diff -r 9371f058625a -r f9c4371d59d4 src/compiler/SemanticAnalysis.cpp
--- a/src/compiler/SemanticAnalysis.cpp	Thu Dec 27 20:44:50 2012 -0800
+++ b/src/compiler/SemanticAnalysis.cpp	Thu Dec 27 21:07:03 2012 -0800
@@ -744,6 +744,8 @@
     }
 
     HIR *hir = eval(node->expression());
+    if (!hir)
+        return;
     if ((hir = coerce(hir, lval->type(), Coerce_Assign)) == NULL)
         return;
 
@@ -1090,35 +1092,56 @@
 void
 SemanticAnalysis::visitUnaryExpression(UnaryExpression *node)
 {
+    HIR *hir = eval(node->expression());
+    if (!hir)
+        return;
+
     switch (node->token()) {
-      case TOK_LABEL:
+      case TOK_MINUS:
       {
-          assert(node->token() == TOK_LABEL);
-          HIR *hir = eval(node->expression());
-          if (!hir)
-            return;
-
-          TypeSymbol *sym = node->tag()->sym()->asType();
-          if (!sym) {
-              cc_.reportError(node->pos(), Message_IdentifierIsNotAType,
-                              sym->name()->chars());
+          if (hir->type()->isInt32() || hir->type()->isEnum()) {
+              Local<Type> type(zone_, zone_->types()->getPrimitive(PrimitiveType_Int32));
+              hir_ = new (pool_) HUnary(node, type, TOK_MINUS, hir);
+              return;
+          }
+          if (hir->type()->isFloat()) {
+              hir_ = new (pool_) HUnary(node, hir->type(), TOK_MINUS, hir);
               return;
           }
 
-          if (!IsValidUncheckedType(sym->type())) {
-              char name[255];
-              cc_.reportError(node->pos(), Message_InvalidUncheckedCastTo,
-                              GetTypeName(hir->type(), name, sizeof(name)));
-              return;
-          }
-          if (!IsValidUncheckedType(hir->type())) {
-              char name[255];
-              cc_.reportError(node->pos(), Message_InvalidUncheckedCastFrom,
-                              GetTypeName(hir->type(), name, sizeof(name)));
-              return;
-          }
+          char name[255];
+          cc_.reportError(node->pos(), Message_InvalidUnaryType,
+                          "-",
+                          GetTypeName(hir->type(), name, sizeof(name)));
+          break;
+      }
+
+      default:
+      {
+        assert(node->token() == TOK_LABEL);
 
-          break;
+        TypeSymbol *sym = node->tag()->sym()->asType();
+        if (!sym) {
+            cc_.reportError(node->pos(), Message_IdentifierIsNotAType,
+                            sym->name()->chars());
+            return;
+        }
+
+        if (!IsValidUncheckedType(sym->type())) {
+            char name[255];
+            cc_.reportError(node->pos(), Message_InvalidUncheckedCastTo,
+                            GetTypeName(hir->type(), name, sizeof(name)));
+            return;
+        }
+        if (!IsValidUncheckedType(hir->type())) {
+            char name[255];
+            cc_.reportError(node->pos(), Message_InvalidUncheckedCastFrom,
+                            GetTypeName(hir->type(), name, sizeof(name)));
+            return;
+        }
+
+        hir_ = new (pool_) HUnary(node, hir->type(), TOK_LABEL, hir);
+        break;
       }
     }
 }