Check resolution of tslib per file

src/compiler/checker.ts

@@ -1461,9 +1461,6 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
     // they no longer need the information (for example, if the user started editing again).
     var cancellationToken: CancellationToken | undefined;
 
-    var requestedExternalEmitHelperNames = new Set<string>();
-    var requestedExternalEmitHelpers: ExternalEmitHelpers;
-    var externalHelpersModule: Symbol;
     var scanner: Scanner | undefined;
 
     var Symbol = objectAllocator.getSymbolConstructor();
@@ -49508,42 +49505,43 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
     }
 
     function checkExternalEmitHelpers(location: Node, helpers: ExternalEmitHelpers) {
-        if ((requestedExternalEmitHelpers & helpers) !== helpers && compilerOptions.importHelpers) {
+        if (compilerOptions.importHelpers) {
             const sourceFile = getSourceFileOfNode(location);
             if (isEffectiveExternalModule(sourceFile, compilerOptions) && !(location.flags & NodeFlags.Ambient)) {
                 const helpersModule = resolveHelpersModule(sourceFile, location);
                 if (helpersModule !== unknownSymbol) {
-                    const uncheckedHelpers = helpers & ~requestedExternalEmitHelpers;
-                    for (let helper = ExternalEmitHelpers.FirstEmitHelper; helper <= ExternalEmitHelpers.LastEmitHelper; helper <<= 1) {
-                        if (uncheckedHelpers & helper) {
-                            for (const name of getHelperNames(helper)) {
-                                if (requestedExternalEmitHelperNames.has(name)) continue;
-                                requestedExternalEmitHelperNames.add(name);
-
-                                const symbol = resolveSymbol(getSymbol(getExportsOfModule(helpersModule), escapeLeadingUnderscores(name), SymbolFlags.Value));
-                                if (!symbol) {
-                                    error(location, Diagnostics.This_syntax_requires_an_imported_helper_named_1_which_does_not_exist_in_0_Consider_upgrading_your_version_of_0, externalHelpersModuleNameText, name);
-                                }
-                                else if (helper & ExternalEmitHelpers.ClassPrivateFieldGet) {
-                                    if (!some(getSignaturesOfSymbol(symbol), signature => getParameterCount(signature) > 3)) {
-                                        error(location, Diagnostics.This_syntax_requires_an_imported_helper_named_1_with_2_parameters_which_is_not_compatible_with_the_one_in_0_Consider_upgrading_your_version_of_0, externalHelpersModuleNameText, name, 4);
+                    const links = getSymbolLinks(helpersModule);
+                    links.requestedExternalEmitHelpers ??= 0 as ExternalEmitHelpers;
+                    if ((links.requestedExternalEmitHelpers & helpers) !== helpers) {
+                        const uncheckedHelpers = helpers & ~links.requestedExternalEmitHelpers;
+                        for (let helper = ExternalEmitHelpers.FirstEmitHelper; helper <= ExternalEmitHelpers.LastEmitHelper; helper <<= 1) {
+                            if (uncheckedHelpers & helper) {
+                                for (const name of getHelperNames(helper)) {
+                                    const symbol = resolveSymbol(getSymbol(getExportsOfModule(helpersModule), escapeLeadingUnderscores(name), SymbolFlags.Value));
+                                    if (!symbol) {
+                                        error(location, Diagnostics.This_syntax_requires_an_imported_helper_named_1_which_does_not_exist_in_0_Consider_upgrading_your_version_of_0, externalHelpersModuleNameText, name);
                                     }
-                                }
-                                else if (helper & ExternalEmitHelpers.ClassPrivateFieldSet) {
-                                    if (!some(getSignaturesOfSymbol(symbol), signature => getParameterCount(signature) > 4)) {
-                                        error(location, Diagnostics.This_syntax_requires_an_imported_helper_named_1_with_2_parameters_which_is_not_compatible_with_the_one_in_0_Consider_upgrading_your_version_of_0, externalHelpersModuleNameText, name, 5);
+                                    else if (helper & ExternalEmitHelpers.ClassPrivateFieldGet) {
+                                        if (!some(getSignaturesOfSymbol(symbol), signature => getParameterCount(signature) > 3)) {
+                                            error(location, Diagnostics.This_syntax_requires_an_imported_helper_named_1_with_2_parameters_which_is_not_compatible_with_the_one_in_0_Consider_upgrading_your_version_of_0, externalHelpersModuleNameText, name, 4);
+                                        }
                                     }
-                                }
-                                else if (helper & ExternalEmitHelpers.SpreadArray) {
-                                    if (!some(getSignaturesOfSymbol(symbol), signature => getParameterCount(signature) > 2)) {
-                                        error(location, Diagnostics.This_syntax_requires_an_imported_helper_named_1_with_2_parameters_which_is_not_compatible_with_the_one_in_0_Consider_upgrading_your_version_of_0, externalHelpersModuleNameText, name, 3);
+                                    else if (helper & ExternalEmitHelpers.ClassPrivateFieldSet) {
+                                        if (!some(getSignaturesOfSymbol(symbol), signature => getParameterCount(signature) > 4)) {
+                                            error(location, Diagnostics.This_syntax_requires_an_imported_helper_named_1_with_2_parameters_which_is_not_compatible_with_the_one_in_0_Consider_upgrading_your_version_of_0, externalHelpersModuleNameText, name, 5);
+                                        }
+                                    }
+                                    else if (helper & ExternalEmitHelpers.SpreadArray) {
+                                        if (!some(getSignaturesOfSymbol(symbol), signature => getParameterCount(signature) > 2)) {
+                                            error(location, Diagnostics.This_syntax_requires_an_imported_helper_named_1_with_2_parameters_which_is_not_compatible_with_the_one_in_0_Consider_upgrading_your_version_of_0, externalHelpersModuleNameText, name, 3);
+                                        }
                                     }
                                 }
                             }
                         }
                     }
+                    links.requestedExternalEmitHelpers |= helpers;
                 }
-                requestedExternalEmitHelpers |= helpers;
             }
         }
     }
@@ -49606,10 +49604,11 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
     }
 
