Use GetConstantValueInSpecific to get the impl's specific interface after deduction (#7584)

During impl lookup, for each (generic) impl candidate, we form a
specific for that impl by deducing its generic arguments. Then we
compare the query interface against the impl's specific interface. That
comparison needs the deduced arguments applied to the impl's specific
interface. Previously we were doing this by getting the impl's
constraint facet type with the impl's specific applied (via
`GetConstantValueInSpecific()`) and then identifying that facet type
with the impl's deduced self.

Identify is a fairly expensive operation. It runs subst, trying to
replace `.Self` references. It walks named constraints. It collects
require declarations. We're looking at making it do _more_ in the future
too, including rewrite constraint resolution and collecting rewrite and
same-type constraints. For this reason we have a cache to make it cheap
on the second run, but it's still a very heavyweight operation to
involve in impl lookup, when all we want is to apply the impl's specific
to its target interface.

We almost have all the information we need to avoid the identification
step. We have the impl's specific after deduction. And we have the
SpecificInterface that the impl is targeting in the `Impl` struct. When
we form the specific for the impl itself, we resolve the declaration
block and form new constant values for all instructions in there, but
that does not cover the SpecificInterface that we're storing in the
`Impl` struct. So we add a new instruction to the impl's eval block,
which will be symbolic when the impl is generic and the target interface
depends on a generic parameter. And we store the `InstId` in the `Impl`
struct. This allows us to gets its constant value later with the impl's
specific applied. From that constant value we can then pull out the
SpecificInterface that the impl is targeting.

toolchain/check/testdata/function/builtin/call.carbon

@@ -32,7 +32,7 @@ fn RuntimeCall(a: i32, b: i32) -> i32 {
 // CHECK:STDOUT:   %a.patt: %pattern_type.6b6 = at_binding_pattern a, %a.param_patt [concrete]
 // CHECK:STDOUT:   %b.param_patt: %pattern_type.6b6 = value_param_pattern [concrete]
 // CHECK:STDOUT:   %b.patt: %pattern_type.6b6 = at_binding_pattern b, %b.param_patt [concrete]
-// CHECK:STDOUT:   %.795: Core.Form = init_form %i32 [concrete]
+// CHECK:STDOUT:   %.795f: Core.Form = init_form %i32 [concrete]
 // CHECK:STDOUT:   %return.param_patt.a9a: %pattern_type.6b6 = out_param_pattern [concrete]
 // CHECK:STDOUT:   %return.patt.e1b: %pattern_type.6b6 = return_slot_pattern %return.param_patt.a9a, %i32 [concrete]
 // CHECK:STDOUT:   %Add.type: type = fn_type @Add [concrete]
@@ -45,8 +45,8 @@ fn RuntimeCall(a: i32, b: i32) -> i32 {
 // CHECK:STDOUT:   %To: Core.IntLiteral = symbolic_binding To, 0 [symbolic]
 // CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.type.e74: type = fn_type @Core.IntLiteral.as.ImplicitAs.impl.Convert, @Core.IntLiteral.as.ImplicitAs.impl(%To) [symbolic]
 // CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.845: %Core.IntLiteral.as.ImplicitAs.impl.Convert.type.e74 = struct_value () [symbolic]
-// CHECK:STDOUT:   %ImplicitAs.type.7cb: type = facet_type <@ImplicitAs, @ImplicitAs(Core.IntLiteral)> [concrete]
 // CHECK:STDOUT:   %From: Core.IntLiteral = symbolic_binding From, 0 [symbolic]
+// CHECK:STDOUT:   %ImplicitAs.type.7cb: type = facet_type <@ImplicitAs, @ImplicitAs(Core.IntLiteral)> [concrete]
 // CHECK:STDOUT:   %Int.as.ImplicitAs.impl.Convert.type.48d: type = fn_type @Int.as.ImplicitAs.impl.Convert, @Int.as.ImplicitAs.impl(%From) [symbolic]
 // CHECK:STDOUT:   %Int.as.ImplicitAs.impl.Convert.0f9: %Int.as.ImplicitAs.impl.Convert.type.48d = struct_value () [symbolic]
 // CHECK:STDOUT:   %ImplicitAs.impl_witness.a23: <witness> = impl_witness imports.%ImplicitAs.impl_witness_table.b3c, @Core.IntLiteral.as.ImplicitAs.impl(%int_32) [concrete]
@@ -126,7 +126,7 @@ fn RuntimeCall(a: i32, b: i32) -> i32 {
 // CHECK:STDOUT:     %return.patt: %pattern_type.6b6 = return_slot_pattern %return.param_patt, %i32.loc15_27 [concrete = constants.%return.patt.e1b]
 // CHECK:STDOUT:   } {
 // CHECK:STDOUT:     %i32.loc15_27: type = type_literal constants.%i32 [concrete = constants.%i32]
-// CHECK:STDOUT:     %.loc15: Core.Form = init_form %i32.loc15_27 [concrete = constants.%.795]
+// CHECK:STDOUT:     %.loc15: Core.Form = init_form %i32.loc15_27 [concrete = constants.%.795f]
 // CHECK:STDOUT:     %a.param: %i32 = value_param call_param0
 // CHECK:STDOUT:     %i32.loc15_11: type = type_literal constants.%i32 [concrete = constants.%i32]
 // CHECK:STDOUT:     %a: %i32 = wrapper_binding a, %a.param
@@ -182,7 +182,7 @@ fn RuntimeCall(a: i32, b: i32) -> i32 {
 // CHECK:STDOUT:     %return.patt: %pattern_type.6b6 = return_slot_pattern %return.param_patt, %i32.loc19_35 [concrete = constants.%return.patt.e1b]
 // CHECK:STDOUT:   } {
 // CHECK:STDOUT:     %i32.loc19_35: type = type_literal constants.%i32 [concrete = constants.%i32]
-// CHECK:STDOUT:     %.loc19: Core.Form = init_form %i32.loc19_35 [concrete = constants.%.795]
+// CHECK:STDOUT:     %.loc19: Core.Form = init_form %i32.loc19_35 [concrete = constants.%.795f]
 // CHECK:STDOUT:     %a.param: %i32 = value_param call_param0
 // CHECK:STDOUT:     %i32.loc19_19: type = type_literal constants.%i32 [concrete = constants.%i32]
 // CHECK:STDOUT:     %a: %i32 = wrapper_binding a, %a.param

