Webpack Failed to Compile after Typescript 2.3.1 upgrade

[omargon]

Getting the following error message on ng start or ng test after upgrading Typescript to 2.3.1

webpack: Failed to compile.

[karma]: Error: AppModule is not an NgModule               
    at Compiler.compiler.plugin (.../node_modules/@angular/cli/plugins/karma-webpack-throw-error.js:10:23)

Versions.

→ ng --version
    _                      _                 ____ _     ___
   / \   _ __   __ _ _   _| | __ _ _ __     / ___| |   |_ _|
  / △ \ | '_ \ / _` | | | | |/ _` | '__|   | |   | |    | |
 / ___ \| | | | (_| | |_| | | (_| | |      | |___| |___ | |
/_/   \_\_| |_|\__, |\__,_|_|\__,_|_|       \____|_____|___|
               |___/
@angular/cli: 1.0.1
node: 6.9.5
os: darwin x64
@angular/common: 4.1.0
@angular/compiler: 4.1.0
@angular/core: 4.1.0
@angular/forms: 4.1.0
@angular/http: 4.1.0
@angular/platform-browser: 4.1.0
@angular/platform-browser-dynamic: 4.1.0
@angular/router: 4.1.0
@angular/cli: 1.0.1
@angular/compiler-cli: 4.1.0

Repro steps.

Upgrade Typescript to 2.3.1

[clydin]

TS 2.3 is not yet supported. Version 2.2.x is the latest currently supported version.

[mmc41]

But Angular 4.1 clearly states that it supports 2.3 ! It is a quite confusing message that angular-cli is giving if it is not aligned with angular. Very annoying.

[teropa]

Downgrading TypeScript from 2.2.2 to 2.3.1 did the trick here. Using Yarn.

Interestingly, the whole problem only surfaced on Travis (running Linux), not locally on OS X. Nuking node_modules and the Yarn cache had no effect on the issue in either environment.

[filipesilva]

This is very weird. Will investigate.

[filipesilva]

On a brand new project, with everything Angular 4.1.1, CLI at 1.0.1 and typescript@2.3.2 I could not reproduce. I tried with npm and yarn.

Does someone have a repro I can follow to see this error?

[filipesilva]

Heya, can you try @angular/cli@1.1.0-beta.0? It should have TS 2.3.x support.

[omargon]

@filipesilva , I just tried with cli@1.1.0-beta.0 and still getting the same error reported initially.

ERROR in AppModule is not an NgModule
webpack: Failed to compile.

    _                      _                 ____ _     ___
   / \   _ __   __ _ _   _| | __ _ _ __     / ___| |   |_ _|
  / △ \ | '_ \ / _` | | | | |/ _` | '__|   | |   | |    | |
 / ___ \| | | | (_| | |_| | | (_| | |      | |___| |___ | |
/_/   \_\_| |_|\__, |\__,_|_|\__,_|_|       \____|_____|___|
               |___/
@angular/cli: 1.1.0-beta.0
node: 6.9.5
os: darwin x64
@angular/common: 4.1.1
@angular/compiler: 4.1.1
@angular/core: 4.1.1
@angular/forms: 4.1.1
@angular/http: 4.1.1
@angular/platform-browser: 4.1.1
@angular/platform-browser-dynamic: 4.1.1
@angular/router: 4.1.1
@angular/cli: 1.1.0-beta.0
@angular/compiler-cli: 4.1.1```