diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index 5b7083e164e..01b4003c0e1 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -387,7 +387,7 @@ module ts {
 
     export interface Identifier extends PrimaryExpression {
         text: string;                 // Text of identifier (with escapes converted to characters)
-        strictModeKind?: SyntaxKind;  // TODO(yuisu): comment
+        strictModeKind?: SyntaxKind;  // SyntaxKind set when violating strict mode reserved word
     }
 
     export interface QualifiedName extends Node {