From 46e8306050b957aad4e72d2c48c2f75dd12afdc3 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <293473+sandersn@users.noreply.github.com>
Date: Thu, 5 May 2022 09:33:32 -0700
Subject: [PATCH] Skip ambient modules in globalThis (#48938)

* Skip ambient modules in globalThis

Previously, globalThis mistakenly included ambient modules, even though
these are not values:

```ts
declare module "ambientModule" {
  export type typ = 1
  export var val: typ
}
type Oops = (typeof globalThis)[\"ambientModule\"]
```

This PR adds ambient modules to the kinds of things that are skipped
when constructing `globalThis`' properties, along with block-scoped
variables.

* Skip only modules with every declaration ambient

The modules are required to have at least one declaration so that our
treatment of `globalThis` stays the same, and
`globalThis.globalThis.globalThis` remains legal.
---
 src/compiler/checker.ts                       |  2 +-
 .../globalThisAmbientModules.errors.txt       | 21 ++++++++++
 .../reference/globalThisAmbientModules.js     | 20 ++++++++++
 .../globalThisAmbientModules.symbols          | 38 +++++++++++++++++++
 .../reference/globalThisAmbientModules.types  | 37 ++++++++++++++++++
 .../es2019/globalThisAmbientModules.ts        | 11 ++++++
 6 files changed, 128 insertions(+), 1 deletion(-)
 create mode 100644 tests/baselines/reference/globalThisAmbientModules.errors.txt
 create mode 100644 tests/baselines/reference/globalThisAmbientModules.js
 create mode 100644 tests/baselines/reference/globalThisAmbientModules.symbols
 create mode 100644 tests/baselines/reference/globalThisAmbientModules.types
 create mode 100644 tests/cases/conformance/es2019/globalThisAmbientModules.ts

