@@ -4140,6 +4140,12 @@ check_tag_decl (cp_decl_specifier_seq *declspecs)
error_p = true;
if (declared_type == NULL_TREE && ! saw_friend && !error_p)
permerror (input_location, "declaration does not declare anything");
+ else if (declared_type != NULL_TREE && type_uses_auto (declared_type))
+ {
+ error ("%<auto%> can only be specified for variables "
+ "or function declarations");
+ return error_mark_node;
+ }
/* Check for an anonymous union. */
else if (declared_type && RECORD_OR_UNION_CODE_P (TREE_CODE (declared_type))
&& TYPE_ANONYMOUS_P (declared_type))
new file mode 100644
@@ -0,0 +1,9 @@
+// Origin PR c++/51473
+// { dg-options "-std=c++11" }
+
+struct A
+{
+ auto friend struct B; // { dg-error "multiple types|can only be specified|friend" }
+};
+
+auto int; // { dg-error "multiple types|can only be specified for variables" }
Hello, It seems to me that [dcl.spec.auto]/1 The auto type-specifier signifies that the type of a variable being declared shall be deduced from its initializer or that a function declarator shall include a trailing-return-type. and the subsequent paragraphs of that section up to [dcl.spec.auto]/5 A program that uses auto in a context not explicitly allowed in this section is ill-formed. imply that it is not possible to have an 'auto' specifier in a simple-declaration that has no declarator. Yet in the example the patch below, G++ doesn't diagnose that and as it goes further in analyzing that example, it encounters inconsistencies that lead to an ICE. Thus I am proposing to error out early in this case. Bootstrapped and tested on x86_64-unknown-linux-gnu against trunk. gcc/cp/ PR c++/51473 * decl.c (check_tag_decl): Error out on auto specifier with no declarator. gcc/testsuite/ PR c++/51473 * g++.dg/cpp0x/auto30.C: New test. --- gcc/cp/decl.c | 6 ++++++ gcc/testsuite/g++.dg/cpp0x/auto30.C | 9 +++++++++ 2 files changed, 15 insertions(+), 0 deletions(-) create mode 100644 gcc/testsuite/g++.dg/cpp0x/auto30.C