[dmd-internals] A major root-cause bug

[Don Clugston]

To clarify -- this bug is not urgent, but it's one that I think we
need to be aware of, because it can have such a wide and unexpected
influence.

On 13 November 2010 05:16, Don Clugston <dclugston at googlemail.com> wrote:
> While tracking down an ICE bug, I found this important issue.
>
> 5195 Forward references ignore const
>
> Most of the front-end uses the 'type' member of a variable to check,
> and assumes that if it's non-null,
> it hasn't been forward referenced.
> The problem is, if x is declared as  'const int *x' or  'const { int
> *x; }' , it has a non-null type member, but it doesn't have the const
> yet!
> This bogus type is a root of all kinds of evil. It manifests in a
> variety of weird ways.
> I think that several previously fixed bugs, were just special cases of this one.
>
> Unfortunately fixing this isn't just a one-liner. It requires a minor
> structural change, and I'm not sure which approach is the best way of
> fixing it.
> Essentially, all the qualifiers need to be resolved before any other
> semantic analysis takes place.
> Walter, can you comment?
>