feat(core): detect more reliably whether a rule requires type informa…

…tion (#33)

packages/cli/lib/worker.ts

@@ -17,6 +17,7 @@ let fileNames: string[] = [];
 let language: Language<string> | undefined;
 let linter: core.Linter;
 let linterLanguageService!: ts.LanguageService;
+let linterSyntaxOnlyLanguageService!: ts.LanguageService;
 
 const snapshots = new Map<string, ts.IScriptSnapshot>();
 const versions = new Map<string, number>();
@@ -68,6 +69,7 @@ const originalHost: ts.LanguageServiceHost = {
 };
 const linterHost: ts.LanguageServiceHost = { ...originalHost };
 const originalService = ts.createLanguageService(linterHost);
+const originalSyntaxOnlyService = ts.createLanguageService(linterHost, undefined, true);
 
 export function createLocal() {
 	return {
@@ -171,6 +173,7 @@ async function setup(
 		}
 	}
 	linterLanguageService = originalService;
+	linterSyntaxOnlyLanguageService = originalSyntaxOnlyService;
 	language = undefined;
 
 	const plugins = await languagePlugins.load(tsconfig, languages);
@@ -190,9 +193,14 @@ async function setup(
 			}
 		);
 		decorateLanguageServiceHost(ts, language, linterHost);
+
 		const proxy = createProxyLanguageService(linterLanguageService);
 		proxy.initialize(language);
 		linterLanguageService = proxy.proxy;
+
+		const syntaxOnly = createProxyLanguageService(linterSyntaxOnlyLanguageService);
+		syntaxOnly.initialize(language);
+		linterSyntaxOnlyLanguageService = syntaxOnly.proxy;
 	}
 
 	projectVersion++;
@@ -204,13 +212,18 @@ async function setup(
 			allowNonTsExtensions: true,
 		}
 		: _options;
-	linter = core.createLinter({
-		configFile,
-		languageService: linterLanguageService,
-		languageServiceHost: linterHost,
-		typescript: ts,
-		tsconfig: ts.server.toNormalizedPath(tsconfig),
-	}, config, 'cli');
+	linter = core.createLinter(
+		{
+			configFile,
+			languageService: linterLanguageService,
+			languageServiceHost: linterHost,
+			typescript: ts,
+			tsconfig: ts.server.toNormalizedPath(tsconfig),
+		},
+		config,
+		'cli',
+		linterSyntaxOnlyLanguageService
+	);
 
 	return true;
 }
@@ -222,7 +235,7 @@ function lintAndFix(fileName: string, fileCache: core.FileLintCache) {
 	let diagnostics!: ts.DiagnosticWithLocation[];
 
 	while (shouldRetry && retry--) {
-		if (Object.values(fileCache[1]).some(([fixes]) => fixes > 0)) {
+		if (Object.values(fileCache[1]).some(([hasFix]) => hasFix)) {
 			// Reset the cache if there are any fixes applied.
 			fileCache[1] = {};
 			fileCache[2] = {};