Index: aggregate.h
===================================================================
--- aggregate.h	(revision 196)
+++ aggregate.h	(working copy)
@@ -220,6 +220,7 @@
 #define OFFSET_RUNTIME 0x76543210
 virtual int isBaseOf(ClassDeclaration *cd, int *poffset);
 
+ virtual int isBaseInfoComplete();
 Dsymbol *search(Loc, Identifier *ident, int flags);
 #if DMDV2
 int isFuncHidden(FuncDeclaration *fd);
@@ -266,6 +267,7 @@
 int isBaseOf(ClassDeclaration *cd, int *poffset);
 int isBaseOf(BaseClass *bc, int *poffset);
 const char *kind();
+ int isBaseInfoComplete();
 int vtblOffset();
 #if DMDV2
 int isCPPinterface();
Index: class.c
===================================================================
--- class.c	(revision 196)
+++ class.c	(working copy)
@@ -803,6 +803,23 @@
 return 0;
 }
 
+/*********************************************
+ * Determine if 'this' has clomplete base class information.
+ * This is used to detect forward references in covariant overloads.
+ */
+
+int ClassDeclaration::isBaseInfoComplete()
+{
+ if (!baseClass)
+	return 0;
+ for (int i = 0; i < baseclasses.dim; i++) + { BaseClass *b = (BaseClass *)baseclasses.data[i]; + if (!b->base &#124;&#124; !b->base->isBaseInfoComplete ())
+	 return 0;
+ }
+ return 1;
+}
+
 Dsymbol *ClassDeclaration::search(Loc loc, Identifier *ident, int flags)
 {
 Dsymbol *s;
@@ -1322,6 +1339,22 @@
 return 0;
 }
 
+/*********************************************
+ * Determine if 'this' has clomplete base class information.
+ * This is used to detect forward references in covariant overloads.
+ */
+
+int InterfaceDeclaration::isBaseInfoComplete()
+{
+ assert(!baseClass);
+ for (int i = 0; i < baseclasses.dim; i++) + { BaseClass *b = (BaseClass *)baseclasses.data[i]; + if (!b->base &#124;&#124; !b->base->isBaseInfoComplete ())
+	 return 0;
+ }
+ return 1;
+}
+
 /****************************************
 * Determine if slot 0 of the vtbl[] is reserved for something else.
 * For class objects, yes, this is where the ClassInfo ptr goes.
Index: mtype.c
===================================================================
--- mtype.c	(revision 196)
+++ mtype.c	(working copy)
@@ -3811,16 +3811,20 @@
 	 t2n->mod == MODconst)
 	 goto Lcovariant;
 
-	// If t1n is forward referenced:
-	ClassDeclaration *cd = ((TypeClass *)t1n)->sym;
-	if (!cd->baseClass && cd->baseclasses.dim && !cd->isInterfaceDeclaration())
-	{
-	 return 3;
-	}
+	// try it, it might already work for incomplete classes
+	if (t1n->implicitConvTo(t2n))
+	 goto Lcovariant;
+
+ 	// If t1n is forward referenced:
+ 	ClassDeclaration *cd = ((TypeClass *)t1n)->sym;
+	if (!cd->isBaseInfoComplete())
+ 	{
+ 	 return 3;
+ 	}
 }
- if (t1n->implicitConvTo(t2n))
-	goto Lcovariant;
- }
+ else if (t1n->implicitConvTo(t2n))
+ 	goto Lcovariant;
+ }
 goto Lnotcovariant;
 
 Lcovariant:
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