Allow untyped imports

src/compiler/checker.ts

@@ -1069,7 +1069,7 @@ namespace ts {
             const moduleSymbol = resolveExternalModuleName(node, (<ImportDeclaration>node.parent).moduleSpecifier);
 
             if (moduleSymbol) {
-                const exportDefaultSymbol = isShorthandAmbientModuleSymbol(moduleSymbol) ?
+                const exportDefaultSymbol = isUntypedModuleSymbol(moduleSymbol) ?
                     moduleSymbol :
                     moduleSymbol.exports["export="] ?
                         getPropertyOfType(getTypeOfSymbol(moduleSymbol.exports["export="]), "default") :
@@ -1145,7 +1145,7 @@ namespace ts {
             if (targetSymbol) {
                 const name = specifier.propertyName || specifier.name;
                 if (name.text) {
-                    if (isShorthandAmbientModuleSymbol(moduleSymbol)) {
+                    if (isUntypedModuleSymbol(moduleSymbol)) {
                         return moduleSymbol;
                     }
 
@@ -1365,8 +1365,9 @@ namespace ts {
             }
 
             const isRelative = isExternalModuleNameRelative(moduleName);
+            const quotedName = '"' + moduleName + '"';
             if (!isRelative) {
-                const symbol = getSymbol(globals, '"' + moduleName + '"', SymbolFlags.ValueModule);
+                const symbol = getSymbol(globals, quotedName, SymbolFlags.ValueModule);
                 if (symbol) {
                     // merged symbol is module declaration symbol combined with all augmentations
                     return getMergedSymbol(symbol);
@@ -1395,6 +1396,28 @@ namespace ts {
                 }
             }
 
+             // May be an untyped module. If so, ignore resolutionDiagnostic.
+            if (!isRelative && resolvedModule && !extensionIsTypeScript(resolvedModule.extension)) {
+                if (compilerOptions.noImplicitAny) {
+                    if (moduleNotFoundError) {
+                        error(errorNode,
+                            Diagnostics.Could_not_find_a_declaration_file_for_module_0_1_implicitly_has_an_any_type,
+                            moduleReference,
+                            resolvedModule.resolvedFileName);
+                    }
+                    return undefined;
+                }
+
+                // Create a new symbol to represent the untyped module and store it in globals.
+                // This provides a name to the module. See the test tests/cases/fourslash/untypedModuleImport.ts
+                const newSymbol = createSymbol(SymbolFlags.ValueModule, quotedName);
+                // Module symbols are expected to have 'exports', although since this is an untyped module it can be empty.
+                newSymbol.exports = createMap<Symbol>();
+                // Cache it so subsequent accesses will return the same module.
+                globals[quotedName] = newSymbol;
+                return newSymbol;
+            }
+
             if (moduleNotFoundError) {
                 // report errors only if it was requested
                 if (resolutionDiagnostic) {
@@ -3462,7 +3485,7 @@ namespace ts {
         function getTypeOfFuncClassEnumModule(symbol: Symbol): Type {
             const links = getSymbolLinks(symbol);
             if (!links.type) {
-                if (symbol.valueDeclaration.kind === SyntaxKind.ModuleDeclaration && isShorthandAmbientModuleSymbol(symbol)) {
+                if (symbol.flags & SymbolFlags.Module && isUntypedModuleSymbol(symbol)) {
                     links.type = anyType;
                 }
                 else {
@@ -19011,7 +19034,7 @@ namespace ts {
 
         function moduleExportsSomeValue(moduleReferenceExpression: Expression): boolean {
             let moduleSymbol = resolveExternalModuleName(moduleReferenceExpression.parent, moduleReferenceExpression);
-            if (!moduleSymbol || isShorthandAmbientModuleSymbol(moduleSymbol)) {
+            if (!moduleSymbol || isUntypedModuleSymbol(moduleSymbol)) {
                 // If the module is not found or is shorthand, assume that it may export a value.
                 return true;
             }
@@ -19512,7 +19535,7 @@ namespace ts {
                             (typeReferenceDirectives || (typeReferenceDirectives = [])).push(typeReferenceDirective);
                         }
                         else {
-                            // found at least one entry that does not originate from type reference directive 
+                            // found at least one entry that does not originate from type reference directive
                             return undefined;
                         }
                     }

