diff --git a/src/compiler/binder.ts b/src/compiler/binder.ts
index 4027539334e..fc08a862007 100644
--- a/src/compiler/binder.ts
+++ b/src/compiler/binder.ts
@@ -2267,8 +2267,8 @@ namespace ts {
             transformFlags |= TransformFlags.AssertTypeScript;
         }
 
-        // If the parameter's name is 'this, then it is TypeScript syntax.
-        if ((node.name as Identifier).text === "this") {
+        // If the parameter's name is 'this', then it is TypeScript syntax.
+        if (node.name && (node.name as Identifier).originalKeywordKind === SyntaxKind.ThisKeyword) {
             transformFlags |= TransformFlags.AssertTypeScript;
         }
 
diff --git a/src/compiler/transformers/ts.ts b/src/compiler/transformers/ts.ts
index 0f96c65a738..f930b7bc93a 100644
--- a/src/compiler/transformers/ts.ts
+++ b/src/compiler/transformers/ts.ts
@@ -2115,12 +2115,12 @@ namespace ts {
          * This function will be called when one of the following conditions are met:
          * - The node has an accessibility modifier.
          * - The node has a questionToken.
-         * - The node's text is "this".
+         * - The node's kind is ThisKeyword.
          *
          * @param node The parameter declaration node.
          */
         function visitParameter(node: ParameterDeclaration) {
-            if ((node.name as Identifier).text === "this") {
+            if (node.name && (node.name as Identifier).originalKeywordKind === SyntaxKind.ThisKeyword) {
                 return undefined;
             }
             const clone = getMutableClone(node);
diff --git a/tests/baselines/reference/thisTypeInFunctions.js b/tests/baselines/reference/thisTypeInFunctions.js
index ccec3c563e8..cfe1706ae99 100644
--- a/tests/baselines/reference/thisTypeInFunctions.js
+++ b/tests/baselines/reference/thisTypeInFunctions.js
@@ -243,8 +243,7 @@ function implicitThis(n) {
 var impl = {
     a: 12,
     explicitVoid2: function () { return _this.a; },
-    explicitVoid1: // ok, this: any because it refers to some outer object (window?)
-    function () { return 12; },
+    explicitVoid1: function () { return 12; },
     explicitStructural: function () {
         return this.a;
     },