Fixed finding a scope for compiler-level defined symbols like `global…

…This` or `undefined`

Fixes #282

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)]`

tests/e2e/test-cases/globalThis/config.ts

@@ -0,0 +1,5 @@
+import { TestCaseConfig } from '../test-case-config';
+
+const config: TestCaseConfig = {};
+
+export = config;

tests/e2e/test-cases/globalThis/index.spec.js

@@ -0,0 +1 @@
+require('../run-test-case').runTestCase(__dirname);

tests/e2e/test-cases/globalThis/input.ts

@@ -0,0 +1,2 @@
+export declare function getGlobal(): typeof globalThis;
+export declare function getUndef(): typeof undefined;

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 {};