src/compiler/diagnosticMessages.json

@@ -2901,6 +2901,10 @@
         "category": "Error",
         "code": 7015
     },
+    "Could not find a declaration file for module '{0}'. '{1}' implicitly has an 'any' type.": {
+        "category": "Error",
+        "code": 7016
+    },
     "Index signature of object type implicitly has an 'any' type.": {
         "category": "Error",
         "code": 7017

src/compiler/program.ts

@@ -1324,6 +1324,7 @@ namespace ts {
                     // - it's not a top level JavaScript module that exceeded the search max
                     const elideImport = isJsFileFromNodeModules && currentNodeModulesDepth > maxNodeModuleJsDepth;
                     // Don't add the file if it has a bad extension (e.g. 'tsx' if we don't have '--allowJs')
+                    // This may still end up being an untyped module -- the file won't be included but imports will be allowed.
                     const shouldAddFile = resolvedFileName && !getResolutionDiagnostic(options, resolution) && !options.noResolve && i < file.imports.length && !elideImport;
 
                     if (elideImport) {
@@ -1571,8 +1572,9 @@ namespace ts {
 
     /* @internal */
     /**
-     * Returns a DiagnosticMessage if we can't use a resolved module due to its extension.
+     * Returns a DiagnosticMessage if we won't include a resolved module due to its extension.
      * The DiagnosticMessage's parameters are the imported module name, and the filename it resolved to.
+     * This returns a diagnostic even if the module will be an untyped module.
      */
     export function getResolutionDiagnostic(options: CompilerOptions, { extension }: ResolvedModule): DiagnosticMessage | undefined {
         switch (extension) {

src/compiler/utilities.ts

@@ -406,8 +406,9 @@ namespace ts {
             ((<ModuleDeclaration>node).name.kind === SyntaxKind.StringLiteral || isGlobalScopeAugmentation(<ModuleDeclaration>node));
     }
 
-    export function isShorthandAmbientModuleSymbol(moduleSymbol: Symbol): boolean {
-        return isShorthandAmbientModule(moduleSymbol.valueDeclaration);
+    /** Given a symbol for a module, checks that it is either an untyped import or a shorthand ambient module. */
+    export function isUntypedModuleSymbol(moduleSymbol: Symbol): boolean {
+        return !moduleSymbol.valueDeclaration || isShorthandAmbientModule(moduleSymbol.valueDeclaration);
     }
 
     function isShorthandAmbientModule(node: Node): boolean {

src/harness/harness.ts

@@ -1108,22 +1108,7 @@ namespace Harness {
                     const option = getCommandLineOption(name);
                     if (option) {
                         const errors: ts.Diagnostic[] = [];
-                        switch (option.type) {
-                            case "boolean":
-                                options[option.name] = value.toLowerCase() === "true";
-                                break;
-                            case "string":
-                                options[option.name] = value;
-                                break;
-                            // If not a primitive, the possible types are specified in what is effectively a map of options.
-                            case "list":
-                                options[option.name] = ts.parseListTypeOption(<ts.CommandLineOptionOfListType>option, value, errors);
-                                break;
-                            default:
-                                options[option.name] = ts.parseCustomTypeOption(<ts.CommandLineOptionOfCustomType>option, value, errors);
-                                break;
-                        }
-
+                        options[option.name] = optionValue(option, value, errors);
                         if (errors.length > 0) {
                             throw new Error(`Unknown value '${value}' for compiler option '${name}'.`);
                         }
@@ -1135,6 +1120,27 @@ namespace Harness {
             }
         }
 
