Form-aware textual format for return parameters and arguments (#6588)

The key changes are:
- Function output parameters are now prefixed with `out`, and more
consistently formatted as named parameters.
- Function and inst output arguments are now written as part of the inst
form, rather than as one of the inst arguments.

As a drive-by fix, this also changes `Temporary::storage_id` from
`DestInstId` to `InstId`, because it doesn't represent an output
parameter of the `Temporary` inst itself.

See the review of
[#6532](https://github.com/carbon-language/carbon-lang/pull/6532) and
[this Discord
discussion](https://discord.com/channels/655572317891461132/999638000126394370/1458268977020141589)
for additional background.

toolchain/check/testdata/interop/cpp/function/class.carbon

@@ -565,7 +565,7 @@ fn F() {
 // CHECK:STDOUT:   %Cpp.ref.loc8_17: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:   %C.ref: type = name_ref C, imports.%C.decl [concrete = constants.%C]
 // CHECK:STDOUT:   %.loc8_12.2: ref %C = temporary_storage
-// CHECK:STDOUT:   %.loc8_12.3: init %C = class_init (), %.loc8_12.2 [concrete = constants.%C.val]
+// CHECK:STDOUT:   %.loc8_12.3: init %C to %.loc8_12.2 = class_init () [concrete = constants.%C.val]
 // CHECK:STDOUT:   %.loc8_12.4: ref %C = temporary %.loc8_12.2, %.loc8_12.3
 // CHECK:STDOUT:   %.loc8_14.1: ref %C = converted %.loc8_12.1, %.loc8_12.4
 // CHECK:STDOUT:   %.loc8_14.2: %C = acquire_value %.loc8_14.1
@@ -618,7 +618,7 @@ fn F() {
 // CHECK:STDOUT:   %Cpp.ref.loc24_17: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:   %C.ref: type = name_ref C, imports.%C.decl [concrete = constants.%C]
 // CHECK:STDOUT:   %.loc24_12.2: ref %C = temporary_storage
-// CHECK:STDOUT:   %.loc24_12.3: init %C = class_init (), %.loc24_12.2 [concrete = constants.%C.val]
+// CHECK:STDOUT:   %.loc24_12.3: init %C to %.loc24_12.2 = class_init () [concrete = constants.%C.val]
 // CHECK:STDOUT:   %.loc24_12.4: ref %C = temporary %.loc24_12.2, %.loc24_12.3
 // CHECK:STDOUT:   %.loc24_14.1: ref %C = converted %.loc24_12.1, %.loc24_12.4
 // CHECK:STDOUT:   %.loc24_14.2: %C = acquire_value %.loc24_14.1
@@ -738,7 +738,7 @@ fn F() {
 // CHECK:STDOUT:   %N.ref.loc8: <namespace> = name_ref N, imports.%N [concrete = imports.%N]
 // CHECK:STDOUT:   %C.ref.loc8: type = name_ref C, imports.%C.decl [concrete = constants.%C]
 // CHECK:STDOUT:   %.loc8_12.2: ref %C = temporary_storage
-// CHECK:STDOUT:   %.loc8_12.3: init %C = class_init (), %.loc8_12.2 [concrete = constants.%C.val]
+// CHECK:STDOUT:   %.loc8_12.3: init %C to %.loc8_12.2 = class_init () [concrete = constants.%C.val]
 // CHECK:STDOUT:   %.loc8_12.4: ref %C = temporary %.loc8_12.2, %.loc8_12.3
 // CHECK:STDOUT:   %.loc8_14.1: ref %C = converted %.loc8_12.1, %.loc8_12.4
 // CHECK:STDOUT:   %.loc8_14.2: %C = acquire_value %.loc8_14.1
@@ -816,7 +816,7 @@ fn F() {
 // CHECK:STDOUT:   %N2.ref: <namespace> = name_ref N2, imports.%N2 [concrete = imports.%N2]
 // CHECK:STDOUT:   %C.ref: type = name_ref C, imports.%C.decl [concrete = constants.%C]
 // CHECK:STDOUT:   %.loc8_15.2: ref %C = temporary_storage
-// CHECK:STDOUT:   %.loc8_15.3: init %C = class_init (), %.loc8_15.2 [concrete = constants.%C.val]
+// CHECK:STDOUT:   %.loc8_15.3: init %C to %.loc8_15.2 = class_init () [concrete = constants.%C.val]
 // CHECK:STDOUT:   %.loc8_15.4: ref %C = temporary %.loc8_15.2, %.loc8_15.3
 // CHECK:STDOUT:   %.loc8_17.1: ref %C = converted %.loc8_15.1, %.loc8_15.4
 // CHECK:STDOUT:   %.loc8_17.2: %C = acquire_value %.loc8_17.1
@@ -876,7 +876,7 @@ fn F() {
 // CHECK:STDOUT:   %O.ref.loc8: type = name_ref O, imports.%O.decl [concrete = constants.%O]
 // CHECK:STDOUT:   %C.ref: type = name_ref C, imports.%C.decl [concrete = constants.%C]
 // CHECK:STDOUT:   %.loc8_12.2: ref %C = temporary_storage
-// CHECK:STDOUT:   %.loc8_12.3: init %C = class_init (), %.loc8_12.2 [concrete = constants.%C.val]
+// CHECK:STDOUT:   %.loc8_12.3: init %C to %.loc8_12.2 = class_init () [concrete = constants.%C.val]
 // CHECK:STDOUT:   %.loc8_12.4: ref %C = temporary %.loc8_12.2, %.loc8_12.3
 // CHECK:STDOUT:   %.loc8_14.1: ref %C = converted %.loc8_12.1, %.loc8_12.4
 // CHECK:STDOUT:   %.loc8_14.2: %C = acquire_value %.loc8_14.1
@@ -954,7 +954,7 @@ fn F() {
 // CHECK:STDOUT:   %Cpp.ref.loc9_17: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:   %C.ref.loc9: type = name_ref C, imports.%C.decl [concrete = constants.%C]
 // CHECK:STDOUT:   %.loc9_12.2: ref %C = temporary_storage
-// CHECK:STDOUT:   %.loc9_12.3: init %C = class_init (), %.loc9_12.2 [concrete = constants.%C.val]
+// CHECK:STDOUT:   %.loc9_12.3: init %C to %.loc9_12.2 = class_init () [concrete = constants.%C.val]
 // CHECK:STDOUT:   %.loc9_12.4: ref %C = temporary %.loc9_12.2, %.loc9_12.3
 // CHECK:STDOUT:   %.loc9_14.1: ref %C = converted %.loc9_12.1, %.loc9_12.4
 // CHECK:STDOUT:   %.loc9_14.2: %C = acquire_value %.loc9_14.1
@@ -1014,7 +1014,7 @@ fn F() {
 // CHECK:STDOUT:   %Cpp.ref.loc8_17: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:   %C.ref.loc8: type = name_ref C, imports.%C.decl [concrete = constants.%C]
 // CHECK:STDOUT:   %.loc8_12.2: ref %C = temporary_storage
-// CHECK:STDOUT:   %.loc8_12.3: init %C = class_init (), %.loc8_12.2 [concrete = constants.%C.val]
+// CHECK:STDOUT:   %.loc8_12.3: init %C to %.loc8_12.2 = class_init () [concrete = constants.%C.val]
 // CHECK:STDOUT:   %.loc8_12.4: ref %C = temporary %.loc8_12.2, %.loc8_12.3
 // CHECK:STDOUT:   %.loc8_14.1: ref %C = converted %.loc8_12.1, %.loc8_12.4
 // CHECK:STDOUT:   %.loc8_14.2: %C = acquire_value %.loc8_14.1
@@ -1138,7 +1138,7 @@ fn F() {
 // CHECK:STDOUT:   %.loc8_11.1: ref %C = temporary_storage
 // CHECK:STDOUT:   %addr: %ptr.d9e = addr_of %.loc8_11.1
 // CHECK:STDOUT:   %foo__carbon_thunk.call: init %empty_tuple.type = call imports.%foo__carbon_thunk.decl(%addr)
-// CHECK:STDOUT:   %.loc8_11.2: init %C = in_place_init %foo__carbon_thunk.call, %.loc8_11.1
+// CHECK:STDOUT:   %.loc8_11.2: init %C to %.loc8_11.1 = in_place_init %foo__carbon_thunk.call
 // CHECK:STDOUT:   %.loc8_11.3: ref %C = temporary %.loc8_11.1, %.loc8_11.2
 // CHECK:STDOUT:   %C.cpp_destructor.bound: <bound method> = bound_method %.loc8_11.3, constants.%C.cpp_destructor
 // CHECK:STDOUT:   %C.cpp_destructor.call: init %empty_tuple.type = call %C.cpp_destructor.bound(%.loc8_11.3)

toolchain/check/testdata/interop/cpp/function/default_arg.carbon

@@ -331,7 +331,7 @@ fn Call() {
 // CHECK:STDOUT:   %Cpp.ref.loc10: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:   %X.ref.loc10: type = name_ref X, imports.%X.decl [concrete = constants.%X]
 // CHECK:STDOUT:   %.loc10_5.2: ref %X = temporary_storage
-// CHECK:STDOUT:   %.loc10_5.3: init %X = class_init (), %.loc10_5.2 [concrete = constants.%X.val]
+// CHECK:STDOUT:   %.loc10_5.3: init %X to %.loc10_5.2 = class_init () [concrete = constants.%X.val]
 // CHECK:STDOUT:   %.loc10_5.4: ref %X = temporary %.loc10_5.2, %.loc10_5.3
 // CHECK:STDOUT:   %.loc10_7: ref %X = converted %.loc10_5.1, %.loc10_5.4
 // CHECK:STDOUT:   %B.ref: %X.B.cpp_overload_set.type = name_ref B, imports.%X.B.cpp_overload_set.value [concrete = constants.%X.B.cpp_overload_set.value]
@@ -377,7 +377,7 @@ fn Call() {
 // CHECK:STDOUT:   %Cpp.ref.loc12: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:   %X.ref.loc12: type = name_ref X, imports.%X.decl [concrete = constants.%X]
 // CHECK:STDOUT:   %.loc12_5.2: ref %X = temporary_storage
-// CHECK:STDOUT:   %.loc12_5.3: init %X = class_init (), %.loc12_5.2 [concrete = constants.%X.val]
+// CHECK:STDOUT:   %.loc12_5.3: init %X to %.loc12_5.2 = class_init () [concrete = constants.%X.val]
 // CHECK:STDOUT:   %.loc12_5.4: ref %X = temporary %.loc12_5.2, %.loc12_5.3
 // CHECK:STDOUT:   %.loc12_7.1: ref %X = converted %.loc12_5.1, %.loc12_5.4
 // CHECK:STDOUT:   %D.ref: %X.D.cpp_overload_set.type = name_ref D, imports.%X.D.cpp_overload_set.value [concrete = constants.%X.D.cpp_overload_set.value]
@@ -727,7 +727,7 @@ fn Call() {
 // CHECK:STDOUT:   %Cpp.ref.loc11: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:   %X.ref.loc11: type = name_ref X, imports.%X.decl [concrete = constants.%X]
 // CHECK:STDOUT:   %.loc11_5.2: ref %X = temporary_storage
-// CHECK:STDOUT:   %.loc11_5.3: init %X = class_init (), %.loc11_5.2 [concrete = constants.%X.val]
+// CHECK:STDOUT:   %.loc11_5.3: init %X to %.loc11_5.2 = class_init () [concrete = constants.%X.val]
 // CHECK:STDOUT:   %.loc11_5.4: ref %X = temporary %.loc11_5.2, %.loc11_5.3
 // CHECK:STDOUT:   %.loc11_7: ref %X = converted %.loc11_5.1, %.loc11_5.4
 // CHECK:STDOUT:   %B.ref: %X.B.cpp_overload_set.type = name_ref B, imports.%X.B.cpp_overload_set.value [concrete = constants.%X.B.cpp_overload_set.value]
@@ -757,7 +757,7 @@ fn Call() {
 // CHECK:STDOUT:   %Cpp.ref.loc13: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:   %X.ref.loc13: type = name_ref X, imports.%X.decl [concrete = constants.%X]
 // CHECK:STDOUT:   %.loc13_5.2: ref %X = temporary_storage
-// CHECK:STDOUT:   %.loc13_5.3: init %X = class_init (), %.loc13_5.2 [concrete = constants.%X.val]
+// CHECK:STDOUT:   %.loc13_5.3: init %X to %.loc13_5.2 = class_init () [concrete = constants.%X.val]
 // CHECK:STDOUT:   %.loc13_5.4: ref %X = temporary %.loc13_5.2, %.loc13_5.3
 // CHECK:STDOUT:   %.loc13_7.1: ref %X = converted %.loc13_5.1, %.loc13_5.4
 // CHECK:STDOUT:   %D.ref: %X.D.cpp_overload_set.type = name_ref D, imports.%X.D.cpp_overload_set.value [concrete = constants.%X.D.cpp_overload_set.value]
@@ -785,9 +785,9 @@ fn Call() {
 // CHECK:STDOUT:
 // CHECK:STDOUT: fn @GlobalNoReturn__carbon_thunk.1(%a.param: %i32, %b.param: %i32);
 // CHECK:STDOUT:
-// CHECK:STDOUT: fn @GlobalReturnInt(%a.param: %i32, %b.param: %i32) -> %i32;
+// CHECK:STDOUT: fn @GlobalReturnInt(%a.param: %i32, %b.param: %i32) -> out %return.param: %i32;
 // CHECK:STDOUT:
-// CHECK:STDOUT: fn @GlobalReturnInt__carbon_thunk(%a.param: %i32, %b.param: %i32) -> %i32;
+// CHECK:STDOUT: fn @GlobalReturnInt__carbon_thunk(%a.param: %i32, %b.param: %i32) -> out %return.param: %i32;
 // CHECK:STDOUT:
 // CHECK:STDOUT: fn @GlobalNoReturn.2(%a.param: %i32, %b.param: %i32, %c.param: %i32);
 // CHECK:STDOUT:
@@ -863,7 +863,7 @@ fn Call() {
 // CHECK:STDOUT:   %Cpp.ref.loc56: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:   %X.ref.loc56: type = name_ref X, imports.%X.decl [concrete = constants.%X]
 // CHECK:STDOUT:   %.loc56_5.2: ref %X = temporary_storage
-// CHECK:STDOUT:   %.loc56_5.3: init %X = class_init (), %.loc56_5.2 [concrete = constants.%X.val]
+// CHECK:STDOUT:   %.loc56_5.3: init %X to %.loc56_5.2 = class_init () [concrete = constants.%X.val]
 // CHECK:STDOUT:   %.loc56_5.4: ref %X = temporary %.loc56_5.2, %.loc56_5.3
 // CHECK:STDOUT:   %.loc56_7: ref %X = converted %.loc56_5.1, %.loc56_5.4
 // CHECK:STDOUT:   %B.ref: %X.B.cpp_overload_set.type = name_ref B, imports.%X.B.cpp_overload_set.value [concrete = constants.%X.B.cpp_overload_set.value]
@@ -875,7 +875,7 @@ fn Call() {
 // CHECK:STDOUT:   %Cpp.ref.loc76: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:   %X.ref.loc76: type = name_ref X, imports.%X.decl [concrete = constants.%X]
 // CHECK:STDOUT:   %.loc76_5.2: ref %X = temporary_storage
-// CHECK:STDOUT:   %.loc76_5.3: init %X = class_init (), %.loc76_5.2 [concrete = constants.%X.val]
+// CHECK:STDOUT:   %.loc76_5.3: init %X to %.loc76_5.2 = class_init () [concrete = constants.%X.val]
 // CHECK:STDOUT:   %.loc76_5.4: ref %X = temporary %.loc76_5.2, %.loc76_5.3
 // CHECK:STDOUT:   %.loc76_7: ref %X = converted %.loc76_5.1, %.loc76_5.4
 // CHECK:STDOUT:   %D.ref: %X.D.cpp_overload_set.type = name_ref D, imports.%X.D.cpp_overload_set.value [concrete = constants.%X.D.cpp_overload_set.value]

