Ouch. I don't know what's happened here. The test suite I provided with the patch in bug 3577 doesn't compile! 
This quick patch fixes the immediate bug reported here, but it still doesn't compile the 3577 test suite.
The culprit is the call to typeCombine(). The test needs to be performed before that.

Index: expression.c
===================================================================
--- expression.c	(revision 324)
+++ expression.c	(working copy)
@@ -9965,6 +9971,9 @@
 	     ) && (e1->op == TOKint64 || e1->op == TOKfloat64)
 	   )
 	{
+	    bool wantCube = (e2->op == TOKint64 && e2->toInteger() == 3) 
+	      || (e2->op == TOKfloat64 && e2->toReal() == 3.0);
+	      
 	    typeCombine(sc);
 	    // Replace x^^2 with (tmp = x, tmp*tmp)
 	    // Replace x^^3 with (tmp = x, tmp*tmp*tmp) 
@@ -9973,8 +9982,8 @@
 	    VarExp * ve = new VarExp(loc, tmp);
 	    Expression *ae = new DeclarationExp(loc, tmp);
 	    Expression *me = new MulExp(loc, ve, ve);
-	    if ( (e2->op == TOKint64 && e2->toInteger() == 3) 
-	      || (e2->op == TOKfloat64 && e2->toReal() == 3.0))
+
+	    if ( wantCube)
 		me = new MulExp(loc, me, ve);
 	    e = new CommaExp(loc, ae, me);
 	    e = e->semantic(sc);

Changeset 332

fixed dmd 2.040