re PR c++/27177 (ICE in build_simple_base_path, at cp/class.c:474)

	PR c++/27177
	* call.c (standard_conversion): Require that the derived type be
	complete when performing a derived-to-base conversion.
	PR c++/27177
	* g++.dg/expr/cast7.C: New test.

From-SVN: r114448

gcc/cp/ChangeLog

+2006-06-06  Mark Mitchell  <mark@codesourcery.com>
+
+	PR c++/27177
+	* call.c (standard_conversion): Require that the derived type be
+	complete when performing a derived-to-base conversion.
+
 2006-06-04  Mark Mitchell  <mark@codesourcery.com>
 
 	PR c++/27819

gcc/cp/call.c

@@ -727,7 +727,19 @@ standard_conversion (tree to, tree from, tree expr, bool c_cast_p,
 		  that necessitates this conversion is ill-formed.
 		  Therefore, we use DERIVED_FROM_P, and do not check
 		  access or uniqueness.  */
-	       && DERIVED_FROM_P (TREE_TYPE (to), TREE_TYPE (from)))
+	       && DERIVED_FROM_P (TREE_TYPE (to), TREE_TYPE (from))
+	       /* If FROM is not yet complete, then we must be parsing
+		  the body of a class.  We know what's derived from
+		  what, but we can't actually perform a
+		  derived-to-base conversion.  For example, in:
+
+		     struct D : public B { 
+                       static const int i = sizeof((B*)(D*)0);
+                     };
+
+                  the D*-to-B* conversion is a reinterpret_cast, not a
+		  static_cast.  */
+	       && COMPLETE_TYPE_P (TREE_TYPE (from)))
 	{
 	  from =
 	    cp_build_qualified_type (TREE_TYPE (to),

gcc/testsuite/ChangeLog

+2006-06-06  Mark Mitchell  <mark@codesourcery.com>
+
+	PR c++/27177
+	* g++.dg/expr/cast7.C: New test.
+
 2006-06-06  Janis Johnson  <janis187@us.ibm.com>
 
 	* lib/gcc-dg.exp (gcc-dg-test-1): Detect and report ICE.

gcc/testsuite/g++.dg/expr/cast7.C

+// PR c++/27177
+
+struct X {};
+
+struct Y : virtual X {};
+struct Z : virtual X {};
+
+struct A : Y, Z {};
+
+struct B : A
+{
+  static const int i = sizeof((Z*)(B*)0);
+};