Finish lodash test case

src/compiler/checker.ts

@@ -41488,8 +41488,14 @@ namespace ts {
                     return isMetaProperty(node.parent) ? checkMetaPropertyKeyword(node.parent).symbol : undefined;
                 case SyntaxKind.MetaProperty:
                     return checkExpression(node as Expression).symbol;
+                case SyntaxKind.BinaryExpression:
+                    // See binary expression handling in `getDeclarationFromName`
+                    return getSymbolOfNode(node as BinaryExpression) || getSymbolOfNode((node as BinaryExpression).left);
 
                 default:
+                    if (isDeclaration(node)) {
+                        return getSymbolOfNode(node);
+                    }
                     return undefined;
             }
         }

src/server/session.ts

@@ -1285,12 +1285,40 @@ namespace ts.server {
             }
 
             let definitions = this.mapDefinitionInfoLocations(unmappedDefinitionAndBoundSpan.definitions, project).slice();
-            const needsJsResolution = every(definitions.filter(d => d.isAliasTarget), d => !!d.isAmbient) || some(definitions, d => !!d.failedAliasResolution);
+            const needsJsResolution = !some(definitions, d => !!d.isAliasTarget && !d.isAmbient) || some(definitions, d => !!d.failedAliasResolution);
             if (needsJsResolution) {
                 project.withAuxiliaryProjectForFiles([file], auxiliaryProject => {
-                    const jsDefinitions = auxiliaryProject.getLanguageService().getDefinitionAndBoundSpan(file, position);
-                    for (const jsDefinition of jsDefinitions?.definitions || emptyArray) {
-                        pushIfUnique(definitions, jsDefinition, (a, b) => a.fileName === b.fileName && a.textSpan.start === b.textSpan.start);
+                    const ls = auxiliaryProject.getLanguageService();
+                    const jsDefinitions = ls.getDefinitionAndBoundSpan(file, position, /*aliasesOnly*/ true);
+                    if (some(jsDefinitions?.definitions)) {
+                        for (const jsDefinition of jsDefinitions!.definitions) {
+                            pushIfUnique(definitions, jsDefinition, (a, b) => a.fileName === b.fileName && a.textSpan.start === b.textSpan.start);
+                        }
+                    }
+                    else {
+                        const ambientCandidates = definitions.filter(d => d.isAliasTarget && d.isAmbient);
+                        for (const candidate of ambientCandidates) {
+                            const candidateFileName = getEffectiveFileNameOfDefinition(candidate, project.getLanguageService().getProgram()!);
+                            if (candidateFileName) {
+                                const fileNameToSearch = findImplementationFileFromDtsFileName(candidateFileName, file, auxiliaryProject);
+                                const scriptInfo = fileNameToSearch ? auxiliaryProject.getScriptInfo(fileNameToSearch) : undefined;
+                                if (!scriptInfo) {
+                                    continue;
+                                }
+                                if (!auxiliaryProject.containsScriptInfo(scriptInfo)) {
+                                    auxiliaryProject.addRoot(scriptInfo);
+                                }
+                                const auxiliaryProgram = auxiliaryProject.getLanguageService().getProgram()!;
+                                const fileToSearch = Debug.checkDefined(auxiliaryProgram.getSourceFile(fileNameToSearch!));
+                                const matches = FindAllReferences.Core.getTopMostDeclarationsInFile(candidate.name, fileToSearch);
+                                for (const match of matches) {
+                                    const symbol = auxiliaryProgram.getTypeChecker().getSymbolAtLocation(match);
+                                    if (symbol) {
+                                        pushIfUnique(definitions, GoToDefinition.createDefinitionInfo(match, auxiliaryProgram.getTypeChecker(), symbol, match));
+                                    }
+                                }
+                            }
+                        }
                     }
                 });
             }
@@ -1309,6 +1337,72 @@ namespace ts.server {
                 definitions: definitions.map(Session.mapToOriginalLocation),
                 textSpan,
             };
+
+            function getEffectiveFileNameOfDefinition(definition: DefinitionInfo, program: Program) {
+                const sourceFile = program.getSourceFile(definition.fileName)!;
+                const checker = program.getTypeChecker();
+                const symbol = checker.getSymbolAtLocation(getTouchingPropertyName(sourceFile, definition.textSpan.start));
+                if (symbol) {
+                    let parent = symbol.parent;
+                    while (parent && !isExternalModuleSymbol(parent)) {
+                        parent = parent.parent;
+                    }
+                    if (parent?.declarations && some(parent.declarations, isExternalModuleAugmentation)) {
+                        // Always CommonJS right now, but who knows in the future
+                        const mode = getModeForUsageLocation(sourceFile, find(parent.declarations, isExternalModuleAugmentation)!.name as StringLiteral);
+                        const fileName = sourceFile.resolvedModules?.get(stripQuotes(parent.name), mode)?.resolvedFileName;
+                        if (fileName) {
+                            return fileName;
+                        }
+                    }
+                    const fileName = tryCast(parent?.valueDeclaration, isSourceFile)?.fileName;
+                    if (fileName) {
+                        return fileName;
+                    }
+                }
+            }
+
+            function findImplementationFileFromDtsFileName(fileName: string, resolveFromFile: string, auxiliaryProject: Project) {
+                const nodeModulesPathParts = getNodeModulePathParts(fileName);
+                if (nodeModulesPathParts && fileName.lastIndexOf(nodeModulesPathPart) === nodeModulesPathParts.topLevelNodeModulesIndex) {
+                    // Second check ensures the fileName only contains one `/node_modules/`. If there's more than one I give up.
+                    const packageDirectory = fileName.substring(0, nodeModulesPathParts.packageRootIndex);
+                    const packageJsonCache = project.getModuleResolutionCache()?.getPackageJsonInfoCache();
+                    const compilerOptions = project.getCompilationSettings();
+                    const packageJson = getPackageScopeForPath(project.toPath(packageDirectory + "/package.json"), packageJsonCache, project, compilerOptions);
+                    if (!packageJson) return undefined;
+                    // Use fake options instead of actual compiler options to avoid following export map if the project uses node12 or nodenext -
+                    // Mapping from an export map entry across packages is out of scope for now. Returned entrypoints will only be what can be
+                    // resolved from the package root under --moduleResolution node
+                    const entrypoints = getEntrypointsFromPackageJsonInfo(
+                        packageJson,
+                        { moduleResolution: ModuleResolutionKind.NodeJs },
+                        project,
+                        project.getModuleResolutionCache());
+                    // This substring is correct only because we checked for a single `/node_modules/` at the top.
+                    const packageNamePathPart = fileName.substring(
+                        nodeModulesPathParts.topLevelPackageNameIndex + 1,
+                        nodeModulesPathParts.packageRootIndex);
+                    const packageName = getPackageNameFromTypesPackageName(unmangleScopedPackageName(packageNamePathPart));
+                    const path = project.toPath(fileName);
+                    if (entrypoints && some(entrypoints, e => project.toPath(e) === path)) {
+                        // This file was the main entrypoint of a package. Try to resolve that same package name with
+                        // the auxiliary project that only resolves to implementation files.
+                        const [implementationResolution] = auxiliaryProject.resolveModuleNames([packageName], resolveFromFile);
+                        return implementationResolution?.resolvedFileName;
+                    }
+                    else {
+                        // It wasn't the main entrypoint but we are in node_modules. Try a subpath into the package.
+                        const pathToFileInPackage = fileName.substring(nodeModulesPathParts.packageRootIndex + 1);
+                        const specifier = `${packageName}/${removeFileExtension(pathToFileInPackage)}`;
+                        const [implementationResolution] = auxiliaryProject.resolveModuleNames([specifier], resolveFromFile);
+                        return implementationResolution?.resolvedFileName;
+                    }
+                }
+                // We're not in node_modules, and we only get to this function if non-dts module resolution failed.
+                // I'm not sure what else I can do here that isn't already covered by that module resolution.
+                return undefined;
+            }
         }
 