toolchain/check/testdata/function/builtin/call_from_operator.carbon

@@ -121,6 +121,7 @@ var arr: array(i32, (1 as i32) + (2 as i32)) = (3, 4, (3 as i32) + (4 as i32));
 // CHECK:STDOUT:   %int_32: Core.IntLiteral = int_value 32 [concrete]
 // CHECK:STDOUT:   %i32.builtin: type = int_type signed, %int_32 [concrete]
 // CHECK:STDOUT:   %AddWith.type.7c6: type = facet_type <@AddWith, @AddWith(%i32.builtin)> [concrete]
+// CHECK:STDOUT:   %.417: <witness> = impl_self_witness %i32.builtin, @AddWith, @AddWith(%i32.builtin) [concrete]
 // CHECK:STDOUT:   %AddWith.impl_witness: <witness> = impl_witness @i32.builtin.as.AddWith.impl.%AddWith.impl_witness_table [concrete]
 // CHECK:STDOUT:   %Self.9ab: %AddWith.type.7c6 = symbolic_binding Self, 1 [symbolic]
 // CHECK:STDOUT:   %AddWith.WithSelf.Op.type.aad: type = fn_type @AddWith.WithSelf.Op, @AddWith.WithSelf(%i32.builtin, %Self.8d5) [symbolic]
@@ -141,6 +142,7 @@ var arr: array(i32, (1 as i32) + (2 as i32)) = (3, 4, (3 as i32) + (4 as i32));
 // CHECK:STDOUT:   %AddWith.WithSelf.Op.type.2dc: type = fn_type @AddWith.WithSelf.Op, @AddWith.WithSelf(%i32.builtin, %AddWith.facet) [concrete]
 // CHECK:STDOUT:   %AddWith.WithSelf.Op.921: %AddWith.WithSelf.Op.type.2dc = struct_value () [concrete]
 // CHECK:STDOUT:   %As.type.dfb: type = facet_type <@As, @As(%i32.builtin)> [concrete]
+// CHECK:STDOUT:   %.559: <witness> = impl_self_witness Core.IntLiteral, @As, @As(%i32.builtin) [concrete]
 // CHECK:STDOUT:   %As.impl_witness: <witness> = impl_witness @Core.IntLiteral.as.As.impl.%As.impl_witness_table [concrete]
 // CHECK:STDOUT:   %Self.2c0: %As.type.dfb = symbolic_binding Self, 1 [symbolic]
 // CHECK:STDOUT:   %As.WithSelf.Convert.type.d9c: type = fn_type @As.WithSelf.Convert, @As.WithSelf(%i32.builtin, %Self.f80) [symbolic]
@@ -155,6 +157,7 @@ var arr: array(i32, (1 as i32) + (2 as i32)) = (3, 4, (3 as i32) + (4 as i32));
 // CHECK:STDOUT:   %As.WithSelf.Convert.type.e08: type = fn_type @As.WithSelf.Convert, @As.WithSelf(%i32.builtin, %As.facet) [concrete]
 // CHECK:STDOUT:   %As.WithSelf.Convert.5a5: %As.WithSelf.Convert.type.e08 = struct_value () [concrete]
 // CHECK:STDOUT:   %ImplicitAs.type.9df: type = facet_type <@ImplicitAs, @ImplicitAs(%i32.builtin)> [concrete]
+// CHECK:STDOUT:   %.e10: <witness> = impl_self_witness Core.IntLiteral, @ImplicitAs, @ImplicitAs(%i32.builtin) [concrete]
 // CHECK:STDOUT:   %ImplicitAs.impl_witness.300: <witness> = impl_witness @Core.IntLiteral.as.ImplicitAs.impl.%ImplicitAs.impl_witness_table [concrete]
 // CHECK:STDOUT:   %Self.19a: %ImplicitAs.type.9df = symbolic_binding Self, 1 [symbolic]
 // CHECK:STDOUT:   %ImplicitAs.WithSelf.Convert.type.247: type = fn_type @ImplicitAs.WithSelf.Convert, @ImplicitAs.WithSelf(%i32.builtin, %Self.bb1) [symbolic]
@@ -167,6 +170,7 @@ var arr: array(i32, (1 as i32) + (2 as i32)) = (3, 4, (3 as i32) + (4 as i32));
 // CHECK:STDOUT:   %ImplicitAs.WithSelf.Convert.type.20b: type = fn_type @ImplicitAs.WithSelf.Convert, @ImplicitAs.WithSelf(%i32.builtin, %ImplicitAs.facet.18f) [concrete]
 // CHECK:STDOUT:   %ImplicitAs.WithSelf.Convert.b9f: %ImplicitAs.WithSelf.Convert.type.20b = struct_value () [concrete]
 // CHECK:STDOUT:   %ImplicitAs.type.7cb: type = facet_type <@ImplicitAs, @ImplicitAs(Core.IntLiteral)> [concrete]
+// CHECK:STDOUT:   %.328: <witness> = impl_self_witness %i32.builtin, @ImplicitAs, @ImplicitAs(Core.IntLiteral) [concrete]
 // CHECK:STDOUT:   %ImplicitAs.impl_witness.9d7: <witness> = impl_witness @i32.builtin.as.ImplicitAs.impl.%ImplicitAs.impl_witness_table [concrete]
 // CHECK:STDOUT:   %Self.c40: %ImplicitAs.type.7cb = symbolic_binding Self, 1 [symbolic]
 // CHECK:STDOUT:   %ImplicitAs.WithSelf.Convert.type.46f: type = fn_type @ImplicitAs.WithSelf.Convert, @ImplicitAs.WithSelf(Core.IntLiteral, %Self.bb1) [symbolic]
@@ -253,24 +257,28 @@ var arr: array(i32, (1 as i32) + (2 as i32)) = (3, 4, (3 as i32) + (4 as i32));
 // CHECK:STDOUT:     %.loc20_21: type = type_literal constants.%i32.builtin [concrete = constants.%i32.builtin]
 // CHECK:STDOUT:     %AddWith.type: type = facet_type <@AddWith, @AddWith(constants.%i32.builtin)> [concrete = constants.%AddWith.type.7c6]
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %.loc20: <witness> = impl_self_witness @i32.builtin.as.AddWith.impl.%.loc20_6, @AddWith, @AddWith(constants.%i32.builtin) [concrete = constants.%.417]
 // CHECK:STDOUT:   impl_decl @Core.IntLiteral.as.As.impl [concrete] {} {
 // CHECK:STDOUT:     %IntLiteral.ref: type = name_ref IntLiteral, file.%IntLiteral [concrete = Core.IntLiteral]
 // CHECK:STDOUT:     %As.ref: %As.type.116 = name_ref As, file.%As.decl [concrete = constants.%As.generic]
 // CHECK:STDOUT:     %.loc24: type = type_literal constants.%i32.builtin [concrete = constants.%i32.builtin]
 // CHECK:STDOUT:     %As.type: type = facet_type <@As, @As(constants.%i32.builtin)> [concrete = constants.%As.type.dfb]
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %.loc24: <witness> = impl_self_witness @Core.IntLiteral.as.As.impl.%IntLiteral.ref, @As, @As(constants.%i32.builtin) [concrete = constants.%.559]
 // CHECK:STDOUT:   impl_decl @Core.IntLiteral.as.ImplicitAs.impl [concrete] {} {
 // CHECK:STDOUT:     %IntLiteral.ref: type = name_ref IntLiteral, file.%IntLiteral [concrete = Core.IntLiteral]
 // CHECK:STDOUT:     %ImplicitAs.ref: %ImplicitAs.type.0ff = name_ref ImplicitAs, file.%ImplicitAs.decl [concrete = constants.%ImplicitAs.generic]
 // CHECK:STDOUT:     %.loc28: type = type_literal constants.%i32.builtin [concrete = constants.%i32.builtin]
 // CHECK:STDOUT:     %ImplicitAs.type: type = facet_type <@ImplicitAs, @ImplicitAs(constants.%i32.builtin)> [concrete = constants.%ImplicitAs.type.9df]
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %.loc28: <witness> = impl_self_witness @Core.IntLiteral.as.ImplicitAs.impl.%IntLiteral.ref, @ImplicitAs, @ImplicitAs(constants.%i32.builtin) [concrete = constants.%.e10]
 // CHECK:STDOUT:   impl_decl @i32.builtin.as.ImplicitAs.impl [concrete] {} {
 // CHECK:STDOUT:     %.loc32: type = type_literal constants.%i32.builtin [concrete = constants.%i32.builtin]
 // CHECK:STDOUT:     %ImplicitAs.ref: %ImplicitAs.type.0ff = name_ref ImplicitAs, file.%ImplicitAs.decl [concrete = constants.%ImplicitAs.generic]
 // CHECK:STDOUT:     %IntLiteral.ref: type = name_ref IntLiteral, file.%IntLiteral [concrete = Core.IntLiteral]
 // CHECK:STDOUT:     %ImplicitAs.type: type = facet_type <@ImplicitAs, @ImplicitAs(Core.IntLiteral)> [concrete = constants.%ImplicitAs.type.7cb]
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %.loc32: <witness> = impl_self_witness @i32.builtin.as.ImplicitAs.impl.%.loc32, @ImplicitAs, @ImplicitAs(Core.IntLiteral) [concrete = constants.%.328]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: generic interface @AddWith(%T.loc8_20.2: type) {

