[clang] 72e8ab7 - [clang][ASTImporter] add processing of SubstNonTypeTemplateParmExpr in isAncestorDeclContextOf (#74991)

[via cfe-commits]

Author: Qizhi Hu
Date: 2023-12-21T15:05:33+08:00
New Revision: 72e8ab7d442f57cd65c89a4a99e76acd94788707

URL: https://github.com/llvm/llvm-project/commit/72e8ab7d442f57cd65c89a4a99e76acd94788707
DIFF: https://github.com/llvm/llvm-project/commit/72e8ab7d442f57cd65c89a4a99e76acd94788707.diff

LOG: [clang][ASTImporter] add processing of SubstNonTypeTemplateParmExpr in isAncestorDeclContextOf (#74991)

Lack of processing of `SubstNonTypeTemplateParmExpr` in
`isAncestorDeclContextOf` would make `hasAutoReturnTypeDeclaredInside`
returns false and lead to infinite recursion. This patch adds the
processor and try to fix [this
issue](https://github.com/llvm/llvm-project/issues/74839)

Co-authored-by: huqizhi <836744285 at qq.com>

Added: 
    

Modified: 
    clang/lib/AST/ASTImporter.cpp
    clang/unittests/AST/ASTImporterTest.cpp

Removed: 
    


################################################################################
diff  --git a/clang/lib/AST/ASTImporter.cpp b/clang/lib/AST/ASTImporter.cpp
index 49d0dd218d6830..1cc47de675bf33 100644
--- a/clang/lib/AST/ASTImporter.cpp
+++ b/clang/lib/AST/ASTImporter.cpp
@@ -3418,10 +3418,16 @@ static bool isAncestorDeclContextOf(const DeclContext *DC, const Stmt *S) {
   while (!ToProcess.empty()) {
     const Stmt *CurrentS = ToProcess.pop_back_val();
     ToProcess.append(CurrentS->child_begin(), CurrentS->child_end());
-    if (const auto *DeclRef = dyn_cast<DeclRefExpr>(CurrentS))
+    if (const auto *DeclRef = dyn_cast<DeclRefExpr>(CurrentS)) {
       if (const Decl *D = DeclRef->getDecl())
         if (isAncestorDeclContextOf(DC, D))
           return true;
+    } else if (const auto *E =
+                   dyn_cast_or_null<SubstNonTypeTemplateParmExpr>(CurrentS)) {
+      if (const Decl *D = E->getAssociatedDecl())
+        if (isAncestorDeclContextOf(DC, D))
+          return true;
+    }
   }
   return false;
 }

diff  --git a/clang/unittests/AST/ASTImporterTest.cpp b/clang/unittests/AST/ASTImporterTest.cpp
index 4dd7510bf8ddf8..4c06152d3eb563 100644
--- a/clang/unittests/AST/ASTImporterTest.cpp
+++ b/clang/unittests/AST/ASTImporterTest.cpp
@@ -7250,6 +7250,26 @@ TEST_P(ImportAutoFunctions, ReturnWithAutoTemplateType) {
       Lang_CXX14, /*FindLast=*/true);
 }
 
+TEST_P(ImportAutoFunctions, ReturnWithSubstNonTypeTemplateParmExpr) {
+  const char *Code =
+      R"(
+      template<int>
+      struct array {};
+
+      template <int N>
+      auto foo() { return array<N>(); }
+
+      void bar() { foo<0>(); }
+      )";
+  Decl *FromTU = getTuDecl(Code, Lang_CXX17);
+
+  auto *FromBar = FirstDeclMatcher<FunctionDecl>().match(
+      FromTU, functionDecl(hasName("bar")));
+
+  auto *ToBar = Import(FromBar, Lang_CXX17);
+  EXPECT_TRUE(ToBar);
+}
+
 struct ImportSourceLocations : ASTImporterOptionSpecificTestBase {};
 
 TEST_P(ImportSourceLocations, PreserveFileIDTreeStructure) {