c++: add -Wdeprecated-literal-operator [CWG2521]

C++23 CWG issue 2521 (https://wg21.link/cwg2521) deprecates user-defined
literal operators declared with the optional space between "" and the
suffix.

Many testcases used that syntax; I removed the space from most of them, and
added C++23 warning tests to a few.

	CWG 2521

gcc/ChangeLog:

	* doc/invoke.texi: Document -Wdeprecated-literal-operator.

gcc/c-family/ChangeLog:

	* c.opt: Add -Wdeprecated-literal-operator.
	* c-opts.cc (c_common_post_options): Default on in C++23.
	* c.opt.urls: Regenerate.

gcc/cp/ChangeLog:

	* parser.cc (location_between): New.
	(cp_parser_operator): Handle -Wdeprecated-literal-operator.

gcc/testsuite/ChangeLog:

	* g++.dg/cpp0x/udlit-string-literal.h
	* g++.dg/cpp0x/Wliteral-suffix2.C
	* g++.dg/cpp0x/constexpr-55708.C
	* g++.dg/cpp0x/gnu_fext-numeric-literals.C
	* g++.dg/cpp0x/gnu_fno-ext-numeric-literals.C
	* g++.dg/cpp0x/pr51420.C
	* g++.dg/cpp0x/pr60209-neg.C
	* g++.dg/cpp0x/pr60209.C
	* g++.dg/cpp0x/pr61038.C
	* g++.dg/cpp0x/std_fext-numeric-literals.C
	* g++.dg/cpp0x/std_fno-ext-numeric-literals.C
	* g++.dg/cpp0x/udlit-addr.C
	* g++.dg/cpp0x/udlit-args-neg.C
	* g++.dg/cpp0x/udlit-args.C
	* g++.dg/cpp0x/udlit-args2.C
	* g++.dg/cpp0x/udlit-clink-neg.C
	* g++.dg/cpp0x/udlit-concat-neg.C
	* g++.dg/cpp0x/udlit-concat.C
	* g++.dg/cpp0x/udlit-constexpr.C
	* g++.dg/cpp0x/udlit-cpp98-neg.C
	* g++.dg/cpp0x/udlit-declare-neg.C
	* g++.dg/cpp0x/udlit-embed-quote.C
	* g++.dg/cpp0x/udlit-extended-id-1.C
	* g++.dg/cpp0x/udlit-extended-id-3.C
	* g++.dg/cpp0x/udlit-extern-c.C
	* g++.dg/cpp0x/udlit-friend.C
	* g++.dg/cpp0x/udlit-general.C
	* g++.dg/cpp0x/udlit-implicit-conv-neg-char8_t.C
	* g++.dg/cpp0x/udlit-implicit-conv-neg.C
	* g++.dg/cpp0x/udlit-inline.C
	* g++.dg/cpp0x/udlit-mangle.C
	* g++.dg/cpp0x/udlit-member-neg.C
	* g++.dg/cpp0x/udlit-namespace.C
	* g++.dg/cpp0x/udlit-nofunc-neg.C
	* g++.dg/cpp0x/udlit-nonempty-str-neg.C
	* g++.dg/cpp0x/udlit-nosuffix-neg.C
	* g++.dg/cpp0x/udlit-nounder-neg.C
	* g++.dg/cpp0x/udlit-operator-neg.C
	* g++.dg/cpp0x/udlit-overflow-neg.C
	* g++.dg/cpp0x/udlit-overflow.C
	* g++.dg/cpp0x/udlit-preproc-neg.C
	* g++.dg/cpp0x/udlit-raw-length.C
	* g++.dg/cpp0x/udlit-raw-op-string-neg.C
	* g++.dg/cpp0x/udlit-raw-op.C
	* g++.dg/cpp0x/udlit-raw-str.C
	* g++.dg/cpp0x/udlit-resolve-char8_t.C
	* g++.dg/cpp0x/udlit-resolve.C
	* g++.dg/cpp0x/udlit-shadow-neg.C
	* g++.dg/cpp0x/udlit-string-length.C
	* g++.dg/cpp0x/udlit-suffix-neg.C
	* g++.dg/cpp0x/udlit-template.C
	* g++.dg/cpp0x/udlit-tmpl-arg-neg.C
	* g++.dg/cpp0x/udlit-tmpl-arg-neg2.C
	* g++.dg/cpp0x/udlit-tmpl-arg.C
	* g++.dg/cpp0x/udlit-tmpl-parms-neg.C
	* g++.dg/cpp0x/udlit-tmpl-parms.C
	* g++.dg/cpp1y/pr57640.C
	* g++.dg/cpp1y/pr88872.C
	* g++.dg/cpp26/unevalstr1.C
	* g++.dg/cpp2a/concepts-pr60391.C
	* g++.dg/cpp2a/consteval-prop21.C
	* g++.dg/cpp2a/nontype-class6.C
	* g++.dg/cpp2a/udlit-class-nttp-ctad-neg.C
	* g++.dg/cpp2a/udlit-class-nttp-ctad-neg2.C
	* g++.dg/cpp2a/udlit-class-nttp-ctad.C
	* g++.dg/cpp2a/udlit-class-nttp-neg.C
	* g++.dg/cpp2a/udlit-class-nttp-neg2.C
	* g++.dg/cpp2a/udlit-class-nttp.C
	* g++.dg/ext/is_convertible2.C
	* g++.dg/lookup/pr87269.C
	* g++.dg/cpp0x/udlit_system_header: Adjust for C++23 deprecated
	operator "" _suffix.
	* g++.dg/DRs/dr2521.C: New test.

