Error NG1006: Two incompatible decorators on class

Which @angular/* package(s) are the source of the bug?

forms

Is this a regression?

No

Description

I have an issue when compiling my project I googled the error and tried some of the things which were suggested to other people, but nothing worked.

I can’t figure out what’s wrong. can anyone help me out here? Here is my package.json file :

{
  "name": "book-store",
  "version": "1.0.0",
  "engines": {
    "node": "12.16.1",
    "npm": "6.14.5"
  },
  "scripts": {
    "ng": "ng",
    "heroku-postbuild": "ng build --prod",
    "start": "node server.js",
    "build": "ng build",
    "test": "ng test",
    "lint": "ng lint",
    "e2e": "ng e2e"
  },
  "private": true,
  "dependencies": {
    "@angular/animations": "^12.0.0-next.6",
    "@angular/cdk": "^11.2.6",
    "@angular/common": "^12.0.0-next.6",
    "@angular/compiler": "^12.0.0-next.6",
    "@angular/core": "^12.0.0-next.6",
    "@angular/flex-layout": "^9.0.0-beta.31",
    "@angular/forms": "^12.2.16",
    "@angular/material": "^11.2.6",
    "@angular/platform-browser": "^12.0.0-next.6",
    "@angular/platform-browser-dynamic": "^12.0.0-next.6",
    "@angular/router": "^12.0.0-next.6",
    "@ng-bootstrap/ng-bootstrap": "^12.0.2",
    "@ngtools/webpack": "^9.1.15",
    "bootstrap": "^5.1.3",
    "express": "^4.17.1",
    "path": "^0.12.7",
    "rxjs": "~6.6.7",
    "tslib": "^1.14.1",
    "typescript": "~4.2.3",
    "undo": "^0.1.4",
    "zone.js": "~0.11.4"
  },
  "devDependencies": {
    "@angular-devkit/build-angular": "^0.1102.6",
    "@angular/cli": "^11.2.6",
    "@angular/compiler-cli": "^12.0.0-next.6",
    "@angular/language-service": "^12.0.0-next.6",
    "@types/jasmine": "^3.6.9",
    "@types/jasminewd2": "~2.0.3",
    "@types/node": "^12.20.7",
    "codelyzer": "^5.1.2",
    "jasmine-core": "~3.5.0",
    "jasmine-spec-reporter": "~4.2.1",
    "karma": "^5.2.3",
    "karma-chrome-launcher": "~3.1.0",
    "karma-coverage-istanbul-reporter": "~2.1.0",
    "karma-jasmine": "~2.0.1",
    "karma-jasmine-html-reporter": "^1.5.4",
    "protractor": "^7.0.0",
    "ts-node": "~8.3.0",
    "tslint": "~6.1.3" 
  }
}

Please provide a link to a minimal reproduction of the bug

No response

Please provide the exception or error you saw

PS C:\Users\hasna\Downloads\A La Marocaine git - Copie\ALaMarocaineFinal\frontend\src\app> ng serve

Compiling @angular/forms : es2015 as esm2015
An unhandled exception occurred: Failed to compile entry-point @angular/forms (`es2015` as esm2015) due to compilation errors:
../../node_modules/@angular/forms/fesm2015/forms.js:6219:1 - error NG1006: Two incompatible decorators on class

6219 class MaxValidator extends AbstractValidatorDirective {
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
6220     constructor() {
     ~~~~~~~~~~~~~~~~~~~
 ... 
6237     }
     ~~~~~
6238 }
     ~
../../node_modules/@angular/forms/fesm2015/forms.js:6279:1 - error NG1006: Two incompatible decorators on class

6279 class MinValidator extends AbstractValidatorDirective {
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
6280     constructor() {
     ~~~~~~~~~~~~~~~~~~~
 ...
6297     }
     ~~~~~
6298 }
     ~
../../node_modules/@angular/forms/fesm2015/forms.js:6758:31 - error NG6001: The class 'MinValidator' is listed in the declarations of the NgModule 'ɵInternalFormsSharedModule', but is not a directive, a component, or a pipe. Either remove it from the NgModule's declarations, or add an appropriate Angular decorator.

6758                 declarations: SHARED_FORM_DIRECTIVES,
                                   ~~~~~~~~~~~~~~~~~~~~~~

  ../../node_modules/@angular/forms/fesm2015/forms.js:6279:7
    6279 class MinValidator extends AbstractValidatorDirective {
               ~~~~~~~~~~~~
    'MinValidator' is declared here.
../../node_modules/@angular/forms/fesm2015/forms.js:6758:31 - error NG6001: The class 'MaxValidator' is listed in the declarations of the NgModule 'ɵInternalFormsSharedModule', but is not a directive, a component, or a pipe. Either remove it from the NgModule's declarations, or add an appropriate Angular decorator.

6758                 declarations: SHARED_FORM_DIRECTIVES,
                                   ~~~~~~~~~~~~~~~~~~~~~~

  ../../node_modules/@angular/forms/fesm2015/forms.js:6219:7
    6219 class MaxValidator extends AbstractValidatorDirective {
               ~~~~~~~~~~~~
    'MaxValidator' is declared here.
../../node_modules/@angular/forms/fesm2015/forms.js:6279:7 - error NG6003: Appears in the NgModule.exports of ɵInternalFormsSharedModule, but could not be resolved to an NgModule, Component, Directive, or Pipe class.

Is it missing an Angular annotation?

6279 class MinValidator extends AbstractValidatorDirective {
           ~~~~~~~~~~~~
../../node_modules/@angular/forms/fesm2015/forms.js:6219:7 - error NG6003: Appears in the NgModule.exports of ɵInternalFormsSharedModule, but could not be resolved to an NgModule, Component, Directive, or Pipe class.

Is it missing an Angular annotation?

6219 class MaxValidator extends AbstractValidatorDirective {
           ~~~~~~~~~~~~
../../node_modules/@angular/forms/fesm2015/forms.js:6754:7 - error NG6003: Appears in the NgModule.exports of FormsModule, but itself has errors

6754 class ɵInternalFormsSharedModule {
           ~~~~~~~~~~~~~~~~~~~~~~~~~~
../../node_modules/@angular/forms/fesm2015/forms.js:6754:7 - error NG6003: Appears in the NgModule.exports of ReactiveFormsModule, but itself has errors

6754 class ɵInternalFormsSharedModule {
           ~~~~~~~~~~~~~~~~~~~~~~~~~~

See "C:\Users\hasna\AppData\Local\Temp\ng-xVPSqM\angular-errors.log" for further details.

Please provide the environment you discovered this bug in (run ng version)

Angular CLI: 13.3.0
Node: 16.14.2
Package Manager: npm 6.14.17
OS: win32 x64

Angular: undefined
...

Package                      Version
------------------------------------------------------
@angular-devkit/architect    0.1303.0 (cli-only)
@angular-devkit/core         13.3.0 (cli-only)
@angular-devkit/schematics   13.3.0 (cli-only)
@schematics/angular          13.3.0 (cli-only)

Anything else?

No response

[JoostK]

Other than that this isn’t actionable for us, so I’m going to close this. Feel free to follow up below though.

[JoostK]

I’d suggest clearing node_modules and reinstalling packages, as this seems like a transient issue. I’d also recommend to go over the project’s dependencies as the currently listed versions in package.json are very misaligned; for example the Angular framework packages, the CLI and Material/CDK need to all be the same major version, but they’re a mix of 12, 11 and 9. If the project structure is not too complicated you may want to consider creating a new project from scratch and moving your existing code.