From 10a91c54269db9e85315dc486f178e18182c800b Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Mon, 17 Jul 2017 16:14:42 -0700
Subject: [PATCH] JSDoc:Object<string, T> creates index signature

And `Object<number, T>` creates a numeric index signature. Other uses
still create `any` as before.
---
 src/compiler/checker.ts                             | 13 +++++++++++--
 .../baselines/reference/jsdocIndexSignature.symbols | 13 +++++++++++++
 tests/baselines/reference/jsdocIndexSignature.types | 13 +++++++++++++
 .../cases/conformance/jsdoc/jsdocIndexSignature.ts  | 10 ++++++++++
 4 files changed, 47 insertions(+), 2 deletions(-)
 create mode 100644 tests/baselines/reference/jsdocIndexSignature.symbols
 create mode 100644 tests/baselines/reference/jsdocIndexSignature.types
 create mode 100644 tests/cases/conformance/jsdoc/jsdocIndexSignature.ts

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index dafa75372e1..8dd81d1b623 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -6872,6 +6872,17 @@ namespace ts {
 
         function getPrimitiveTypeFromJSDocTypeReference(node: TypeReferenceNode): Type {
             if (isIdentifier(node.typeName)) {
+                if (node.typeName.text === "Object") {
+                    if (node.typeArguments && node.typeArguments.length === 2) {
+                        const from = getTypeFromTypeNode(node.typeArguments[0]);
+                        const to = getTypeFromTypeNode(node.typeArguments[1]);
+                        let index = createIndexInfo(to, /*isReadonly*/ false);
+                        if (from === stringType || from === numberType) {
+                            return createAnonymousType(undefined, emptySymbols, emptyArray, emptyArray, from === stringType ? index : undefined, from === numberType ? index : undefined)
+                        }
+                    }
+                    return anyType;
+                }
                 switch (node.typeName.text) {
                     case "String":
                         return stringType;
@@ -6885,8 +6896,6 @@ namespace ts {
                         return undefinedType;
                     case "Null":
                         return nullType;
-                    case "Object":
-                        return anyType;
                     case "Function":
                     case "function":
                         return globalFunctionType;
diff --git a/tests/baselines/reference/jsdocIndexSignature.symbols b/tests/baselines/reference/jsdocIndexSignature.symbols
new file mode 100644
index 00000000000..8814fc18b6f
--- /dev/null
+++ b/tests/baselines/reference/jsdocIndexSignature.symbols
@@ -0,0 +1,13 @@
+=== tests/cases/conformance/jsdoc/indices.js ===
+/** @type {Object.<string, number>} */
+var o1;
+>o1 : Symbol(o1, Decl(indices.js, 1, 3))
+
+/** @type {Object.<number, boolean>} */
+var o2;
+>o2 : Symbol(o2, Decl(indices.js, 3, 3))
+
+/** @type {Object.<boolean, string>} */
+var o3;
+>o3 : Symbol(o3, Decl(indices.js, 5, 3))
+
diff --git a/tests/baselines/reference/jsdocIndexSignature.types b/tests/baselines/reference/jsdocIndexSignature.types
new file mode 100644
index 00000000000..4c1feaa2721
--- /dev/null
+++ b/tests/baselines/reference/jsdocIndexSignature.types
@@ -0,0 +1,13 @@
+=== tests/cases/conformance/jsdoc/indices.js ===
+/** @type {Object.<string, number>} */
+var o1;
+>o1 : { [x: string]: number; }
+
+/** @type {Object.<number, boolean>} */
+var o2;
+>o2 : { [x: number]: boolean; }
+
+/** @type {Object.<boolean, string>} */
+var o3;
+>o3 : any
+
diff --git a/tests/cases/conformance/jsdoc/jsdocIndexSignature.ts b/tests/cases/conformance/jsdoc/jsdocIndexSignature.ts
new file mode 100644
index 00000000000..fdf9e06e61e
--- /dev/null
+++ b/tests/cases/conformance/jsdoc/jsdocIndexSignature.ts
@@ -0,0 +1,10 @@
+// @allowJs: true
+// @checkJs: true
+// @noEmit: true
+// @Filename: indices.js
+/** @type {Object.<string, number>} */
+var o1;
+/** @type {Object.<number, boolean>} */
+var o2;
+/** @type {Object.<boolean, string>} */
+var o3;