toolchain/check/testdata/interop/cpp/function/extern_c.carbon

@@ -191,7 +191,7 @@ fn MyF(a: Cpp.X, b: Cpp.X) -> Cpp.X {
 // CHECK:STDOUT:   %Copy.impl_witness_table.e76 = impl_witness_table (%Core.import_ref.18d), @Int.as.Copy.impl [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: fn @MyF() -> %i32 {
+// CHECK:STDOUT: fn @MyF() -> out %return.param: %i32 {
 // CHECK:STDOUT: !entry:
 // CHECK:STDOUT:   %Cpp.ref: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:   <elided>
@@ -223,7 +223,7 @@ fn MyF(a: Cpp.X, b: Cpp.X) -> Cpp.X {
 // CHECK:STDOUT:   }
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: fn @MyF(%a.param: %X, %b.param: %X) -> %return.param: %X {
+// CHECK:STDOUT: fn @MyF(%a.param: %X, %b.param: %X) -> out %return.param: %X {
 // CHECK:STDOUT: !entry:
 // CHECK:STDOUT:   %a.ref: %X = name_ref a, %a
 // CHECK:STDOUT:   %b.ref: %X = name_ref b, %b
@@ -234,7 +234,7 @@ fn MyF(a: Cpp.X, b: Cpp.X) -> Cpp.X {
 // CHECK:STDOUT:   %addr.loc11_12.2: %ptr.1f9 = addr_of %.loc11_14
 // CHECK:STDOUT:   %addr.loc11_12.3: %ptr.1f9 = addr_of %.loc9_34.1
 // CHECK:STDOUT:   %operator_Plus__carbon_thunk.call: init %empty_tuple.type = call imports.%operator_Plus__carbon_thunk.decl(%addr.loc11_12.1, %addr.loc11_12.2, %addr.loc11_12.3)
-// CHECK:STDOUT:   %.loc11_12: init %X = in_place_init %operator_Plus__carbon_thunk.call, %.loc9_34.1
+// CHECK:STDOUT:   %.loc11_12: init %X to %.loc9_34.1 = in_place_init %operator_Plus__carbon_thunk.call
 // CHECK:STDOUT:   return %.loc11_12 to %return.param
 // CHECK:STDOUT: }
 // CHECK:STDOUT:

toolchain/check/testdata/interop/cpp/function/full_semir.carbon

@@ -370,7 +370,7 @@ fn F() {
 // CHECK:STDOUT:   return
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: fn @foo_short() -> %i16;
+// CHECK:STDOUT: fn @foo_short() -> out %return.param: %i16;
 // CHECK:STDOUT:
 // CHECK:STDOUT: fn @foo_short__carbon_thunk(%return.param: %ptr);
 // CHECK:STDOUT:

toolchain/check/testdata/interop/cpp/function/function.carbon

@@ -385,7 +385,7 @@ fn G() -> i32 {
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: fn @G() -> %i32 {
+// CHECK:STDOUT: fn @G() -> out %return.param: %i32 {
 // CHECK:STDOUT: !entry:
 // CHECK:STDOUT:   %Cpp.ref: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:   %bar.ref: %bar.cpp_overload_set.type = name_ref bar, imports.%bar.cpp_overload_set.value [concrete = constants.%bar.cpp_overload_set.value]