         private getEmitOutput(args: protocol.EmitOutputRequestArgs): EmitOutput | protocol.EmitOutput {

src/services/findAllReferences.ts

@@ -1333,6 +1333,30 @@ namespace ts.FindAllReferences {
             }
         }
 
+        export function getTopMostDeclarationsInFile(declarationName: string, sourceFile: SourceFile): readonly Declaration[] {
+            const candidates = mapDefined(getPossibleSymbolReferenceNodes(sourceFile, declarationName), getDeclarationFromName);
+            return candidates.reduce((topMost, decl) => {
+                const depth = getDepth(decl);
+                if (!some(topMost.declarations) || depth === topMost.depth) {
+                    topMost.declarations.push(decl);
+                }
+                else if (depth < topMost.depth) {
+                    topMost.declarations = [decl];
+                }
+                topMost.depth = depth;
+                return topMost;
+            }, { depth: Infinity, declarations: [] as Declaration[] }).declarations;
+
+            function getDepth(declaration: Declaration | undefined) {
+                let depth = 0;
+                while (declaration) {
+                    declaration = getContainerNode(declaration);
+                    depth++;
+                }
+                return depth;
+            }
+        }
+
         export function someSignatureUsage(
             signature: SignatureDeclaration,
             sourceFiles: readonly SourceFile[],

