Re: [C++ Patch / RFC] Change DERIVED_FROM_P to use tf_none?!?

[Paolo Carlini]

Hi,

On 07/22/2013 11:38 PM, Jason Merrill wrote:
I guess ptr_reasonably_similar should return false if one of the 
target types is incomplete.
Thanks.
The below passes testing on x86_64-linux. I'm also taking the chance to 
change the return type to bool, consistently with comptypes, 
error_type_p, etc.

A slightly less conservative version just doing:

    if (!COMPLETE_TYPE_P (to) || !COMPLETE_TYPE_P (from))
        return false;

also passes testing.

Thanks!
Paolo.

/////////////////////////////

/cp
2013-07-23  Paolo Carlini  <paolo.carl...@oracle.com>

        PR c++/57942
        * typeck.c (ptr_reasonably_similar): Return false if one of the
        target types is incomplete; return a bool, not an int.
        * cp-tree.h (ptr_reasonably_similar): Adjust declaration.

/testsuite
2013-07-23  Paolo Carlini  <paolo.carl...@oracle.com>

        PR c++/57942
        * g++.dg/inherit/pr57942.C: New.
Index: cp/cp-tree.h
===================================================================
--- cp/cp-tree.h        (revision 201148)
+++ cp/cp-tree.h        (working copy)
@@ -6022,7 +6022,7 @@ extern tree convert_for_initialization            (tree, 
tre
 extern int comp_ptr_ttypes                     (tree, tree);
 extern bool comp_ptr_ttypes_const              (tree, tree);
 extern bool error_type_p                       (const_tree);
-extern int ptr_reasonably_similar              (const_tree, const_tree);
+extern bool ptr_reasonably_similar             (const_tree, const_tree);
 extern tree build_ptrmemfunc                   (tree, tree, int, bool,
                                                 tsubst_flags_t);
 extern int cp_type_quals                       (const_tree);
Index: cp/typeck.c
===================================================================
--- cp/typeck.c (revision 201148)
+++ cp/typeck.c (working copy)
@@ -8599,10 +8599,10 @@ error_type_p (const_tree type)
     }
 }
 
-/* Returns 1 if to and from are (possibly multi-level) pointers to the same
+/* Returns true if to and from are (possibly multi-level) pointers to the same
    type or inheritance-related types, regardless of cv-quals.  */
 
-int
+bool
 ptr_reasonably_similar (const_tree to, const_tree from)
 {
   for (; ; to = TREE_TYPE (to), from = TREE_TYPE (from))
@@ -8614,8 +8614,11 @@ ptr_reasonably_similar (const_tree to, const_tree
        return !error_type_p (to);
 
       if (TREE_CODE (to) != TREE_CODE (from))
-       return 0;
+       return false;
 
+      if (COMPLETE_TYPE_P (to) != COMPLETE_TYPE_P (from))
+       return false;
+
       if (TREE_CODE (from) == OFFSET_TYPE
          && comptypes (TYPE_OFFSET_BASETYPE (to),
                        TYPE_OFFSET_BASETYPE (from),
@@ -8624,11 +8627,11 @@ ptr_reasonably_similar (const_tree to, const_tree
 
       if (TREE_CODE (to) == VECTOR_TYPE
          && vector_types_convertible_p (to, from, false))
-       return 1;
+       return true;
 
       if (TREE_CODE (to) == INTEGER_TYPE
          && TYPE_PRECISION (to) == TYPE_PRECISION (from))
-       return 1;
+       return true;
 
       if (TREE_CODE (to) == FUNCTION_TYPE)
        return !error_type_p (to) && !error_type_p (from);
Index: testsuite/g++.dg/inherit/pr57942.C
===================================================================
--- testsuite/g++.dg/inherit/pr57942.C  (revision 0)
+++ testsuite/g++.dg/inherit/pr57942.C  (working copy)
@@ -0,0 +1,7 @@
+// PR c++/57942
+
+template<typename T> struct S { typename T::error type; };
+struct X {};
+void f(S<int>*);
+void f(...);
+void g() { f((X*)0); }