Skip typechecking before declaration file on js files with nocheck

Author: sheetalkamat

src/compiler/checker.ts

@@ -2428,10 +2428,10 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
         return visitEachChild(node, markAsSynthetic, /*context*/ undefined);
     }
 
-    function getEmitResolver(sourceFile: SourceFile, cancellationToken: CancellationToken) {
+    function getEmitResolver(sourceFile: SourceFile, cancellationToken: CancellationToken, skipCheck?: boolean) {
         // Ensure we have all the type information in place for this file so that all the
         // emitter questions of this resolver will return the right information.
-        getDiagnostics(sourceFile, cancellationToken);
+        getDiagnostics(sourceFile, cancellationToken, skipCheck);
         return emitResolver;
     }
 
@@ -47483,10 +47483,10 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
         tracing?.pop();
     }
 
-    function checkSourceFile(node: SourceFile) {
+    function checkSourceFile(node: SourceFile, skipCheck: boolean | undefined) {
         tracing?.push(tracing.Phase.Check, "checkSourceFile", { path: node.path }, /*separateBeginAndEnd*/ true);
         performance.mark("beforeCheck");
-        checkSourceFileWorker(node);
+        checkSourceFileWorker(node, skipCheck);
         performance.mark("afterCheck");
         performance.measure("Check", "beforeCheck", "afterCheck");
         tracing?.pop();
@@ -47511,10 +47511,10 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
     }
 
     // Fully type check a source file and collect the relevant diagnostics.
-    function checkSourceFileWorker(node: SourceFile) {
+    function checkSourceFileWorker(node: SourceFile, skipCheck: boolean | undefined) {
         const links = getNodeLinks(node);
         if (!(links.flags & NodeCheckFlags.TypeChecked)) {
-            if (skipTypeChecking(node, compilerOptions, host)) {
+            if (skipCheck || skipTypeChecking(node, compilerOptions, host)) {
                 return;
             }
 
@@ -47578,13 +47578,13 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
         }
     }
 
-    function getDiagnostics(sourceFile: SourceFile, ct: CancellationToken): Diagnostic[] {
+    function getDiagnostics(sourceFile: SourceFile, ct: CancellationToken, skipCheck?: boolean): Diagnostic[] {
         try {
             // Record the cancellation token so it can be checked later on during checkSourceElement.
             // Do this in a finally block so we can ensure that it gets reset back to nothing after
             // this call is done.
             cancellationToken = ct;
-            return getDiagnosticsWorker(sourceFile);
+            return getDiagnosticsWorker(sourceFile, skipCheck);
         }
         finally {
             cancellationToken = undefined;
@@ -47599,7 +47599,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
         deferredDiagnosticsCallbacks = [];
     }
 
-    function checkSourceFileWithEagerDiagnostics(sourceFile: SourceFile) {
+    function checkSourceFileWithEagerDiagnostics(sourceFile: SourceFile, skipCheck?: boolean) {
         ensurePendingDiagnosticWorkComplete();
         // then setup diagnostics for immediate invocation (as we are about to collect them, and
         // this avoids the overhead of longer-lived callbacks we don't need to allocate)
@@ -47608,11 +47608,11 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
         // thus much more likely retaining the same union ordering as before we had lazy diagnostics)
         const oldAddLazyDiagnostics = addLazyDiagnostic;
         addLazyDiagnostic = cb => cb();
-        checkSourceFile(sourceFile);
+        checkSourceFile(sourceFile, skipCheck);
         addLazyDiagnostic = oldAddLazyDiagnostics;
     }
 
-    function getDiagnosticsWorker(sourceFile: SourceFile): Diagnostic[] {
+    function getDiagnosticsWorker(sourceFile: SourceFile, skipCheck: boolean | undefined): Diagnostic[] {
         if (sourceFile) {
             ensurePendingDiagnosticWorkComplete();
             // Some global diagnostics are deferred until they are needed and
@@ -47621,7 +47621,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
             const previousGlobalDiagnostics = diagnostics.getGlobalDiagnostics();
             const previousGlobalDiagnosticsSize = previousGlobalDiagnostics.length;
 
-            checkSourceFileWithEagerDiagnostics(sourceFile);
+            checkSourceFileWithEagerDiagnostics(sourceFile, skipCheck);
 
             const semanticDiagnostics = diagnostics.getDiagnostics(sourceFile.fileName);
             const currentGlobalDiagnostics = diagnostics.getGlobalDiagnostics();
@@ -47642,7 +47642,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
 
