re PR c++/6331 (g++ 3.1 looses const qualifiers)

        PR c++/6331
        * method.c (do_build_copy_constructor): Use cp_build_qualified_type.
        * typeck.c (build_modify_expr): Allow arrays to differ in cv-quals.

From-SVN: r52709

gcc/cp/ChangeLog

 2002-04-24  Jason Merrill  <jason@redhat.com>
 
+	PR c++/6331
+	* method.c (do_build_copy_constructor): Use cp_build_qualified_type.
+	* typeck.c (build_modify_expr): Allow arrays to differ in cv-quals.
+
 	PR c++/6395
 	* decl.c (make_rtl_for_nonlocal_decl): Don't mess with #pragma i/i
 	stuff for comdats.

gcc/cp/method.c

@@ -585,7 +585,7 @@ do_build_copy_constructor (fndecl)
 	    continue;
 
 	  init = build (COMPONENT_REF,
-	                build_qualified_type (TREE_TYPE (field), cvquals),
+	                cp_build_qualified_type (TREE_TYPE (field), cvquals),
 	                init, field);
 	  init = build_tree_list (NULL_TREE, init);
 

gcc/cp/typeck.c

@@ -5665,10 +5665,11 @@ build_modify_expr (lhs, modifycode, rhs)
     {
       int from_array;
       
-      if (!same_or_base_type_p (lhstype, TREE_TYPE (rhs)))
+      if (!same_or_base_type_p (TYPE_MAIN_VARIANT (lhstype),
+				TYPE_MAIN_VARIANT (TREE_TYPE (rhs))))
 	{
 	  error ("incompatible types in assignment of `%T' to `%T'",
-		    TREE_TYPE (rhs), lhstype);
+		 TREE_TYPE (rhs), lhstype);
 	  return error_mark_node;
 	}
 

gcc/testsuite/g++.dg/init/array3.C

+// PR c++/6331
+// Bug: we were generating a badly cv-qualified ARRAY_TYPE in the
+// synthesized copy constructor for A, which then became the canonical
+// version, confusing later uses.
+
+struct A {
+  virtual ~A();
+  const float* f();
+  float fa[3];
+};
+
+struct B {
+  B(const A& ai) : a (ai) {}
+  A a;
+};
+
+void g (const float pos[3]);
+
+extern A& a;
+void h()
+{
+  g (a.f());
+}