[clang] [clang][ASTImporter] Fix typos in trailing return testing on lambda p… (PR #101031)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Ding Fei (danix800)

<details>
<summary>Changes</summary>

The test should be true on function with trailing return.

This fixes crashes (infinite recursion) on lambda expr without parameters (no parentheses).

---
Full diff: https://github.com/llvm/llvm-project/pull/101031.diff


2 Files Affected:

- (modified) clang/lib/AST/ASTImporter.cpp (+3-5) 
- (modified) clang/unittests/AST/ASTImporterTest.cpp (+17) 


``````````diff
diff --git a/clang/lib/AST/ASTImporter.cpp b/clang/lib/AST/ASTImporter.cpp
index da1981d8dd05f..83aa017a00a7f 100644
--- a/clang/lib/AST/ASTImporter.cpp
+++ b/clang/lib/AST/ASTImporter.cpp
@@ -3665,13 +3665,10 @@ bool ASTNodeImporter::hasReturnTypeDeclaredInside(FunctionDecl *D) {
   const auto *FromFPT = FromTy->getAs<FunctionProtoType>();
   assert(FromFPT && "Must be called on FunctionProtoType");
 
-  auto IsCXX11LambdaWithouTrailingReturn = [&]() {
+  auto IsCXX11LambdaWithoutTrailingReturn = [&]() {
     if (Importer.FromContext.getLangOpts().CPlusPlus14) // C++14 or later
       return false;
 
-    if (FromFPT->hasTrailingReturn())
-      return false;
-
     if (const auto *MD = dyn_cast<CXXMethodDecl>(D))
       return cast<CXXRecordDecl>(MD->getDeclContext())->isLambda();
 
@@ -3679,7 +3676,8 @@ bool ASTNodeImporter::hasReturnTypeDeclaredInside(FunctionDecl *D) {
   };
 
   QualType RetT = FromFPT->getReturnType();
-  if (isa<AutoType>(RetT.getTypePtr()) || IsCXX11LambdaWithouTrailingReturn()) {
+  if (FromFPT->hasTrailingReturn() || isa<AutoType>(RetT.getTypePtr()) ||
+      IsCXX11LambdaWithoutTrailingReturn()) {
     FunctionDecl *Def = D->getDefinition();
     IsTypeDeclaredInsideVisitor Visitor(Def ? Def : D);
     return Visitor.CheckType(RetT);
diff --git a/clang/unittests/AST/ASTImporterTest.cpp b/clang/unittests/AST/ASTImporterTest.cpp
index 57c5f79651824..d275a08dca895 100644
--- a/clang/unittests/AST/ASTImporterTest.cpp
+++ b/clang/unittests/AST/ASTImporterTest.cpp
@@ -6738,6 +6738,23 @@ TEST_P(ASTImporterOptionSpecificTestBase,
   EXPECT_TRUE(ToLambda);
 }
 
+TEST_P(ASTImporterOptionSpecificTestBase,
+       ReturnTypeDeclaredInsideOfCXX11LambdaWithTrailingReturn) {
+  Decl *From, *To;
+  std::tie(From, To) = getImportedDecl(
+      R"(
+      void foo() {
+        (void) [] {
+          struct X {};
+          return X();
+        };
+      }
+      )",
+      Lang_CXX11, "", Lang_CXX11, "foo"); // c++11 only
+  auto *ToLambda = FirstDeclMatcher<LambdaExpr>().match(To, lambdaExpr());
+  EXPECT_TRUE(ToLambda);
+}
+
 TEST_P(ASTImporterOptionSpecificTestBase, LambdaInFunctionParam) {
   Decl *FromTU = getTuDecl(
       R"(

``````````

</details>


https://github.com/llvm/llvm-project/pull/101031