[cfe-dev] test case for stmt.label.

[Douglas Gregor]

On Nov 27, 2010, at 9:27 PM, sashan wrote:

> Hi
> 
> I felt like getting my feet wet with clang so I've attached a test case for
> stmt.label in test/CXX/stmt.stmt/stmt.label.

Thanks! Committed as Clang r120291.

> Additionally I think that there's a bug in the clang error reporting since it
> incorrectly identifies the location of the previous definition of the 'default'
> label. If you compile the attached file with:
> 
> clang++ -fsyntax-only
> 
> You'll see these errors:
> 
> test/CXX/stmt.stmt/stmt.label/p1.cpp:22:5: error: multiple default labels in one switch
>    default:; // expected-error{{multiple default labels in one switch}}
>    ^
> test/CXX/stmt.stmt/stmt.label/p1.cpp:23:5: note: previous case defined here
>    default:; // expected-note{{previous case defined here}}
>    ^
> Note that clang thinks that the line location of the previous 'default' label is
> after the first place the label 'default' is defined.  I think the note and
> error messages should be swapped around.

I agree. The issue is that we store the list of case and default statements *backwards* in the AST, which I find rather unintuitive. It also means that we give warnings in the wrong order for code like this:

void f(char c) {
  switch (c) {
  case 1000: break;
  case 1001: break;  
  }
}

Would you like to provide a patch that reverses the list of case/default statements, to fix both issues and make the AST cleaner?

	- Doug