toolchain/check/testdata/interop/cpp/function/operators.carbon

@@ -1141,7 +1141,7 @@ fn F() {
 // CHECK:STDOUT:   %.loc8_3: ref %C = splice_block %c.var {}
 // CHECK:STDOUT:   %addr.loc8: %ptr.d9e = addr_of %.loc8_3
 // CHECK:STDOUT:   %C__carbon_thunk.call: init %empty_tuple.type = call imports.%C__carbon_thunk.decl(%addr.loc8)
-// CHECK:STDOUT:   %.loc8_26: init %C = in_place_init %C__carbon_thunk.call, %.loc8_3
+// CHECK:STDOUT:   %.loc8_26: init %C to %.loc8_3 = in_place_init %C__carbon_thunk.call
 // CHECK:STDOUT:   assign %c.var, %.loc8_26
 // CHECK:STDOUT:   %.loc8_13: type = splice_block %C.ref.loc8_13 [concrete = constants.%C] {
 // CHECK:STDOUT:     %Cpp.ref.loc8_10: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
@@ -1162,7 +1162,7 @@ fn F() {
 // CHECK:STDOUT:   %addr.loc15_22.1: %ptr.d9e = addr_of %.loc15_23.2
 // CHECK:STDOUT:   %addr.loc15_22.2: %ptr.d9e = addr_of %.loc15_22.1
 // CHECK:STDOUT:   %operator_Minus__carbon_thunk.call: init %empty_tuple.type = call imports.%operator_Minus__carbon_thunk.decl(%addr.loc15_22.1, %addr.loc15_22.2)
-// CHECK:STDOUT:   %.loc15_22.2: init %C = in_place_init %operator_Minus__carbon_thunk.call, %.loc15_22.1
+// CHECK:STDOUT:   %.loc15_22.2: init %C to %.loc15_22.1 = in_place_init %operator_Minus__carbon_thunk.call
 // CHECK:STDOUT:   %.loc15_17: type = splice_block %C.ref.loc15 [concrete = constants.%C] {
 // CHECK:STDOUT:     %Cpp.ref.loc15: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %C.ref.loc15: type = name_ref C, imports.%C.decl [concrete = constants.%C]
@@ -1180,7 +1180,7 @@ fn F() {
 // CHECK:STDOUT:   %addr.loc18_27.1: %ptr.d9e = addr_of %.loc18_28.2
 // CHECK:STDOUT:   %addr.loc18_27.2: %ptr.d9e = addr_of %.loc18_27.1
 // CHECK:STDOUT:   %operator_Tilde__carbon_thunk.call: init %empty_tuple.type = call imports.%operator_Tilde__carbon_thunk.decl(%addr.loc18_27.1, %addr.loc18_27.2)
-// CHECK:STDOUT:   %.loc18_27.2: init %C = in_place_init %operator_Tilde__carbon_thunk.call, %.loc18_27.1
+// CHECK:STDOUT:   %.loc18_27.2: init %C to %.loc18_27.1 = in_place_init %operator_Tilde__carbon_thunk.call
 // CHECK:STDOUT:   %.loc18_22: type = splice_block %C.ref.loc18 [concrete = constants.%C] {
 // CHECK:STDOUT:     %Cpp.ref.loc18: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %C.ref.loc18: type = name_ref C, imports.%C.decl [concrete = constants.%C]
@@ -1468,7 +1468,7 @@ fn F() {
 // CHECK:STDOUT:   %.loc8_3: ref %C = splice_block %c1.var {}
 // CHECK:STDOUT:   %addr.loc8: %ptr.d9e = addr_of %.loc8_3
 // CHECK:STDOUT:   %C__carbon_thunk.call.loc8: init %empty_tuple.type = call imports.%C__carbon_thunk.decl(%addr.loc8)
-// CHECK:STDOUT:   %.loc8_27: init %C = in_place_init %C__carbon_thunk.call.loc8, %.loc8_3
+// CHECK:STDOUT:   %.loc8_27: init %C to %.loc8_3 = in_place_init %C__carbon_thunk.call.loc8
 // CHECK:STDOUT:   assign %c1.var, %.loc8_27
 // CHECK:STDOUT:   %.loc8_14: type = splice_block %C.ref.loc8_14 [concrete = constants.%C] {
 // CHECK:STDOUT:     %Cpp.ref.loc8_11: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
@@ -1486,7 +1486,7 @@ fn F() {
 // CHECK:STDOUT:   %.loc9_3: ref %C = splice_block %c2.var {}
 // CHECK:STDOUT:   %addr.loc9: %ptr.d9e = addr_of %.loc9_3
 // CHECK:STDOUT:   %C__carbon_thunk.call.loc9: init %empty_tuple.type = call imports.%C__carbon_thunk.decl(%addr.loc9)
-// CHECK:STDOUT:   %.loc9_27: init %C = in_place_init %C__carbon_thunk.call.loc9, %.loc9_3
+// CHECK:STDOUT:   %.loc9_27: init %C to %.loc9_3 = in_place_init %C__carbon_thunk.call.loc9
 // CHECK:STDOUT:   assign %c2.var, %.loc9_27
 // CHECK:STDOUT:   %.loc9_14: type = splice_block %C.ref.loc9_14 [concrete = constants.%C] {
 // CHECK:STDOUT:     %Cpp.ref.loc9_11: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
@@ -1507,7 +1507,7 @@ fn F() {
 // CHECK:STDOUT:   %addr.loc12_28.2: %ptr.d9e = addr_of %.loc12_30.2
 // CHECK:STDOUT:   %addr.loc12_28.3: %ptr.d9e = addr_of %.loc12_28.1
 // CHECK:STDOUT:   %operator_Plus__carbon_thunk.call: init %empty_tuple.type = call imports.%operator_Plus__carbon_thunk.decl(%addr.loc12_28.1, %addr.loc12_28.2, %addr.loc12_28.3)
-// CHECK:STDOUT:   %.loc12_28.2: init %C = in_place_init %operator_Plus__carbon_thunk.call, %.loc12_28.1
+// CHECK:STDOUT:   %.loc12_28.2: init %C to %.loc12_28.1 = in_place_init %operator_Plus__carbon_thunk.call
 // CHECK:STDOUT:   %.loc12_20: type = splice_block %C.ref.loc12 [concrete = constants.%C] {
 // CHECK:STDOUT:     %Cpp.ref.loc12: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %C.ref.loc12: type = name_ref C, imports.%C.decl [concrete = constants.%C]
@@ -1529,7 +1529,7 @@ fn F() {
 // CHECK:STDOUT:   %addr.loc13_31.2: %ptr.d9e = addr_of %.loc13_33.2
 // CHECK:STDOUT:   %addr.loc13_31.3: %ptr.d9e = addr_of %.loc13_31.1
 // CHECK:STDOUT:   %operator_Minus__carbon_thunk.call: init %empty_tuple.type = call imports.%operator_Minus__carbon_thunk.decl(%addr.loc13_31.1, %addr.loc13_31.2, %addr.loc13_31.3)
-// CHECK:STDOUT:   %.loc13_31.2: init %C = in_place_init %operator_Minus__carbon_thunk.call, %.loc13_31.1
+// CHECK:STDOUT:   %.loc13_31.2: init %C to %.loc13_31.1 = in_place_init %operator_Minus__carbon_thunk.call
 // CHECK:STDOUT:   %.loc13_23: type = splice_block %C.ref.loc13 [concrete = constants.%C] {
 // CHECK:STDOUT:     %Cpp.ref.loc13: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %C.ref.loc13: type = name_ref C, imports.%C.decl [concrete = constants.%C]
@@ -1551,7 +1551,7 @@ fn F() {
 // CHECK:STDOUT:   %addr.loc14_34.2: %ptr.d9e = addr_of %.loc14_36.2
 // CHECK:STDOUT:   %addr.loc14_34.3: %ptr.d9e = addr_of %.loc14_34.1
 // CHECK:STDOUT:   %operator_Star__carbon_thunk.call: init %empty_tuple.type = call imports.%operator_Star__carbon_thunk.decl(%addr.loc14_34.1, %addr.loc14_34.2, %addr.loc14_34.3)
-// CHECK:STDOUT:   %.loc14_34.2: init %C = in_place_init %operator_Star__carbon_thunk.call, %.loc14_34.1
+// CHECK:STDOUT:   %.loc14_34.2: init %C to %.loc14_34.1 = in_place_init %operator_Star__carbon_thunk.call
 // CHECK:STDOUT:   %.loc14_26: type = splice_block %C.ref.loc14 [concrete = constants.%C] {
 // CHECK:STDOUT:     %Cpp.ref.loc14: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %C.ref.loc14: type = name_ref C, imports.%C.decl [concrete = constants.%C]
@@ -1573,7 +1573,7 @@ fn F() {
 // CHECK:STDOUT:   %addr.loc15_28.2: %ptr.d9e = addr_of %.loc15_30.2
 // CHECK:STDOUT:   %addr.loc15_28.3: %ptr.d9e = addr_of %.loc15_28.1
 // CHECK:STDOUT:   %operator_Slash__carbon_thunk.call: init %empty_tuple.type = call imports.%operator_Slash__carbon_thunk.decl(%addr.loc15_28.1, %addr.loc15_28.2, %addr.loc15_28.3)
-// CHECK:STDOUT:   %.loc15_28.2: init %C = in_place_init %operator_Slash__carbon_thunk.call, %.loc15_28.1
+// CHECK:STDOUT:   %.loc15_28.2: init %C to %.loc15_28.1 = in_place_init %operator_Slash__carbon_thunk.call
 // CHECK:STDOUT:   %.loc15_20: type = splice_block %C.ref.loc15 [concrete = constants.%C] {
 // CHECK:STDOUT:     %Cpp.ref.loc15: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %C.ref.loc15: type = name_ref C, imports.%C.decl [concrete = constants.%C]
@@ -1595,7 +1595,7 @@ fn F() {
 // CHECK:STDOUT:   %addr.loc16_26.2: %ptr.d9e = addr_of %.loc16_28.2
 // CHECK:STDOUT:   %addr.loc16_26.3: %ptr.d9e = addr_of %.loc16_26.1
 // CHECK:STDOUT:   %operator_Percent__carbon_thunk.call: init %empty_tuple.type = call imports.%operator_Percent__carbon_thunk.decl(%addr.loc16_26.1, %addr.loc16_26.2, %addr.loc16_26.3)
-// CHECK:STDOUT:   %.loc16_26.2: init %C = in_place_init %operator_Percent__carbon_thunk.call, %.loc16_26.1
+// CHECK:STDOUT:   %.loc16_26.2: init %C to %.loc16_26.1 = in_place_init %operator_Percent__carbon_thunk.call
 // CHECK:STDOUT:   %.loc16_18: type = splice_block %C.ref.loc16 [concrete = constants.%C] {
 // CHECK:STDOUT:     %Cpp.ref.loc16: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %C.ref.loc16: type = name_ref C, imports.%C.decl [concrete = constants.%C]
@@ -1617,7 +1617,7 @@ fn F() {
 // CHECK:STDOUT:   %addr.loc19_31.2: %ptr.d9e = addr_of %.loc19_33.2
 // CHECK:STDOUT:   %addr.loc19_31.3: %ptr.d9e = addr_of %.loc19_31.1
 // CHECK:STDOUT:   %operator_Amp__carbon_thunk.call: init %empty_tuple.type = call imports.%operator_Amp__carbon_thunk.decl(%addr.loc19_31.1, %addr.loc19_31.2, %addr.loc19_31.3)
-// CHECK:STDOUT:   %.loc19_31.2: init %C = in_place_init %operator_Amp__carbon_thunk.call, %.loc19_31.1
+// CHECK:STDOUT:   %.loc19_31.2: init %C to %.loc19_31.1 = in_place_init %operator_Amp__carbon_thunk.call
 // CHECK:STDOUT:   %.loc19_23: type = splice_block %C.ref.loc19 [concrete = constants.%C] {
 // CHECK:STDOUT:     %Cpp.ref.loc19: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %C.ref.loc19: type = name_ref C, imports.%C.decl [concrete = constants.%C]
@@ -1639,7 +1639,7 @@ fn F() {
 // CHECK:STDOUT:   %addr.loc20_30.2: %ptr.d9e = addr_of %.loc20_32.2
 // CHECK:STDOUT:   %addr.loc20_30.3: %ptr.d9e = addr_of %.loc20_30.1
 // CHECK:STDOUT:   %operator_Pipe__carbon_thunk.call: init %empty_tuple.type = call imports.%operator_Pipe__carbon_thunk.decl(%addr.loc20_30.1, %addr.loc20_30.2, %addr.loc20_30.3)
-// CHECK:STDOUT:   %.loc20_30.2: init %C = in_place_init %operator_Pipe__carbon_thunk.call, %.loc20_30.1
+// CHECK:STDOUT:   %.loc20_30.2: init %C to %.loc20_30.1 = in_place_init %operator_Pipe__carbon_thunk.call
 // CHECK:STDOUT:   %.loc20_22: type = splice_block %C.ref.loc20 [concrete = constants.%C] {
 // CHECK:STDOUT:     %Cpp.ref.loc20: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %C.ref.loc20: type = name_ref C, imports.%C.decl [concrete = constants.%C]
@@ -1661,7 +1661,7 @@ fn F() {
 // CHECK:STDOUT:   %addr.loc21_31.2: %ptr.d9e = addr_of %.loc21_33.2
 // CHECK:STDOUT:   %addr.loc21_31.3: %ptr.d9e = addr_of %.loc21_31.1
 // CHECK:STDOUT:   %operator_Caret__carbon_thunk.call: init %empty_tuple.type = call imports.%operator_Caret__carbon_thunk.decl(%addr.loc21_31.1, %addr.loc21_31.2, %addr.loc21_31.3)
-// CHECK:STDOUT:   %.loc21_31.2: init %C = in_place_init %operator_Caret__carbon_thunk.call, %.loc21_31.1
+// CHECK:STDOUT:   %.loc21_31.2: init %C to %.loc21_31.1 = in_place_init %operator_Caret__carbon_thunk.call
 // CHECK:STDOUT:   %.loc21_23: type = splice_block %C.ref.loc21 [concrete = constants.%C] {
 // CHECK:STDOUT:     %Cpp.ref.loc21: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %C.ref.loc21: type = name_ref C, imports.%C.decl [concrete = constants.%C]
@@ -1687,7 +1687,7 @@ fn F() {
 // CHECK:STDOUT:   %addr.loc22_30.1: %ptr.d9e = addr_of %.loc22_27.2
 // CHECK:STDOUT:   %addr.loc22_30.2: %ptr.d9e = addr_of %.loc22_30.1
 // CHECK:STDOUT:   %operator_LessLess__carbon_thunk.call: init %empty_tuple.type = call imports.%operator_LessLess__carbon_thunk.decl(%addr.loc22_30.1, %.loc22_33.2, %addr.loc22_30.2)
-// CHECK:STDOUT:   %.loc22_30.2: init %C = in_place_init %operator_LessLess__carbon_thunk.call, %.loc22_30.1
+// CHECK:STDOUT:   %.loc22_30.2: init %C to %.loc22_30.1 = in_place_init %operator_LessLess__carbon_thunk.call
 // CHECK:STDOUT:   %.loc22_22: type = splice_block %C.ref.loc22 [concrete = constants.%C] {
 // CHECK:STDOUT:     %Cpp.ref.loc22: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %C.ref.loc22: type = name_ref C, imports.%C.decl [concrete = constants.%C]
@@ -1713,7 +1713,7 @@ fn F() {
