diff -r 9308d52205a0 -r bab29bcec7fe src/SemanticAnalysis.cpp
--- a/src/SemanticAnalysis.cpp	Sun Sep 16 19:02:23 2012 -0700
+++ b/src/SemanticAnalysis.cpp	Sun Sep 16 21:34:10 2012 -0700
@@ -1420,13 +1420,22 @@
         } else {
             Local<Type> actual(zone_, type->parameterAt(i));
 
-            if (expression->isIndexExpression() && actual->isArray()) {
-                // We special case the ability to pass x[y] into x[], which
-                // creates an array slice. We only do this if we know the
-                // assignment would otherwise not type-check.
-                IndexExpression *index = expression->toIndexExpression();
-                if (index->left()->type()->levels() == actual->levels())
-                    given = index->left()->type();
+            if (expression->isIndexExpression()) {
+                // Disabled until we can make it work.
+#if 0
+                if (actual->isArray()) {
+                    // We special case the ability to pass x[y] into x[], which
+                    // creates an array slice. We only do this if we know the
+                    // assignment would otherwise not type-check.
+                    IndexExpression *index = expression->toIndexExpression();
+                    if (index->left()->type()->levels() == actual->levels())
+                        given = index->left()->type();
+                } else
+#endif
+                if (actual->isReference()) {
+                    cc_.reportError(expression->pos(), Message_CannotComputeIndexRef);
+                    return;
+                }
             }
 
             if (!typeCheckParameter(expression, given, actual))