Sema: An extern declaration can't be a redeclaration of a parameter

In the following:
void f(int x) { extern int x; }

The second declaration of 'x' shouldn't be considered a redeclaration of
the parameter.

llvm-svn: 225780

2 files changed, 6 insertions, 4 deletions

diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index baa6822da71..82ffd4da5f8 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -3282,14 +3282,12 @@ void Sema::MergeVarDecl(VarDecl *New, LookupResult &Previous) {
   }
 
   // Check if extern is followed by non-extern and vice-versa.
-  if (New->hasExternalStorage() &&
-      !Old->hasLinkage() && Old->isLocalVarDecl()) {
+  if (New->hasGlobalStorage() && !Old->hasLinkage() && Old->hasLocalStorage()) {
     Diag(New->getLocation(), diag::err_extern_non_extern) << New->getDeclName();
     Diag(OldLocation, PrevDiag);
     return New->setInvalidDecl();
   }
-  if (Old->hasLinkage() && New->isLocalVarDecl() &&
-      !New->hasExternalStorage()) {
+  if (Old->hasGlobalStorage() && !New->hasLinkage() && New->hasLocalStorage()) {
     Diag(New->getLocation(), diag::err_non_extern_extern) << New->getDeclName();
     Diag(OldLocation, PrevDiag);
     return New->setInvalidDecl();
diff --git a/clang/test/Sema/private-extern.c b/clang/test/Sema/private-extern.c
index 0c13c92bba7..94afd87fbb8 100644
--- a/clang/test/Sema/private-extern.c
+++ b/clang/test/Sema/private-extern.c
@@ -83,3 +83,7 @@ __private_extern__ int g19;
 int g19 = 0;
 
 __private_extern__ int g20 = 0;
+
+void f10(int g20) { // expected-note{{previous definition is here}}
+  extern int g20; // expected-error{{extern declaration of 'g20' follows non-extern declaration}}
+}