@stryker-mutator/typescript-checker is incompatible with TypeScript 3.7

[nicojs]

Summary

As reported by @LayZeeDK here: #2548 (comment)

After I added back the TypeScript Checker, this error is reported:

    19:38:51 (3931) ERROR Stryker Error: Error: An error occurred during initialization of the "typescript" checker. Inner error: Error: TypeScript error(s) found in dry run compilation: ../../node_modules/@stryker-mutator/api/src/core/range.d.ts(4,36): error TS1005: ',' expected.\n
    ../../node_modules/@stryker-mutator/api/src/core/range.d.ts(4,57): error TS1005: ',' expected.

    Error: TypeScript error(s) found in dry run compilation: ../../node_modules/@stryker-mutator/api/src/core/range.d.ts(4,36): error TS1005: ',' expected.
    ../../node_modules/@stryker-mutator/api/src/core/range.d.ts(4,57): error TS1005: ',' expected.

        at TypescriptChecker.init (/home/runner/work/stryker/stryker/e2e/test/angular-project/node_modules/@stryker-mutator/typescript-checker/src/typescript-checker.ts:118:13)
        at processTicksAndRejections (internal/process/task_queues.js:97:5)
        at CheckerWorker.init (/home/runner/work/stryker/stryker/e2e/test/angular-project/node_modules/@stryker-mutator/core/src/checker/checker-worker.js:21:21
        at ChildProcessProxyWorker.handleCall (/home/runner/work/stryker/stryker/e2e/test/angular-project/node_modules/@stryker-mutator/core/src/child-proxy/child-process-proxy-worker.js:62:28)
    Error: An error occurred during initialization of the "typescript" checker. Inner error: Error: TypeScript error(s) found in dry run compilation: ../../node_modules/@stryker-mutator/api/src/core/range.d.ts(4,36): error TS1005: ',' expected.
    ../../node_modules/@stryker-mutator/api/src/core/range.d.ts(4,57): error TS1005: ',' expected.

    Error: TypeScript error(s) found in dry run compilation: ../../node_modules/@stryker-mutator/api/src/core/range.d.ts(4,36): error TS1005: ',' expected.
    ../../node_modules/@stryker-mutator/api/src/core/range.d.ts(4,57): error TS1005: ',' expected.

        at TypescriptChecker.init (/home/runner/work/stryker/stryker/e2e/test/angular-project/node_modules/@stryker-mutator/typescript-checker/src/typescript-checker.ts:118:13)
        at processTicksAndRejections (internal/process/task_queues.js:97:5)
        at CheckerWorker.init (/home/runner/work/stryker/stryker/e2e/test/angular-project/node_modules/@stryker-mutator/core/src/checker/checker-worker.js:21:21)
        at ChildProcessProxyWorker.handleCall (/home/runner/work/stryker/stryker/e2e/test/angular-project/node_modules/@stryker-mutator/core/src/child-proxy/child-process-proxy-worker.js:62:28)
        at CheckerWorker.init (/home/runner/work/stryker/stryker/e2e/test/angular-project/node_modules/@stryker-mutator/core/src/checker/checker-worker.js:24:27)
        at processTicksAndRejections (internal/process/task_queues.js:97:5)
        at ChildProcess.<anonymous> (/home/runner/work/stryker/stryker/e2e/test/angular-project/node_modules/@stryker-mutator/core/src/child-proxy/child-process-proxy.js:132:68)
        at ChildProcess.emit (events.js:315:20)
        at emit (internal/child_process.js:876:12)
        at processTicksAndRejections (internal/process/task_queues.js:85:21)

Remember that this project uses TypeScript version 3.7.5.

As seen in this TypeScript playground, range.ts is incompatible with TypeScript 3.7.

Labeled tuple elements were added in TypeScript 4.0, so range.ts is currently incompatible with e2e project using TypeScript <4.0.