     function resolveHelpersModule(file: SourceFile, errorNode: Node) {
-        if (!externalHelpersModule) {
-            externalHelpersModule = resolveExternalModule(getImportHelpersImportSpecifier(file), externalHelpersModuleNameText, Diagnostics.This_syntax_requires_an_imported_helper_but_module_0_cannot_be_found, errorNode) || unknownSymbol;
+        const links = getNodeLinks(file);
+        if (!links.externalHelpersModule) {
+            links.externalHelpersModule = resolveExternalModule(getImportHelpersImportSpecifier(file), externalHelpersModuleNameText, Diagnostics.This_syntax_requires_an_imported_helper_but_module_0_cannot_be_found, errorNode) || unknownSymbol;
         }
-        return externalHelpersModule;
+        return links.externalHelpersModule;
     }
 
     // GRAMMAR CHECKING

src/compiler/types.ts

@@ -5953,6 +5953,7 @@ export interface SymbolLinks {
     tupleLabelDeclaration?: NamedTupleMember | ParameterDeclaration; // Declaration associated with the tuple's label
     accessibleChainCache?: Map<string, Symbol[] | undefined>;
     filteredIndexSymbolCache?: Map<string, Symbol> //Symbol with applicable declarations
+    requestedExternalEmitHelpers?: ExternalEmitHelpers; // External emit helpers already checked for this symbol.
 }
 
 // dprint-ignore
@@ -6139,6 +6140,7 @@ export interface NodeLinks {
     parameterInitializerContainsUndefined?: boolean; // True if this is a parameter declaration whose type annotation contains "undefined".
     fakeScopeForSignatureDeclaration?: "params" | "typeParams"; // If present, this is a fake scope injected into an enclosing declaration chain.
     assertionExpressionType?: Type;     // Cached type of the expression of a type assertion
+    externalHelpersModule?: Symbol;     // Resolved symbol for the external helpers module
 }
 
 /** @internal */

tests/baselines/reference/esModuleInteropTslibHelpers.errors.txt

@@ -1,4 +1,6 @@
 file2.ts(1,1): error TS2354: This syntax requires an imported helper but module 'tslib' cannot be found.
+file3.ts(1,9): error TS2354: This syntax requires an imported helper but module 'tslib' cannot be found.
+file4.ts(1,14): error TS2354: This syntax requires an imported helper but module 'tslib' cannot be found.
 