 // CHECK:STDOUT:   %addr.loc23_31.1: %ptr.d9e = addr_of %.loc23_28.2
 // CHECK:STDOUT:   %addr.loc23_31.2: %ptr.d9e = addr_of %.loc23_31.1
 // CHECK:STDOUT:   %operator_GreaterGreater__carbon_thunk.call: init %empty_tuple.type = call imports.%operator_GreaterGreater__carbon_thunk.decl(%addr.loc23_31.1, %.loc23_34.2, %addr.loc23_31.2)
-// CHECK:STDOUT:   %.loc23_31.2: init %C = in_place_init %operator_GreaterGreater__carbon_thunk.call, %.loc23_31.1
+// CHECK:STDOUT:   %.loc23_31.2: init %C to %.loc23_31.1 = in_place_init %operator_GreaterGreater__carbon_thunk.call
 // CHECK:STDOUT:   %.loc23_23: type = splice_block %C.ref.loc23 [concrete = constants.%C] {
 // CHECK:STDOUT:     %Cpp.ref.loc23: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %C.ref.loc23: type = name_ref C, imports.%C.decl [concrete = constants.%C]
@@ -2024,7 +2024,7 @@ fn F() {
 // CHECK:STDOUT:   %.loc8_27.1: ref %C = temporary_storage
 // CHECK:STDOUT:   %addr.loc8: %ptr.d9e = addr_of %.loc8_27.1
 // CHECK:STDOUT:   %C__carbon_thunk.call.loc8: init %empty_tuple.type = call imports.%C__carbon_thunk.decl(%addr.loc8)
-// CHECK:STDOUT:   %.loc8_27.2: init %C = in_place_init %C__carbon_thunk.call.loc8, %.loc8_27.1
+// CHECK:STDOUT:   %.loc8_27.2: init %C to %.loc8_27.1 = in_place_init %C__carbon_thunk.call.loc8
 // CHECK:STDOUT:   %.loc8_14: type = splice_block %C.ref.loc8_14 [concrete = constants.%C] {
 // CHECK:STDOUT:     %Cpp.ref.loc8_11: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %C.ref.loc8_14: type = name_ref C, imports.%C.decl [concrete = constants.%C]
@@ -2041,7 +2041,7 @@ fn F() {
 // CHECK:STDOUT:   %.loc9_27.1: ref %C = temporary_storage
 // CHECK:STDOUT:   %addr.loc9: %ptr.d9e = addr_of %.loc9_27.1
 // CHECK:STDOUT:   %C__carbon_thunk.call.loc9: init %empty_tuple.type = call imports.%C__carbon_thunk.decl(%addr.loc9)
-// CHECK:STDOUT:   %.loc9_27.2: init %C = in_place_init %C__carbon_thunk.call.loc9, %.loc9_27.1
+// CHECK:STDOUT:   %.loc9_27.2: init %C to %.loc9_27.1 = in_place_init %C__carbon_thunk.call.loc9
 // CHECK:STDOUT:   %.loc9_14: type = splice_block %C.ref.loc9_14 [concrete = constants.%C] {
 // CHECK:STDOUT:     %Cpp.ref.loc9_11: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %C.ref.loc9_14: type = name_ref C, imports.%C.decl [concrete = constants.%C]
@@ -2061,7 +2061,7 @@ fn F() {
 // CHECK:STDOUT:   %addr.loc10_22.2: %ptr.d9e = addr_of %.loc10_24
 // CHECK:STDOUT:   %addr.loc10_22.3: %ptr.d9e = addr_of %.loc10_22.1
 // CHECK:STDOUT:   %operator_Plus__carbon_thunk.call.loc10: init %empty_tuple.type = call imports.%operator_Plus__carbon_thunk.decl(%addr.loc10_22.1, %addr.loc10_22.2, %addr.loc10_22.3)
-// CHECK:STDOUT:   %.loc10_22.2: init %C = in_place_init %operator_Plus__carbon_thunk.call.loc10, %.loc10_22.1
+// CHECK:STDOUT:   %.loc10_22.2: init %C to %.loc10_22.1 = in_place_init %operator_Plus__carbon_thunk.call.loc10
 // CHECK:STDOUT:   %.loc10_14: type = splice_block %C.ref.loc10 [concrete = constants.%C] {
 // CHECK:STDOUT:     %Cpp.ref.loc10: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %C.ref.loc10: type = name_ref C, imports.%C.decl [concrete = constants.%C]
@@ -2081,7 +2081,7 @@ fn F() {
 // CHECK:STDOUT:   %addr.loc11_22.2: %ptr.d9e = addr_of %.loc11_24
 // CHECK:STDOUT:   %addr.loc11_22.3: %ptr.d9e = addr_of %.loc11_22.1
 // CHECK:STDOUT:   %operator_Plus__carbon_thunk.call.loc11: init %empty_tuple.type = call imports.%operator_Plus__carbon_thunk.decl(%addr.loc11_22.1, %addr.loc11_22.2, %addr.loc11_22.3)
-// CHECK:STDOUT:   %.loc11_22.2: init %C = in_place_init %operator_Plus__carbon_thunk.call.loc11, %.loc11_22.1
+// CHECK:STDOUT:   %.loc11_22.2: init %C to %.loc11_22.1 = in_place_init %operator_Plus__carbon_thunk.call.loc11
 // CHECK:STDOUT:   %.loc11_14: type = splice_block %C.ref.loc11 [concrete = constants.%C] {
 // CHECK:STDOUT:     %Cpp.ref.loc11: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %C.ref.loc11: type = name_ref C, imports.%C.decl [concrete = constants.%C]
@@ -2101,7 +2101,7 @@ fn F() {
 // CHECK:STDOUT:   %addr.loc12_22.2: %ptr.d9e = addr_of %.loc12_24
 // CHECK:STDOUT:   %addr.loc12_22.3: %ptr.d9e = addr_of %.loc12_22.1
 // CHECK:STDOUT:   %operator_Plus__carbon_thunk.call.loc12: init %empty_tuple.type = call imports.%operator_Plus__carbon_thunk.decl(%addr.loc12_22.1, %addr.loc12_22.2, %addr.loc12_22.3)
-// CHECK:STDOUT:   %.loc12_22.2: init %C = in_place_init %operator_Plus__carbon_thunk.call.loc12, %.loc12_22.1
+// CHECK:STDOUT:   %.loc12_22.2: init %C to %.loc12_22.1 = in_place_init %operator_Plus__carbon_thunk.call.loc12
 // CHECK:STDOUT:   %.loc12_14: type = splice_block %C.ref.loc12 [concrete = constants.%C] {
 // CHECK:STDOUT:     %Cpp.ref.loc12: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %C.ref.loc12: type = name_ref C, imports.%C.decl [concrete = constants.%C]
@@ -2184,7 +2184,7 @@ fn F() {
 // CHECK:STDOUT:   %.loc15_3: ref %C = splice_block %c1.var {}
 // CHECK:STDOUT:   %addr.loc15: %ptr.d9e = addr_of %.loc15_3
 // CHECK:STDOUT:   %C__carbon_thunk.call.loc15: init %empty_tuple.type = call imports.%C__carbon_thunk.decl(%addr.loc15)
-// CHECK:STDOUT:   %.loc15_27: init %C = in_place_init %C__carbon_thunk.call.loc15, %.loc15_3
+// CHECK:STDOUT:   %.loc15_27: init %C to %.loc15_3 = in_place_init %C__carbon_thunk.call.loc15
 // CHECK:STDOUT:   assign %c1.var, %.loc15_27
 // CHECK:STDOUT:   %.loc15_14: type = splice_block %C.ref.loc15_14 [concrete = constants.%C] {
 // CHECK:STDOUT:     %Cpp.ref.loc15_11: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
@@ -2202,7 +2202,7 @@ fn F() {
 // CHECK:STDOUT:   %.loc16_3: ref %C = splice_block %c2.var {}
 // CHECK:STDOUT:   %addr.loc16: %ptr.d9e = addr_of %.loc16_3
 // CHECK:STDOUT:   %C__carbon_thunk.call.loc16: init %empty_tuple.type = call imports.%C__carbon_thunk.decl(%addr.loc16)
-// CHECK:STDOUT:   %.loc16_27: init %C = in_place_init %C__carbon_thunk.call.loc16, %.loc16_3
+// CHECK:STDOUT:   %.loc16_27: init %C to %.loc16_3 = in_place_init %C__carbon_thunk.call.loc16
 // CHECK:STDOUT:   assign %c2.var, %.loc16_27
 // CHECK:STDOUT:   %.loc16_14: type = splice_block %C.ref.loc16_14 [concrete = constants.%C] {
 // CHECK:STDOUT:     %Cpp.ref.loc16_11: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
@@ -2339,7 +2339,7 @@ fn F() {
 // CHECK:STDOUT:   %.loc12_3: ref %C = splice_block %c1.var {}
 // CHECK:STDOUT:   %addr.loc12: %ptr.d9e = addr_of %.loc12_3
 // CHECK:STDOUT:   %C__carbon_thunk.call.loc12: init %empty_tuple.type = call imports.%C__carbon_thunk.decl(%addr.loc12)
-// CHECK:STDOUT:   %.loc12_27: init %C = in_place_init %C__carbon_thunk.call.loc12, %.loc12_3
+// CHECK:STDOUT:   %.loc12_27: init %C to %.loc12_3 = in_place_init %C__carbon_thunk.call.loc12
 // CHECK:STDOUT:   assign %c1.var, %.loc12_27
 // CHECK:STDOUT:   %.loc12_14: type = splice_block %C.ref.loc12_14 [concrete = constants.%C] {
 // CHECK:STDOUT:     %Cpp.ref.loc12_11: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
@@ -2357,7 +2357,7 @@ fn F() {
 // CHECK:STDOUT:   %.loc13_3: ref %C = splice_block %c2.var {}
 // CHECK:STDOUT:   %addr.loc13: %ptr.d9e = addr_of %.loc13_3
 // CHECK:STDOUT:   %C__carbon_thunk.call.loc13: init %empty_tuple.type = call imports.%C__carbon_thunk.decl(%addr.loc13)
-// CHECK:STDOUT:   %.loc13_27: init %C = in_place_init %C__carbon_thunk.call.loc13, %.loc13_3
+// CHECK:STDOUT:   %.loc13_27: init %C to %.loc13_3 = in_place_init %C__carbon_thunk.call.loc13
 // CHECK:STDOUT:   assign %c2.var, %.loc13_27
 // CHECK:STDOUT:   %.loc13_14: type = splice_block %C.ref.loc13_14 [concrete = constants.%C] {
 // CHECK:STDOUT:     %Cpp.ref.loc13_11: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
@@ -2459,7 +2459,7 @@ fn F() {
 // CHECK:STDOUT:   %.loc8_31.1: ref %C = temporary_storage
 // CHECK:STDOUT:   %addr.loc8: %ptr.838 = addr_of %.loc8_31.1
 // CHECK:STDOUT:   %C__carbon_thunk.call.loc8: init %empty_tuple.type = call imports.%C__carbon_thunk.decl(%addr.loc8)
-// CHECK:STDOUT:   %.loc8_31.2: init %C = in_place_init %C__carbon_thunk.call.loc8, %.loc8_31.1
+// CHECK:STDOUT:   %.loc8_31.2: init %C to %.loc8_31.1 = in_place_init %C__carbon_thunk.call.loc8
 // CHECK:STDOUT:   %.loc8_16: type = splice_block %C.ref.loc8_16 [concrete = constants.%C] {
 // CHECK:STDOUT:     %Cpp.ref.loc8_11: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %N.ref.loc8_14: <namespace> = name_ref N, imports.%N [concrete = imports.%N]
@@ -2478,7 +2478,7 @@ fn F() {
 // CHECK:STDOUT:   %.loc9_31.1: ref %C = temporary_storage
 // CHECK:STDOUT:   %addr.loc9: %ptr.838 = addr_of %.loc9_31.1
 // CHECK:STDOUT:   %C__carbon_thunk.call.loc9: init %empty_tuple.type = call imports.%C__carbon_thunk.decl(%addr.loc9)
-// CHECK:STDOUT:   %.loc9_31.2: init %C = in_place_init %C__carbon_thunk.call.loc9, %.loc9_31.1
+// CHECK:STDOUT:   %.loc9_31.2: init %C to %.loc9_31.1 = in_place_init %C__carbon_thunk.call.loc9
 // CHECK:STDOUT:   %.loc9_16: type = splice_block %C.ref.loc9_16 [concrete = constants.%C] {
 // CHECK:STDOUT:     %Cpp.ref.loc9_11: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %N.ref.loc9_14: <namespace> = name_ref N, imports.%N [concrete = imports.%N]
@@ -2499,7 +2499,7 @@ fn F() {
 // CHECK:STDOUT:   %addr.loc10_24.2: %ptr.838 = addr_of %.loc10_26
 // CHECK:STDOUT:   %addr.loc10_24.3: %ptr.838 = addr_of %.loc10_24.1
 // CHECK:STDOUT:   %operator_Plus__carbon_thunk.call: init %empty_tuple.type = call imports.%operator_Plus__carbon_thunk.decl(%addr.loc10_24.1, %addr.loc10_24.2, %addr.loc10_24.3)
-// CHECK:STDOUT:   %.loc10_24.2: init %C = in_place_init %operator_Plus__carbon_thunk.call, %.loc10_24.1
+// CHECK:STDOUT:   %.loc10_24.2: init %C to %.loc10_24.1 = in_place_init %operator_Plus__carbon_thunk.call
 // CHECK:STDOUT:   %.loc10_16: type = splice_block %C.ref.loc10 [concrete = constants.%C] {
 // CHECK:STDOUT:     %Cpp.ref.loc10: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %N.ref.loc10: <namespace> = name_ref N, imports.%N [concrete = imports.%N]
@@ -2599,7 +2599,7 @@ fn F() {
 // CHECK:STDOUT:   %.loc8_36.1: ref %C1 = temporary_storage
 // CHECK:STDOUT:   %addr.loc8: %ptr.087 = addr_of %.loc8_36.1
 // CHECK:STDOUT:   %C1__carbon_thunk.call: init %empty_tuple.type = call imports.%C1__carbon_thunk.decl(%addr.loc8)
-// CHECK:STDOUT:   %.loc8_36.2: init %C1 = in_place_init %C1__carbon_thunk.call, %.loc8_36.1
+// CHECK:STDOUT:   %.loc8_36.2: init %C1 to %.loc8_36.1 = in_place_init %C1__carbon_thunk.call
 // CHECK:STDOUT:   %.loc8_17: type = splice_block %C1.ref.loc8_17 [concrete = constants.%C1] {
 // CHECK:STDOUT:     %Cpp.ref.loc8_11: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %N1.ref.loc8_14: <namespace> = name_ref N1, imports.%N1 [concrete = imports.%N1]
@@ -2618,7 +2618,7 @@ fn F() {
 // CHECK:STDOUT:   %.loc9_36.1: ref %C2 = temporary_storage
 // CHECK:STDOUT:   %addr.loc9: %ptr.51f = addr_of %.loc9_36.1
 // CHECK:STDOUT:   %C2__carbon_thunk.call: init %empty_tuple.type = call imports.%C2__carbon_thunk.decl(%addr.loc9)
-// CHECK:STDOUT:   %.loc9_36.2: init %C2 = in_place_init %C2__carbon_thunk.call, %.loc9_36.1
+// CHECK:STDOUT:   %.loc9_36.2: init %C2 to %.loc9_36.1 = in_place_init %C2__carbon_thunk.call
 // CHECK:STDOUT:   %.loc9_17: type = splice_block %C2.ref.loc9_17 [concrete = constants.%C2] {
