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
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index 5a4e027..0f0931e 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -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))
diff --git a/gcc/testsuite/g++.dg/cpp0x/auto30.C
b/gcc/testsuite/g++.dg/cpp0x/auto30.C
new file mode 100644
index 0000000..d26e290
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/auto30.C
@@ -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" }
--
1.7.6.4
--
Dodji
