Improving Compiler Error Messages

[Walter Bright]

Marianne Gagnon wrote:
> If my code contains :
> 
> foo(z); bar(z); foobar(x, y, z);
> 
> then GCC will spew something like :
> 
> error: no matching call for foo( type_error ) error: no matching call for
> bar( type_error ) error: no matching call for foobar( type_error )
> 
> I think that if you indeed have as goal to reduce useless cascading error
> messages, then it would be great to avoid that; I would tend to say it'd work
> to just plain ignore any line using "z" after that, or avoid checking the
> type of "z" if we know it's an error. That'd spare lots of useless error
> messages :)

You're right, gcc has an incomplete implementation of this. The idea is that 
there will be no further error messages if any part of those messages would 
contain the "error" production.

dmd partially does that, and it's definitely the direction we want to push it.