For bugs 54372 and 60063, we changed attributes used and unused to be
applied immediately in a template even if what they apply to is
dependent, to avoid bogus warnings from
maybe_warn_unused_local_typedefs. But that's only an issue for
TYPE_DECL, so we can use the normal logic for other things.
Tested x86_64-pc-linux-gnu, applying to trunk.
commit dac88137f97d9737fa2e0c5b27ec6431b2d29c7c
Author: Jason Merrill <ja...@redhat.com>
Date: Wed Apr 4 13:43:26 2018 -0400
PR c++/84221 - bogus -Wunused with attribute and template.
* decl2.c (is_late_template_attribute): Handle unused and used
normally on non-TYPE_DECL.
diff --git a/gcc/cp/decl2.c b/gcc/cp/decl2.c
index 6ae6cef78dd..6078fb668a7 100644
--- a/gcc/cp/decl2.c
+++ b/gcc/cp/decl2.c
@@ -1145,10 +1145,11 @@ is_late_template_attribute (tree attr, tree decl)
if (is_attribute_p ("weak", name))
return true;
- /* Attributes used and unused are applied directly, as they appertain to
- decls. */
- if (is_attribute_p ("unused", name)
- || is_attribute_p ("used", name))
+ /* Attributes used and unused are applied directly to typedefs for the
+ benefit of maybe_warn_unused_local_typedefs. */
+ if (TREE_CODE (decl) == TYPE_DECL
+ && (is_attribute_p ("unused", name)
+ || is_attribute_p ("used", name)))
return false;
/* Attribute tls_model wants to modify the symtab. */
diff --git a/gcc/testsuite/g++.dg/warn/Wunused-var-32.C b/gcc/testsuite/g++.dg/warn/Wunused-var-32.C
new file mode 100644
index 00000000000..5558f9361fc
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/Wunused-var-32.C
@@ -0,0 +1,9 @@
+// PR c++/84221
+// { dg-additional-options -Wunused }
+
+template <class T> struct __attribute((unused)) A { };
+
+void f (void)
+{
+ A<int> a; // shouldn't warn
+}