toolchain/check/testdata/function/builtin/method.carbon

@@ -45,13 +45,14 @@ var arr: array(i32, (1 as i32).(I.F)(2));
 // CHECK:STDOUT:   %Int.type: type = generic_class_type @Int [concrete]
 // CHECK:STDOUT:   %Int.generic: %Int.type = struct_value () [concrete]
 // CHECK:STDOUT:   %i32: type = class_type @Int, @Int(%int_32) [concrete]
+// CHECK:STDOUT:   %.2a7: <witness> = impl_self_witness %i32, @I [concrete]
 // CHECK:STDOUT:   %I.impl_witness: <witness> = impl_witness @i32.as.I.impl.%I.impl_witness_table [concrete]
 // CHECK:STDOUT:   %pattern_type.6b6: type = pattern_type %i32 [concrete]
 // CHECK:STDOUT:   %self.param_patt.049: %pattern_type.6b6 = value_param_pattern [concrete]
 // CHECK:STDOUT:   %self.patt.f6c: %pattern_type.6b6 = at_binding_pattern self, %self.param_patt.049 [concrete]
 // CHECK:STDOUT:   %other.param_patt.12c: %pattern_type.6b6 = value_param_pattern [concrete]
 // CHECK:STDOUT:   %other.patt.656: %pattern_type.6b6 = at_binding_pattern other, %other.param_patt.12c [concrete]
-// CHECK:STDOUT:   %.795: Core.Form = init_form %i32 [concrete]
+// CHECK:STDOUT:   %.795f: Core.Form = init_form %i32 [concrete]
 // CHECK:STDOUT:   %return.param_patt.a9a: %pattern_type.6b6 = out_param_pattern [concrete]
 // CHECK:STDOUT:   %return.patt.e1b: %pattern_type.6b6 = return_slot_pattern %return.param_patt.a9a, %i32 [concrete]
 // CHECK:STDOUT:   %i32.as.I.impl.F.type: type = fn_type @i32.as.I.impl.F [concrete]
@@ -159,6 +160,7 @@ var arr: array(i32, (1 as i32).(I.F)(2));
 // CHECK:STDOUT:     %i32: type = type_literal constants.%i32 [concrete = constants.%i32]
 // CHECK:STDOUT:     %I.ref: type = name_ref I, file.%I.decl [concrete = constants.%I.type]
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %.loc19: <witness> = impl_self_witness @i32.as.I.impl.%i32, @I [concrete = constants.%.2a7]
 // CHECK:STDOUT:   %arr.var: ref %array_type = var_storage %arr.var_patt [concrete]
 // CHECK:STDOUT:   %.loc23_40: type = splice_block %array_type [concrete = constants.%array_type] {
 // CHECK:STDOUT:     %i32.loc23_16: type = type_literal constants.%i32 [concrete = constants.%i32]
@@ -256,7 +258,7 @@ var arr: array(i32, (1 as i32).(I.F)(2));
 // CHECK:STDOUT:     %return.patt: %pattern_type.6b6 = return_slot_pattern %return.param_patt, %i32.loc20_34 [concrete = constants.%return.patt.e1b]
 // CHECK:STDOUT:   } {
 // CHECK:STDOUT:     %i32.loc20_34: type = type_literal constants.%i32 [concrete = constants.%i32]
-// CHECK:STDOUT:     %.loc20: Core.Form = init_form %i32.loc20_34 [concrete = constants.%.795]
+// CHECK:STDOUT:     %.loc20: Core.Form = init_form %i32.loc20_34 [concrete = constants.%.795f]
 // CHECK:STDOUT:     %self.param: %i32 = value_param call_param0
 // CHECK:STDOUT:     %i32.loc20_14: type = type_literal constants.%i32 [concrete = constants.%i32]
 // CHECK:STDOUT:     %self: %i32 = wrapper_binding self, %self.param
@@ -340,7 +342,7 @@ var arr: array(i32, (1 as i32).(I.F)(2));
 // CHECK:STDOUT:   %self.patt.loc16_8.2 => constants.%self.patt.f6c
 // CHECK:STDOUT:   %other.param_patt.loc16_19.2 => constants.%other.param_patt.12c
 // CHECK:STDOUT:   %other.patt.loc16_19.2 => constants.%other.patt.656
-// CHECK:STDOUT:   %.loc16_30.1 => constants.%.795
+// CHECK:STDOUT:   %.loc16_30.1 => constants.%.795f
 // CHECK:STDOUT:   %return.param_patt.loc16_30.2 => constants.%return.param_patt.a9a
 // CHECK:STDOUT:   %return.patt.loc16_27.2 => constants.%return.patt.e1b
 // CHECK:STDOUT: }

