Implement copying for CppCompat.Long32 (#6625)

Context: https://github.com/carbon-language/carbon-lang/issues/6275.

Part of https://github.com/carbon-language/carbon-lang/issues/5263.

core/prelude/types/cpp/int.carbon

@@ -4,6 +4,7 @@
 
 package Core library "prelude/types/cpp/int";
 
+import library "prelude/copy";
 import library "prelude/operators";
 import library "prelude/types/int";
 import library "prelude/types/int_literal";
@@ -27,7 +28,13 @@ class CppCompat.ULongLong64 {
   adapt u64;
 }
 
-// TODO: Copy.
+// Copy
+
+impl CppCompat.Long32 as Copy {
+  fn Op[self: Self]() -> Self = "primitive_copy";
+}
+
+// TODO: Copy for ULong32, LongLong64, ULongLong64.
 
 // Conversions.
 

toolchain/check/testdata/interop/cpp/builtins.llp64.carbon

@@ -69,6 +69,19 @@ fn F() {
   //@dump-sem-ir-end
 }
 
+// --- copy_long.carbon
+
+library "[[@TEST_NAME]]";
+
+import Cpp;
+
+fn CopyLong() {
+  //@dump-sem-ir-begin
+  var a: Cpp.long = 1;
+  var b: Cpp.long = a;
+  //@dump-sem-ir-end
+}
+
 // operators
 