 // CHECK:STDOUT:     %Cpp.ref.loc9_11: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %N2.ref.loc9_14: <namespace> = name_ref N2, imports.%N2 [concrete = imports.%N2]
@@ -2639,7 +2639,7 @@ fn F() {
 // CHECK:STDOUT:   %addr.loc10_26.2: %ptr.51f = addr_of %.loc10_28
 // CHECK:STDOUT:   %addr.loc10_26.3: %ptr.51f = addr_of %.loc10_26.1
 // CHECK:STDOUT:   %operator_Plus__carbon_thunk.call: init %empty_tuple.type = call imports.%operator_Plus__carbon_thunk.decl(%addr.loc10_26.1, %addr.loc10_26.2, %addr.loc10_26.3)
-// CHECK:STDOUT:   %.loc10_26.2: init %C2 = in_place_init %operator_Plus__carbon_thunk.call, %.loc10_26.1
+// CHECK:STDOUT:   %.loc10_26.2: init %C2 to %.loc10_26.1 = in_place_init %operator_Plus__carbon_thunk.call
 // CHECK:STDOUT:   %.loc10_17: type = splice_block %C2.ref.loc10 [concrete = constants.%C2] {
 // CHECK:STDOUT:     %Cpp.ref.loc10: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %N2.ref.loc10: <namespace> = name_ref N2, imports.%N2 [concrete = imports.%N2]
@@ -2660,7 +2660,7 @@ fn F() {
 // CHECK:STDOUT:   %addr.loc11_26.2: %ptr.087 = addr_of %.loc11_28
 // CHECK:STDOUT:   %addr.loc11_26.3: %ptr.51f = addr_of %.loc11_26.1
 // CHECK:STDOUT:   %operator_Minus__carbon_thunk.call: init %empty_tuple.type = call imports.%operator_Minus__carbon_thunk.decl(%addr.loc11_26.1, %addr.loc11_26.2, %addr.loc11_26.3)
-// CHECK:STDOUT:   %.loc11_26.2: init %C2 = in_place_init %operator_Minus__carbon_thunk.call, %.loc11_26.1
+// CHECK:STDOUT:   %.loc11_26.2: init %C2 to %.loc11_26.1 = in_place_init %operator_Minus__carbon_thunk.call
 // CHECK:STDOUT:   %.loc11_17: type = splice_block %C2.ref.loc11 [concrete = constants.%C2] {
 // CHECK:STDOUT:     %Cpp.ref.loc11: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %N2.ref.loc11: <namespace> = name_ref N2, imports.%N2 [concrete = imports.%N2]
@@ -2729,7 +2729,7 @@ fn F() {
 // CHECK:STDOUT:   %.loc8_31.1: ref %C = temporary_storage
 // CHECK:STDOUT:   %addr.loc8: %ptr.838 = addr_of %.loc8_31.1
 // CHECK:STDOUT:   %C__carbon_thunk.call.loc8: init %empty_tuple.type = call imports.%C__carbon_thunk.decl(%addr.loc8)
-// CHECK:STDOUT:   %.loc8_31.2: init %C = in_place_init %C__carbon_thunk.call.loc8, %.loc8_31.1
+// CHECK:STDOUT:   %.loc8_31.2: init %C to %.loc8_31.1 = in_place_init %C__carbon_thunk.call.loc8
 // CHECK:STDOUT:   %.loc8_16: type = splice_block %C.ref.loc8_16 [concrete = constants.%C] {
 // CHECK:STDOUT:     %Cpp.ref.loc8_11: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %N.ref.loc8_14: <namespace> = name_ref N, imports.%N [concrete = imports.%N]
@@ -2748,7 +2748,7 @@ fn F() {
 // CHECK:STDOUT:   %.loc9_31.1: ref %C = temporary_storage
 // CHECK:STDOUT:   %addr.loc9: %ptr.838 = addr_of %.loc9_31.1
 // CHECK:STDOUT:   %C__carbon_thunk.call.loc9: init %empty_tuple.type = call imports.%C__carbon_thunk.decl(%addr.loc9)
-// CHECK:STDOUT:   %.loc9_31.2: init %C = in_place_init %C__carbon_thunk.call.loc9, %.loc9_31.1
+// CHECK:STDOUT:   %.loc9_31.2: init %C to %.loc9_31.1 = in_place_init %C__carbon_thunk.call.loc9
 // CHECK:STDOUT:   %.loc9_16: type = splice_block %C.ref.loc9_16 [concrete = constants.%C] {
 // CHECK:STDOUT:     %Cpp.ref.loc9_11: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %N.ref.loc9_14: <namespace> = name_ref N, imports.%N [concrete = imports.%N]
@@ -2827,7 +2827,7 @@ fn F() {
 // CHECK:STDOUT:   %.loc8_31.1: ref %C = temporary_storage
 // CHECK:STDOUT:   %addr.loc8: %ptr.de2 = addr_of %.loc8_31.1
 // CHECK:STDOUT:   %C__carbon_thunk.call.loc8: init %empty_tuple.type = call imports.%C__carbon_thunk.decl(%addr.loc8)
-// CHECK:STDOUT:   %.loc8_31.2: init %C = in_place_init %C__carbon_thunk.call.loc8, %.loc8_31.1
+// CHECK:STDOUT:   %.loc8_31.2: init %C to %.loc8_31.1 = in_place_init %C__carbon_thunk.call.loc8
 // CHECK:STDOUT:   %.loc8_16: type = splice_block %C.ref.loc8_16 [concrete = constants.%C] {
 // CHECK:STDOUT:     %Cpp.ref.loc8_11: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %O.ref.loc8_14: type = name_ref O, imports.%O.decl [concrete = constants.%O]
@@ -2846,7 +2846,7 @@ fn F() {
 // CHECK:STDOUT:   %.loc9_31.1: ref %C = temporary_storage
 // CHECK:STDOUT:   %addr.loc9: %ptr.de2 = addr_of %.loc9_31.1
 // CHECK:STDOUT:   %C__carbon_thunk.call.loc9: init %empty_tuple.type = call imports.%C__carbon_thunk.decl(%addr.loc9)
-// CHECK:STDOUT:   %.loc9_31.2: init %C = in_place_init %C__carbon_thunk.call.loc9, %.loc9_31.1
+// CHECK:STDOUT:   %.loc9_31.2: init %C to %.loc9_31.1 = in_place_init %C__carbon_thunk.call.loc9
 // CHECK:STDOUT:   %.loc9_16: type = splice_block %C.ref.loc9_16 [concrete = constants.%C] {
 // CHECK:STDOUT:     %Cpp.ref.loc9_11: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %O.ref.loc9_14: type = name_ref O, imports.%O.decl [concrete = constants.%O]
@@ -2867,7 +2867,7 @@ fn F() {
 // CHECK:STDOUT:   %addr.loc10_24.2: %ptr.de2 = addr_of %.loc10_26
 // CHECK:STDOUT:   %addr.loc10_24.3: %ptr.de2 = addr_of %.loc10_24.1
 // CHECK:STDOUT:   %operator_Plus__carbon_thunk.call: init %empty_tuple.type = call imports.%operator_Plus__carbon_thunk.decl(%addr.loc10_24.1, %addr.loc10_24.2, %addr.loc10_24.3)
-// CHECK:STDOUT:   %.loc10_24.2: init %C = in_place_init %operator_Plus__carbon_thunk.call, %.loc10_24.1
+// CHECK:STDOUT:   %.loc10_24.2: init %C to %.loc10_24.1 = in_place_init %operator_Plus__carbon_thunk.call
 // CHECK:STDOUT:   %.loc10_16: type = splice_block %C.ref.loc10 [concrete = constants.%C] {
 // CHECK:STDOUT:     %Cpp.ref.loc10: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %O.ref.loc10: type = name_ref O, imports.%O.decl [concrete = constants.%O]
@@ -2942,7 +2942,7 @@ fn F() {
 // CHECK:STDOUT:   %.loc8_35.1: ref %C = temporary_storage
 // CHECK:STDOUT:   %addr.loc8: %ptr.4b2 = addr_of %.loc8_35.1
 // CHECK:STDOUT:   %C__carbon_thunk.call.loc8: init %empty_tuple.type = call imports.%C__carbon_thunk.decl(%addr.loc8)
-// CHECK:STDOUT:   %.loc8_35.2: init %C = in_place_init %C__carbon_thunk.call.loc8, %.loc8_35.1
+// CHECK:STDOUT:   %.loc8_35.2: init %C to %.loc8_35.1 = in_place_init %C__carbon_thunk.call.loc8
 // CHECK:STDOUT:   %.loc8_18: type = splice_block %C.ref.loc8_18 [concrete = constants.%C] {
 // CHECK:STDOUT:     %Cpp.ref.loc8_11: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %N.ref.loc8_14: <namespace> = name_ref N, imports.%N [concrete = imports.%N]
@@ -2963,7 +2963,7 @@ fn F() {
 // CHECK:STDOUT:   %.loc9_35.1: ref %C = temporary_storage
 // CHECK:STDOUT:   %addr.loc9: %ptr.4b2 = addr_of %.loc9_35.1
 // CHECK:STDOUT:   %C__carbon_thunk.call.loc9: init %empty_tuple.type = call imports.%C__carbon_thunk.decl(%addr.loc9)
-// CHECK:STDOUT:   %.loc9_35.2: init %C = in_place_init %C__carbon_thunk.call.loc9, %.loc9_35.1
+// CHECK:STDOUT:   %.loc9_35.2: init %C to %.loc9_35.1 = in_place_init %C__carbon_thunk.call.loc9
 // CHECK:STDOUT:   %.loc9_18: type = splice_block %C.ref.loc9_18 [concrete = constants.%C] {
 // CHECK:STDOUT:     %Cpp.ref.loc9_11: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %N.ref.loc9_14: <namespace> = name_ref N, imports.%N [concrete = imports.%N]
@@ -2985,7 +2985,7 @@ fn F() {
 // CHECK:STDOUT:   %addr.loc10_26.2: %ptr.4b2 = addr_of %.loc10_28
 // CHECK:STDOUT:   %addr.loc10_26.3: %ptr.4b2 = addr_of %.loc10_26.1
 // CHECK:STDOUT:   %operator_Plus__carbon_thunk.call: init %empty_tuple.type = call imports.%operator_Plus__carbon_thunk.decl(%addr.loc10_26.1, %addr.loc10_26.2, %addr.loc10_26.3)
-// CHECK:STDOUT:   %.loc10_26.2: init %C = in_place_init %operator_Plus__carbon_thunk.call, %.loc10_26.1
+// CHECK:STDOUT:   %.loc10_26.2: init %C to %.loc10_26.1 = in_place_init %operator_Plus__carbon_thunk.call
 // CHECK:STDOUT:   %.loc10_18: type = splice_block %C.ref.loc10 [concrete = constants.%C] {
 // CHECK:STDOUT:     %Cpp.ref.loc10: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %N.ref.loc10: <namespace> = name_ref N, imports.%N [concrete = imports.%N]
@@ -3084,7 +3084,7 @@ fn F() {
 // CHECK:STDOUT:   %.loc8_3: ref %C = splice_block %c1.var {}
 // CHECK:STDOUT:   %addr.loc8: %ptr.d9e = addr_of %.loc8_3
 // CHECK:STDOUT:   %C__carbon_thunk.call: init %empty_tuple.type = call imports.%C__carbon_thunk.decl(%addr.loc8)
-// CHECK:STDOUT:   %.loc8_27: init %C = in_place_init %C__carbon_thunk.call, %.loc8_3
+// CHECK:STDOUT:   %.loc8_27: init %C to %.loc8_3 = in_place_init %C__carbon_thunk.call
 // CHECK:STDOUT:   assign %c1.var, %.loc8_27
 // CHECK:STDOUT:   %.loc8_14: type = splice_block %C.ref.loc8_14 [concrete = constants.%C] {
 // CHECK:STDOUT:     %Cpp.ref.loc8_11: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
@@ -3101,7 +3101,7 @@ fn F() {
 // CHECK:STDOUT:   %.loc9_3: ref %C = splice_block %c2.var {}
 // CHECK:STDOUT:   %addr.loc9: %ptr.d9e = addr_of %.loc9_3
 // CHECK:STDOUT:   %operator_Minus__carbon_thunk.call: init %empty_tuple.type = call imports.%operator_Minus__carbon_thunk.decl(%c1.ref.loc9, %addr.loc9)
-// CHECK:STDOUT:   %.loc9_19: init %C = in_place_init %operator_Minus__carbon_thunk.call, %.loc9_3
+// CHECK:STDOUT:   %.loc9_19: init %C to %.loc9_3 = in_place_init %operator_Minus__carbon_thunk.call
 // CHECK:STDOUT:   assign %c2.var, %.loc9_19
 // CHECK:STDOUT:   %.loc9_14: type = splice_block %C.ref.loc9 [concrete = constants.%C] {
 // CHECK:STDOUT:     %Cpp.ref.loc9: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
@@ -3122,7 +3122,7 @@ fn F() {
 // CHECK:STDOUT:   %addr.loc10_22.1: %ptr.d9e = addr_of %.loc10_24.2
 // CHECK:STDOUT:   %addr.loc10_22.2: %ptr.d9e = addr_of %.loc10_3
 // CHECK:STDOUT:   %operator_Plus__carbon_thunk.call: init %empty_tuple.type = call imports.%operator_Plus__carbon_thunk.decl(%c1.ref.loc10, %addr.loc10_22.1, %addr.loc10_22.2)
-// CHECK:STDOUT:   %.loc10_22: init %C = in_place_init %operator_Plus__carbon_thunk.call, %.loc10_3
+// CHECK:STDOUT:   %.loc10_22: init %C to %.loc10_3 = in_place_init %operator_Plus__carbon_thunk.call
 // CHECK:STDOUT:   assign %c3.var, %.loc10_22
 // CHECK:STDOUT:   %.loc10_14: type = splice_block %C.ref.loc10 [concrete = constants.%C] {
 // CHECK:STDOUT:     %Cpp.ref.loc10: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
@@ -3159,7 +3159,7 @@ fn F() {
 // CHECK:STDOUT:   }
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: fn @F(%x.param: %B) -> %i32 {
+// CHECK:STDOUT: fn @F(%x.param: %B) -> out %return.param: %i32 {
 // CHECK:STDOUT: !entry:
 // CHECK:STDOUT:   %x.ref.loc14_10: %B = name_ref x, %x
 // CHECK:STDOUT:   %x.ref.loc14_14: %B = name_ref x, %x
@@ -3212,7 +3212,7 @@ fn F() {
 // CHECK:STDOUT:   %addr.loc10_22.2: %ptr.d9e = addr_of %.loc10_24
 // CHECK:STDOUT:   %addr.loc10_22.3: %ptr.d9e = addr_of %.loc10_22.1
 // CHECK:STDOUT:   %operator_Plus__carbon_thunk.call: init %empty_tuple.type = call imports.%operator_Plus__carbon_thunk.decl(%addr.loc10_22.1, %addr.loc10_22.2, %addr.loc10_22.3)
-// CHECK:STDOUT:   %.loc10_22.2: init %C = in_place_init %operator_Plus__carbon_thunk.call, %.loc10_22.1
+// CHECK:STDOUT:   %.loc10_22.2: init %C to %.loc10_22.1 = in_place_init %operator_Plus__carbon_thunk.call
 // CHECK:STDOUT:   %.loc10_14: type = splice_block %C.ref.loc10 [concrete = constants.%C] {
 // CHECK:STDOUT:     %Cpp.ref.loc10: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %C.ref.loc10: type = name_ref C, imports.%C.decl [concrete = constants.%C]

