fixes #206, add checking for unary ops

test/codegen/expect/opassign.txt

Index: test/codegen/expect/opassign.txt
diff --git a/test/codegen/expect/opassign.txt b/test/codegen/expect/opassign.txt
index 53b91a05e0d3ff67ef22ace689de1f76cedfd502..0aa69fb412d0470fbb975fa9eaf51bd2babe34d4 100644
--- a/test/codegen/expect/opassign.txt
+++ b/test/codegen/expect/opassign.txt
@@ -1,7 +1,19 @@
 // Messages from compiling opassign.dart
+info: line 21, column 3 of test/codegen/opassign.dart: [DynamicInvoke] ++f[index] requires dynamic invoke
+  ++f[index];
+  ^^^^^^^^^^
+info: line 22, column 16 of test/codegen/opassign.dart: [DynamicInvoke] f[index]++ requires dynamic invoke
+  forcePostfix(f[index]++);
+               ^^^^^^^^^^
+info: line 25, column 3 of test/codegen/opassign.dart: [DynamicInvoke] ++foo.x requires dynamic invoke
+  ++foo.x;
+  ^^^^^^^
 info: line 25, column 5 of test/codegen/opassign.dart: [DynamicInvoke] foo.x requires dynamic invoke
   ++foo.x;
     ^^^^^
+info: line 26, column 16 of test/codegen/opassign.dart: [DynamicInvoke] foo.x++ requires dynamic invoke
+  forcePostfix(foo.x++);
+               ^^^^^^^
 info: line 26, column 16 of test/codegen/opassign.dart: [DynamicInvoke] foo.x requires dynamic invoke
   forcePostfix(foo.x++);
                ^^^^^