commit 2e52e13c1e7e9a41d47b808fc5d668b7b738b94c
author Wei Wang <apollo.mobility@gmail.com> Wed Jan 24 11:06:20 2024 -0800
committer GitHub <noreply@github.com> Wed Jan 24 11:06:20 2024 -0800
tree b6526a1debe362dc1f52c2708ab8ccd8e0d56b88
parent 123c83ddc71048fb0a682218e6961d71ec08c2ea

[clang] Make sure the same UsingType is searched and inserted (#79182)

When creating a new UsingType, the underlying type may change if it is a
declaration. This creates an inconsistency between the type searched and
type created. Update member and non-member Profile functions so that
they return the same ID.

clang/include/clang/AST/Type.h

diff --git a/clang/include/clang/AST/Type.h b/clang/include/clang/AST/Type.h
index ea42579..3d41105 100644
--- a/clang/include/clang/AST/Type.h
+++ b/clang/include/clang/AST/Type.h
@@ -4729,13 +4729,12 @@
   bool typeMatchesDecl() const { return !UsingBits.hasTypeDifferentFromDecl; }
 
   void Profile(llvm::FoldingSetNodeID &ID) {
-    Profile(ID, Found, typeMatchesDecl() ? QualType() : getUnderlyingType());
+    Profile(ID, Found, getUnderlyingType());
   }
   static void Profile(llvm::FoldingSetNodeID &ID, const UsingShadowDecl *Found,
                       QualType Underlying) {
     ID.AddPointer(Found);
-    if (!Underlying.isNull())
-      Underlying.Profile(ID);
+    Underlying.Profile(ID);
   }
   static bool classof(const Type *T) { return T->getTypeClass() == Using; }
 };

clang/test/AST/ast-dump-using.cpp

diff --git a/clang/test/AST/ast-dump-using.cpp b/clang/test/AST/ast-dump-using.cpp
index c007ecd..5a4e910 100644
--- a/clang/test/AST/ast-dump-using.cpp
+++ b/clang/test/AST/ast-dump-using.cpp
@@ -12,7 +12,13 @@
 typedef S f; // to dump the introduced type
 // CHECK:      TypedefDecl
 // CHECK-NEXT: `-ElaboratedType {{.*}} 'S' sugar
-// CHECK-NEXT:   `-UsingType {{.*}} 'a::S' sugar
-// CHECK-NEXT:     |-UsingShadow {{.*}} 'S'
+// CHECK-NEXT:   `-UsingType [[TYPE_ADDR:.*]] 'a::S' sugar
+// CHECK-NEXT:     |-UsingShadow [[SHADOW_ADDR:.*]] 'S'
+// CHECK-NEXT:     `-RecordType {{.*}} 'a::S'
+typedef S e; // check the same UsingType is reused.
+// CHECK:      TypedefDecl
+// CHECK-NEXT: `-ElaboratedType {{.*}} 'S' sugar
+// CHECK-NEXT:   `-UsingType [[TYPE_ADDR]] 'a::S' sugar
+// CHECK-NEXT:     |-UsingShadow [[SHADOW_ADDR]] 'S'
 // CHECK-NEXT:     `-RecordType {{.*}} 'a::S'
 }