c++: Report invalid id-expression in decltype [PR100482]

This patch ensures that any errors raised by finish_id_expression when
parsing a decltype expression are properly reported, rather than
potentially going ignored and causing invalid code to be accepted.

We can also now remove the separate check for templates without args as
this is also checked for in finish_id_expression.

	PR c++/100482

gcc/cp/ChangeLog:

	* parser.cc (cp_parser_decltype_expr): Report errors raised by
	finish_id_expression.

gcc/testsuite/ChangeLog:

	* g++.dg/cpp0x/decltype-100482.C: New test.

Signed-off-by: Nathaniel Shead <nathanieloshead@gmail.com>

diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc
index ba15a095e83ebdeedf3ca285d39af1c3adcf3fe3..5b6d03e5a4459eb7fda9b1a193bba7ee8a26ed77 100644 (file)
--- a/gcc/cp/parser.cc
+++ b/gcc/cp/parser.cc
@@ -16520,10 +16520,6 @@ cp_parser_decltype_expr (cp_parser *parser,
        expr = cp_parser_lookup_name_simple (parser, expr,
                                             id_expr_start_token->location);
 
-      if (expr && TREE_CODE (expr) == TEMPLATE_DECL)
-       /* A template without args is not a complete id-expression.  */
-       expr = error_mark_node;
-
       if (expr
           && expr != error_mark_node
           && TREE_CODE (expr) != TYPE_DECL
@@ -16544,13 +16540,17 @@ cp_parser_decltype_expr (cp_parser *parser,
                    &error_msg,
                   id_expr_start_token->location));
 
-          if (expr == error_mark_node)
-            /* We found an id-expression, but it was something that we
-               should not have found. This is an error, not something
-               we can recover from, so note that we found an
-               id-expression and we'll recover as gracefully as
-               possible.  */
-            id_expression_or_member_access_p = true;
+         if (error_msg)
+           {
+             /* We found an id-expression, but it was something that we
+                should not have found. This is an error, not something
+                we can recover from, so report the error we found and
+                we'll recover as gracefully as possible.  */
+             cp_parser_parse_definitely (parser);
+             cp_parser_error (parser, error_msg);
+             id_expression_or_member_access_p = true;
+             return error_mark_node;
+           }
         }
 
       if (expr

diff --git a/gcc/testsuite/g++.dg/cpp0x/decltype-100482.C b/gcc/testsuite/g++.dg/cpp0x/decltype-100482.C
new file mode 100644 (file)
index 0000000..1df8b16
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/decltype-100482.C
@@ -0,0 +1,12 @@
+// PR c++/100482
+// { dg-do compile { target c++11 } }
+
+namespace N {}
+decltype(N) x;   // { dg-error "expected primary-expression" }
+
+struct S {};
+decltype(S) y;  // { dg-error "argument to .decltype. must be an expression" }
+
+template <typename T>
+struct U {};
+decltype(U) z;  // { dg-error "missing template arguments" }