[Bug c++/88095] class nontype template parameter UDL string literals doesn't accepts deduction placeholder

[jeff-gcc at caffeinated dot me.uk]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88095

Jeff Snyder <jeff-gcc at caffeinated dot me.uk> changed:

           What    |Removed                     |Added
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                 CC|                            |jeff-gcc at caffeinated dot me.uk

--- Comment #1 from Jeff Snyder <jeff-gcc at caffeinated dot me.uk> ---
I had a go at fixing this, and the following makes Hana's example work:

-------------------8<-------------------
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -27875,7 +27875,8 @@ cp_parser_template_declaration_after_parameters
(cp_parser* parser,
            {
              tree parm_list = TREE_VEC_ELT (parameter_list, 0);
              tree parm = INNERMOST_TEMPLATE_PARMS (parm_list);
-             if (CLASS_TYPE_P (TREE_TYPE (parm)))
+             if (CLASS_TYPE_P (TREE_TYPE (parm))
+                     || TREE_CODE (TREE_TYPE (parm)) == TEMPLATE_TYPE_PARM)
                /* OK, C++20 string literal operator template.  We don't need
                   to warn in lower dialects here because we will have already
                   warned about the template parameter.  */;
------------------->8-------------------