I didn't get this reviewed previously so I'll try again for 4.7 ...
---------- Forwarded message ----------
Here's my attempt to fix PR c++/18016 so that we get a warning from
struct S {
int i;
S() : i(i) { }
};
As I said in the audit trail, -Winit-self is broken for C++ (PR
c++/34772) so I made this warn with
-Wuninitialized and not affected by -Winit-self.
Even if -Winit-self wasn't broken I don't think it applies here,
there's no valid reason to initialize a member with itself, if you
really want to leave a member uninitialized then don't use a
mem-initializer in the constructor (which will work at least until
someone fixes PR c++/2972)
cp/ChangeLog:
PR c++/18016
* init.c (perform_member_init): Check for self-initialization.
testsuite/ChangeLog:
PR c++/18016
* g++.dg/warn/pr18016.C: New.
tested x86_64-linux with no regressions, ok for trunk?
Index: cp/init.c
===================================================================
--- cp/init.c (revision 174044)
+++ cp/init.c (working copy)
@@ -501,6 +501,17 @@
if (decl == error_mark_node)
return;
+ if (warn_uninitialized && init && TREE_CODE (init) == TREE_LIST
+ && TREE_CHAIN (init) == NULL_TREE)
+ {
+ tree val = TREE_VALUE (init);
+ if (TREE_CODE (val) == COMPONENT_REF && TREE_OPERAND (val, 1) == member
+ && TREE_OPERAND (val, 0) == current_class_ref)
+ warning_at (DECL_SOURCE_LOCATION (current_function_decl),
+ OPT_Wuninitialized, "%qD is initialized with itself",
+ member);
+ }
+
if (init == void_type_node)
{
/* mem() means value-initialization. */
Index: testsuite/g++.dg/warn/pr18016.C
===================================================================
--- testsuite/g++.dg/warn/pr18016.C (revision 0)
+++ testsuite/g++.dg/warn/pr18016.C (revision 0)
@@ -0,0 +1,11 @@
+/* { dg-do compile } */
+/* { dg-options "-Wuninitialized" } */
+
+class X {
+ int i;
+ X() : i(i) { } // { dg-warning "initialized with itself" }
+ X(int i) : i(i) { }
+ X(const X& x) : i(x.i) { }
+};
+
+// { dg-prune-output "In constructor" }