toolchain/check/testdata/function/call/form.carbon

@@ -335,7 +335,7 @@ fn G() {
 // CHECK:STDOUT:   %int_32: Core.IntLiteral = int_value 32 [concrete]
 // CHECK:STDOUT:   %empty_tuple.type: type = tuple_type () [concrete]
 // CHECK:STDOUT:   %i32: type = class_type @Int, @Int(%int_32) [concrete]
-// CHECK:STDOUT:   %.795: Core.Form = init_form %i32 [concrete]
+// CHECK:STDOUT:   %.795f: Core.Form = init_form %i32 [concrete]
 // CHECK:STDOUT:   %pattern_type.6b6: type = pattern_type %i32 [concrete]
 // CHECK:STDOUT:   %x.param_patt: %pattern_type.6b6 = ref_param_pattern [concrete]
 // CHECK:STDOUT:   %x.var_patt: %pattern_type.6b6 = var_pattern %x.param_patt [concrete]
@@ -374,9 +374,9 @@ fn G() {
 // CHECK:STDOUT:     %x.patt: %pattern_type.6b6 = at_binding_pattern x, %x.var_patt [concrete = constants.%x.patt]
 // CHECK:STDOUT:   } {
 // CHECK:STDOUT:     %x.param: ref %i32 = ref_param call_param0
-// CHECK:STDOUT:     %.loc4_15.1: Core.Form = splice_block %.loc4_15.2 [concrete = constants.%.795] {
+// CHECK:STDOUT:     %.loc4_15.1: Core.Form = splice_block %.loc4_15.2 [concrete = constants.%.795f] {
 // CHECK:STDOUT:       %i32: type = type_literal constants.%i32 [concrete = constants.%i32]
-// CHECK:STDOUT:       %.loc4_15.2: Core.Form = init_form %i32 [concrete = constants.%.795]
+// CHECK:STDOUT:       %.loc4_15.2: Core.Form = init_form %i32 [concrete = constants.%.795f]
 // CHECK:STDOUT:       %.loc4_15.3: type = type_component_of %.loc4_15.2 [concrete = constants.%i32]
 // CHECK:STDOUT:     }
 // CHECK:STDOUT:     %x: ref %i32 = wrapper_binding x, %x.param
@@ -699,7 +699,7 @@ fn G() {
 // CHECK:STDOUT:   %ImplicitAs.WithSelf.Convert.type.740: type = fn_type @ImplicitAs.WithSelf.Convert, @ImplicitAs.WithSelf(%i32, %ImplicitAs.facet) [concrete]
 // CHECK:STDOUT:   %.1c5: type = fn_type_with_self_type %ImplicitAs.WithSelf.Convert.type.740, %ImplicitAs.facet [concrete]
 // CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.bound: <bound method> = bound_method %int_0.5c6, %Core.IntLiteral.as.ImplicitAs.impl.Convert.e39 [concrete]
-// CHECK:STDOUT:   %.795: Core.Form = init_form %i32 [concrete]
+// CHECK:STDOUT:   %.795f: Core.Form = init_form %i32 [concrete]
 // CHECK:STDOUT:   %return.param_patt.a9a4c7.1: %pattern_type.6b6 = out_param_pattern [concrete]
 // CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.specific_fn: <specific function> = specific_function %Core.IntLiteral.as.ImplicitAs.impl.Convert.e39, @Core.IntLiteral.as.ImplicitAs.impl.Convert(%int_32) [concrete]
 // CHECK:STDOUT:   %bound_method: <bound method> = bound_method %int_0.5c6, %Core.IntLiteral.as.ImplicitAs.impl.Convert.specific_fn [concrete]
@@ -719,7 +719,7 @@ fn G() {
 // CHECK:STDOUT:     %return.param_patt.a9a4c7.2: %pattern_type.6b6 = out_param_pattern [concrete = %return.param_patt.a9a4c7.1]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %return.patt.e1b: %pattern_type.6b6 = return_slot_pattern %return.param_patt.a9a4c7.1, %i32 [concrete]
-// CHECK:STDOUT:   %F.specific_fn.8ea: <specific function> = specific_function %F, @F(%.795) [concrete]
+// CHECK:STDOUT:   %F.specific_fn.8ea: <specific function> = specific_function %F, @F(%.795f) [concrete]
 // CHECK:STDOUT:   %Copy.type: type = facet_type <@Copy> [concrete]
 // CHECK:STDOUT:   %Int.as.Copy.impl.Op.type.ac8: type = fn_type @Int.as.Copy.impl.Op, @Int.as.Copy.impl(%N) [symbolic]
 // CHECK:STDOUT:   %Int.as.Copy.impl.Op.5e0: %Int.as.Copy.impl.Op.type.ac8 = struct_value () [symbolic]
@@ -870,9 +870,9 @@ fn G() {
 // CHECK:STDOUT:   %x.var: ref %i32 = var_storage %x.var_patt
 // CHECK:STDOUT:   %F.ref.loc13: %F.type = name_ref F, file.%F.decl [concrete = constants.%F]
 // CHECK:STDOUT:   %i32.loc13_34: type = type_literal constants.%i32 [concrete = constants.%i32]
-// CHECK:STDOUT:   %.loc13_30: Core.Form = init_form %i32.loc13_34 [concrete = constants.%.795]
+// CHECK:STDOUT:   %.loc13_30: Core.Form = init_form %i32.loc13_34 [concrete = constants.%.795f]
 // CHECK:STDOUT:   %v.ref.loc13: ref %i32 = name_ref v, %v
-// CHECK:STDOUT:   %F.specific_fn.loc13: <specific function> = specific_function %F.ref.loc13, @F(constants.%.795) [concrete = constants.%F.specific_fn.8ea]
+// CHECK:STDOUT:   %F.specific_fn.loc13: <specific function> = specific_function %F.ref.loc13, @F(constants.%.795f) [concrete = constants.%F.specific_fn.8ea]
 // CHECK:STDOUT:   %.loc13_40: %i32 = acquire_value %v.ref.loc13
 // CHECK:STDOUT:   %impl.elem0.loc13: %.7a6 = impl_witness_access constants.%Copy.impl_witness.0e0, element0 [concrete = constants.%Int.as.Copy.impl.Op.4f6]
 // CHECK:STDOUT:   %bound_method.loc13_40.1: <bound method> = bound_method %.loc13_40, %impl.elem0.loc13
@@ -946,9 +946,9 @@ fn G() {
 // CHECK:STDOUT:   %.loc4_37.5 => constants.%.efc
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: specific @F(constants.%.795) {
+// CHECK:STDOUT: specific @F(constants.%.795f) {
 // CHECK:STDOUT:   %Fm.patt.loc4_16.2 => constants.%Fm.patt
-// CHECK:STDOUT:   %Fm.loc4_16.1 => constants.%.795
+// CHECK:STDOUT:   %Fm.loc4_16.1 => constants.%.795f
 // CHECK:STDOUT:   %.loc4_33.1 => constants.%i32
 // CHECK:STDOUT:   %.loc4_30.3 => constants.%inst.splice_block
 // CHECK:STDOUT:   %pattern_type => constants.%pattern_type.6b6

toolchain/check/testdata/function/call/i32.carbon

@@ -32,7 +32,7 @@ fn Main() {
 // CHECK:STDOUT:   %pattern_type.6b6: type = pattern_type %i32 [concrete]
 // CHECK:STDOUT:   %a.param_patt: %pattern_type.6b6 = value_param_pattern [concrete]
 // CHECK:STDOUT:   %a.patt: %pattern_type.6b6 = at_binding_pattern a, %a.param_patt [concrete]
-// CHECK:STDOUT:   %.795: Core.Form = init_form %i32 [concrete]
+// CHECK:STDOUT:   %.795f: Core.Form = init_form %i32 [concrete]
 // CHECK:STDOUT:   %return.param_patt.a9a: %pattern_type.6b6 = out_param_pattern [concrete]
 // CHECK:STDOUT:   %return.patt.e1b: %pattern_type.6b6 = return_slot_pattern %return.param_patt.a9a, %i32 [concrete]
 // CHECK:STDOUT:   %Echo.type: type = fn_type @Echo [concrete]
@@ -107,7 +107,7 @@ fn Main() {
 // CHECK:STDOUT:     %return.patt: %pattern_type.6b6 = return_slot_pattern %return.param_patt, %i32.loc15_20 [concrete = constants.%return.patt.e1b]
 // CHECK:STDOUT:   } {
 // CHECK:STDOUT:     %i32.loc15_20: type = type_literal constants.%i32 [concrete = constants.%i32]
-// CHECK:STDOUT:     %.loc15: Core.Form = init_form %i32.loc15_20 [concrete = constants.%.795]
+// CHECK:STDOUT:     %.loc15: Core.Form = init_form %i32.loc15_20 [concrete = constants.%.795f]
 // CHECK:STDOUT:     %a.param: %i32 = value_param call_param0
 // CHECK:STDOUT:     %i32.loc15_12: type = type_literal constants.%i32 [concrete = constants.%i32]
 // CHECK:STDOUT:     %a: %i32 = wrapper_binding a, %a.param

