On 09/29/2014 10:55 AM, Andrew Sutton wrote:
Jason, do you want to review this before I commit? This is a pretty small patch.
No need to wait for review before committing to the branch.
+ // If fn was declared with auto, make sure the result type is bool.
+ if (FNDECL_USED_AUTO (fn) && TREE_TYPE (fn) != boolean_type_node)
+ error_at (loc, "deduced type of concept definition %qD is not %qT",
+ fn, boolean_type_node);
This should say what the deduced type is.
+ // Check that the function is comprised of only a single
+ // return statements.
*statement
+template<typename T>
+ concept bool Tuple() { // { dg-error "multiple statements" }
+ static_assert(T::value, "");
+ return true;
+ }
Hmm, have we actually discussed this in core review? I'm not seeing it
on the wiki. Constexpr started out this way too, and allowing
static_assert was added pretty fast. C++11 said
its function-body shall be = delete, = default, or a compound-statement
that contains only
— null statements,
— static_assert-declarations
— typedef declarations and alias-declarations that do not define classes
or enumerations,
— using-declarations,
— using-directives,
— and exactly one return statement;
Is there a reason we want to be more strict than this for concept functions?
Jason