 
 ==== refs.d.ts (0 errors) ====
@@ -13,11 +15,15 @@ file2.ts(1,1): error TS2354: This syntax requires an imported helper but module
 !!! error TS2354: This syntax requires an imported helper but module 'tslib' cannot be found.
     path.resolve("", "../");
     export class Foo2 { }
-==== file3.ts (0 errors) ====
+==== file3.ts (1 errors) ====
     import {default as resolve} from "path";
+            ~~~~~~~~~~~~~~~~~~
+!!! error TS2354: This syntax requires an imported helper but module 'tslib' cannot be found.
     resolve("", "../");
     export class Foo3 { }
-==== file4.ts (0 errors) ====
+==== file4.ts (1 errors) ====
     import {Bar, default as resolve} from "path";
+                 ~~~~~~~~~~~~~~~~~~
+!!! error TS2354: This syntax requires an imported helper but module 'tslib' cannot be found.
     resolve("", "../");
     export { Bar }

tests/baselines/reference/tslibMissingHelper.errors.txt

@@ -0,0 +1,36 @@
+/package1/index.ts(2,16): error TS2343: This syntax requires an imported helper named '__awaiter' which does not exist in 'tslib'. Consider upgrading your version of 'tslib'.
+
+
+==== /tsconfig.json (0 errors) ====
+    {
+        "compilerOptions": {
+            "strict": true,
+            "target": "ES2016",
+            "importHelpers": true,
+            "module": "commonjs",
+        }
+    }
+
+==== /package1/index.ts (1 errors) ====
+    export {};
+    async function foo(): Promise<void> {}
+                   ~~~
+!!! error TS2343: This syntax requires an imported helper named '__awaiter' which does not exist in 'tslib'. Consider upgrading your version of 'tslib'.
+    async function bar(): Promise<void> {}
+
+==== /package2/index.ts (0 errors) ====
+    export {};
+    async function foo(): Promise<void> {}
+
+==== /node_modules/tslib/package.json (0 errors) ====
+    {
+        "name": "tslib",
+        "main": "tslib.js",
+        "typings": "tslib.d.ts"
+    }
+
+==== /node_modules/tslib/tslib.d.ts (0 errors) ====
+    export const notAHelper: any;
+
+==== /node_modules/tslib/tslib.js (0 errors) ====
+    module.exports.notAHelper = 3;

tests/baselines/reference/tslibMissingHelper.js

@@ -0,0 +1,41 @@
+//// [tests/cases/compiler/tslibMissingHelper.ts] ////
+
+//// [package.json]
+{
+    "name": "tslib",
+    "main": "tslib.js",
+    "typings": "tslib.d.ts"
+}
+
+//// [tslib.d.ts]
+export const notAHelper: any;
+
+//// [tslib.js]
+module.exports.notAHelper = 3;
+//// [index.ts]
+export {};
+async function foo(): Promise<void> {}
+async function bar(): Promise<void> {}
+
+//// [index.ts]
+export {};
+async function foo(): Promise<void> {}
+
+
+//// [index.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+const tslib_1 = require("tslib");
+function foo() {
+    return tslib_1.__awaiter(this, void 0, void 0, function* () { });
+}
+function bar() {
+    return tslib_1.__awaiter(this, void 0, void 0, function* () { });
+}
+//// [index.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+const tslib_1 = require("tslib");
+function foo() {
+    return tslib_1.__awaiter(this, void 0, void 0, function* () { });
+}

tests/baselines/reference/tslibMissingHelper.symbols

@@ -0,0 +1,22 @@
+//// [tests/cases/compiler/tslibMissingHelper.ts] ////
+
+=== /package1/index.ts ===
+export {};
+async function foo(): Promise<void> {}
+>foo : Symbol(foo, Decl(index.ts, 0, 10))
+>Promise : Symbol(Promise, Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.promise.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+
+async function bar(): Promise<void> {}
+>bar : Symbol(bar, Decl(index.ts, 1, 38))
+>Promise : Symbol(Promise, Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.promise.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+
