--- a/dmd/CmpExp.d	Sun Aug 29 14:39:08 2010 +0100
+++ b/dmd/CmpExp.d	Mon Aug 30 03:57:51 2010 +0200
@@ -38,8 +38,6 @@
 	override Expression semantic(Scope sc)
 	{
 		Expression e;
-		Type t1;
-		Type t2;
 
 	version (LOGSEMANTIC) {
 		printf("CmpExp.semantic('%s')\n", toChars());
@@ -49,8 +47,10 @@
 
 		BinExp.semanticp(sc);
 
-		if (e1.type.toBasetype().ty == Tclass && e2.op == TOKnull ||
-			e2.type.toBasetype().ty == Tclass && e1.op == TOKnull)
+		Type t1 = e1.type.toBasetype();
+		Type t2 = e2.type.toBasetype();
+		if (t1.ty == Tclass && e2.op == TOKnull ||
+			t2.ty == Tclass && e1.op == TOKnull)
 		{
 			error("do not use null when comparing class types");
 		}
@@ -71,6 +71,14 @@
 			return e;
 		}
 
+	    // Disallow comparing T[]==T and T==T[]
+	    if (e1.op == TOKslice && t1.ty == Tarray && e2.implicitConvTo(t1.nextOf()) ||
+	        e2.op == TOKslice && t2.ty == Tarray && e1.implicitConvTo(t2.nextOf()))
+	    {
+			incompatibleTypes();
+			return new ErrorExp();
+	    }
+
 		typeCombine(sc);
 		type = Type.tboolean;