From 6a132dde62ec6261a4a68bfb26efd85dc0bae699 Mon Sep 17 00:00:00 2001
From: Evgeniy Timokhov <timocov@gmail.com>
Date: Sat, 30 Dec 2023 08:44:36 +0000
Subject: [PATCH] Fixed finding a scope for compiler-level defined symbols like
 `globalThis` or `undefined`

Fixes #282
---
 src/collisions-resolver.ts                    | 18 +++++++++++++++---
 tests/e2e/test-cases/globalThis/config.ts     |  5 +++++
 tests/e2e/test-cases/globalThis/index.spec.js |  1 +
 tests/e2e/test-cases/globalThis/input.ts      |  2 ++
 tests/e2e/test-cases/globalThis/output.d.ts   |  4 ++++
 5 files changed, 27 insertions(+), 3 deletions(-)
 create mode 100644 tests/e2e/test-cases/globalThis/config.ts
 create mode 100644 tests/e2e/test-cases/globalThis/index.spec.js
 create mode 100644 tests/e2e/test-cases/globalThis/input.ts
 create mode 100644 tests/e2e/test-cases/globalThis/output.d.ts

diff --git a/src/collisions-resolver.ts b/src/collisions-resolver.ts
index b412c5f..5f9b6c0 100644
--- a/src/collisions-resolver.ts
+++ b/src/collisions-resolver.ts
@@ -78,9 +78,7 @@ export class CollisionsResolver {
 			return null;
 		}
 
-		// we assume that all symbols for a given identifier will be in the same scope (i.e. defined in the same namespaces-chain)
-		// so we can use any declaration to find that scope as they all will have the same scope
-		const symbolScopePath = this.getNodeScope(getDeclarationsForSymbol(identifierSymbol)[0]);
+		const symbolScopePath = this.getSymbolScope(identifierSymbol);
 
 		// this scope defines where the current identifier is located
 		const currentIdentifierScope = this.getNodeScope(referencedIdentifier);
@@ -184,6 +182,20 @@ export class CollisionsResolver {
 		return identifierParts.join('.');
 	}
 
+	private getSymbolScope(identifierSymbol: ts.Symbol): ts.Symbol[] {
+		const identifierDeclarations = getDeclarationsForSymbol(identifierSymbol);
+
+		// not all symbols have declarations, e.g. `globalThis` or `undefined` (not type but value e.g. in `typeof undefined`)
+		// they are "fake" symbols that exist only at the compiler level (see checker.ts file in in the compiler or `globals.set()` calls)
+		if (identifierDeclarations.length === 0) {
+			return [];
+		}
+
+		// we assume that all symbols for a given identifier will be in the same scope (i.e. defined in the same namespaces-chain)
+		// so we can use any declaration to find that scope as they all will have the same scope
+		return this.getNodeScope(identifierDeclarations[0]);
+	}
+
 	/**
 	 * Returns a node's scope where it is located in terms of namespaces/modules.
 	 * E.g. A scope for `Opt` in `declare module foo { type Opt = number; }` is `[Symbol(foo)]`
diff --git a/tests/e2e/test-cases/globalThis/config.ts b/tests/e2e/test-cases/globalThis/config.ts
new file mode 100644
index 0000000..a1953e7
--- /dev/null
+++ b/tests/e2e/test-cases/globalThis/config.ts
@@ -0,0 +1,5 @@
+import { TestCaseConfig } from '../test-case-config';
+
+const config: TestCaseConfig = {};
+
+export = config;
diff --git a/tests/e2e/test-cases/globalThis/index.spec.js b/tests/e2e/test-cases/globalThis/index.spec.js
new file mode 100644
index 0000000..c015c26
--- /dev/null
+++ b/tests/e2e/test-cases/globalThis/index.spec.js
@@ -0,0 +1 @@
+require('../run-test-case').runTestCase(__dirname);
diff --git a/tests/e2e/test-cases/globalThis/input.ts b/tests/e2e/test-cases/globalThis/input.ts
new file mode 100644
index 0000000..043ad2a
--- /dev/null
+++ b/tests/e2e/test-cases/globalThis/input.ts
@@ -0,0 +1,2 @@
+export declare function getGlobal(): typeof globalThis;
+export declare function getUndef(): typeof undefined;
diff --git a/tests/e2e/test-cases/globalThis/output.d.ts b/tests/e2e/test-cases/globalThis/output.d.ts
new file mode 100644
index 0000000..b26352d
--- /dev/null
+++ b/tests/e2e/test-cases/globalThis/output.d.ts
@@ -0,0 +1,4 @@
+export declare function getGlobal(): typeof globalThis;
+export declare function getUndef(): typeof undefined;
+
+export {};