diff -r 23627f8bc421 -r 8aa89dd41e25 jitcraft/SemanticAnalysis.cpp
--- a/jitcraft/SemanticAnalysis.cpp	Sat Jun 30 22:45:25 2012 -0700
+++ b/jitcraft/SemanticAnalysis.cpp	Sat Jun 30 23:40:17 2012 -0700
@@ -395,6 +395,8 @@
     assert(node->arguments()->size() == type->parameters()->length());
 
     for (unsigned i = 0; i < node->arguments()->size(); i++) {
+        // Note: we don't compute references unless the callee needs a
+        // reference type.
         Expression *expression = node->arguments()->at(i);
         expression->accept(this);
 
@@ -402,6 +404,12 @@
         if (!given)
             return;
 
+        // If it's an IndexExpression, we special case the ability to compute
+        // a reference. Maybe we should compute actual Ref types for
+        // IndexExpression?
+        if (expression->isIndexExpression())
+            given = given->contained();
+
         Type *actual = Type::cast(type->parameters()->at(i));
         assert(TypeCheckParameter(given, actual));