toolchain/check/testdata/function/call/prefer_unqualified_lookup.carbon

@@ -43,7 +43,7 @@ fn Class(F: type).Inner.G() -> i32 { return F(); }
 // CHECK:STDOUT:   %Int.type: type = generic_class_type @Int [concrete]
 // CHECK:STDOUT:   %Int.generic: %Int.type = struct_value () [concrete]
 // CHECK:STDOUT:   %i32: type = class_type @Int, @Int(%int_32) [concrete]
-// CHECK:STDOUT:   %.795: Core.Form = init_form %i32 [concrete]
+// CHECK:STDOUT:   %.795f: Core.Form = init_form %i32 [concrete]
 // CHECK:STDOUT:   %pattern_type.6b6: type = pattern_type %i32 [concrete]
 // CHECK:STDOUT:   %return.param_patt.a9a: %pattern_type.6b6 = out_param_pattern [concrete]
 // CHECK:STDOUT:   %return.patt.e1b: %pattern_type.6b6 = return_slot_pattern %return.param_patt.a9a, %i32 [concrete]
@@ -111,7 +111,7 @@ fn Class(F: type).Inner.G() -> i32 { return F(); }
 // CHECK:STDOUT:     }
 // CHECK:STDOUT:     %F.loc13_11: type = symbolic_binding F, 0 [symbolic = @Class.%F.loc5_14.1 (constants.%F)]
 // CHECK:STDOUT:     %i32.loc13: type = type_literal constants.%i32 [concrete = constants.%i32]
-// CHECK:STDOUT:     %.loc13_32: Core.Form = init_form %i32.loc13 [concrete = constants.%.795]
+// CHECK:STDOUT:     %.loc13_32: Core.Form = init_form %i32.loc13 [concrete = constants.%.795f]
 // CHECK:STDOUT:     %return.param.loc13: ref %i32 = out_param call_param0
 // CHECK:STDOUT:     %return.loc13: ref %i32 = return_slot %return.param.loc13
 // CHECK:STDOUT:   }
@@ -149,7 +149,7 @@ fn Class(F: type).Inner.G() -> i32 { return F(); }
 // CHECK:STDOUT:       %return.patt: %pattern_type.6b6 = return_slot_pattern %return.param_patt, %i32 [concrete = constants.%return.patt.e1b]
 // CHECK:STDOUT:     } {
 // CHECK:STDOUT:       %i32: type = type_literal constants.%i32 [concrete = constants.%i32]
-// CHECK:STDOUT:       %.loc8_15: Core.Form = init_form %i32 [concrete = constants.%.795]
+// CHECK:STDOUT:       %.loc8_15: Core.Form = init_form %i32 [concrete = constants.%.795f]
 // CHECK:STDOUT:       %return.param: ref %i32 = out_param call_param0
 // CHECK:STDOUT:       %return: ref %i32 = return_slot %return.param
 // CHECK:STDOUT:     }
@@ -158,7 +158,7 @@ fn Class(F: type).Inner.G() -> i32 { return F(); }
 // CHECK:STDOUT:       %return.patt: %pattern_type.6b6 = return_slot_pattern %return.param_patt, %i32.loc13 [concrete = constants.%return.patt.e1b]
 // CHECK:STDOUT:     } {
 // CHECK:STDOUT:       %i32.loc9: type = type_literal constants.%i32 [concrete = constants.%i32]
-// CHECK:STDOUT:       %.loc9: Core.Form = init_form %i32.loc9 [concrete = constants.%.795]
+// CHECK:STDOUT:       %.loc9: Core.Form = init_form %i32.loc9 [concrete = constants.%.795f]
 // CHECK:STDOUT:       %return.param.loc9: ref %i32 = out_param call_param0
 // CHECK:STDOUT:       %return.loc9: ref %i32 = return_slot %return.param.loc9
 // CHECK:STDOUT:     }

toolchain/check/testdata/function/declaration/import.carbon

@@ -676,7 +676,7 @@ import library "extern_api";
 // CHECK:STDOUT:   %Int.generic: %Int.type = struct_value () [concrete]
 // CHECK:STDOUT:   %i32: type = class_type @Int, @Int(%int_32) [concrete]
 // CHECK:STDOUT:   %pattern_type.6b6: type = pattern_type %i32 [concrete]
-// CHECK:STDOUT:   %.795: Core.Form = init_form %i32 [concrete]
+// CHECK:STDOUT:   %.795f: Core.Form = init_form %i32 [concrete]
 // CHECK:STDOUT:   %B.type: type = fn_type @B [concrete]
 // CHECK:STDOUT:   %B: %B.type = struct_value () [concrete]
 // CHECK:STDOUT:   %tuple.type.85c: type = tuple_type (type) [concrete]
@@ -761,7 +761,7 @@ import library "extern_api";
 // CHECK:STDOUT:   %A.decl: %A.type = fn_decl @A [concrete = constants.%A] {} {}
 // CHECK:STDOUT:   %B.decl: %B.type = fn_decl @B [concrete = constants.%B] {} {
 // CHECK:STDOUT:     %i32.loc23_24: type = type_literal constants.%i32 [concrete = constants.%i32]
-// CHECK:STDOUT:     %.loc23: Core.Form = init_form %i32.loc23_24 [concrete = constants.%.795]
+// CHECK:STDOUT:     %.loc23: Core.Form = init_form %i32.loc23_24 [concrete = constants.%.795f]
 // CHECK:STDOUT:     %b.param: %i32 = value_param call_param0
 // CHECK:STDOUT:     %i32.loc23_16: type = type_literal constants.%i32 [concrete = constants.%i32]
 // CHECK:STDOUT:     %b: %i32 = wrapper_binding b, %b.param
@@ -896,7 +896,7 @@ import library "extern_api";
 // CHECK:STDOUT:   %Int.generic: %Int.type = struct_value () [concrete]
 // CHECK:STDOUT:   %i32: type = class_type @Int, @Int(%int_32) [concrete]
 // CHECK:STDOUT:   %pattern_type.6b6: type = pattern_type %i32 [concrete]
-// CHECK:STDOUT:   %.795: Core.Form = init_form %i32 [concrete]
+// CHECK:STDOUT:   %.795f: Core.Form = init_form %i32 [concrete]
 // CHECK:STDOUT:   %C.type: type = fn_type @C [concrete]
 // CHECK:STDOUT:   %C: %C.type = struct_value () [concrete]
 // CHECK:STDOUT:   %struct_type.c: type = struct_type {.c: %i32} [concrete]
@@ -979,7 +979,7 @@ import library "extern_api";
 // CHECK:STDOUT:   %A.decl: %A.type = fn_decl @A [concrete = constants.%A] {} {}
 // CHECK:STDOUT:   %B.decl: %B.type = fn_decl @B [concrete = constants.%B] {} {
 // CHECK:STDOUT:     %i32.loc7_24: type = type_literal constants.%i32 [concrete = constants.%i32]
-// CHECK:STDOUT:     %.loc7: Core.Form = init_form %i32.loc7_24 [concrete = constants.%.795]
+// CHECK:STDOUT:     %.loc7: Core.Form = init_form %i32.loc7_24 [concrete = constants.%.795f]
 // CHECK:STDOUT:     %b.param: %i32 = value_param call_param0
 // CHECK:STDOUT:     %i32.loc7_16: type = type_literal constants.%i32 [concrete = constants.%i32]
 // CHECK:STDOUT:     %b: %i32 = wrapper_binding b, %b.param