toolchain/check/testdata/interop/cpp/function/overloads.carbon

@@ -1385,11 +1385,11 @@ fn F() {
 // CHECK:STDOUT:   return
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: fn @foo.1(%a.param: %i32) -> %i32;
+// CHECK:STDOUT: fn @foo.1(%a.param: %i32) -> out %return.param: %i32;
 // CHECK:STDOUT:
-// CHECK:STDOUT: fn @foo.2(%a.param: %i64) -> %i64;
+// CHECK:STDOUT: fn @foo.2(%a.param: %i64) -> out %return.param: %i64;
 // CHECK:STDOUT:
-// CHECK:STDOUT: fn @foo.3(%a.param: %i128) -> %i128;
+// CHECK:STDOUT: fn @foo.3(%a.param: %i128) -> out %return.param: %i128;
 // CHECK:STDOUT:
 // CHECK:STDOUT: fn @foo__carbon_thunk(%a.param: %ptr.974, %return.param: %ptr.974);
 // CHECK:STDOUT:
@@ -1826,7 +1826,7 @@ fn F() {
 // CHECK:STDOUT:   return
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: fn @foo(%a.param: %f64.d77) -> %f64.d77;
+// CHECK:STDOUT: fn @foo(%a.param: %f64.d77) -> out %return.param: %f64.d77;
 // CHECK:STDOUT:
 // CHECK:STDOUT: fn @foo__carbon_thunk(%a.param: %ptr.bcc, %return.param: %ptr.bcc);
 // CHECK:STDOUT:
@@ -1876,6 +1876,8 @@ fn F() {
 // CHECK:STDOUT:   %.c41: type = fn_type_with_self_type %Copy.Op.type, %Copy.facet [concrete]
 // CHECK:STDOUT:   %Float.as.Copy.impl.Op.specific_fn: <specific function> = specific_function %Float.as.Copy.impl.Op.f05, @Float.as.Copy.impl.Op(%int_64) [concrete]
 // CHECK:STDOUT:   %Destroy.type: type = facet_type <@Destroy> [concrete]
+// CHECK:STDOUT:   %DestroyOp.type: type = fn_type @DestroyOp [concrete]
+// CHECK:STDOUT:   %DestroyOp: %DestroyOp.type = struct_value () [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: imports {
@@ -1952,16 +1954,18 @@ fn F() {
 // CHECK:STDOUT:   %specific_fn.loc15_11.2: <specific function> = specific_function %impl.elem0.loc15_11.2, @Float.as.Copy.impl.Op(constants.%int_64) [concrete = constants.%Float.as.Copy.impl.Op.specific_fn]
 // CHECK:STDOUT:   %bound_method.loc15_11.4: <bound method> = bound_method %.loc15_11.2, %specific_fn.loc15_11.2 [concrete = <error>]
 // CHECK:STDOUT:   %Float.as.Copy.impl.Op.call: init %f64.d77 = call %bound_method.loc15_11.4(%.loc15_11.2) [concrete = <error>]
-// CHECK:STDOUT:   %.loc15_11.4: ref %f64.d77 = temporary %.loc15_11.3, %Float.as.Copy.impl.Op.call [concrete = <error>]
-// CHECK:STDOUT:   %addr.loc15_19.1: %ptr.bcc = addr_of %.loc15_11.4 [concrete = <error>]
+// CHECK:STDOUT:   %.loc15_11.4: ref %f64.d77 = temporary %.loc15_11.3, %Float.as.Copy.impl.Op.call
+// CHECK:STDOUT:   %addr.loc15_19.1: %ptr.bcc = addr_of %.loc15_11.4
 // CHECK:STDOUT:   %.loc15_19.1: ref %f64.d77 = temporary_storage
 // CHECK:STDOUT:   %addr.loc15_19.2: %ptr.bcc = addr_of %.loc15_19.1
 // CHECK:STDOUT:   %foo__carbon_thunk.call: init %empty_tuple.type = call imports.%foo__carbon_thunk.decl(%addr.loc15_19.1, %addr.loc15_19.2)
 // CHECK:STDOUT:   %.loc15_19.2: init %f64.d77 = in_place_init %foo__carbon_thunk.call, %.loc15_19.1
+// CHECK:STDOUT:   %DestroyOp.bound: <bound method> = bound_method %.loc15_11.4, constants.%DestroyOp
+// CHECK:STDOUT:   %DestroyOp.call: init %empty_tuple.type = call %DestroyOp.bound(%.loc15_11.4)
 // CHECK:STDOUT:   return
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: fn @foo(%a.param: %f64.d77) -> %f64.d77;
+// CHECK:STDOUT: fn @foo(%a.param: %f64.d77) -> out %return.param: %f64.d77;
 // CHECK:STDOUT:
 // CHECK:STDOUT: fn @foo__carbon_thunk(%a.param: %ptr.bcc, %return.param: %ptr.bcc);
 // CHECK:STDOUT:

toolchain/check/testdata/interop/cpp/function/pointer.carbon

@@ -468,7 +468,7 @@ fn F() {
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %s.var: ref %S = var %s.var_patt
 // CHECK:STDOUT:   %.loc8_19.1: %empty_struct_type = struct_literal () [concrete = constants.%empty_struct]
-// CHECK:STDOUT:   %.loc8_19.2: init %S = class_init (), %s.var [concrete = constants.%S.val]
+// CHECK:STDOUT:   %.loc8_19.2: init %S to %s.var = class_init () [concrete = constants.%S.val]
 // CHECK:STDOUT:   %.loc8_3: init %S = converted %.loc8_19.1, %.loc8_19.2 [concrete = constants.%S.val]
 // CHECK:STDOUT:   assign %s.var, %.loc8_3
 // CHECK:STDOUT:   %.loc8_13: type = splice_block %S.ref [concrete = constants.%S] {
@@ -610,7 +610,7 @@ fn F() {
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %s.var: ref %S = var %s.var_patt
 // CHECK:STDOUT:   %.loc8_19.1: %empty_struct_type = struct_literal () [concrete = constants.%empty_struct]
-// CHECK:STDOUT:   %.loc8_19.2: init %S = class_init (), %s.var [concrete = constants.%S.val]
+// CHECK:STDOUT:   %.loc8_19.2: init %S to %s.var = class_init () [concrete = constants.%S.val]
 // CHECK:STDOUT:   %.loc8_3: init %S = converted %.loc8_19.1, %.loc8_19.2 [concrete = constants.%S.val]
 // CHECK:STDOUT:   assign %s.var, %.loc8_3
 // CHECK:STDOUT:   %.loc8_13: type = splice_block %S.ref.loc8 [concrete = constants.%S] {
@@ -695,7 +695,7 @@ fn F() {
 // CHECK:STDOUT:   %s.var: ref %const = var %s.var_patt
 // CHECK:STDOUT:   %G.ref: %G.type = name_ref G, file.%G.decl [concrete = constants.%G]
 // CHECK:STDOUT:   %.loc10_3: ref %const = splice_block %s.var {}
-// CHECK:STDOUT:   %G.call: init %const = call %G.ref() to %.loc10_3
+// CHECK:STDOUT:   %G.call: init %const to %.loc10_3 = call %G.ref()
 // CHECK:STDOUT:   assign %s.var, %G.call
 // CHECK:STDOUT:   %.loc10_10: type = splice_block %const [concrete = constants.%const] {
 // CHECK:STDOUT:     %Cpp.ref.loc10: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
@@ -758,7 +758,7 @@ fn F() {
 // CHECK:STDOUT:   %s.var: ref %S = var %s.var_patt
 // CHECK:STDOUT:   %G.ref: %G.type = name_ref G, file.%G.decl [concrete = constants.%G]
 // CHECK:STDOUT:   %.loc8_3: ref %S = splice_block %s.var {}
-// CHECK:STDOUT:   %G.call: init %S = call %G.ref() to %.loc8_3
+// CHECK:STDOUT:   %G.call: init %S to %.loc8_3 = call %G.ref()
 // CHECK:STDOUT:   assign %s.var, %G.call
 // CHECK:STDOUT:   %.loc8_13: type = splice_block %S.ref [concrete = constants.%S] {
 // CHECK:STDOUT:     %Cpp.ref.loc8: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
@@ -1384,7 +1384,7 @@ fn F() {
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %s.var: ref %S = var %s.var_patt
 // CHECK:STDOUT:   %.loc8_19.1: %empty_struct_type = struct_literal () [concrete = constants.%empty_struct]
-// CHECK:STDOUT:   %.loc8_19.2: init %S = class_init (), %s.var [concrete = constants.%S.val]
+// CHECK:STDOUT:   %.loc8_19.2: init %S to %s.var = class_init () [concrete = constants.%S.val]
 // CHECK:STDOUT:   %.loc8_3: init %S = converted %.loc8_19.1, %.loc8_19.2 [concrete = constants.%S.val]
 // CHECK:STDOUT:   assign %s.var, %.loc8_3
 // CHECK:STDOUT:   %.loc8_13: type = splice_block %S.ref [concrete = constants.%S] {
@@ -1602,7 +1602,7 @@ fn F() {
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %s.var: ref %S = var %s.var_patt
 // CHECK:STDOUT:   %.loc8_19.1: %empty_struct_type = struct_literal () [concrete = constants.%empty_struct]
-// CHECK:STDOUT:   %.loc8_19.2: init %S = class_init (), %s.var [concrete = constants.%S.val]
+// CHECK:STDOUT:   %.loc8_19.2: init %S to %s.var = class_init () [concrete = constants.%S.val]
 // CHECK:STDOUT:   %.loc8_3: init %S = converted %.loc8_19.1, %.loc8_19.2 [concrete = constants.%S.val]
 // CHECK:STDOUT:   assign %s.var, %.loc8_3
 // CHECK:STDOUT:   %.loc8_13: type = splice_block %S.ref.loc8 [concrete = constants.%S] {
@@ -1770,7 +1770,7 @@ fn F() {
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %s.var: ref %S = var %s.var_patt
 // CHECK:STDOUT:   %.loc8_19.1: %empty_struct_type = struct_literal () [concrete = constants.%empty_struct]
-// CHECK:STDOUT:   %.loc8_19.2: init %S = class_init (), %s.var [concrete = constants.%S.val]
+// CHECK:STDOUT:   %.loc8_19.2: init %S to %s.var = class_init () [concrete = constants.%S.val]
 // CHECK:STDOUT:   %.loc8_3: init %S = converted %.loc8_19.1, %.loc8_19.2 [concrete = constants.%S.val]
 // CHECK:STDOUT:   assign %s.var, %.loc8_3
 // CHECK:STDOUT:   %.loc8_13: type = splice_block %S.ref.loc8 [concrete = constants.%S] {
@@ -1924,7 +1924,7 @@ fn F() {
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %s.var: ref %S = var %s.var_patt
 // CHECK:STDOUT:   %.loc10_19.1: %empty_struct_type = struct_literal () [concrete = constants.%empty_struct]
-// CHECK:STDOUT:   %.loc10_19.2: init %S = class_init (), %s.var [concrete = constants.%S.val]
+// CHECK:STDOUT:   %.loc10_19.2: init %S to %s.var = class_init () [concrete = constants.%S.val]
 // CHECK:STDOUT:   %.loc10_3: init %S = converted %.loc10_19.1, %.loc10_19.2 [concrete = constants.%S.val]
 // CHECK:STDOUT:   assign %s.var, %.loc10_3
 // CHECK:STDOUT:   %.loc10_13: type = splice_block %S.ref.loc10 [concrete = constants.%S] {
@@ -1955,7 +1955,7 @@ fn F() {
 // CHECK:STDOUT:   %Cpp.ref.loc13_53: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:   %S.ref.loc13_56: type = name_ref S, imports.%S.decl [concrete = constants.%S]
 // CHECK:STDOUT:   %.loc13_48.2: ref %S = temporary_storage
-// CHECK:STDOUT:   %.loc13_48.3: init %S = class_init (), %.loc13_48.2 [concrete = constants.%S.val]
+// CHECK:STDOUT:   %.loc13_48.3: init %S to %.loc13_48.2 = class_init () [concrete = constants.%S.val]
 // CHECK:STDOUT:   %.loc13_48.4: ref %S = temporary %.loc13_48.2, %.loc13_48.3
 // CHECK:STDOUT:   %.loc13_50.1: ref %S = converted %.loc13_48.1, %.loc13_48.4
 // CHECK:STDOUT:   %.loc13_50.2: %S = acquire_value %.loc13_50.1

