Hello,
In the example of this patch, gcc/g++ invoked with
-Wunused-local-typedefs warns on dependant entities even when those
are decorated with the 'unused' attribute.
This is because in cplus_decl_attributes, save_template_attributes
makes so that the 'unused' attribute is applied to its appertaining
entity only at instantiation time. But then at parsing time
maybe_warn_unused_local_typedefs checks for TREE_USED before warning.
This patch makes maybe_warn_unused_local_typedefs check for the
syntactic presence of the 'unused' attribute.
Tested on x86_64-unknown-linux-gnu against trunk.
gcc/c-family/
* c-common.c (maybe_warn_unused_local_typedefs): Check for the
presence of the attribute 'unused'.
gcc/testsuite/
* g++.dg/warn/Wunused-local-typedefs-2.C: New test.
---
gcc/c-family/c-common.c | 3 +-
.../g++.dg/warn/Wunused-local-typedefs-2.C | 35 ++++++++++++++++++++
2 files changed, 37 insertions(+), 1 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/warn/Wunused-local-typedefs-2.C
diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c
index 6de2f1c..cf8b1e1 100644
--- a/gcc/c-family/c-common.c
+++ b/gcc/c-family/c-common.c
@@ -10899,7 +10899,8 @@ maybe_warn_unused_local_typedefs (void)
&& errorcount == unused_local_typedefs_warn_count)
{
FOR_EACH_VEC_ELT (tree, l->local_typedefs, i, decl)
- if (!TREE_USED (decl))
+ if (!TREE_USED (decl)
+ && !lookup_attribute ("unused", DECL_ATTRIBUTES (decl)))
warning_at (DECL_SOURCE_LOCATION (decl),
OPT_Wunused_local_typedefs,
"typedef %qD locally defined but not used", decl);
diff --git a/gcc/testsuite/g++.dg/warn/Wunused-local-typedefs-2.C
b/gcc/testsuite/g++.dg/warn/Wunused-local-typedefs-2.C
new file mode 100644
index 0000000..77bacd7
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/Wunused-local-typedefs-2.C
@@ -0,0 +1,35 @@
+/* Origin PR c++/54372
+ { dg-options "-Wunused-local-typedefs" }
+ { dg-do compile }
+*/
+
+template <typename T>
+void f2()
+{
+ typedef T t __attribute__((unused));
+}
+
+class S
+{
+ template <typename T>
+ void f4()
+ {
+ typedef T t __attribute__((unused));
+ }
+};
+
+template <typename T>
+class tS
+{
+ void f()
+ {
+ typedef T t2 __attribute__((unused));
+ }
+
+ template <typename U>
+ void f2()
+ {
+ typedef T t1 __attribute__((unused));
+ typedef U t2 __attribute__((unused));
+ }
+};
--
Dodji