+        function optionValue(option: ts.CommandLineOption, value: string, errors: ts.Diagnostic[]): any {
+            switch (option.type) {
+                case "boolean":
+                    return value.toLowerCase() === "true";
+                case "string":
+                    return value;
+                case "number": {
+                    const number = parseInt(value, 10);
+                    if (isNaN(number)) {
+                        throw new Error(`Value must be a number, got: ${JSON.stringify(value)}`);
+                    }
+                    return number;
+                }
+                // If not a primitive, the possible types are specified in what is effectively a map of options.
+                case "list":
+                    return ts.parseListTypeOption(<ts.CommandLineOptionOfListType>option, value, errors);
+                default:
+                    return ts.parseCustomTypeOption(<ts.CommandLineOptionOfCustomType>option, value, errors);
+            }
+        }
+
         export interface TestFile {
             unitName: string;
             content: string;

tests/baselines/reference/untypedModuleImport.js

@@ -0,0 +1,37 @@
+//// [tests/cases/conformance/moduleResolution/untypedModuleImport.ts] ////
+
+//// [index.js]
+// This tests that importing from a JS file globally works in an untyped way.
+// (Assuming we don't have `--noImplicitAny` or `--allowJs`.)
+
+This file is not processed.
+
+//// [a.ts]
+import * as foo from "foo";
+foo.bar();
+
+//// [b.ts]
+import foo = require("foo");
+foo();
+
+//// [c.ts]
+import foo, { bar } from "foo";
+import "./a";
+import "./b";
+foo(bar());
+
+
+//// [a.js]
+"use strict";
+var foo = require("foo");
+foo.bar();
+//// [b.js]
+"use strict";
+var foo = require("foo");
+foo();
+//// [c.js]
+"use strict";
+var foo_1 = require("foo");
+require("./a");
+require("./b");
+foo_1["default"](foo_1.bar());

tests/baselines/reference/untypedModuleImport.symbols

@@ -0,0 +1,25 @@
+=== /c.ts ===
+import foo, { bar } from "foo";
+>foo : Symbol(foo, Decl(c.ts, 0, 6))
+>bar : Symbol(bar, Decl(c.ts, 0, 13))
+
+import "./a";
+import "./b";
+foo(bar());
+>foo : Symbol(foo, Decl(c.ts, 0, 6))
+>bar : Symbol(bar, Decl(c.ts, 0, 13))
+
+=== /a.ts ===
+import * as foo from "foo";
+>foo : Symbol(foo, Decl(a.ts, 0, 6))
+
+foo.bar();
+>foo : Symbol(foo, Decl(a.ts, 0, 6))
+
+=== /b.ts ===
+import foo = require("foo");
+>foo : Symbol(foo, Decl(b.ts, 0, 0))
+
+foo();
+>foo : Symbol(foo, Decl(b.ts, 0, 0))
+

tests/baselines/reference/untypedModuleImport.types

@@ -0,0 +1,31 @@
+=== /c.ts ===
+import foo, { bar } from "foo";
+>foo : any
+>bar : any
+
+import "./a";
+import "./b";
+foo(bar());
+>foo(bar()) : any
+>foo : any
+>bar() : any
+>bar : any
+
+=== /a.ts ===
+import * as foo from "foo";
+>foo : any
+
+foo.bar();
+>foo.bar() : any
+>foo.bar : any
+>foo : any
+>bar : any
+
+=== /b.ts ===
+import foo = require("foo");
+>foo : any
+
+foo();
+>foo() : any
+>foo : any
+

tests/baselines/reference/untypedModuleImport_allowJs.js

@@ -0,0 +1,16 @@
+//// [tests/cases/conformance/moduleResolution/untypedModuleImport_allowJs.ts] ////
+
+//// [index.js]
+// Same as untypedModuleImport.ts but with --allowJs, so the package will actually be typed.
+
+exports.default = { bar() { return 0; } }
+
+//// [a.ts]
+import foo from "foo";
+foo.bar();
+
+
+//// [a.js]
+"use strict";
+var foo_1 = require("foo");
+foo_1["default"].bar();