toolchain/check/testdata/interop/cpp/function/qualified_param.carbon

@@ -117,7 +117,7 @@ fn F() {
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %s.var: ref %S = var %s.var_patt
 // CHECK:STDOUT:   %.loc10_19.1: %empty_struct_type = struct_literal () [concrete = constants.%empty_struct]
-// CHECK:STDOUT:   %.loc10_19.2: init %S = class_init (), %s.var [concrete = constants.%S.val]
+// CHECK:STDOUT:   %.loc10_19.2: init %S to %s.var = class_init () [concrete = constants.%S.val]
 // CHECK:STDOUT:   %.loc10_3: init %S = converted %.loc10_19.1, %.loc10_19.2 [concrete = constants.%S.val]
 // CHECK:STDOUT:   assign %s.var, %.loc10_3
 // CHECK:STDOUT:   %.loc10_13: type = splice_block %S.ref [concrete = constants.%S] {

toolchain/check/testdata/interop/cpp/function/reference.carbon

@@ -353,7 +353,7 @@ fn F() {
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %s.var: ref %S = var %s.var_patt
 // CHECK:STDOUT:   %.loc8_19.1: %empty_struct_type = struct_literal () [concrete = constants.%empty_struct]
-// CHECK:STDOUT:   %.loc8_19.2: init %S = class_init (), %s.var [concrete = constants.%S.val]
+// CHECK:STDOUT:   %.loc8_19.2: init %S to %s.var = class_init () [concrete = constants.%S.val]
 // CHECK:STDOUT:   %.loc8_3: init %S = converted %.loc8_19.1, %.loc8_19.2 [concrete = constants.%S.val]
 // CHECK:STDOUT:   assign %s.var, %.loc8_3
 // CHECK:STDOUT:   %.loc8_13: type = splice_block %S.ref [concrete = constants.%S] {
@@ -519,7 +519,7 @@ fn F() {
 // CHECK:STDOUT:   %Cpp.ref.loc8_25: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:   %S.ref: type = name_ref S, imports.%S.decl [concrete = constants.%S]
 // CHECK:STDOUT:   %.loc8_20.2: ref %S = temporary_storage
-// CHECK:STDOUT:   %.loc8_20.3: init %S = class_init (), %.loc8_20.2 [concrete = constants.%S.val]
+// CHECK:STDOUT:   %.loc8_20.3: init %S to %.loc8_20.2 = class_init () [concrete = constants.%S.val]
 // CHECK:STDOUT:   %.loc8_20.4: ref %S = temporary %.loc8_20.2, %.loc8_20.3
 // CHECK:STDOUT:   %.loc8_22.1: ref %S = converted %.loc8_20.1, %.loc8_20.4
 // CHECK:STDOUT:   %.loc8_22.2: %S = acquire_value %.loc8_22.1
@@ -577,7 +577,7 @@ fn F() {
 // CHECK:STDOUT:     %S.ref: type = name_ref S, imports.%S.decl [concrete = constants.%S]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %.loc12_19.2: ref %S = temporary_storage
-// CHECK:STDOUT:   %.loc12_19.3: init %S = class_init (), %.loc12_19.2 [concrete = constants.%S.val]
+// CHECK:STDOUT:   %.loc12_19.3: init %S to %.loc12_19.2 = class_init () [concrete = constants.%S.val]
 // CHECK:STDOUT:   %.loc12_19.4: ref %S = temporary %.loc12_19.2, %.loc12_19.3
 // CHECK:STDOUT:   %.loc12_19.5: ref %S = converted %.loc12_19.1, %.loc12_19.4
 // CHECK:STDOUT:   %.loc12_19.6: %S = acquire_value %.loc12_19.5
@@ -661,7 +661,7 @@ fn F() {
 // CHECK:STDOUT:   %Cpp.ref.loc38_26: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:   %S.ref.loc38_29: type = name_ref S, imports.%S.decl [concrete = constants.%S]
 // CHECK:STDOUT:   %.loc38_21.2: ref %S = temporary_storage
-// CHECK:STDOUT:   %.loc38_21.3: init %S = class_init (), %.loc38_21.2 [concrete = constants.%S.val]
+// CHECK:STDOUT:   %.loc38_21.3: init %S to %.loc38_21.2 = class_init () [concrete = constants.%S.val]
 // CHECK:STDOUT:   %.loc38_21.4: ref %S = temporary %.loc38_21.2, %.loc38_21.3
 // CHECK:STDOUT:   %.loc38_23: ref %S = converted %.loc38_21.1, %.loc38_21.4
 // CHECK:STDOUT:   %Cpp.ref.loc38_42: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
@@ -725,7 +725,7 @@ fn F() {
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %s.var: ref %S = var %s.var_patt
 // CHECK:STDOUT:   %.loc8_19.1: %empty_struct_type = struct_literal () [concrete = constants.%empty_struct]
-// CHECK:STDOUT:   %.loc8_19.2: init %S = class_init (), %s.var [concrete = constants.%S.val]
+// CHECK:STDOUT:   %.loc8_19.2: init %S to %s.var = class_init () [concrete = constants.%S.val]
 // CHECK:STDOUT:   %.loc8_3: init %S = converted %.loc8_19.1, %.loc8_19.2 [concrete = constants.%S.val]
 // CHECK:STDOUT:   assign %s.var, %.loc8_3
 // CHECK:STDOUT:   %.loc8_13: type = splice_block %S.ref.loc8 [concrete = constants.%S] {
@@ -811,7 +811,7 @@ fn F() {
 // CHECK:STDOUT:     %S.ref.loc8: type = name_ref S, imports.%S.decl [concrete = constants.%S]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %.loc8_19.2: ref %S = temporary_storage
-// CHECK:STDOUT:   %.loc8_19.3: init %S = class_init (), %.loc8_19.2 [concrete = constants.%S.val]
+// CHECK:STDOUT:   %.loc8_19.3: init %S to %.loc8_19.2 = class_init () [concrete = constants.%S.val]
 // CHECK:STDOUT:   %.loc8_19.4: ref %S = temporary %.loc8_19.2, %.loc8_19.3
 // CHECK:STDOUT:   %.loc8_19.5: ref %S = converted %.loc8_19.1, %.loc8_19.4
 // CHECK:STDOUT:   %.loc8_19.6: %S = acquire_value %.loc8_19.5