src/services/goToDefinition.ts

@@ -44,7 +44,7 @@ namespace ts.GoToDefinition {
         const { symbol, isAliasTarget, failedAliasResolution } = getSymbol(node, typeChecker);
         if (!symbol && isModuleSpecifierLike(node)) {
             // We couldn't resolve the symbol as an external module, but it could
-            // that module resolution succeeded but the target was not a module.
+            // be that module resolution succeeded but the target was not a module.
             const ref = sourceFile.resolvedModules?.get(node.text, getModeForUsageLocation(sourceFile, node));
             if (ref) {
                 return [{
@@ -379,7 +379,7 @@ namespace ts.GoToDefinition {
     }
 
     /** Creates a DefinitionInfo from a Declaration, using the declaration's name if possible. */
-    function createDefinitionInfo(declaration: Declaration, checker: TypeChecker, symbol: Symbol, node: Node, isAliasTarget?: boolean, failedAliasResolution?: boolean): DefinitionInfo {
+    export function createDefinitionInfo(declaration: Declaration, checker: TypeChecker, symbol: Symbol, node: Node, isAliasTarget?: boolean, failedAliasResolution?: boolean): DefinitionInfo {
         const symbolName = checker.symbolToString(symbol); // Do not get scoped name, just the name of the symbol
         const symbolKind = SymbolDisplay.getSymbolKind(checker, symbol, node);
         const containerName = symbol.parent ? checker.symbolToString(symbol.parent, node) : "";

tests/cases/fourslash/server/goToSource8_mapFromAtTypes.ts

@@ -0,0 +1,77 @@
+/// <reference path="../fourslash.ts" />
+
+// @moduleResolution: node
+
+// @Filename: /node_modules/lodash/package.json
+//// { "name": "lodash", "version": "4.17.15", "main": "./lodash.js" }
+
+// @Filename: /node_modules/lodash/lodash.js
+//// ;(function() {
+////     /**
+////      * Adds two numbers.
+////      *
+////      * @static
+////      * @memberOf _
+////      * @since 3.4.0
+////      * @category Math
+////      * @param {number} augend The first number in an addition.
+////      * @param {number} addend The second number in an addition.
+////      * @returns {number} Returns the total.
+////      * @example
+////      *
+////      * _.add(6, 4);
+////      * // => 10
+////      */
+////     var [|/*variable*/add|] = createMathOperation(function(augend, addend) {
+////      return augend + addend;
+////     }, 0);
+////
+////     function lodash(value) {}
+////     lodash.[|/*property*/add|] = add;
+////
+////     /** Detect free variable `global` from Node.js. */
+////     var freeGlobal = typeof global == 'object' && global && global.Object === Object && global;
+////     /** Detect free variable `self`. */
+////     var freeSelf = typeof self == 'object' && self && self.Object === Object && self;
+////     /** Used as a reference to the global object. */
+////     var root = freeGlobal || freeSelf || Function('return this')();
+////     /** Detect free variable `exports`. */
+////     var freeExports = typeof exports == 'object' && exports && !exports.nodeType && exports;////     
+////     /** Detect free variable `module`. */
+////     var freeModule = freeExports && typeof module == 'object' && module && !module.nodeType && module;
+////     if (freeModule) {
+////       // Export for Node.js.
+////       (freeModule.exports = _)._ = _;
+////       // Export for CommonJS support.
+////       freeExports._ = _;
+////     }
+////     else {
+////       // Export to the global object.
+////       root._ = _;
+////     }
+//// }.call(this));
+
+// @Filename: /node_modules/@types/lodash/package.json
+//// { "name": "@types/lodash", "version": "4.14.97", "types": "index.d.ts" }
+
+// @Filename: /node_modules/@types/lodash/index.d.ts
+//// /// <reference path="./common/math.d.ts" />
+//// export = _;
+//// export as namespace _;
+//// declare const _: _.LoDashStatic;
+//// declare namespace _ {
+////     interface LoDashStatic {}
+//// }
+
+// @Filename: /node_modules/@types/lodash/common/math.d.ts
+//// import _ = require("../index");
+//// declare module "../index" {
+////     interface LoDashStatic {
+////         add(augend: number, addend: number): number;
+////     }
+//// }
+
+// @Filename: /index.ts
+//// import { [|/*start*/add|] } from 'lodash';
+
+verify.goToSourceDefinition("start", ["variable", "property"]);