Re: [Tinycc-devel] Variable declaration as first statement in a 'case' block gives error.

[Herman ten Brugge]

On 1/17/24 16:15, grischka wrote:
> On 15.01.2024 00:34, Brad Robinson via Tinycc-devel wrote:
> > Hey All,
> >
> > First post here.  Firstly, thank you all for your work on this 
> > project.  I discovered tcc just a month or so ago and really enjoying 
> > using it as a back-end code generator for a custom scripting language 
> > I'm working on.
> >
> > Anyway, I noticed this small bug:
> >
> > A variable declaration as the first statement in a switch case block 
> > fails when it shouldn't:
> >
> >          case 1:
> >              int z = 123;        // This fails with "identifier 
> > expected"
> >              break;
>
> Hi,
>
> well, yes, no.  As a fact, a variable declaration is not a
> statement.
>
> > There's a pretty easy workaround, just insert an empty statement before.
> >
> >          case 1:
> >              ;                   // This fixes it
> >              int z = 123;
> >              break;
>
> Yes, label before statement is allowed, also label before empty
> statement, just not label before no statement.
>
> As for example "label: }" is not allowed either (in the theory).
>
> See also what gcc has to say:
>
> test.c: In function 'main':
> test.c:7:23: error: a label can only be part of a statement and a 
> declaration is not a statement
>     switch(a) case 1: int z;
>                       ^~~
>
> Which of course if a lot better than just "identifier expected"
> I would agree that far.
That depends on the version of gcc / clang.
Gcc 13.2.1 prints no error.
Clang 17.0.6 prints "error: expected expression"
Clang 18.0.0(not released yet) prints "warning: label followed by a 
declaration is a C23 extension [-Wc23-extensions]"

I probably should have mentioned it when committing the fix.

    Herman