diff -r 765ab1b672a3 -r 8a31742781c1 jitcraft/SemanticAnalysis.cpp
--- a/jitcraft/SemanticAnalysis.cpp	Sun Jul 01 16:36:39 2012 -0700
+++ b/jitcraft/SemanticAnalysis.cpp	Sun Jul 01 18:21:15 2012 -0700
@@ -211,30 +211,46 @@
     return left;
 }
 
+Type *
+SemanticAnalysis::visitForLValue(Expression *expression)
+{
+    if (expression->isIndexExpression()) {
+        expression->accept(this);
+        if (!expression->type())
+            return NULL;
+        return expression->type()->contained();
+    }
+
+    if (!expression->isNameProxy()) {
+        assert(false);
+        return NULL;
+    }
+
+    NameProxy *proxy = expression->toNameProxy();
+    if (!proxy->binding()->kind() == BoundName::VARIABLE) {
+        fprintf(stderr, "error\n");
+        return NULL;
+    }
+
+    Variable *var = proxy->binding()->toVariable();
+    if (!var->type())
+        return NULL;
+
+    if  (var->type()->isReference())
+        return var->type()->contained();
+    return var->type();
+}
+
 void
 SemanticAnalysis::visit(Assignment *node)
 {
     visitForLoad(node->expression());
 
-    if (node->lvalue()->isIndexExpression()) {
-        node->lvalue()->accept(this);
-        node->setType(node->lvalue()->type()->contained());
-    } else {
-        NameProxy *proxy = node->lvalue()->toNameProxy();
-        if (!proxy->binding()->kind() == BoundName::VARIABLE) {
-            fprintf(stderr, "error\n");
-            return;
-        }
-
-        Variable *var = proxy->binding()->toVariable();
-        if (!var->type())
-            return;
-
-        if  (var->type()->isReference())
-            node->setType(var->type()->contained());
-        else
-            node->setType(var->type());
-    }
+    // :TODO: use Local
+    Type *type = visitForLValue(node->lvalue());
+    if (!type)
+        return;
+    node->setType(type);
 
     if (node->token() != TOK_ASSIGN)
         assert(TypeCheckBinary(node->token(), node->type(), node->expression()->type()));
@@ -243,6 +259,25 @@
 }
 
 void
+SemanticAnalysis::visit(IncDecExpression *node)
+{
+    // :TODO: use Local
+    Type *type = visitForLValue(node->expression());
+    if (!type)
+        return;
+
+    assert(!type->isReference());
+    if (type->isArray()) {
+        // can't a[]++
+        assert(false);
+        return;
+    }
+
+    assert((type->isInt32() && !type->tag()) || type->isFloat());
+    node->setType(type);
+}
+
+void
 SemanticAnalysis::visit(BinaryExpression *node)
 {
     // :TODO: use Local