tests/baselines/reference/untypedModuleImport_allowJs.symbols

@@ -0,0 +1,17 @@
+=== /a.ts ===
+import foo from "foo";
+>foo : Symbol(foo, Decl(a.ts, 0, 6))
+
+foo.bar();
+>foo.bar : Symbol(bar, Decl(index.js, 2, 19))
+>foo : Symbol(foo, Decl(a.ts, 0, 6))
+>bar : Symbol(bar, Decl(index.js, 2, 19))
+
+=== /node_modules/foo/index.js ===
+// Same as untypedModuleImport.ts but with --allowJs, so the package will actually be typed.
+
+exports.default = { bar() { return 0; } }
+>exports : Symbol(default, Decl(index.js, 0, 0))
+>default : Symbol(default, Decl(index.js, 0, 0))
+>bar : Symbol(bar, Decl(index.js, 2, 19))
+

tests/baselines/reference/untypedModuleImport_allowJs.types

@@ -0,0 +1,22 @@
+=== /a.ts ===
+import foo from "foo";
+>foo : { bar(): number; }
+
+foo.bar();
+>foo.bar() : number
+>foo.bar : () => number
+>foo : { bar(): number; }
+>bar : () => number
+
+=== /node_modules/foo/index.js ===
+// Same as untypedModuleImport.ts but with --allowJs, so the package will actually be typed.
+
+exports.default = { bar() { return 0; } }
+>exports.default = { bar() { return 0; } } : { bar(): number; }
+>exports.default : any
+>exports : any
+>default : any
+>{ bar() { return 0; } } : { bar(): number; }
+>bar : () => number
+>0 : 0
+

tests/baselines/reference/untypedModuleImport_noImplicitAny.errors.txt

@@ -0,0 +1,13 @@
+/a.ts(1,22): error TS7016: Could not find a declaration file for module 'foo'. '/node_modules/foo/index.js' implicitly has an 'any' type.
+
+
+==== /a.ts (1 errors) ====
+    import * as foo from "foo";
+                         ~~~~~
+!!! error TS7016: Could not find a declaration file for module 'foo'. '/node_modules/foo/index.js' implicitly has an 'any' type.
+
+==== /node_modules/foo/index.js (0 errors) ====
+    // This tests that `--noImplicitAny` disables untyped modules.
+
+    This file is not processed.
+

tests/baselines/reference/untypedModuleImport_noImplicitAny.js

@@ -0,0 +1,13 @@
+//// [tests/cases/conformance/moduleResolution/untypedModuleImport_noImplicitAny.ts] ////
+
+//// [index.js]
+// This tests that `--noImplicitAny` disables untyped modules.
+
+This file is not processed.
+
+//// [a.ts]
+import * as foo from "foo";
+
+
+//// [a.js]
+"use strict";

tests/baselines/reference/untypedModuleImport_noLocalImports.errors.txt

@@ -0,0 +1,13 @@
+/a.ts(1,22): error TS6143: Module './foo' was resolved to '/foo.js', but '--allowJs' is not set.
+
+
+==== /a.ts (1 errors) ====
+    import * as foo from "./foo";
+                         ~~~~~~~
+!!! error TS6143: Module './foo' was resolved to '/foo.js', but '--allowJs' is not set.
+
+==== /foo.js (0 errors) ====
+    // This tests that untyped module imports don't happen with local imports.
+
+    This file is not processed.
+

tests/baselines/reference/untypedModuleImport_noLocalImports.js

@@ -0,0 +1,13 @@
+//// [tests/cases/conformance/moduleResolution/untypedModuleImport_noLocalImports.ts] ////
+
+//// [foo.js]
+// This tests that untyped module imports don't happen with local imports.
+
+This file is not processed.
+
+//// [a.ts]
+import * as foo from "./foo";
+
+
+//// [a.js]
+"use strict";