commit a3b04cea0458481ccdd29573e52931ad70fd3a63
author David Majnemer <david.majnemer@gmail.com> Wed Jan 14 00:31:13 2015 +0000
committer David Majnemer <david.majnemer@gmail.com> Wed Jan 14 00:31:13 2015 +0000
tree bf5cbc93ed83629f7522efd6796a8096dd3f3daf
parent 11f5032368144703bc2bc88623338333ae941dc1

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.

This is a different approach to r225780.

llvm-svn: 225875

clang/include/clang/AST/Decl.h

diff --git a/clang/include/clang/AST/Decl.h b/clang/include/clang/AST/Decl.h
index cdba3bd..a39888f 100644
--- a/clang/include/clang/AST/Decl.h
+++ b/clang/include/clang/AST/Decl.h
@@ -906,6 +906,11 @@
     return false;
   }
 
+  /// \brief Similar to isLocalVarDecl but also includes parameters.
+  bool isLocalVarDeclOrParm() const {
+    return isLocalVarDecl() || getKind() == Decl::ParmVar;
+  }
+
   /// isFunctionOrMethodVarDecl - Similar to isLocalVarDecl, but
   /// excludes variables declared in blocks.
   bool isFunctionOrMethodVarDecl() const {

clang/lib/Sema/SemaDecl.cpp

diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 7d1e28e..1bf57f6 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -3285,12 +3285,12 @@
 
   // Check if extern is followed by non-extern and vice-versa.
   if (New->hasExternalStorage() &&
-      !Old->hasLinkage() && Old->isLocalVarDecl()) {
+      !Old->hasLinkage() && Old->isLocalVarDeclOrParm()) {
     Diag(New->getLocation(), diag::err_extern_non_extern) << New->getDeclName();
     Diag(OldLocation, PrevDiag);
     return New->setInvalidDecl();
   }
-  if (Old->hasLinkage() && New->isLocalVarDecl() &&
+  if (Old->hasLinkage() && New->isLocalVarDeclOrParm() &&
       !New->hasExternalStorage()) {
     Diag(New->getLocation(), diag::err_non_extern_extern) << New->getDeclName();
     Diag(OldLocation, PrevDiag);

clang/test/Sema/var-redecl.c

diff --git a/clang/test/Sema/var-redecl.c b/clang/test/Sema/var-redecl.c
index 0e30aa2..5ba6965 100644
--- a/clang/test/Sema/var-redecl.c
+++ b/clang/test/Sema/var-redecl.c
@@ -60,3 +60,7 @@
 static int a;
 extern int a; // expected-note {{previous declaration is here}}
 int a;	// expected-error {{non-static declaration of 'a' follows static declaration}}
+
+void f(int x) { // expected-note {{previous definition is here}}
+  extern int x; // expected-error {{extern declaration of 'x' follows non-extern declaration}}
+}