c++: designators in single-element init lists
While looking at PR100489, it occurred to me that places that currently
use an initializer-list with a single element to initialize an object of the
same type shouldn't do that if the element has a designator.
gcc/cp/ChangeLog:
* call.c (reference_binding): Check for designator.
(implicit_conversion_1, build_special_member_call): Likewise.
* decl.c (reshape_init_r): Likewise.
* pt.c (do_class_deduction): Likewise.
* typeck2.c (digest_init_r): Likewise.
gcc/testsuite/ChangeLog:
* g++.dg/cpp2a/desig19.C: New test.