On 10/15/24 12:45 AM, Patrick Palka wrote:
This patch further cleans up the concepts code following the removal of
Concepts TS support:
* concept-ids are now the only kind of "concept check", so we can
simplify some code accordingly. In particular resolve_concept_check
seems like a no-op and can be removed.
* In turn, deduce_constrained_parameter doesn't seem to do anything
interesting.
* In light of the above we might as well inline finish_type_constraints
into its only caller. Note that the "prototype parameter" of a
concept is just the first template parameter which the caller can
easily obtain itself.
But it's still a defined term in the language
(https://eel.is/c++draft/temp#concept-7) so I think it's worth having an
accessor function. I agree with doing away with the function that
returns a pair.
* placeholder_extract_concept_and_args is only ever called on a
concept-id, so it's simpler to inline it into its callers.
* There's no such thing as a template-template-parameter wtih a
type-constraint, so we can remove such handling from the parser.
This means is_constrained_parameter is currently equivalent to
declares_constrained_template_template_parameter, so let's prefer
to use the latter.
Why prefer the longer name?
We might be able to remove WILDCARD_DECL and CONSTRAINED_PARM_PROTOTYPE
now as well, but I left that as future work.
@@ -18901,7 +18842,8 @@ cp_parser_template_parameter (cp_parser* parser, bool
*is_non_type,
}
/* The parameter may have been constrained type parameter. */
- if (is_constrained_parameter (parameter_declarator))
+ tree type = parameter_declarator->decl_specifiers.type;
+ if (declares_constrained_type_template_parameter (type))
Why not retain a function that takes the declarator?
return finish_constrained_parameter (parser,
parameter_declarator,
is_non_type);
@@ -20987,11 +20929,12 @@ cp_parser_placeholder_type_specifier (cp_parser
*parser, location_t loc,
tsubst_flags_t complain = tentative ? tf_none : tf_warning_or_error;
/* Get the concept and prototype parameter for the constraint. */
- tree_pair info = finish_type_constraints (tmpl, args, complain);
- tree con = info.first;
- tree proto = info.second;
- if (con == error_mark_node)
+ tree check = build_type_constraint (tmpl, args, complain);
+ if (check == error_mark_node)
return error_mark_node;
+ tree con = STRIP_TEMPLATE (tmpl);
+ tree parms = DECL_INNERMOST_TEMPLATE_PARMS (tmpl);
+ tree proto = TREE_VALUE (TREE_VEC_ELT (parms, 0));
And as mentioned above, let's have a small function that returns the
prototype parameter of a concept, to use here.
Incidentally, why do we want to strip the template from con? Is that
also a relic of the different possible forms of concept?
Jason