toolchain/check/testdata/function/generic/call_method_on_generic_facet.carbon

@@ -60,6 +60,7 @@ fn G() {
 // CHECK:STDOUT:   %complete_type.357: <witness> = complete_type_witness %empty_struct_type [concrete]
 // CHECK:STDOUT:   %ImplsGeneric: type = class_type @ImplsGeneric [concrete]
 // CHECK:STDOUT:   %Generic.type.b40: type = facet_type <@Generic, @Generic(%GenericParam)> [concrete]
+// CHECK:STDOUT:   %.e53: <witness> = impl_self_witness %ImplsGeneric, @Generic, @Generic(%GenericParam) [concrete]
 // CHECK:STDOUT:   %Generic.impl_witness: <witness> = impl_witness @ImplsGeneric.as.Generic.impl.%Generic.impl_witness_table [concrete]
 // CHECK:STDOUT:   %Self.685: %Generic.type.b40 = symbolic_binding Self, 1 [symbolic]
 // CHECK:STDOUT:   %Generic.WithSelf.F.type.e39: type = fn_type @Generic.WithSelf.F, @Generic.WithSelf(%GenericParam, %Self.8ea1ea.1) [symbolic]
@@ -77,6 +78,7 @@ fn G() {
 // CHECK:STDOUT:   %Other.WithSelf.G.050: %Other.WithSelf.G.type.eee = struct_value () [symbolic]
 // CHECK:STDOUT:   %Other.assoc_type: type = assoc_entity_type @Other [concrete]
 // CHECK:STDOUT:   %assoc0.e70: %Other.assoc_type = assoc_entity element0, @Other.WithSelf.%Other.WithSelf.G.decl [concrete]
+// CHECK:STDOUT:   %.13c: <witness> = impl_self_witness %ImplsGeneric, @Other [concrete]
 // CHECK:STDOUT:   %Other.impl_witness: <witness> = impl_witness @ImplsGeneric.as.Other.impl.%Other.impl_witness_table [concrete]
 // CHECK:STDOUT:   %ImplsGeneric.as.Other.impl.G.type: type = fn_type @ImplsGeneric.as.Other.impl.G [concrete]
 // CHECK:STDOUT:   %ImplsGeneric.as.Other.impl.G: %ImplsGeneric.as.Other.impl.G.type = struct_value () [concrete]
@@ -148,11 +150,13 @@ fn G() {
 // CHECK:STDOUT:     %GenericParam.ref: type = name_ref GenericParam, file.%GenericParam.decl [concrete = constants.%GenericParam]
 // CHECK:STDOUT:     %Generic.type: type = facet_type <@Generic, @Generic(constants.%GenericParam)> [concrete = constants.%Generic.type.b40]
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %.loc22: <witness> = impl_self_witness @ImplsGeneric.as.Generic.impl.%ImplsGeneric.ref, @Generic, @Generic(constants.%GenericParam) [concrete = constants.%.e53]
 // CHECK:STDOUT:   %Other.decl: type = interface_decl @Other [concrete = constants.%Other.type] {} {}
 // CHECK:STDOUT:   impl_decl @ImplsGeneric.as.Other.impl [concrete] {} {
 // CHECK:STDOUT:     %ImplsGeneric.ref: type = name_ref ImplsGeneric, file.%ImplsGeneric.decl [concrete = constants.%ImplsGeneric]
 // CHECK:STDOUT:     %Other.ref: type = name_ref Other, file.%Other.decl [concrete = constants.%Other.type]
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %.loc29: <witness> = impl_self_witness @ImplsGeneric.as.Other.impl.%ImplsGeneric.ref, @Other [concrete = constants.%.13c]
 // CHECK:STDOUT:   %CallGenericMethod.decl: %CallGenericMethod.type = fn_decl @CallGenericMethod [concrete = constants.%CallGenericMethod] {
 // CHECK:STDOUT:     %T.patt.loc33_31.1: %pattern_type.98f = symbolic_binding_pattern T, 0 [symbolic = %T.patt.loc33_31.2 (constants.%T.patt)]
 // CHECK:STDOUT:     %U.patt.loc33_48.1: @CallGenericMethod.%pattern_type (%pattern_type.4e0) = symbolic_binding_pattern U, 1 [symbolic = %U.patt.loc33_48.2 (constants.%U.patt.8a6)]

