[C++ PATCH] PR c++/65923

[Ville Voutilainen]

Finishing testing with the full suite on Linux-PPC64, tested partially
on Linux-x64.

2018-04-03  Ville Voutilainen  <ville.voutilai...@gmail.com>

    gcc/cp

     PR c++/65923
    * parser.c (cp_parser_unqualified_id): Add a new parameter
    and check it for the literal diagnostic.
    (cp_parser_using_declaration): Adjust.

    testsuite/

     PR c++/65923
    * g++.dg/diagnostic/pr65923.C: New.

diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index d526a4e..677ad61 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -2033,7 +2033,7 @@ static cp_expr cp_parser_primary_expression
 static cp_expr cp_parser_id_expression
   (cp_parser *, bool, bool, bool *, bool, bool);
 static cp_expr cp_parser_unqualified_id
-  (cp_parser *, bool, bool, bool, bool);
+  (cp_parser *, bool, bool, bool, bool, bool = false);
 static tree cp_parser_nested_name_specifier_opt
   (cp_parser *, bool, bool, bool, bool, bool = false);
 static tree cp_parser_nested_name_specifier
@@ -5822,7 +5822,8 @@ cp_parser_unqualified_id (cp_parser* parser,
 			  bool template_keyword_p,
 			  bool check_dependency_p,
 			  bool declarator_p,
-			  bool optional_p)
+			  bool optional_p,
+			  bool using_decl_p)
 {
   cp_token *token;
 
@@ -6105,7 +6106,7 @@ cp_parser_unqualified_id (cp_parser* parser,
 	      /* 17.6.3.3.5  */
 	      const char *name = UDLIT_OP_SUFFIX (id);
 	      if (name[0] != '_' && !in_system_header_at (input_location)
-		  && declarator_p)
+		  && declarator_p && !using_decl_p)
 		warning (OPT_Wliteral_suffix,
 			 "literal operator suffixes not preceded by %<_%>"
 			 " are reserved for future standardization");
@@ -18775,7 +18776,8 @@ cp_parser_using_declaration (cp_parser* parser,
 					 /*template_keyword_p=*/false,
 					 /*check_dependency_p=*/true,
 					 /*declarator_p=*/true,
-					 /*optional_p=*/false);
+					 /*optional_p=*/false,
+					 /*using_decl_p=*/true);
 
   if (access_declaration_p)
     {
diff --git a/gcc/testsuite/g++.dg/diagnostic/pr65923.C b/gcc/testsuite/g++.dg/diagnostic/pr65923.C
new file mode 100644
index 0000000..b9584d0
--- /dev/null
+++ b/gcc/testsuite/g++.dg/diagnostic/pr65923.C
@@ -0,0 +1,5 @@
+// { dg-do compile { target c++14 } }
+
+#include <chrono>
+
+using std::literals::chrono_literals::operator""s;  // warning here