From 08ae02263ae8b8c4d11034c3678c733c99561aa3 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Mon, 17 Jul 2017 15:59:18 -0700
Subject: [PATCH] Contextually type this in object literals in JS

Previously, `this` would only get a contextual type inside object
literals with `--noImplicitThis` turned on in Typescript files.
---
 src/compiler/checker.ts                       |  2 +-
 .../contextualThisTypeInJavascript.symbols    | 25 +++++++++++++++++
 .../contextualThisTypeInJavascript.types      | 27 +++++++++++++++++++
 .../contextualThisTypeInJavascript.ts         | 12 +++++++++
 4 files changed, 65 insertions(+), 1 deletion(-)
 create mode 100644 tests/baselines/reference/contextualThisTypeInJavascript.symbols
 create mode 100644 tests/baselines/reference/contextualThisTypeInJavascript.types
 create mode 100644 tests/cases/conformance/types/thisType/contextualThisTypeInJavascript.ts

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index dafa75372e1..d4c7cd7bd9b 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -12602,7 +12602,7 @@ namespace ts {
                     }
                 }
             }
-            if (noImplicitThis) {
+            if (noImplicitThis || isInJavaScriptFile(func)) {
                 const containingLiteral = getContainingObjectLiteral(func);
                 if (containingLiteral) {
                     // We have an object literal method. Check if the containing object literal has a contextual type
diff --git a/tests/baselines/reference/contextualThisTypeInJavascript.symbols b/tests/baselines/reference/contextualThisTypeInJavascript.symbols
new file mode 100644
index 00000000000..6c146d654d0
--- /dev/null
+++ b/tests/baselines/reference/contextualThisTypeInJavascript.symbols
@@ -0,0 +1,25 @@
+=== tests/cases/conformance/types/thisType/context.js ===
+const obj = {
+>obj : Symbol(obj, Decl(context.js, 0, 5))
+
+    prop: 2,
+>prop : Symbol(prop, Decl(context.js, 0, 13))
+
+    method() {
+>method : Symbol(method, Decl(context.js, 1, 12))
+
+        this;
+>this : Symbol(obj, Decl(context.js, 0, 11))
+
+        this.prop;
+>this.prop : Symbol(prop, Decl(context.js, 0, 13))
+>this : Symbol(obj, Decl(context.js, 0, 11))
+>prop : Symbol(prop, Decl(context.js, 0, 13))
+
+        this.method;
+>this.method : Symbol(method, Decl(context.js, 1, 12))
+>this : Symbol(obj, Decl(context.js, 0, 11))
+>method : Symbol(method, Decl(context.js, 1, 12))
+    }
+}
+
diff --git a/tests/baselines/reference/contextualThisTypeInJavascript.types b/tests/baselines/reference/contextualThisTypeInJavascript.types
new file mode 100644
index 00000000000..c3ec4123071
--- /dev/null
+++ b/tests/baselines/reference/contextualThisTypeInJavascript.types
@@ -0,0 +1,27 @@
+=== tests/cases/conformance/types/thisType/context.js ===
+const obj = {
+>obj : { [x: string]: any; prop: number; method(): void; }
+>{    prop: 2,    method() {        this;        this.prop;        this.method;    }} : { [x: string]: any; prop: number; method(): void; }
+
+    prop: 2,
+>prop : number
+>2 : 2
+
+    method() {
+>method : () => void
+
+        this;
+>this : { [x: string]: any; prop: number; method(): void; }
+
+        this.prop;
+>this.prop : number
+>this : { [x: string]: any; prop: number; method(): void; }
+>prop : number
+
+        this.method;
+>this.method : () => void
+>this : { [x: string]: any; prop: number; method(): void; }
+>method : () => void
+    }
+}
+
diff --git a/tests/cases/conformance/types/thisType/contextualThisTypeInJavascript.ts b/tests/cases/conformance/types/thisType/contextualThisTypeInJavascript.ts
new file mode 100644
index 00000000000..8ccbc65f545
--- /dev/null
+++ b/tests/cases/conformance/types/thisType/contextualThisTypeInJavascript.ts
@@ -0,0 +1,12 @@
+// @allowJs: true
+// @checkJs: true
+// @noEmit: true
+// @Filename: context.js
+const obj = {
+    prop: 2,
+    method() {
+        this;
+        this.prop;
+        this.method;
+    }
+}