Apply review suggestions

Author: ivanaivanovska

toolchain/check/cpp/import.cpp

@@ -2235,8 +2235,9 @@ static auto MapConstant(Context& context, SemIR::LocId loc_id,
 
   SemIR::TypeId type_id = MapType(context, loc_id, expr->getType()).type_id;
   if (!type_id.has_value()) {
-    context.TODO(
-        loc_id, "Unsupported: constant type: " + expr->getType().getAsString());
+    context.TODO(loc_id, llvm::formatv("Unsupported: C++ literal's type `{0}` "
+                                       "could not be mapped to a Carbon type",
+                                       expr->getType().getAsString()));
     return SemIR::ErrorInst::InstId;
   }
 
@@ -2258,8 +2259,9 @@ static auto MapConstant(Context& context, SemIR::LocId loc_id,
                                    context, imported_loc_id,
                                    {.type_id = type_id, .float_id = float_id}));
   } else {
-    context.TODO(
-        loc_id, "Unsupported: constant type: " + expr->getType().getAsString());
+    context.TODO(loc_id, llvm::formatv(
+                             "Unsupported: C++ constant expression type: '{0}'",
+                             expr->getType().getAsString()));
     return SemIR::ErrorInst::InstId;
   }
 

toolchain/check/cpp/macros.cpp

@@ -62,26 +62,24 @@ auto TryEvaluateMacroToConstant(Context& context, SemIR::LocId loc_id,
   }
 
   clang::Expr::EvalResult evaluated_result;
-  if (!result_expr->EvaluateAsConstantExpr(evaluated_result,
-                                           sema.getASTContext())) {
-    context.TODO(loc_id,
-                 "failed to evaluate macro to a valid constant expression");
-    return nullptr;
-  }
+  CARBON_CHECK(result_expr->EvaluateAsConstantExpr(evaluated_result,
+                                                   sema.getASTContext()));
   clang::APValue ap_value = evaluated_result.Val;
-  if (ap_value.isInt()) {
-    return clang::IntegerLiteral::Create(
-        sema.getASTContext(), ap_value.getInt(), result_expr->getType(),
-        result_expr->getExprLoc());
-  }
-  if (ap_value.isFloat()) {
-    return clang::FloatingLiteral::Create(
-        sema.getASTContext(), ap_value.getFloat(),
-        /*isExact=*/true, result_expr->getType(), result_expr->getExprLoc());
+  switch (ap_value.getKind()) {
+    case clang::APValue::Int:
+      return clang::IntegerLiteral::Create(
+          sema.getASTContext(), ap_value.getInt(), result_expr->getType(),
+          result_expr->getExprLoc());
+    case clang::APValue::Float:
+      return clang::FloatingLiteral::Create(
+          sema.getASTContext(), ap_value.getFloat(),
+          /*isExact=*/true, result_expr->getType(), result_expr->getExprLoc());
+    default:
+      context.TODO(loc_id,
+                   "Unsupported: macro evaluated to a constant of type: " +
+                       result_expr->getType().getAsString());
+      return nullptr;
   }
-  context.TODO(loc_id, "Unsupported: constant type:" +
-                           result_expr->getType().getAsString());
-  return nullptr;
 }
 
 }  // namespace Carbon::Check

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

@@ -89,7 +89,7 @@ fn F() {
   // CHECK:STDERR:   Cpp.CONFIG_VALUE;
   // CHECK:STDERR:   ^~~~~~~~~~~~~~~~
   // CHECK:STDERR:
-  // CHECK:STDERR: fail_import_integer_literal_too_big.carbon:[[@LINE+11]]:3: error: semantics TODO: `Unsupported: constant type: unsigned long long` [SemanticsTodo]
+  // CHECK:STDERR: fail_import_integer_literal_too_big.carbon:[[@LINE+11]]:3: error: semantics TODO: `Unsupported: C++ literal's type `unsigned long long` could not be mapped to a Carbon type` [SemanticsTodo]
   // CHECK:STDERR:   Cpp.CONFIG_VALUE;
   // CHECK:STDERR:   ^~~~~~~~~~~~~~~~
   // CHECK:STDERR: fail_import_integer_literal_too_big.carbon:[[@LINE+8]]:3: note: in `Cpp` name lookup for `CONFIG_VALUE` [InCppNameLookup]
@@ -264,7 +264,7 @@ import Cpp library "string_literal_object_like_macro.h";
 
 fn F() {
   // TODO: Get rid of the second error.
-  // CHECK:STDERR: fail_todo_import_string_literal_object_like_macro.carbon:[[@LINE+11]]:3: error: semantics TODO: `Unsupported: constant type:const char[4]` [SemanticsTodo]
+  // CHECK:STDERR: fail_todo_import_string_literal_object_like_macro.carbon:[[@LINE+11]]:3: error: semantics TODO: `Unsupported: macro evaluated to a constant of type: const char[4]` [SemanticsTodo]
   // CHECK:STDERR:   Cpp.CONFIG_VALUE;
   // CHECK:STDERR:   ^~~~~~~~~~~~~~~~
   // CHECK:STDERR: fail_todo_import_string_literal_object_like_macro.carbon:[[@LINE+8]]:3: note: in `Cpp` name lookup for `CONFIG_VALUE` [InCppNameLookup]
@@ -307,7 +307,7 @@ library "[[@TEST_NAME]]";
 import Cpp library "unsupported_floating_point_literal_macro.h";
 
 fn F() {
-  // CHECK:STDERR: fail_import_unsupported_floating_point_literal_macro.carbon:[[@LINE+11]]:3: error: semantics TODO: `Unsupported: constant type: long double` [SemanticsTodo]
+  // CHECK:STDERR: fail_import_unsupported_floating_point_literal_macro.carbon:[[@LINE+11]]:3: error: semantics TODO: `Unsupported: C++ literal's type `long double` could not be mapped to a Carbon type` [SemanticsTodo]
   // CHECK:STDERR:   Cpp.MyLongDouble;
   // CHECK:STDERR:   ^~~~~~~~~~~~~~~~
   // CHECK:STDERR: fail_import_unsupported_floating_point_literal_macro.carbon:[[@LINE+8]]:3: note: in `Cpp` name lookup for `MyLongDouble` [InCppNameLookup]
@@ -335,6 +335,19 @@ fn F() {
   Cpp.MyDouble = 1.0;
 }
 
+// --- lambda.carbon
+
+library "[[@TEST_NAME]]";
+
+import Cpp inline '''
+  #define MyIntLambda (([] { return 7; })())
+''';
+
+fn F() {
+  let i: i32 = Cpp.MyIntLambda;
+}
+
+
 // --- macro_undefined.h
 
 #define CONFIG_VALUE 1