// range.ts
/**
 * Represents a location in a file by range.
 */
type Range = [fromInclusive: number, toExclusive: number];

export default Range;

This is the declarations output in range.d.ts in @stryker-mutator/core v4.0.0:

// range.d.ts
/**
 * Represents a location in a file by range.
 */
declare type Range = [fromInclusive: number, toExclusive: number];
export default Range;
//# sourceMappingURL=Range.d.ts.map

Meaning TypeScript <4.0 is not supported for a bunch of the APIs.

TypeScript 4.0 is supported by Angular 10.1.

[nicojs]

I can't reproduce it with this simple example. Will try the e2e tests now.
Uploading ts3.7-example.zip…

[LayZeeDK]

I just tested in an Angular 9.0 + TypeScript 3.7 project with the following dependencies and configuration and it doesn't seem to be an issue outside of the stryker monorepo.

package.json

{
  "name": "ngx-stryker-cli900",
  "version": "0.0.0",
  "scripts": {
    "postinstall": "ngcc",
    "ng": "ng",
    "start": "ng serve",
    "build": "ng build",
    "test": "ng test",
    "lint": "ng lint",
    "e2e": "ng e2e"
  },
  "private": true,
  "dependencies": {
    "@angular/animations": "~9.0.0",
    "@angular/common": "~9.0.0",
    "@angular/compiler": "~9.0.0",
    "@angular/core": "~9.0.0",
    "@angular/forms": "~9.0.0",
    "@angular/platform-browser": "~9.0.0",
    "@angular/platform-browser-dynamic": "~9.0.0",
    "@angular/router": "~9.0.0",
    "rxjs": "~6.5.4",
    "tslib": "^1.10.0",
    "zone.js": "~0.10.2"
  },
  "devDependencies": {
    "@angular-devkit/build-angular": "~0.900.0",
    "@angular/cli": "~9.0.0",
    "@angular/compiler-cli": "~9.0.0",
    "@angular/language-service": "~9.0.0",
    "@stryker-mutator/core": "^4.0.0",
    "@stryker-mutator/karma-runner": "^4.0.0",
    "@stryker-mutator/typescript-checker": "^4.0.0",
    "@types/jasmine": "~3.5.0",
    "@types/jasminewd2": "~2.0.3",
    "@types/node": "^12.11.1",
    "codelyzer": "^5.1.2",
    "jasmine-core": "~3.5.0",
    "jasmine-spec-reporter": "~4.2.1",
    "karma": "~4.3.0",
    "karma-chrome-launcher": "~3.1.0",
    "karma-coverage-istanbul-reporter": "~2.1.0",
    "karma-jasmine": "~2.0.1",
    "karma-jasmine-html-reporter": "^1.4.2",
    "protractor": "~5.4.3",
    "ts-node": "~8.3.0",
    "tslint": "~5.18.0",
    "typescript": "~3.7.5"
  }
}

stryker.conf.json

{
  "$schema": "./node_modules/@stryker-mutator/core/schema/stryker-schema.json",
  "_comment": "This config was generated using a preset. Please see the handbook for more information: https://github.com/stryker-mutator/stryker-handbook/blob/master/stryker/guides/angular.md#angular",
  "mutate": [
    "src/**/*.ts",
    "!src/**/*.spec.ts",
    "!src/test.ts",
    "!src/environments/*.ts"
  ],
  "testRunner": "karma",
  "checkers": ["typescript"],
  "karma": {
    "configFile": "karma.conf.js",
    "projectType": "angular-cli",
    "config": {
      "browsers": ["ChromeHeadless"]
    }
  },
  "reporters": ["progress", "clear-text", "html"],
  "concurrency": 4,
  "concurrency_comment": "Recommended to use about half of your available cores when running stryker with angular",
  "coverageAnalysis": "perTest"
}

[nicojs]

Thanks. It is indeed the mono repo setup. We have the verify, which was used in the typescript compilation. See #2548 (comment) for more info.