1 files changed, 29 insertions, 4 deletions

diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc
index 0944827..08f9c89 100644
--- a/gcc/cp/parser.cc
+++ b/gcc/cp/parser.cc
@@ -943,6 +943,18 @@ make_location (cp_token *caret, cp_token *start, cp_token *end)
   return make_location (caret->location, start->location, end->location);
 }
 
+/* Location for the whitespace between two tokens.  */
+
+static location_t
+location_between (cp_token *stok, cp_token *etok)
+{
+  location_t s = get_finish (stok->location);
+  s = linemap_position_for_loc_and_offset (line_table, s, 1);
+  location_t e = get_start (etok->location);
+  e = linemap_position_for_loc_and_offset (line_table, e, -1);
+  return make_location (s, s, e);
+}
+
 /* nonzero if we are presently saving tokens.  */
 
 static inline int
@@ -18325,6 +18337,8 @@ cp_parser_operator (cp_parser* parser, location_t start_loc)
 	if (cxx_dialect == cxx98)
 	  maybe_warn_cpp0x (CPP0X_USER_DEFINED_LITERALS);
 
+	token = cp_lexer_peek_token (parser->lexer);
+
 	/* Consume the string.  */
 	cp_expr str = cp_parser_userdef_string_literal (parser,
 							/*lookup_udlit=*/false);
@@ -18340,13 +18354,24 @@ cp_parser_operator (cp_parser* parser, location_t start_loc)
 	  {
 	    string_tree = str;
 	    /* Look for the suffix identifier.  */
-	    token = cp_lexer_peek_token (parser->lexer);
-	    if (token->type == CPP_NAME)
+	    cp_token *id_tok = cp_lexer_peek_token (parser->lexer);
+	    if (id_tok->type == CPP_NAME)
 	      {
 		id = cp_parser_identifier (parser);
-		end_loc = token->location;
+		end_loc = id_tok->location;
+
+		/* Deprecated by CWG2521 in C++23.  */
+		if (warn_deprecated_literal_operator)
+		  {
+		    gcc_rich_location
+		      space (location_between (token, id_tok));
+		    space.add_fixit_remove ();
+		    warning_at (&space, OPT_Wdeprecated_literal_operator,
+				"space between quotes and suffix is "
+				"deprecated in C++23");
+		  }
 	      }
-	    else if (token->type == CPP_KEYWORD)
+	    else if (id_tok->type == CPP_KEYWORD)
 	      {
 		error ("unexpected keyword;"
 		       " remove space between quotes and suffix identifier");