // CHECK:STDOUT: !136 = !DILocation(line: 121, column: 5, scope: !131)
-// CHECK:STDOUT: !137 = distinct !DISubprogram(name: "Convert", linkageName: "_CConvert.14b8745117b2bc54:ImplicitAs.a9271c1e04015f9c.Core.64ccbb8e5d9a0b8e", scope: null, file: !57, line: 35, type: !138, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !140)
-// CHECK:STDOUT: !138 = !DISubroutineType(types: !139)
-// CHECK:STDOUT: !139 = !{!20, !20}
-// CHECK:STDOUT: !140 = !{!141}
-// CHECK:STDOUT: !141 = !DILocalVariable(arg: 1, scope: !137, type: !20)
-// CHECK:STDOUT: !142 = !DILocation(line: 35, column: 38, scope: !137)
-// CHECK:STDOUT: !143 = distinct !DISubprogram(name: "Some", linkageName: "_CSome.3e8267224c5dc9c2:OptionalStorage.Core.5325ffa2b57e13bd", scope: null, file: !34, line: 115, type: !45, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !144)
-// CHECK:STDOUT: !144 = !{!145}
-// CHECK:STDOUT: !145 = !DILocalVariable(arg: 1, scope: !143, type: !20)
-// CHECK:STDOUT: !146 = !DILocation(line: 119, column: 5, scope: !143)
-// CHECK:STDOUT: !147 = !DILocation(line: 119, column: 28, scope: !143)
-// CHECK:STDOUT: !148 = !DILocation(line: 120, column: 5, scope: !143)
-// CHECK:STDOUT: !149 = !DILocation(line: 121, column: 5, scope: !143)
-// CHECK:STDOUT: !150 = distinct !DISubprogram(name: "Op", linkageName: "_COp.34e7a685d3648824:Copy.Core.64ccbb8e5d9a0b8e", scope: null, file: !151, line: 19, type: !45, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !152)
-// CHECK:STDOUT: !151 = !DIFile(filename: "{{.*}}/prelude/copy.carbon", directory: "")
-// CHECK:STDOUT: !152 = !{!153}
-// CHECK:STDOUT: !153 = !DILocalVariable(arg: 1, scope: !150, type: !20)
-// CHECK:STDOUT: !154 = !DILocation(line: 19, column: 33, scope: !150)
+// CHECK:STDOUT: !137 = distinct !DISubprogram(name: "Convert", linkageName: "_CConvert.272fc3e88346d0d9:ImplicitAs.d993a5132e000405.Core.628184612c80324d", scope: null, file: !138, line: 59, type: !139, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !141)
+// CHECK:STDOUT: !138 = !DIFile(filename: "{{.*}}/prelude/types/int.carbon", directory: "")
+// CHECK:STDOUT: !139 = !DISubroutineType(types: !140)
+// CHECK:STDOUT: !140 = !{!20, !20}
+// CHECK:STDOUT: !141 = !{!142}
+// CHECK:STDOUT: !142 = !DILocalVariable(arg: 1, scope: !137, type: !20)
+// CHECK:STDOUT: !143 = !DILocation(line: 61, column: 17, scope: !137)
+// CHECK:STDOUT: !144 = !DILocation(line: 61, column: 5, scope: !137)
+// CHECK:STDOUT: !145 = distinct !DISubprogram(name: "Some", linkageName: "_CSome.3e8267224c5dc9c2:OptionalStorage.Core.5325ffa2b57e13bd", scope: null, file: !34, line: 115, type: !45, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !146)
+// CHECK:STDOUT: !146 = !{!147}
+// CHECK:STDOUT: !147 = !DILocalVariable(arg: 1, scope: !145, type: !20)
+// CHECK:STDOUT: !148 = !DILocation(line: 119, column: 5, scope: !145)
+// CHECK:STDOUT: !149 = !DILocation(line: 119, column: 28, scope: !145)
+// CHECK:STDOUT: !150 = !DILocation(line: 120, column: 5, scope: !145)
+// CHECK:STDOUT: !151 = !DILocation(line: 121, column: 5, scope: !145)
+// CHECK:STDOUT: !152 = distinct !DISubprogram(name: "AsInt", linkageName: "_CAsInt.Int.9452f4c51951679b.Core:AnyInt.Core.be1e879c1ad406d8", scope: null, file: !138, line: 54, type: !139, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !153)
+// CHECK:STDOUT: !153 = !{!154}
+// CHECK:STDOUT: !154 = !DILocalVariable(arg: 1, scope: !152, type: !20)
+// CHECK:STDOUT: !155 = !DILocation(line: 54, column: 36, scope: !152)
+// CHECK:STDOUT: !156 = distinct !DISubprogram(name: "Op", linkageName: "_COp.34e7a685d3648824:Copy.Core.64ccbb8e5d9a0b8e", scope: null, file: !157, line: 19, type: !45, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !158)
+// CHECK:STDOUT: !157 = !DIFile(filename: "{{.*}}/prelude/copy.carbon", directory: "")
+// CHECK:STDOUT: !158 = !{!159}
+// CHECK:STDOUT: !159 = !DILocalVariable(arg: 1, scope: !156, type: !20)
+// CHECK:STDOUT: !160 = !DILocation(line: 19, column: 33, scope: !156)