2 files changed, 107 insertions, 1 deletions

diff --git a/clang/lib/AST/ODRHash.cpp b/clang/lib/AST/ODRHash.cpp
index ba3b2ee49c5..e47154088d9 100644
--- a/clang/lib/AST/ODRHash.cpp
+++ b/clang/lib/AST/ODRHash.cpp
@@ -696,7 +696,52 @@ public:
     ID.AddInteger(Quals.getAsOpaqueValue());
   }
 
+  // Return the RecordType if the typedef only strips away a keyword.
+  // Otherwise, return the original type.
+  static const Type *RemoveTypedef(const Type *T) {
+    const auto *TypedefT = dyn_cast<TypedefType>(T);
+    if (!TypedefT) {
+      return T;
+    }
+
+    const TypedefNameDecl *D = TypedefT->getDecl();
+    QualType UnderlyingType = D->getUnderlyingType();
+
+    if (UnderlyingType.hasLocalQualifiers()) {
+      return T;
+    }
+
+    const auto *ElaboratedT = dyn_cast<ElaboratedType>(UnderlyingType);
+    if (!ElaboratedT) {
+      return T;
+    }
+
+    if (ElaboratedT->getQualifier() != nullptr) {
+      return T;
+    }
+
+    QualType NamedType = ElaboratedT->getNamedType();
+    if (NamedType.hasLocalQualifiers()) {
+      return T;
+    }
+
+    const auto *RecordT = dyn_cast<RecordType>(NamedType);
+    if (!RecordT) {
+      return T;
+    }
+
+    const IdentifierInfo *TypedefII = TypedefT->getDecl()->getIdentifier();
+    const IdentifierInfo *RecordII = RecordT->getDecl()->getIdentifier();
+    if (!TypedefII || !RecordII ||
+        TypedefII->getName() != RecordII->getName()) {
+      return T;
+    }
+
+    return RecordT;
+  }
+
   void Visit(const Type *T) {
+    T = RemoveTypedef(T);
     ID.AddInteger(T->getTypeClass());
     Inherited::Visit(T);
   }
diff --git a/clang/test/Modules/odr_hash.cpp b/clang/test/Modules/odr_hash.cpp
index f22a8b8f8a0..ff7cfb3ae7f 100644
--- a/clang/test/Modules/odr_hash.cpp
+++ b/clang/test/Modules/odr_hash.cpp
@@ -4621,9 +4621,70 @@ struct S2 {
 #else
 S2 s2;
 #endif
-
 }
 
+namespace TypedefStruct {
+#if defined(FIRST)
+struct T1;
+class S1 {
+  T1* t;
+};
+#elif defined(SECOND)
+typedef struct T1 {} T1;
+class S1 {
+  T1* t;
+};
+#else
+S1 s1;
+#endif
+
+#if defined(FIRST)
+struct T2;
+class S2 {
+  const T2* t = nullptr;
+};
+#elif defined(SECOND)
+typedef struct T2 {} T2;
+class S2 {
+  const T2* t = nullptr;
+};
+#else
+S2 s2;
+#endif
+
+#if defined(FIRST)
+struct T3;
+class S3 {
+  T3* const t = nullptr;
+};
+#elif defined(SECOND)
+typedef struct T3 {} T3;
+class S3 {
+  T3* const t = nullptr;
+};
+#else
+S3 s3;
+#endif
+
+#if defined(FIRST)
+namespace NS4 {
+struct T4;
+} // namespace NS4
+class S4 {
+  NS4::T4* t = 0;
+};
+#elif defined(SECOND)
+namespace NS4 {
+typedef struct T4 {} T4;
+} // namespace NS4
+class S4 {
+  NS4::T4* t = 0;
+};
+#else
+S4 s4;
+#endif
+} // namespace TypedefStruct
+
 // Keep macros contained to one file.
 #ifdef FIRST
 #undef FIRST