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 8dc1e1df76f..504cdf669c7 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -11504,7 +11504,7 @@ namespace ts {
                 if (symbol === globalThisSymbol) {
                     const varsOnly = new Map<string, Symbol>() as SymbolTable;
                     members.forEach(p => {
-                        if (!(p.flags & SymbolFlags.BlockScoped)) {
+                        if (!(p.flags & SymbolFlags.BlockScoped) && !(p.flags & SymbolFlags.ValueModule && p.declarations?.length && every(p.declarations, isAmbientModule))) {
                             varsOnly.set(p.escapedName, p);
                         }
                     });
diff --git a/tests/baselines/reference/globalThisAmbientModules.errors.txt b/tests/baselines/reference/globalThisAmbientModules.errors.txt
new file mode 100644
index 00000000000..b29d977475f
--- /dev/null
+++ b/tests/baselines/reference/globalThisAmbientModules.errors.txt
@@ -0,0 +1,21 @@
+tests/cases/conformance/es2019/globalThisAmbientModules.ts(8,39): error TS2339: Property '"ambientModule"' does not exist on type 'typeof globalThis'.
+tests/cases/conformance/es2019/globalThisAmbientModules.ts(11,33): error TS2339: Property '"ambientModule"' does not exist on type 'typeof globalThis'.
+
+
+==== tests/cases/conformance/es2019/globalThisAmbientModules.ts (2 errors) ====
+    declare module "ambientModule" {
+        export type typ = 1
+        export var val: typ
+    }
+    namespace valueModule { export var val = 1 }
+    namespace namespaceModule { export type typ = 1 }
+    // should error
+    type GlobalBad1 = (typeof globalThis)["\"ambientModule\""]
+                                          ~~~~~~~~~~~~~~~~~~~
+!!! error TS2339: Property '"ambientModule"' does not exist on type 'typeof globalThis'.
+    type GlobalOk1 = (typeof globalThis)["valueModule"]
+    type GlobalOk2 = globalThis.namespaceModule.typ
+    const bad1: (typeof globalThis)["\"ambientModule\""] = 'ambientModule'
+                                    ~~~~~~~~~~~~~~~~~~~
+!!! error TS2339: Property '"ambientModule"' does not exist on type 'typeof globalThis'.
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/globalThisAmbientModules.js b/tests/baselines/reference/globalThisAmbientModules.js
new file mode 100644
index 00000000000..ec032568e9b
--- /dev/null
+++ b/tests/baselines/reference/globalThisAmbientModules.js
@@ -0,0 +1,20 @@
+//// [globalThisAmbientModules.ts]
+declare module "ambientModule" {
+    export type typ = 1
+    export var val: typ
+}
+namespace valueModule { export var val = 1 }
+namespace namespaceModule { export type typ = 1 }
+// should error
+type GlobalBad1 = (typeof globalThis)["\"ambientModule\""]
+type GlobalOk1 = (typeof globalThis)["valueModule"]
+type GlobalOk2 = globalThis.namespaceModule.typ
+const bad1: (typeof globalThis)["\"ambientModule\""] = 'ambientModule'
+
+
+//// [globalThisAmbientModules.js]
+var valueModule;
+(function (valueModule) {
+    valueModule.val = 1;
+})(valueModule || (valueModule = {}));
+var bad1 = 'ambientModule';
diff --git a/tests/baselines/reference/globalThisAmbientModules.symbols b/tests/baselines/reference/globalThisAmbientModules.symbols
new file mode 100644
index 00000000000..f27f2461baa
--- /dev/null
+++ b/tests/baselines/reference/globalThisAmbientModules.symbols
@@ -0,0 +1,38 @@
+=== tests/cases/conformance/es2019/globalThisAmbientModules.ts ===
+declare module "ambientModule" {
+>"ambientModule" : Symbol("ambientModule", Decl(globalThisAmbientModules.ts, 0, 0))
+
+    export type typ = 1
+>typ : Symbol(typ, Decl(globalThisAmbientModules.ts, 0, 32))
+
+    export var val: typ
+>val : Symbol(val, Decl(globalThisAmbientModules.ts, 2, 14))
+>typ : Symbol(typ, Decl(globalThisAmbientModules.ts, 0, 32))
+}
+namespace valueModule { export var val = 1 }
+>valueModule : Symbol(valueModule, Decl(globalThisAmbientModules.ts, 3, 1))
+>val : Symbol(val, Decl(globalThisAmbientModules.ts, 4, 34))
+
+namespace namespaceModule { export type typ = 1 }
+>namespaceModule : Symbol(namespaceModule, Decl(globalThisAmbientModules.ts, 4, 44))
+>typ : Symbol(typ, Decl(globalThisAmbientModules.ts, 5, 27))
+
+// should error
+type GlobalBad1 = (typeof globalThis)["\"ambientModule\""]
+>GlobalBad1 : Symbol(GlobalBad1, Decl(globalThisAmbientModules.ts, 5, 49))
+>globalThis : Symbol(globalThis)
+
+type GlobalOk1 = (typeof globalThis)["valueModule"]
+>GlobalOk1 : Symbol(GlobalOk1, Decl(globalThisAmbientModules.ts, 7, 58))
+>globalThis : Symbol(globalThis)
+
+type GlobalOk2 = globalThis.namespaceModule.typ
+>GlobalOk2 : Symbol(GlobalOk2, Decl(globalThisAmbientModules.ts, 8, 51))
+>globalThis : Symbol(globalThis)
+>namespaceModule : Symbol(namespaceModule, Decl(globalThisAmbientModules.ts, 4, 44))
+>typ : Symbol(namespaceModule.typ, Decl(globalThisAmbientModules.ts, 5, 27))
+
+const bad1: (typeof globalThis)["\"ambientModule\""] = 'ambientModule'
+>bad1 : Symbol(bad1, Decl(globalThisAmbientModules.ts, 10, 5))
+>globalThis : Symbol(globalThis)
+
diff --git a/tests/baselines/reference/globalThisAmbientModules.types b/tests/baselines/reference/globalThisAmbientModules.types
new file mode 100644
index 00000000000..9357ee67ead
--- /dev/null
+++ b/tests/baselines/reference/globalThisAmbientModules.types
@@ -0,0 +1,37 @@
+=== tests/cases/conformance/es2019/globalThisAmbientModules.ts ===
+declare module "ambientModule" {
+>"ambientModule" : typeof import("ambientModule")
+
+    export type typ = 1
+>typ : 1
+
+    export var val: typ
+>val : 1
+}
+namespace valueModule { export var val = 1 }
+>valueModule : typeof valueModule
+>val : number
+>1 : 1
+
+namespace namespaceModule { export type typ = 1 }
+>typ : 1
+
+// should error
+type GlobalBad1 = (typeof globalThis)["\"ambientModule\""]
+>GlobalBad1 : any
+>globalThis : typeof globalThis
+
+type GlobalOk1 = (typeof globalThis)["valueModule"]
+>GlobalOk1 : typeof valueModule
+>globalThis : typeof globalThis
+
+type GlobalOk2 = globalThis.namespaceModule.typ
+>GlobalOk2 : 1
+>globalThis : any
+>namespaceModule : any
+
+const bad1: (typeof globalThis)["\"ambientModule\""] = 'ambientModule'
+>bad1 : any
+>globalThis : typeof globalThis
+>'ambientModule' : "ambientModule"
+
diff --git a/tests/cases/conformance/es2019/globalThisAmbientModules.ts b/tests/cases/conformance/es2019/globalThisAmbientModules.ts
new file mode 100644
index 00000000000..5f170a0de27
--- /dev/null
+++ b/tests/cases/conformance/es2019/globalThisAmbientModules.ts
@@ -0,0 +1,11 @@
+declare module "ambientModule" {
+    export type typ = 1
+    export var val: typ
+}
+namespace valueModule { export var val = 1 }
+namespace namespaceModule { export type typ = 1 }
+// should error
+type GlobalBad1 = (typeof globalThis)["\"ambientModule\""]
+type GlobalOk1 = (typeof globalThis)["valueModule"]
+type GlobalOk2 = globalThis.namespaceModule.typ
+const bad1: (typeof globalThis)["\"ambientModule\""] = 'ambientModule'