1 files changed, 4 insertions, 0 deletions
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 2024acc9755..5abacca732c 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -2305,6 +2305,10 @@ bool Sema::MergeFunctionDecl(FunctionDecl *New, Decl *OldD, Scope *S) {
     return true;
   }
 
+  // If the old declaration is invalid, just give up here.
+  if (Old->isInvalidDecl())
+    return true;
+
   // Determine whether the previous declaration was a definition,
   // implicit declaration, or a declaration.
   diag::kind PrevDiag;