Improve handling of variables with different storage spec

[llvmbot]

Bugzilla Link	3983
Resolution	FIXED
Resolved on	Jun 21, 2012 16:31
Version	unspecified
OS	All
Reporter	LLVM Bugzilla Contributor

Extended Description

This seems wrong, and the diagnostics could be nicer (see gcc):

void f0() {
// FIXME: Diagnose this?
int g6;
extern int g6;
}

void f1() {
// FIXME: Diagnose this?
int g7;
private_extern int g7;
}

void f2() {
extern int g8; // expected-note{{previous definition}}
// FIXME: Improve this diagnostic.
int g8; // expected-error{{redefinition of 'g8'}}
}

void f3() {
private_extern int g9; // expected-note{{previous definition}}
// FIXME: Improve this diagnostic.
int g9; // expected-error{{redefinition of 'g9'}}
}

[llvmbot]

With the 3.1 release, clang provides quite nice diagnostics (and much better than gcc 4.7's "error: redeclaration of..." messages):

$ cat tmp.cc
void f0() {
// FIXME: Diagnose this?
int g6;
extern int g6;
}

void f1() {
// FIXME: Diagnose this?
int g7;
private_extern int g7;
}

void f2() {
extern int g8; // expected-note{{previous definition}}
// FIXME: Improve this diagnostic.
int g8; // expected-error{{redefinition of 'g8'}}
}

void f3() {
private_extern int g9; // expected-note{{previous definition}}
// FIXME: Improve this diagnostic.
int g9; // expected-error{{redefinition of 'g9'}}
}

$ clang -fsyntax-only tmp.cc
tmp.cc:4:14: error: extern declaration of 'g6' follows non-extern declaration
extern int g6;
^
tmp.cc:3:7: note: previous definition is here
int g6;
^
tmp.cc:10:26: error: extern declaration of 'g7' follows non-extern declaration
private_extern int g7;
^
tmp.cc:9:7: note: previous definition is here
int g7;
^
tmp.cc:16:7: error: non-extern declaration of 'g8' follows extern declaration
int g8; // expected-error{{redefinition of 'g8'}}
^
tmp.cc:14:14: note: previous definition is here
extern int g8; // expected-note{{previous definition}}
^
tmp.cc:22:7: error: non-extern declaration of 'g9' follows extern declaration
int g9; // expected-error{{redefinition of 'g9'}}
^
tmp.cc:20:26: note: previous definition is here
private_extern int g9; // expected-note{{previous definition}}
^
4 errors generated.