re PR c++/18016 (Warn about member variables initialized with itself)

2011-05-23  Jonathan Wakely  <jwakely.gcc@gmail.com>

	PR c++/18016
	* init.c (perform_member_init): Check for self-initialization.

From-SVN: r174058

gcc/cp/ChangeLog

+2011-05-23  Jonathan Wakely  <jwakely.gcc@gmail.com>
+
+	PR c++/18016
+	* init.c (perform_member_init): Check for self-initialization.
+
 2011-05-22  Jason Merrill  <jason@redhat.com>
 
 	PR c++/48647

gcc/cp/init.c

@@ -501,6 +501,17 @@ perform_member_init (tree member, tree init)
   if (decl == error_mark_node)
     return;
 
+  if (warn_init_self && 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.  */

gcc/testsuite/ChangeLog

+2011-05-23  Jonathan Wakely  <jwakely.gcc@gmail.com>
+
+	PR c++/18016
+	* g++.dg/warn/pr18016.C: New.
+
 2011-05-23  Tom de Vries  <tom@codesourcery.com>
 
 	PR target/45098

gcc/testsuite/g++.dg/warn/pr18016.C

+/* { dg-do compile } */
+/* { dg-options "-Wuninitialized -Winit-self" } */
+
+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" }