On 6/28/23 11:28, Jason Merrill wrote:
On 5/3/23 09:50, Patrick Palka wrote:
This patch makes us coerce the arguments of a variable template-id ahead
of time, as we do for other template-ids, which allows us to immediately
diagnose template parameter/argument kind mismatches and arity
mismatches.
Unfortunately this causes a regression in cpp1z/constexpr-if20.C:
coercing
the variable template-id m<ar, as> ahead of time means we strip it of
typedefs, yielding m<typename C<i>::q, typename C<j>::q>, but in this
stripped form we're directly using 'i' and so we expect to have captured
it. This is PR107437 but with a variable template instead of a class
template. I'm not sure how to fix this :(
Hmm, it does seem like strip_typedefs needs to be more conservative in a
lambda. We can probably stop stripping dependent function-scope
typedefs in general without breaking things like cpp0x/decltype62.C.
@@ -22097,7 +22099,7 @@ instantiate_template (tree tmpl, tree
orig_args, tsubst_flags_t complain)
/* We need to determine if we're using a partial or explicit
specialization now, because the type of the variable could be
different. */
- tree tid = lookup_template_variable (tmpl, targ_ptr);
+ tree tid = build2 (TEMPLATE_ID_EXPR, NULL_TREE, tmpl, targ_ptr);
Why? I'd think we want to consider partial specializations based on the
coerced arguments.
...ah, but presumably we would have already come through
lookup_template_variable, so we don't need to call it again here. The
patch is OK.
Jason