+=== /package2/index.ts ===
+export {};
+async function foo(): Promise<void> {}
+>foo : Symbol(foo, Decl(index.ts, 0, 10))
+>Promise : Symbol(Promise, Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.promise.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+
+=== /node_modules/tslib/tslib.d.ts ===
+export const notAHelper: any;
+>notAHelper : Symbol(notAHelper, Decl(tslib.d.ts, --, --))
+

tests/baselines/reference/tslibMissingHelper.types

@@ -0,0 +1,23 @@
+//// [tests/cases/compiler/tslibMissingHelper.ts] ////
+
+=== /package1/index.ts ===
+export {};
+async function foo(): Promise<void> {}
+>foo : () => Promise<void>
+>    : ^^^^^^             
+
+async function bar(): Promise<void> {}
+>bar : () => Promise<void>
+>    : ^^^^^^             
+
+=== /package2/index.ts ===
+export {};
+async function foo(): Promise<void> {}
+>foo : () => Promise<void>
+>    : ^^^^^^             
+
+=== /node_modules/tslib/tslib.d.ts ===
+export const notAHelper: any;
+>notAHelper : any
+>           : ^^^
+

tests/baselines/reference/tslibMultipleMissingHelper.errors.txt

@@ -0,0 +1,62 @@
+/package1/index.ts(2,16): error TS2343: This syntax requires an imported helper named '__awaiter' which does not exist in 'tslib'. Consider upgrading your version of 'tslib'.
+/package1/other.ts(3,32): error TS2343: This syntax requires an imported helper named '__rest' which does not exist in 'tslib'. Consider upgrading your version of 'tslib'.
+/package2/index.ts(2,16): error TS2343: This syntax requires an imported helper named '__awaiter' which does not exist in 'tslib'. Consider upgrading your version of 'tslib'.
+
+
+==== /tsconfig.json (0 errors) ====
+    {
+        "compilerOptions": {
+            "strict": true,
+            "target": "ES2016",
+            "importHelpers": true,
+            "module": "commonjs",
+        }
+    }
+
+==== /package1/index.ts (1 errors) ====
+    export {};
+    async function foo(): Promise<void> {}
+                   ~~~
+!!! error TS2343: This syntax requires an imported helper named '__awaiter' which does not exist in 'tslib'. Consider upgrading your version of 'tslib'.
+    async function bar(): Promise<void> {}
+
+==== /package1/other.ts (1 errors) ====
+    export {};
+    export async function noop(): Promise<void> {}
+    export function spread({ a, ...rest }: { a: number, b: number}) {
+                                   ~~~~
+!!! error TS2343: This syntax requires an imported helper named '__rest' which does not exist in 'tslib'. Consider upgrading your version of 'tslib'.
+        return { c: "c", ...rest };
+    }
+
+==== /package2/index.ts (1 errors) ====
+    export {};
+    async function foo(): Promise<void> {}
+                   ~~~
+!!! error TS2343: This syntax requires an imported helper named '__awaiter' which does not exist in 'tslib'. Consider upgrading your version of 'tslib'.
+
+==== /package1/node_modules/tslib/package.json (0 errors) ====
+    {
+        "name": "tslib",
+        "main": "tslib.js",
+        "typings": "tslib.d.ts"
+    }
+
+==== /package1/node_modules/tslib/tslib.d.ts (0 errors) ====
+    export const notAHelper: any;
+
+==== /package1/node_modules/tslib/tslib.js (0 errors) ====
+    module.exports.notAHelper = 3;
+
+==== /package2/node_modules/tslib/package.json (0 errors) ====
+    {
+        "name": "tslib",
+        "main": "tslib.js",
+        "typings": "tslib.d.ts"
+    }
+
+==== /package2/node_modules/tslib/tslib.d.ts (0 errors) ====
+    export const notAHelper: any;
+
+==== /package2/node_modules/tslib/tslib.js (0 errors) ====
+    module.exports.notAHelper = 3;