         // Global diagnostics are always added when a file is not provided to
         // getDiagnostics
-        forEach(host.getSourceFiles(), checkSourceFileWithEagerDiagnostics);
+        forEach(host.getSourceFiles(), sourceFile => checkSourceFileWithEagerDiagnostics(sourceFile, skipCheck));
         return diagnostics.getDiagnostics();
     }
 

src/compiler/program.ts

@@ -2870,7 +2870,11 @@ export function createProgram(rootNamesOrOptions: readonly string[] | CreateProg
         // This is because in the -out scenario all files need to be emitted, and therefore all
         // files need to be type checked. And the way to specify that all files need to be type
         // checked is to not pass the file to getEmitResolver.
-        const emitResolver = getTypeChecker().getEmitResolver(options.outFile ? undefined : sourceFile, cancellationToken);
+        const emitResolver = getTypeChecker().getEmitResolver(
+            options.outFile ? undefined : sourceFile,
+            cancellationToken,
+            forceDtsEmit && sourceFile && !canIncludeBindAndCheckDiagnsotics(sourceFile),
+        );
 
         performance.mark("beforeEmit");
 
@@ -3006,14 +3010,12 @@ export function createProgram(rootNamesOrOptions: readonly string[] | CreateProg
             const isJs = sourceFile.scriptKind === ScriptKind.JS || sourceFile.scriptKind === ScriptKind.JSX;
             const isCheckJs = isJs && isCheckJsEnabledForFile(sourceFile, options);
             const isPlainJs = isPlainJsFile(sourceFile, options.checkJs);
-            const isTsNoCheck = !!sourceFile.checkJsDirective && sourceFile.checkJsDirective.enabled === false;
 
             // By default, only type-check .ts, .tsx, Deferred, plain JS, checked JS and External
             // - plain JS: .js files with no // ts-check and checkJs: undefined
             // - check JS: .js files with either // ts-check or checkJs: true
             // - external: files that are added by plugins
-            const includeBindAndCheckDiagnostics = !isTsNoCheck && (sourceFile.scriptKind === ScriptKind.TS || sourceFile.scriptKind === ScriptKind.TSX
-                || sourceFile.scriptKind === ScriptKind.External || isPlainJs || isCheckJs || sourceFile.scriptKind === ScriptKind.Deferred);
+            const includeBindAndCheckDiagnostics = canIncludeBindAndCheckDiagnsotics(sourceFile);
             let bindDiagnostics: readonly Diagnostic[] = includeBindAndCheckDiagnostics ? sourceFile.bindDiagnostics : emptyArray;
             let checkDiagnostics = includeBindAndCheckDiagnostics ? typeChecker.getDiagnostics(sourceFile, cancellationToken) : emptyArray;
             if (isPlainJs) {
@@ -3025,6 +3027,20 @@ export function createProgram(rootNamesOrOptions: readonly string[] | CreateProg
         });
     }
 
+    function canIncludeBindAndCheckDiagnsotics(sourceFile: SourceFile) {
+        const isJs = sourceFile.scriptKind === ScriptKind.JS || sourceFile.scriptKind === ScriptKind.JSX;
+        const isCheckJs = isJs && isCheckJsEnabledForFile(sourceFile, options);
+        const isPlainJs = isPlainJsFile(sourceFile, options.checkJs);
+        const isTsNoCheck = !!sourceFile.checkJsDirective && sourceFile.checkJsDirective.enabled === false;
+
+        // By default, only type-check .ts, .tsx, Deferred, plain JS, checked JS and External
+        // - plain JS: .js files with no // ts-check and checkJs: undefined
+        // - check JS: .js files with either // ts-check or checkJs: true
+        // - external: files that are added by plugins
+        return !isTsNoCheck && (sourceFile.scriptKind === ScriptKind.TS || sourceFile.scriptKind === ScriptKind.TSX
+            || sourceFile.scriptKind === ScriptKind.External || isPlainJs || isCheckJs || sourceFile.scriptKind === ScriptKind.Deferred);
+    }
+
     function getMergedBindAndCheckDiagnostics(sourceFile: SourceFile, includeBindAndCheckDiagnostics: boolean, ...allDiagnostics: (readonly Diagnostic[] | undefined)[]) {
         const flatDiagnostics = flatten(allDiagnostics);
         if (!includeBindAndCheckDiagnostics || !sourceFile.commentDirectives?.length) {

src/compiler/types.ts

@@ -5264,7 +5264,7 @@ export interface TypeChecker {
     // Should not be called directly.  Should only be accessed through the Program instance.
     /** @internal */ getDiagnostics(sourceFile?: SourceFile, cancellationToken?: CancellationToken): Diagnostic[];
     /** @internal */ getGlobalDiagnostics(): Diagnostic[];
-    /** @internal */ getEmitResolver(sourceFile?: SourceFile, cancellationToken?: CancellationToken): EmitResolver;
+    /** @internal */ getEmitResolver(sourceFile?: SourceFile, cancellationToken?: CancellationToken, skipCheck?: boolean): EmitResolver;
 
     /** @internal */ getNodeCount(): number;
     /** @internal */ getIdentifierCount(): number;