Sort the paths for module specifier by closeness to importing file path

src/compiler/moduleSpecifiers.ts

@@ -186,6 +186,18 @@ namespace ts.moduleSpecifiers {
         return result;
     }
 
+    function numberOfDirectorySeparators(str: string) {
+        const match = str.match(/\//g);
+        return match ? match.length : 0;
+    }
+
+    function comparePathsByNumberOfDirectrorySeparators(a: string, b: string) {
+        return compareValues(
+            numberOfDirectorySeparators(a),
+            numberOfDirectorySeparators(b)
+        );
+    }
+
     /**
      * Looks for existing imports that use symlinks to this module.
      * Symlinks will be returned first so they are preferred over the real path.
@@ -214,7 +226,32 @@ namespace ts.moduleSpecifiers {
             }
         });
         result.push(...targets);
-        return result;
+        if (result.length < 2) return result;
+
+        // Sort by paths closest to importing file Name directory
+        const allFileNames = arrayToMap(result, identity, getCanonicalFileName);
+        const sortedPaths: string[] = [];
+        for (
+            let directory = getDirectoryPath(toPath(importingFileName, cwd, getCanonicalFileName));
+            allFileNames.size !== 0;
+            directory = getDirectoryPath(directory)
+        ) {
+            const directoryStart = ensureTrailingDirectorySeparator(directory);
+            let pathsInDirectory: string[] | undefined;
+            allFileNames.forEach((canonicalFileName, fileName) => {
+                if (startsWith(canonicalFileName, directoryStart)) {
+                    (pathsInDirectory || (pathsInDirectory = [])).push(fileName);
+                    allFileNames.delete(fileName);
+                }
+            });
+            if (pathsInDirectory) {
+                if (pathsInDirectory.length > 1) {
+                    pathsInDirectory.sort(comparePathsByNumberOfDirectrorySeparators);
+                }
+                sortedPaths.push(...pathsInDirectory);
+            }
+        }
+        return sortedPaths;
     }
 
     function tryGetModuleNameFromAmbientModule(moduleSymbol: Symbol): string | undefined {

src/compiler/watch.ts

@@ -122,7 +122,11 @@ namespace ts {
     export function listFiles(program: ProgramToEmitFilesAndReportErrors, writeFileName: (s: string) => void) {
         if (program.getCompilerOptions().listFiles) {
             forEach(program.getSourceFiles(), file => {
-                writeFileName(file.fileName);
+                writeFileName(
+                    !file.redirectInfo ?
+                        file.fileName :
+                        `${file.fileName} -> ${file.redirectInfo.redirectTarget.fileName}`
+                );
             });
         }
     }

src/testRunner/tsconfig.json

@@ -109,6 +109,7 @@
         "unittests/tsbuild/transitiveReferences.ts",
         "unittests/tsbuild/watchEnvironment.ts",
         "unittests/tsbuild/watchMode.ts",
+        "unittests/tsc/declarationEmit.ts",
         "unittests/tscWatch/consoleClearing.ts",
         "unittests/tscWatch/emit.ts",
         "unittests/tscWatch/emitAndErrorUpdates.ts",

src/testRunner/unittests/tsc/declarationEmit.ts

@@ -0,0 +1,73 @@
+namespace ts {
+    describe("unittests:: tsc:: declarationEmit::", () => {
+        verifyTsc({
+            scenario: "declarationEmit",
+            subScenario: "when same version is referenced through source and another symlinked package",
+            fs: () => {
+                const fsaPackageJson = utils.dedent`
+                    {
+                        "name": "typescript-fsa",
+                        "version": "3.0.0-beta-2"
+                    }`;
+                const fsaIndex = utils.dedent`
+                    export interface Action<Payload> {
+                        type: string;
+                        payload: Payload;
+                    }
+                    export declare type ActionCreator<Payload> = {
+                        type: string;
+                        (payload: Payload): Action<Payload>;
+                    }
+                    export interface ActionCreatorFactory {
+                        <Payload = void>(type: string): ActionCreator<Payload>;
+                    }
+                    export declare function actionCreatorFactory(prefix?: string | null): ActionCreatorFactory;
+                    export default actionCreatorFactory;`;
+                return loadProjectFromFiles({
+                    "/plugin-two/index.d.ts": utils.dedent`
+                        declare const _default: {
+                            features: {
+                                featureOne: {
+                                    actions: {
+                                        featureOne: {
+                                            (payload: {
+                                                name: string;
+                                                order: number;
+                                            }, meta?: {
+                                                [key: string]: any;
+                                            }): import("typescript-fsa").Action<{
+                                                name: string;
+                                                order: number;
+                                            }>;
+                                        };
+                                    };
+                                    path: string;
+                                };
+                            };
+                        };
+                        export default _default;`,
+                    "/plugin-two/node_modules/typescript-fsa/package.json": fsaPackageJson,
+                    "/plugin-two/node_modules/typescript-fsa/index.d.ts": fsaIndex,
+                    "/plugin-one/tsconfig.json": utils.dedent`
+                        {
+                            "compilerOptions": {
+                                "target": "es5",
+                                "declaration": true,
+                            },
+                        }`,
+                    "/plugin-one/index.ts": utils.dedent`
+                        import pluginTwo from "plugin-two"; // include this to add reference to symlink`,
+                    "/plugin-one/action.ts": utils.dedent`
+                        import { actionCreatorFactory } from "typescript-fsa"; // Include version of shared lib
+                        const action = actionCreatorFactory("somekey");
+                        const featureOne = action<{ route: string }>("feature-one");
+                        export const actions = { featureOne };`,
+                    "/plugin-one/node_modules/typescript-fsa/package.json": fsaPackageJson,
+                    "/plugin-one/node_modules/typescript-fsa/index.d.ts": fsaIndex,
+                    "/plugin-one/node_modules/plugin-two": new vfs.Symlink("/plugin-two"),
+                });
+            },
+            commandLineArgs: ["-p", "plugin-one", "--listFiles"]
+        });
+    });
+}

tests/baselines/reference/tsc/declarationEmit/initial-build/when-same-version-is-referenced-through-source-and-another-symlinked-package.js

@@ -0,0 +1,37 @@
+//// [/lib/initial-buildOutput.txt]
+/lib/tsc -p plugin-one --listFiles
+/lib/lib.d.ts
+/plugin-one/node_modules/typescript-fsa/index.d.ts
+/plugin-one/action.ts
+/plugin-two/node_modules/typescript-fsa/index.d.ts -> /plugin-one/node_modules/typescript-fsa/index.d.ts
+/plugin-two/index.d.ts
+/plugin-one/index.ts
+exitCode:: 0
+
+
+//// [/plugin-one/action.d.ts]
+export declare const actions: {
+    featureOne: import("typescript-fsa").ActionCreator<{
+        route: string;
+    }>;
+};
+
+
+//// [/plugin-one/action.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+var typescript_fsa_1 = require("typescript-fsa"); // Include version of shared lib
+var action = typescript_fsa_1.actionCreatorFactory("somekey");
+var featureOne = action("feature-one");
+exports.actions = { featureOne: featureOne };
+
+
+//// [/plugin-one/index.d.ts]
+export {};
+
+
+//// [/plugin-one/index.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+
+