toolchain/check/testdata/interop/cpp/function/struct.carbon

@@ -564,7 +564,7 @@ fn F() {
 // CHECK:STDOUT:   %Cpp.ref.loc8_17: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:   %S.ref: type = name_ref S, imports.%S.decl [concrete = constants.%S]
 // CHECK:STDOUT:   %.loc8_12.2: ref %S = temporary_storage
-// CHECK:STDOUT:   %.loc8_12.3: init %S = class_init (), %.loc8_12.2 [concrete = constants.%S.val]
+// CHECK:STDOUT:   %.loc8_12.3: init %S to %.loc8_12.2 = class_init () [concrete = constants.%S.val]
 // CHECK:STDOUT:   %.loc8_12.4: ref %S = temporary %.loc8_12.2, %.loc8_12.3
 // CHECK:STDOUT:   %.loc8_14.1: ref %S = converted %.loc8_12.1, %.loc8_12.4
 // CHECK:STDOUT:   %.loc8_14.2: %S = acquire_value %.loc8_14.1
@@ -617,7 +617,7 @@ fn F() {
 // CHECK:STDOUT:   %Cpp.ref.loc24_17: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:   %S.ref: type = name_ref S, imports.%S.decl [concrete = constants.%S]
 // CHECK:STDOUT:   %.loc24_12.2: ref %S = temporary_storage
-// CHECK:STDOUT:   %.loc24_12.3: init %S = class_init (), %.loc24_12.2 [concrete = constants.%S.val]
+// CHECK:STDOUT:   %.loc24_12.3: init %S to %.loc24_12.2 = class_init () [concrete = constants.%S.val]
 // CHECK:STDOUT:   %.loc24_12.4: ref %S = temporary %.loc24_12.2, %.loc24_12.3
 // CHECK:STDOUT:   %.loc24_14.1: ref %S = converted %.loc24_12.1, %.loc24_12.4
 // CHECK:STDOUT:   %.loc24_14.2: %S = acquire_value %.loc24_14.1
@@ -737,7 +737,7 @@ fn F() {
 // CHECK:STDOUT:   %N.ref.loc8: <namespace> = name_ref N, imports.%N [concrete = imports.%N]
 // CHECK:STDOUT:   %S.ref.loc8: type = name_ref S, imports.%S.decl [concrete = constants.%S]
 // CHECK:STDOUT:   %.loc8_12.2: ref %S = temporary_storage
-// CHECK:STDOUT:   %.loc8_12.3: init %S = class_init (), %.loc8_12.2 [concrete = constants.%S.val]
+// CHECK:STDOUT:   %.loc8_12.3: init %S to %.loc8_12.2 = class_init () [concrete = constants.%S.val]
 // CHECK:STDOUT:   %.loc8_12.4: ref %S = temporary %.loc8_12.2, %.loc8_12.3
 // CHECK:STDOUT:   %.loc8_14.1: ref %S = converted %.loc8_12.1, %.loc8_12.4
 // CHECK:STDOUT:   %.loc8_14.2: %S = acquire_value %.loc8_14.1
@@ -815,7 +815,7 @@ fn F() {
 // CHECK:STDOUT:   %N2.ref: <namespace> = name_ref N2, imports.%N2 [concrete = imports.%N2]
 // CHECK:STDOUT:   %S.ref: type = name_ref S, imports.%S.decl [concrete = constants.%S]
 // CHECK:STDOUT:   %.loc8_15.2: ref %S = temporary_storage
-// CHECK:STDOUT:   %.loc8_15.3: init %S = class_init (), %.loc8_15.2 [concrete = constants.%S.val]
+// CHECK:STDOUT:   %.loc8_15.3: init %S to %.loc8_15.2 = class_init () [concrete = constants.%S.val]
 // CHECK:STDOUT:   %.loc8_15.4: ref %S = temporary %.loc8_15.2, %.loc8_15.3
 // CHECK:STDOUT:   %.loc8_17.1: ref %S = converted %.loc8_15.1, %.loc8_15.4
 // CHECK:STDOUT:   %.loc8_17.2: %S = acquire_value %.loc8_17.1
@@ -875,7 +875,7 @@ fn F() {
 // CHECK:STDOUT:   %O.ref.loc8: type = name_ref O, imports.%O.decl [concrete = constants.%O]
 // CHECK:STDOUT:   %S.ref: type = name_ref S, imports.%S.decl [concrete = constants.%S]
 // CHECK:STDOUT:   %.loc8_12.2: ref %S = temporary_storage
-// CHECK:STDOUT:   %.loc8_12.3: init %S = class_init (), %.loc8_12.2 [concrete = constants.%S.val]
+// CHECK:STDOUT:   %.loc8_12.3: init %S to %.loc8_12.2 = class_init () [concrete = constants.%S.val]
 // CHECK:STDOUT:   %.loc8_12.4: ref %S = temporary %.loc8_12.2, %.loc8_12.3
 // CHECK:STDOUT:   %.loc8_14.1: ref %S = converted %.loc8_12.1, %.loc8_12.4
 // CHECK:STDOUT:   %.loc8_14.2: %S = acquire_value %.loc8_14.1
@@ -953,7 +953,7 @@ fn F() {
 // CHECK:STDOUT:   %Cpp.ref.loc9_17: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:   %S.ref.loc9: type = name_ref S, imports.%S.decl [concrete = constants.%S]
 // CHECK:STDOUT:   %.loc9_12.2: ref %S = temporary_storage
-// CHECK:STDOUT:   %.loc9_12.3: init %S = class_init (), %.loc9_12.2 [concrete = constants.%S.val]
+// CHECK:STDOUT:   %.loc9_12.3: init %S to %.loc9_12.2 = class_init () [concrete = constants.%S.val]
 // CHECK:STDOUT:   %.loc9_12.4: ref %S = temporary %.loc9_12.2, %.loc9_12.3
 // CHECK:STDOUT:   %.loc9_14.1: ref %S = converted %.loc9_12.1, %.loc9_12.4
 // CHECK:STDOUT:   %.loc9_14.2: %S = acquire_value %.loc9_14.1
@@ -1013,7 +1013,7 @@ fn F() {
 // CHECK:STDOUT:   %Cpp.ref.loc8_17: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:   %S.ref.loc8: type = name_ref S, imports.%S.decl [concrete = constants.%S]
 // CHECK:STDOUT:   %.loc8_12.2: ref %S = temporary_storage
-// CHECK:STDOUT:   %.loc8_12.3: init %S = class_init (), %.loc8_12.2 [concrete = constants.%S.val]
+// CHECK:STDOUT:   %.loc8_12.3: init %S to %.loc8_12.2 = class_init () [concrete = constants.%S.val]
 // CHECK:STDOUT:   %.loc8_12.4: ref %S = temporary %.loc8_12.2, %.loc8_12.3
 // CHECK:STDOUT:   %.loc8_14.1: ref %S = converted %.loc8_12.1, %.loc8_12.4
 // CHECK:STDOUT:   %.loc8_14.2: %S = acquire_value %.loc8_14.1
@@ -1137,7 +1137,7 @@ fn F() {
 // CHECK:STDOUT:   %.loc8_11.1: ref %S = temporary_storage
 // CHECK:STDOUT:   %addr: %ptr.5c7 = addr_of %.loc8_11.1
 // CHECK:STDOUT:   %foo__carbon_thunk.call: init %empty_tuple.type = call imports.%foo__carbon_thunk.decl(%addr)
-// CHECK:STDOUT:   %.loc8_11.2: init %S = in_place_init %foo__carbon_thunk.call, %.loc8_11.1
+// CHECK:STDOUT:   %.loc8_11.2: init %S to %.loc8_11.1 = in_place_init %foo__carbon_thunk.call
 // CHECK:STDOUT:   %.loc8_11.3: ref %S = temporary %.loc8_11.1, %.loc8_11.2
 // CHECK:STDOUT:   %S.cpp_destructor.bound: <bound method> = bound_method %.loc8_11.3, constants.%S.cpp_destructor
 // CHECK:STDOUT:   %S.cpp_destructor.call: init %empty_tuple.type = call %S.cpp_destructor.bound(%.loc8_11.3)

toolchain/check/testdata/interop/cpp/function/union.carbon

@@ -556,7 +556,7 @@ fn F() {
 // CHECK:STDOUT:   %Cpp.ref.loc8_17: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:   %U.ref: type = name_ref U, imports.%U.decl [concrete = constants.%U]
 // CHECK:STDOUT:   %.loc8_12.2: ref %U = temporary_storage
-// CHECK:STDOUT:   %.loc8_12.3: init %U = class_init (), %.loc8_12.2 [concrete = constants.%U.val]
+// CHECK:STDOUT:   %.loc8_12.3: init %U to %.loc8_12.2 = class_init () [concrete = constants.%U.val]
 // CHECK:STDOUT:   %.loc8_12.4: ref %U = temporary %.loc8_12.2, %.loc8_12.3
 // CHECK:STDOUT:   %.loc8_14.1: ref %U = converted %.loc8_12.1, %.loc8_12.4
 // CHECK:STDOUT:   %.loc8_14.2: %U = acquire_value %.loc8_14.1
@@ -678,7 +678,7 @@ fn F() {
 // CHECK:STDOUT:   %N.ref.loc8: <namespace> = name_ref N, imports.%N [concrete = imports.%N]
 // CHECK:STDOUT:   %U.ref.loc8: type = name_ref U, imports.%U.decl [concrete = constants.%U]
 // CHECK:STDOUT:   %.loc8_12.2: ref %U = temporary_storage
-// CHECK:STDOUT:   %.loc8_12.3: init %U = class_init (), %.loc8_12.2 [concrete = constants.%U.val]
+// CHECK:STDOUT:   %.loc8_12.3: init %U to %.loc8_12.2 = class_init () [concrete = constants.%U.val]
 // CHECK:STDOUT:   %.loc8_12.4: ref %U = temporary %.loc8_12.2, %.loc8_12.3
 // CHECK:STDOUT:   %.loc8_14.1: ref %U = converted %.loc8_12.1, %.loc8_12.4
 // CHECK:STDOUT:   %.loc8_14.2: %U = acquire_value %.loc8_14.1
@@ -756,7 +756,7 @@ fn F() {
 // CHECK:STDOUT:   %N2.ref: <namespace> = name_ref N2, imports.%N2 [concrete = imports.%N2]
 // CHECK:STDOUT:   %U.ref: type = name_ref U, imports.%U.decl [concrete = constants.%U]
 // CHECK:STDOUT:   %.loc8_15.2: ref %U = temporary_storage
-// CHECK:STDOUT:   %.loc8_15.3: init %U = class_init (), %.loc8_15.2 [concrete = constants.%U.val]
+// CHECK:STDOUT:   %.loc8_15.3: init %U to %.loc8_15.2 = class_init () [concrete = constants.%U.val]
 // CHECK:STDOUT:   %.loc8_15.4: ref %U = temporary %.loc8_15.2, %.loc8_15.3
 // CHECK:STDOUT:   %.loc8_17.1: ref %U = converted %.loc8_15.1, %.loc8_15.4
 // CHECK:STDOUT:   %.loc8_17.2: %U = acquire_value %.loc8_17.1
@@ -816,7 +816,7 @@ fn F() {
 // CHECK:STDOUT:   %O.ref.loc8: type = name_ref O, imports.%O.decl [concrete = constants.%O]
 // CHECK:STDOUT:   %U.ref: type = name_ref U, imports.%U.decl [concrete = constants.%U]
 // CHECK:STDOUT:   %.loc8_12.2: ref %U = temporary_storage
-// CHECK:STDOUT:   %.loc8_12.3: init %U = class_init (), %.loc8_12.2 [concrete = constants.%U.val]
+// CHECK:STDOUT:   %.loc8_12.3: init %U to %.loc8_12.2 = class_init () [concrete = constants.%U.val]
 // CHECK:STDOUT:   %.loc8_12.4: ref %U = temporary %.loc8_12.2, %.loc8_12.3
 // CHECK:STDOUT:   %.loc8_14.1: ref %U = converted %.loc8_12.1, %.loc8_12.4
 // CHECK:STDOUT:   %.loc8_14.2: %U = acquire_value %.loc8_14.1
@@ -894,7 +894,7 @@ fn F() {
 // CHECK:STDOUT:   %Cpp.ref.loc9_17: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:   %U.ref.loc9: type = name_ref U, imports.%U.decl [concrete = constants.%U]
 // CHECK:STDOUT:   %.loc9_12.2: ref %U = temporary_storage
-// CHECK:STDOUT:   %.loc9_12.3: init %U = class_init (), %.loc9_12.2 [concrete = constants.%U.val]
+// CHECK:STDOUT:   %.loc9_12.3: init %U to %.loc9_12.2 = class_init () [concrete = constants.%U.val]
 // CHECK:STDOUT:   %.loc9_12.4: ref %U = temporary %.loc9_12.2, %.loc9_12.3
 // CHECK:STDOUT:   %.loc9_14.1: ref %U = converted %.loc9_12.1, %.loc9_12.4
 // CHECK:STDOUT:   %.loc9_14.2: %U = acquire_value %.loc9_14.1
@@ -954,7 +954,7 @@ fn F() {
 // CHECK:STDOUT:   %Cpp.ref.loc8_17: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:   %U.ref.loc8: type = name_ref U, imports.%U.decl [concrete = constants.%U]
 // CHECK:STDOUT:   %.loc8_12.2: ref %U = temporary_storage
-// CHECK:STDOUT:   %.loc8_12.3: init %U = class_init (), %.loc8_12.2 [concrete = constants.%U.val]
+// CHECK:STDOUT:   %.loc8_12.3: init %U to %.loc8_12.2 = class_init () [concrete = constants.%U.val]
 // CHECK:STDOUT:   %.loc8_12.4: ref %U = temporary %.loc8_12.2, %.loc8_12.3
 // CHECK:STDOUT:   %.loc8_14.1: ref %U = converted %.loc8_12.1, %.loc8_12.4
 // CHECK:STDOUT:   %.loc8_14.2: %U = acquire_value %.loc8_14.1
@@ -1078,7 +1078,7 @@ fn F() {
 // CHECK:STDOUT:   %.loc8_11.1: ref %U = temporary_storage
 // CHECK:STDOUT:   %addr: %ptr.86f = addr_of %.loc8_11.1
 // CHECK:STDOUT:   %foo__carbon_thunk.call: init %empty_tuple.type = call imports.%foo__carbon_thunk.decl(%addr)
-// CHECK:STDOUT:   %.loc8_11.2: init %U = in_place_init %foo__carbon_thunk.call, %.loc8_11.1
+// CHECK:STDOUT:   %.loc8_11.2: init %U to %.loc8_11.1 = in_place_init %foo__carbon_thunk.call
 // CHECK:STDOUT:   %.loc8_11.3: ref %U = temporary %.loc8_11.1, %.loc8_11.2
 // CHECK:STDOUT:   %U.cpp_destructor.bound: <bound method> = bound_method %.loc8_11.3, constants.%U.cpp_destructor
 // CHECK:STDOUT:   %U.cpp_destructor.call: init %empty_tuple.type = call %U.cpp_destructor.bound(%.loc8_11.3)