Fix linkage related crash.

This test was exactly the opposite of what it should be. We should check if
there old decl has linkage (where it makes sense) and if the new decl has
the extern keyword.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@178735 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 10 insertions, 2 deletions

diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index 42d7d2bdf5..a25204d808 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -2929,8 +2929,8 @@ void Sema::MergeVarDecl(VarDecl *New, LookupResult &Previous,
     Diag(Old->getLocation(), diag::note_previous_definition);
     return New->setInvalidDecl();
   }
-  if (Old->hasExternalStorage() &&
-      New->isLocalVarDecl() && !New->hasLinkage()) {
+  if (Old->hasLinkage() && New->isLocalVarDecl() &&
+      !New->hasExternalStorage()) {
     Diag(New->getLocation(), diag::err_non_extern_extern) << New->getDeclName();
     Diag(Old->getLocation(), diag::note_previous_definition);
     return New->setInvalidDecl();
diff --git a/test/SemaCXX/linkage2.cpp b/test/SemaCXX/linkage2.cpp
index c2dbf1e308..94ac25c99d 100644
--- a/test/SemaCXX/linkage2.cpp
+++ b/test/SemaCXX/linkage2.cpp
@@ -126,3 +126,11 @@ extern "C" {
     void  __attribute__((overloadable)) test11_g(double);
   }
 }
+
+namespace test12 {
+  const int n = 0;
+  extern const int n;
+  void f() {
+    extern const int n;
+  }
+}