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

This reverts commit r225780, we can't compile line 181 in
sanitizer_platform_limits_posix.cc with this commit.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@225781 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 4 insertions, 6 deletions

diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index 82ffd4da5f..baa6822da7 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -3282,12 +3282,14 @@ void Sema::MergeVarDecl(VarDecl *New, LookupResult &Previous) {
   }
 
   // Check if extern is followed by non-extern and vice-versa.
-  if (New->hasGlobalStorage() && !Old->hasLinkage() && Old->hasLocalStorage()) {
+  if (New->hasExternalStorage() &&
+      !Old->hasLinkage() && Old->isLocalVarDecl()) {
     Diag(New->getLocation(), diag::err_extern_non_extern) << New->getDeclName();
     Diag(OldLocation, PrevDiag);
     return New->setInvalidDecl();
   }
-  if (Old->hasGlobalStorage() && !New->hasLinkage() && New->hasLocalStorage()) {
+  if (Old->hasLinkage() && New->isLocalVarDecl() &&
+      !New->hasExternalStorage()) {
     Diag(New->getLocation(), diag::err_non_extern_extern) << New->getDeclName();
     Diag(OldLocation, PrevDiag);
     return New->setInvalidDecl();
diff --git a/test/Sema/private-extern.c b/test/Sema/private-extern.c
index 94afd87fbb..0c13c92bba 100644
--- a/test/Sema/private-extern.c
+++ b/test/Sema/private-extern.c
@@ -83,7 +83,3 @@ __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}}
-}