From 58da6fbd7206406fdfdb25d99dab8a729fb13c4a Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Tue, 14 Jun 2016 15:21:46 -0700
Subject: [PATCH] Prevent renaming `this` parameters

---
 src/services/services.ts                         | 2 +-
 tests/cases/fourslash/noRenameOfThisParameter.ts | 6 ++++++
 2 files changed, 7 insertions(+), 1 deletion(-)
 create mode 100644 tests/cases/fourslash/noRenameOfThisParameter.ts

diff --git a/src/services/services.ts b/src/services/services.ts
index 8bf6a572ec754..f20bb69661d49 100644
--- a/src/services/services.ts
+++ b/src/services/services.ts
@@ -7999,7 +7999,7 @@ namespace ts {
 
             // Can only rename an identifier.
             if (node) {
-                if (node.kind === SyntaxKind.Identifier ||
+                if ((node.kind === SyntaxKind.Identifier && (node as Identifier).originalKeywordKind !== SyntaxKind.ThisKeyword) ||
                     node.kind === SyntaxKind.StringLiteral ||
                     isLiteralNameOfPropertyDeclarationOrIndexAccess(node)) {
                     const symbol = typeChecker.getSymbolAtLocation(node);
diff --git a/tests/cases/fourslash/noRenameOfThisParameter.ts b/tests/cases/fourslash/noRenameOfThisParameter.ts
new file mode 100644
index 0000000000000..7d0ad0a694cd8
--- /dev/null
+++ b/tests/cases/fourslash/noRenameOfThisParameter.ts
@@ -0,0 +1,6 @@
+/// <reference path="fourslash.ts" />
+////function f(this/**/: string, x: number) {
+////    return this.length + x;
+////}
+goTo.marker();
+verify.renameInfoFailed();