[cfe-commits] [PATCH] Improve error recovery for comma/semicolon typo in declaration group

[Eli Friedman]

On Wed, Oct 5, 2011 at 4:26 PM, Richard Smith <richard at metafoo.co.uk> wrote:
> Based on a true story...
>
> Clang currently gives unhelpful diagnostics for cases such as this:
>
>      static const char *const Triples[] = {
>        "powerpc-linux-gnu",
>        "powerpc-unknown-linux-gnu"
>      },
>      CandidateLibDirs.append(LibDirs, LibDirs + llvm::array_lengthof(LibDirs));
>
> Viz:
>
> lib/Driver/ToolChains.cpp:1582:7: error: default initialization of an object
> of const type 'const char'
>     CandidateLibDirs.append(LibDirs, LibDirs + llvm::array_lengthof(LibDirs));
>     ^
> lib/Driver/ToolChains.cpp:1582:23: error: expected ';' at end of declaration
>     CandidateLibDirs.append(LibDirs, LibDirs + llvm::array_lengthof(LibDirs));
>                     ^
>                     ;
>
> The attached patch is a conservative fix for this issue. In cases where a
> declarator group contains a comma followed by a newline followed by something
> which obviously is neither a declarator nor a typo for a declarator, we give a
> fixit suggesting that a ; was intended:
>
> lib/Driver/ToolChains.cpp:1581:8: error: expected ';' at end of declaration
>      },
>       ^ ;
>
> OK to commit?

I don't really like Parser::MightBeDeclarator... I can see at least
two cases where it rejects valid code.  Can you use
Parser::TryParseDeclarator or something?

-Eli