re PR c++/31449 ([4.1] static_cast can remove const-ness)

	PR c++/31449
	* class.c (build_base_path): Ensure that the converted pointer has
	the same cv-qualification as the input.
	PR c++/31449
	* g++.dg/init/const5.C: New test.

From-SVN: r123679

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 9f21ddc..b9823db 100644 (file)
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,9 @@
+2007-04-09  Mark Mitchell  <mark@codesourcery.com>
+
+       PR c++/31449
+       * class.c (build_base_path): Ensure that the converted pointer has
+       the same cv-qualification as the input.
+
 2007-04-09  Paolo Carlini  <pcarlini@suse.de>
 
        * tree.c (cp_tree_equal): Deal with TRAIT_EXPR.

diff --git a/gcc/cp/class.c b/gcc/cp/class.c
index 0bb441e..e01fbe1 100644 (file)
--- a/gcc/cp/class.c
+++ b/gcc/cp/class.c
@@ -303,7 +303,18 @@ build_base_path (enum tree_code code,
         field, because other parts of the compiler know that such
         expressions are always non-NULL.  */
       if (!virtual_access && integer_zerop (offset))
-       return build_nop (build_pointer_type (target_type), expr);
+       {
+         tree class_type;
+         /* TARGET_TYPE has been extracted from BINFO, and, is
+            therefore always cv-unqualified.  Extract the
+            cv-qualifiers from EXPR so that the expression returned
+            matches the input.  */
+         class_type = TREE_TYPE (TREE_TYPE (expr));
+         target_type
+           = cp_build_qualified_type (target_type,
+                                      cp_type_quals (class_type));
+         return build_nop (build_pointer_type (target_type), expr);
+       }
       null_test = error_mark_node;
     }
 

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 90550f2..037e7a2 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2007-04-09  Mark Mitchell  <mark@codesourcery.com>
+
+       PR c++/31449
+       * g++.dg/init/const5.C: New test.
+
 2007-04-09  Jan Hubicka  <jh@suse.cz>
 
        * gcc.dg/tree-ssa/foldaddr-3.c: New file.

diff --git a/gcc/testsuite/g++.dg/init/const5.C b/gcc/testsuite/g++.dg/init/const5.C
new file mode 100644 (file)
index 0000000..fa8d8fc
--- /dev/null
+++ b/gcc/testsuite/g++.dg/init/const5.C
@@ -0,0 +1,11 @@
+// PR c++/31449
+
+class Foo {};
+class Bar : public Foo {};
+static const Foo *foo = 0;
+
+static Bar *bar = static_cast<const Bar*>(foo); // { dg-error "conversion" }
+
+void func(const Foo *foo) {
+  Bar *bar = static_cast<const Bar*>(foo);  // { dg-error "conversion" }
+}