 // --- arithmetic_homogeneous_long.carbon
@@ -913,6 +926,87 @@ fn F() {
 // CHECK:STDOUT:
 // CHECK:STDOUT: fn @DestroyOp.loc19(%self.param: %LongResult) = "no_op";
 // CHECK:STDOUT:
+// CHECK:STDOUT: --- copy_long.carbon
+// CHECK:STDOUT:
+// CHECK:STDOUT: constants {
+// CHECK:STDOUT:   %empty_tuple.type: type = tuple_type () [concrete]
+// CHECK:STDOUT:   %Cpp.long: type = class_type @Long32 [concrete]
+// CHECK:STDOUT:   %pattern_type.68c: type = pattern_type %Cpp.long [concrete]
+// CHECK:STDOUT:   %int_1.5b8: Core.IntLiteral = int_value 1 [concrete]
+// CHECK:STDOUT:   %ImplicitAs.type.819: type = facet_type <@ImplicitAs, @ImplicitAs(%Cpp.long)> [concrete]
+// CHECK:STDOUT:   %ImplicitAs.Convert.type.4c2: type = fn_type @ImplicitAs.Convert, @ImplicitAs(%Cpp.long) [concrete]
+// CHECK:STDOUT:   %Copy.type: type = facet_type <@Copy> [concrete]
+// CHECK:STDOUT:   %Copy.Op.type: type = fn_type @Copy.Op [concrete]
+// CHECK:STDOUT:   %ImplicitAs.impl_witness.2ce: <witness> = impl_witness imports.%ImplicitAs.impl_witness_table.903 [concrete]
+// CHECK:STDOUT:   %ImplicitAs.facet: %ImplicitAs.type.819 = facet_value Core.IntLiteral, (%ImplicitAs.impl_witness.2ce) [concrete]
+// CHECK:STDOUT:   %.dad: type = fn_type_with_self_type %ImplicitAs.Convert.type.4c2, %ImplicitAs.facet [concrete]
+// CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.type: type = fn_type @Core.IntLiteral.as.ImplicitAs.impl.Convert [concrete]
+// CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert: %Core.IntLiteral.as.ImplicitAs.impl.Convert.type = struct_value () [concrete]
+// CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.bound: <bound method> = bound_method %int_1.5b8, %Core.IntLiteral.as.ImplicitAs.impl.Convert [concrete]
+// CHECK:STDOUT:   %int_1.5a4: %Cpp.long = int_value 1 [concrete]
+// CHECK:STDOUT:   %Copy.impl_witness.e75: <witness> = impl_witness imports.%Copy.impl_witness_table.572 [concrete]
+// CHECK:STDOUT:   %Copy.facet: %Copy.type = facet_value %Cpp.long, (%Copy.impl_witness.e75) [concrete]
+// CHECK:STDOUT:   %.03e: type = fn_type_with_self_type %Copy.Op.type, %Copy.facet [concrete]
+// CHECK:STDOUT:   %Cpp.long.as.Copy.impl.Op.type: type = fn_type @Cpp.long.as.Copy.impl.Op [concrete]
+// CHECK:STDOUT:   %Cpp.long.as.Copy.impl.Op: %Cpp.long.as.Copy.impl.Op.type = struct_value () [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 {
+// CHECK:STDOUT:   %Cpp: <namespace> = namespace file.%Cpp.import_cpp, [concrete] {
+// CHECK:STDOUT:     .long = constants.%Cpp.long
+// CHECK:STDOUT:     import Cpp//...
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import_ref.b8a: %Core.IntLiteral.as.ImplicitAs.impl.Convert.type = import_ref Core//prelude/types/cpp/int, loc{{\d+_\d+}}, loaded [concrete = constants.%Core.IntLiteral.as.ImplicitAs.impl.Convert]
+// CHECK:STDOUT:   %ImplicitAs.impl_witness_table.903 = impl_witness_table (%Core.import_ref.b8a), @Core.IntLiteral.as.ImplicitAs.impl.052 [concrete]
+// CHECK:STDOUT:   %Core.import_ref.915: %Cpp.long.as.Copy.impl.Op.type = import_ref Core//prelude/types/cpp/int, loc{{\d+_\d+}}, loaded [concrete = constants.%Cpp.long.as.Copy.impl.Op]
+// CHECK:STDOUT:   %Copy.impl_witness_table.572 = impl_witness_table (%Core.import_ref.915), @Cpp.long.as.Copy.impl [concrete]
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: fn @CopyLong() {
+// CHECK:STDOUT: !entry:
+// CHECK:STDOUT:   name_binding_decl {
+// CHECK:STDOUT:     %a.patt: %pattern_type.68c = ref_binding_pattern a [concrete]
+// CHECK:STDOUT:     %a.var_patt: %pattern_type.68c = var_pattern %a.patt [concrete]
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %a.var: ref %Cpp.long = var %a.var_patt
+// CHECK:STDOUT:   %int_1: Core.IntLiteral = int_value 1 [concrete = constants.%int_1.5b8]
+// CHECK:STDOUT:   %impl.elem0.loc8: %.dad = impl_witness_access constants.%ImplicitAs.impl_witness.2ce, element0 [concrete = constants.%Core.IntLiteral.as.ImplicitAs.impl.Convert]
+// CHECK:STDOUT:   %bound_method.loc8: <bound method> = bound_method %int_1, %impl.elem0.loc8 [concrete = constants.%Core.IntLiteral.as.ImplicitAs.impl.Convert.bound]
+// CHECK:STDOUT:   %Core.IntLiteral.as.ImplicitAs.impl.Convert.call: init %Cpp.long = call %bound_method.loc8(%int_1) [concrete = constants.%int_1.5a4]
+// CHECK:STDOUT:   %.loc8_3: init %Cpp.long = converted %int_1, %Core.IntLiteral.as.ImplicitAs.impl.Convert.call [concrete = constants.%int_1.5a4]
+// CHECK:STDOUT:   assign %a.var, %.loc8_3
+// CHECK:STDOUT:   %.loc8_13: type = splice_block %long.ref.loc8 [concrete = constants.%Cpp.long] {
+// CHECK:STDOUT:     %Cpp.ref.loc8: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
+// CHECK:STDOUT:     %long.ref.loc8: type = name_ref long, constants.%Cpp.long [concrete = constants.%Cpp.long]
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %a: ref %Cpp.long = ref_binding a, %a.var
+// CHECK:STDOUT:   name_binding_decl {
+// CHECK:STDOUT:     %b.patt: %pattern_type.68c = ref_binding_pattern b [concrete]
+// CHECK:STDOUT:     %b.var_patt: %pattern_type.68c = var_pattern %b.patt [concrete]
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %b.var: ref %Cpp.long = var %b.var_patt
+// CHECK:STDOUT:   %a.ref: ref %Cpp.long = name_ref a, %a
+// CHECK:STDOUT:   %.loc9_21: %Cpp.long = acquire_value %a.ref
+// CHECK:STDOUT:   %impl.elem0.loc9: %.03e = impl_witness_access constants.%Copy.impl_witness.e75, element0 [concrete = constants.%Cpp.long.as.Copy.impl.Op]
+// CHECK:STDOUT:   %bound_method.loc9: <bound method> = bound_method %.loc9_21, %impl.elem0.loc9
+// CHECK:STDOUT:   %Cpp.long.as.Copy.impl.Op.call: init %Cpp.long = call %bound_method.loc9(%.loc9_21)
+// CHECK:STDOUT:   assign %b.var, %Cpp.long.as.Copy.impl.Op.call
+// CHECK:STDOUT:   %.loc9_13: type = splice_block %long.ref.loc9 [concrete = constants.%Cpp.long] {
+// CHECK:STDOUT:     %Cpp.ref.loc9: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
+// CHECK:STDOUT:     %long.ref.loc9: type = name_ref long, constants.%Cpp.long [concrete = constants.%Cpp.long]
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %b: ref %Cpp.long = ref_binding b, %b.var
+// CHECK:STDOUT:   %DestroyOp.bound.loc9: <bound method> = bound_method %b.var, constants.%DestroyOp
+// CHECK:STDOUT:   %DestroyOp.call.loc9: init %empty_tuple.type = call %DestroyOp.bound.loc9(%b.var)
+// CHECK:STDOUT:   %DestroyOp.bound.loc8: <bound method> = bound_method %a.var, constants.%DestroyOp
+// CHECK:STDOUT:   %DestroyOp.call.loc8: init %empty_tuple.type = call %DestroyOp.bound.loc8(%a.var)
+// CHECK:STDOUT:   <elided>
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: fn @DestroyOp(%self.param: %Cpp.long) = "no_op";
+// CHECK:STDOUT:
 // CHECK:STDOUT: --- arithmetic_homogeneous_long.carbon
 // CHECK:STDOUT:
 // CHECK:STDOUT: constants {