toolchain/check/testdata/function/generic/deduce.carbon

@@ -1853,6 +1853,7 @@ fn F() {
 // CHECK:STDOUT:   %EE: type = class_type @EE [concrete]
 // CHECK:STDOUT:   %empty_struct_type: type = struct_type {} [concrete]
 // CHECK:STDOUT:   %complete_type: <witness> = complete_type_witness %empty_struct_type [concrete]
+// CHECK:STDOUT:   %.236: <witness> = impl_self_witness %EE, @Z [concrete]
 // CHECK:STDOUT:   %Z.impl_witness.0e0: <witness> = impl_witness @EE.as.Z.impl.%Z.impl_witness_table [concrete]
 // CHECK:STDOUT:   %Z.facet.a2d: %Z.type = facet_value %EE, (%Z.impl_witness.0e0) [concrete]
 // CHECK:STDOUT:   %type: type = facet_type <type> [concrete]
@@ -1863,6 +1864,7 @@ fn F() {
 // CHECK:STDOUT:   %DD.type: type = generic_class_type @DD [concrete]
 // CHECK:STDOUT:   %DD.generic: %DD.type = struct_value () [concrete]
 // CHECK:STDOUT:   %DD.699: type = class_type @DD, @DD(%E) [symbolic]
+// CHECK:STDOUT:   %.91f: <witness> = impl_self_witness %DD.699, @Z [symbolic]
 // CHECK:STDOUT:   %Z.impl_witness.7fb: <witness> = impl_witness @DD.as.Z.impl.%Z.impl_witness_table, @DD.as.Z.impl(%E) [symbolic]
 // CHECK:STDOUT:   %Z.facet.419: %Z.type = facet_value %DD.699, (%Z.impl_witness.7fb) [symbolic]
 // CHECK:STDOUT:   %pattern_type.5d7: type = pattern_type %Z.type [concrete]
@@ -1875,15 +1877,18 @@ fn F() {
 // CHECK:STDOUT:   %.8d3: require_specific_def_type = require_specific_def @DD.as.Z.impl(%E) [symbolic]
 // CHECK:STDOUT:   %Z.facet.0b6: %Z.type = facet_value %DD.699, (%Z.lookup_impl_witness) [symbolic]
 // CHECK:STDOUT:   %CC.2a8: type = class_type @CC, @CC(%Z.facet.0b6) [symbolic]
+// CHECK:STDOUT:   %.e93: <witness> = impl_self_witness %CC.2a8, @Z [symbolic]
 // CHECK:STDOUT:   %Z.impl_witness.458: <witness> = impl_witness @CC.as.Z.impl.%Z.impl_witness_table, @CC.as.Z.impl(%E) [symbolic]
 // CHECK:STDOUT:   %Z.facet.2d1: %Z.type = facet_value %CC.2a8, (%Z.impl_witness.458) [symbolic]
 // CHECK:STDOUT:   %F.type: type = fn_type @F [concrete]
 // CHECK:STDOUT:   %F: %F.type = struct_value () [concrete]
 // CHECK:STDOUT:   %DD.cfc: type = class_type @DD, @DD(%EE) [concrete]
+// CHECK:STDOUT:   %.890: <witness> = impl_self_witness %DD.cfc, @Z [concrete]
 // CHECK:STDOUT:   %Z.impl_witness.7dd: <witness> = impl_witness @DD.as.Z.impl.%Z.impl_witness_table, @DD.as.Z.impl(%EE) [concrete]
 // CHECK:STDOUT:   %.061: require_specific_def_type = require_specific_def @DD.as.Z.impl(%EE) [concrete]
 // CHECK:STDOUT:   %Z.facet.da0: %Z.type = facet_value %DD.cfc, (%Z.impl_witness.7dd) [concrete]
 // CHECK:STDOUT:   %CC.a5a: type = class_type @CC, @CC(%Z.facet.da0) [concrete]
+// CHECK:STDOUT:   %.371: <witness> = impl_self_witness %CC.a5a, @Z [concrete]
 // CHECK:STDOUT:   %Z.impl_witness.df9: <witness> = impl_witness @CC.as.Z.impl.%Z.impl_witness_table, @CC.as.Z.impl(%EE) [concrete]
 // CHECK:STDOUT:   %Z.facet.57d: %Z.type = facet_value %CC.a5a, (%Z.impl_witness.df9) [concrete]
 // CHECK:STDOUT: }
@@ -1911,6 +1916,7 @@ fn F() {
 // CHECK:STDOUT:     %EE.ref: type = name_ref EE, file.%EE.decl [concrete = constants.%EE]
 // CHECK:STDOUT:     %Z.ref: type = name_ref Z, file.%Z.decl [concrete = constants.%Z.type]
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %.loc6: <witness> = impl_self_witness @EE.as.Z.impl.%EE.ref, @Z [concrete = constants.%.236]
 // CHECK:STDOUT:   %DD.decl: %DD.type = class_decl @DD [concrete = constants.%DD.generic] {
 // CHECK:STDOUT:     %E.patt.loc8_11.1: %pattern_type.98f = symbolic_binding_pattern E, 0 [symbolic = %E.patt.loc8_11.2 (constants.%E.patt)]
 // CHECK:STDOUT:   } {
@@ -1933,6 +1939,7 @@ fn F() {
 // CHECK:STDOUT:     }
 // CHECK:STDOUT:     %E.loc9_15.1: type = symbolic_binding E, 0 [symbolic = %E.loc9_15.2 (constants.%E)]
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %.loc9: <witness> = impl_self_witness @DD.as.Z.impl.%DD.loc9_27.1, @Z [symbolic = @DD.as.Z.impl.%.loc9_34 (constants.%.91f)]
 // CHECK:STDOUT:   %CC.decl: %CC.type = class_decl @CC [concrete = constants.%CC.generic] {
 // CHECK:STDOUT:     %D.patt.loc11_11.1: %pattern_type.5d7 = symbolic_binding_pattern D, 0 [symbolic = %D.patt.loc11_11.2 (constants.%D.patt)]
 // CHECK:STDOUT:   } {
@@ -1959,6 +1966,7 @@ fn F() {
 // CHECK:STDOUT:     }
 // CHECK:STDOUT:     %E.loc12_15.1: type = symbolic_binding E, 0 [symbolic = %E.loc12_15.2 (constants.%E)]
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %.loc12: <witness> = impl_self_witness @CC.as.Z.impl.%CC.loc12_31.1, @Z [symbolic = @CC.as.Z.impl.%.loc12_38 (constants.%.e93)]
 // CHECK:STDOUT:   %F.decl: %F.type = fn_decl @F [concrete = constants.%F] {} {}
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -1986,6 +1994,7 @@ fn F() {
 // CHECK:STDOUT:   %E.patt.loc9_15.2: %pattern_type.98f = symbolic_binding_pattern E, 0 [symbolic = %E.patt.loc9_15.2 (constants.%E.patt)]
 // CHECK:STDOUT:   %E.loc9_15.2: type = symbolic_binding E, 0 [symbolic = %E.loc9_15.2 (constants.%E)]
 // CHECK:STDOUT:   %DD.loc9_27.2: type = class_type @DD, @DD(%E.loc9_15.2) [symbolic = %DD.loc9_27.2 (constants.%DD.699)]
+// CHECK:STDOUT:   %.loc9_34: <witness> = impl_self_witness %DD.loc9_27.2, @Z [symbolic = %.loc9_34 (constants.%.91f)]
 // CHECK:STDOUT:   %Z.impl_witness.loc9_34.2: <witness> = impl_witness %Z.impl_witness_table, @DD.as.Z.impl(%E.loc9_15.2) [symbolic = %Z.impl_witness.loc9_34.2 (constants.%Z.impl_witness.7fb)]
 // CHECK:STDOUT:
 // CHECK:STDOUT: !definition:
@@ -2008,6 +2017,7 @@ fn F() {
 // CHECK:STDOUT:   %Z.lookup_impl_witness: <witness> = lookup_impl_witness %DD.loc12_30.2, @Z [symbolic = %Z.lookup_impl_witness (constants.%Z.lookup_impl_witness)]
 // CHECK:STDOUT:   %Z.facet.loc12_31.2: %Z.type = facet_value %DD.loc12_30.2, (%Z.lookup_impl_witness) [symbolic = %Z.facet.loc12_31.2 (constants.%Z.facet.0b6)]
 // CHECK:STDOUT:   %CC.loc12_31.2: type = class_type @CC, @CC(%Z.facet.loc12_31.2) [symbolic = %CC.loc12_31.2 (constants.%CC.2a8)]
+// CHECK:STDOUT:   %.loc12_38: <witness> = impl_self_witness %CC.loc12_31.2, @Z [symbolic = %.loc12_38 (constants.%.e93)]
 // CHECK:STDOUT:   %Z.impl_witness.loc12_38.2: <witness> = impl_witness %Z.impl_witness_table, @CC.as.Z.impl(%E.loc12_15.2) [symbolic = %Z.impl_witness.loc12_38.2 (constants.%Z.impl_witness.458)]
 // CHECK:STDOUT:
 // CHECK:STDOUT: !definition:
@@ -2092,6 +2102,7 @@ fn F() {
 // CHECK:STDOUT:   %E.patt.loc9_15.2 => constants.%E.patt
 // CHECK:STDOUT:   %E.loc9_15.2 => constants.%E
 // CHECK:STDOUT:   %DD.loc9_27.2 => constants.%DD.699
+// CHECK:STDOUT:   %.loc9_34 => constants.%.91f
 // CHECK:STDOUT:   %Z.impl_witness.loc9_34.2 => constants.%Z.impl_witness.7fb
 // CHECK:STDOUT:
 // CHECK:STDOUT: !definition:
@@ -2119,6 +2130,7 @@ fn F() {
 // CHECK:STDOUT:   %Z.lookup_impl_witness => constants.%Z.lookup_impl_witness
 // CHECK:STDOUT:   %Z.facet.loc12_31.2 => constants.%Z.facet.0b6
 // CHECK:STDOUT:   %CC.loc12_31.2 => constants.%CC.2a8
+// CHECK:STDOUT:   %.loc12_38 => constants.%.e93
 // CHECK:STDOUT:   %Z.impl_witness.loc12_38.2 => constants.%Z.impl_witness.458
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -2135,6 +2147,7 @@ fn F() {
 // CHECK:STDOUT:   %E.patt.loc9_15.2 => constants.%E.patt
 // CHECK:STDOUT:   %E.loc9_15.2 => constants.%EE
 // CHECK:STDOUT:   %DD.loc9_27.2 => constants.%DD.cfc
+// CHECK:STDOUT:   %.loc9_34 => constants.%.890
 // CHECK:STDOUT:   %Z.impl_witness.loc9_34.2 => constants.%Z.impl_witness.7dd
 // CHECK:STDOUT:
 // CHECK:STDOUT: !definition:
@@ -2153,6 +2166,7 @@ fn F() {
 // CHECK:STDOUT:   %Z.lookup_impl_witness => constants.%Z.impl_witness.7dd
 // CHECK:STDOUT:   %Z.facet.loc12_31.2 => constants.%Z.facet.da0
 // CHECK:STDOUT:   %CC.loc12_31.2 => constants.%CC.a5a
+// CHECK:STDOUT:   %.loc12_38 => constants.%.371
 // CHECK:STDOUT:   %Z.impl_witness.loc12_38.2 => constants.%Z.impl_witness.df9
 // CHECK:STDOUT:
 // CHECK:STDOUT: !definition:

toolchain/check/testdata/function/generic/deduce_nested_facet_value.carbon

@@ -47,8 +47,10 @@ fn F() {
 // CHECK:STDOUT:   %DD: type = class_type @DD [concrete]
 // CHECK:STDOUT:   %empty_struct_type: type = struct_type {} [concrete]
 // CHECK:STDOUT:   %complete_type: <witness> = complete_type_witness %empty_struct_type [concrete]
+// CHECK:STDOUT:   %.565: <witness> = impl_self_witness %DD, @Y [concrete]
 // CHECK:STDOUT:   %Y.impl_witness: <witness> = impl_witness @DD.as.Y.impl.%Y.impl_witness_table [concrete]
 // CHECK:STDOUT:   %Y.facet.2a4: %Y.type = facet_value %DD, (%Y.impl_witness) [concrete]
+// CHECK:STDOUT:   %.918: <witness> = impl_self_witness %DD, @W [concrete]
 // CHECK:STDOUT:   %W.impl_witness: <witness> = impl_witness @DD.as.W.impl.%W.impl_witness_table [concrete]
 // CHECK:STDOUT:   %W.facet: %W.type = facet_value %DD, (%W.impl_witness) [concrete]
 // CHECK:STDOUT:   %type: type = facet_type <type> [concrete]
@@ -79,12 +81,14 @@ fn F() {
 // CHECK:STDOUT:   %Y.lookup_impl_witness: <witness> = lookup_impl_witness %E, @Y [symbolic]
 // CHECK:STDOUT:   %Y.facet.18f: %Y.type = facet_value %E.as_type, (%Y.lookup_impl_witness) [symbolic]
 // CHECK:STDOUT:   %CC.db5: type = class_type @CC, @CC(%Y.facet.18f) [symbolic]
+// CHECK:STDOUT:   %.bd6: <witness> = impl_self_witness %CC.db5, @Z [symbolic]
 // CHECK:STDOUT:   %Z.impl_witness.6a9: <witness> = impl_witness @CC.as.Z.impl.%Z.impl_witness_table, @CC.as.Z.impl(%E) [symbolic]
 // CHECK:STDOUT:   %Z.facet.674: %Z.type = facet_value %CC.db5, (%Z.impl_witness.6a9) [symbolic]
 // CHECK:STDOUT:   %F.type: type = fn_type @F [concrete]
 // CHECK:STDOUT:   %F: %F.type = struct_value () [concrete]
 // CHECK:STDOUT:   %CC.d62: type = class_type @CC, @CC(%Y.facet.2a4) [concrete]
 // CHECK:STDOUT:   %facet_value: %facet_type = facet_value %DD, (%Y.impl_witness, %W.impl_witness) [concrete]
+// CHECK:STDOUT:   %.343: <witness> = impl_self_witness %CC.d62, @Z [concrete]
 // CHECK:STDOUT:   %Z.impl_witness.b3a: <witness> = impl_witness @CC.as.Z.impl.%Z.impl_witness_table, @CC.as.Z.impl(%facet_value) [concrete]
 // CHECK:STDOUT:   %Z.facet.737: %Z.type = facet_value %CC.d62, (%Z.impl_witness.b3a) [concrete]
 // CHECK:STDOUT: }
@@ -118,10 +122,12 @@ fn F() {
 // CHECK:STDOUT:     %DD.ref: type = name_ref DD, file.%DD.decl [concrete = constants.%DD]
 // CHECK:STDOUT:     %Y.ref: type = name_ref Y, file.%Y.decl [concrete = constants.%Y.type]
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %.loc8: <witness> = impl_self_witness @DD.as.Y.impl.%DD.ref, @Y [concrete = constants.%.565]
 // CHECK:STDOUT:   impl_decl @DD.as.W.impl [concrete] {} {
 // CHECK:STDOUT:     %DD.ref: type = name_ref DD, file.%DD.decl [concrete = constants.%DD]
 // CHECK:STDOUT:     %W.ref: type = name_ref W, file.%W.decl [concrete = constants.%W.type]
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %.loc9: <witness> = impl_self_witness @DD.as.W.impl.%DD.ref, @W [concrete = constants.%.918]
 // CHECK:STDOUT:   %CC.decl: %CC.type = class_decl @CC [concrete = constants.%CC.generic] {
 // CHECK:STDOUT:     %D.patt.loc12_11.1: %pattern_type.cfb = symbolic_binding_pattern D, 0 [symbolic = %D.patt.loc12_11.2 (constants.%D.patt)]
 // CHECK:STDOUT:   } {
@@ -154,6 +160,7 @@ fn F() {
 // CHECK:STDOUT:     }
 // CHECK:STDOUT:     %E.loc19_15.1: %facet_type = symbolic_binding E, 0 [symbolic = %E.loc19_15.2 (constants.%E)]
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %.loc19: <witness> = impl_self_witness @CC.as.Z.impl.%CC.loc19_28.1, @Z [symbolic = @CC.as.Z.impl.%.loc19_35 (constants.%.bd6)]
 // CHECK:STDOUT:   %F.decl: %F.type = fn_decl @F [concrete = constants.%F] {} {}
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -215,6 +222,7 @@ fn F() {
 // CHECK:STDOUT:   %Y.lookup_impl_witness: <witness> = lookup_impl_witness %E.loc19_15.2, @Y [symbolic = %Y.lookup_impl_witness (constants.%Y.lookup_impl_witness)]
 // CHECK:STDOUT:   %Y.facet.loc19_28.2: %Y.type = facet_value %E.as_type.loc19_28.2, (%Y.lookup_impl_witness) [symbolic = %Y.facet.loc19_28.2 (constants.%Y.facet.18f)]
 // CHECK:STDOUT:   %CC.loc19_28.2: type = class_type @CC, @CC(%Y.facet.loc19_28.2) [symbolic = %CC.loc19_28.2 (constants.%CC.db5)]
+// CHECK:STDOUT:   %.loc19_35: <witness> = impl_self_witness %CC.loc19_28.2, @Z [symbolic = %.loc19_35 (constants.%.bd6)]
 // CHECK:STDOUT:   %Z.impl_witness.loc19_35.2: <witness> = impl_witness %Z.impl_witness_table, @CC.as.Z.impl(%E.loc19_15.2) [symbolic = %Z.impl_witness.loc19_35.2 (constants.%Z.impl_witness.6a9)]
 // CHECK:STDOUT:
 // CHECK:STDOUT: !definition:
@@ -302,6 +310,7 @@ fn F() {
 // CHECK:STDOUT:   %Y.lookup_impl_witness => constants.%Y.lookup_impl_witness
 // CHECK:STDOUT:   %Y.facet.loc19_28.2 => constants.%Y.facet.18f
 // CHECK:STDOUT:   %CC.loc19_28.2 => constants.%CC.db5
+// CHECK:STDOUT:   %.loc19_35 => constants.%.bd6
 // CHECK:STDOUT:   %Z.impl_witness.loc19_35.2 => constants.%Z.impl_witness.6a9
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -321,6 +330,7 @@ fn F() {
 // CHECK:STDOUT:   %Y.lookup_impl_witness => constants.%Y.impl_witness
 // CHECK:STDOUT:   %Y.facet.loc19_28.2 => constants.%Y.facet.2a4
 // CHECK:STDOUT:   %CC.loc19_28.2 => constants.%CC.d62
+// CHECK:STDOUT:   %.loc19_35 => constants.%.343
 // CHECK:STDOUT:   %Z.impl_witness.loc19_35.2 => constants.%Z.impl_witness.b3a
 // CHECK:STDOUT:
 // CHECK:STDOUT: !definition: