error TS1086: An accessor cannot be declared in an ambient context in Angular 9

I'm learning Angular Material and I'm getting this error when importing { MatButtonModule } from "@angular/material/button".

From what I read in other answers, it looks like package compatibility issues but I couldn't fix it.

Here's the full error

ERROR in node_modules/@angular/cdk/a11y/focus-trap/focus-trap.d.ts(29,9): error TS1086: An accessor cannot be declared in an ambient context.
    node_modules/@angular/cdk/a11y/focus-trap/focus-trap.d.ts(30,9): error TS1086: An accessor cannot be declared in an ambient context.
    node_modules/@angular/cdk/a11y/focus-trap/focus-trap.d.ts(128,9): error TS1086: An accessor cannot be declared in an ambient context.
    node_modules/@angular/cdk/a11y/focus-trap/focus-trap.d.ts(129,9): error TS1086: An accessor cannot be declared in an ambient context.
    node_modules/@angular/cdk/a11y/focus-trap/focus-trap.d.ts(134,9): error TS1086: An accessor cannot be declared in an ambient context.
    node_modules/@angular/cdk/a11y/focus-trap/focus-trap.d.ts(135,9): error TS1086: An accessor cannot be declared in an ambient context.
    node_modules/@angular/cdk/a11y/key-manager/list-key-manager.d.ts(96,9): error TS1086: An accessor cannot be declared in an ambient context.
    node_modules/@angular/cdk/a11y/key-manager/list-key-manager.d.ts(98,9): error TS1086: An accessor cannot be declared in an ambient context.
    node_modules/@angular/cdk/a11y/live-announcer/live-announcer.d.ts(69,9): error TS1086: An accessor cannot be declared in an ambient context.
    node_modules/@angular/cdk/a11y/live-announcer/live-announcer.d.ts(70,9): error TS1086: An accessor cannot be declared in an ambient context.
    node_modules/@angular/cdk/observers/observe-content.d.ts(62,9): error TS1086: An accessor cannot be declared in an ambient context.
    node_modules/@angular/cdk/observers/observe-content.d.ts(63,9): error TS1086: An accessor cannot be declared in an ambient context.
    node_modules/@angular/cdk/observers/observe-content.d.ts(66,9): error TS1086: An accessor cannot be declared in an ambient context.
    node_modules/@angular/cdk/observers/observe-content.d.ts(67,9): error TS1086: An accessor cannot be declared in an ambient context.

Here's my package.json

"name": "football",
  "version": "0.0.0",
  "scripts": {
    "ng": "ng",
    "start": "ng serve",
    "build": "ng build",
    "test": "ng test",
    "lint": "ng lint",
    "e2e": "ng e2e"
  },
  "private": true,
  "dependencies": {
    "@angular/animations": "~8.2.14",
    "@angular/cdk": "^9.0.0",
    "@angular/common": "~8.2.14",
    "@angular/compiler": "~8.2.14",
    "@angular/core": "~8.2.14",
    "@angular/forms": "~8.2.14",
    "@angular/material": "8.2.3",
    "@angular/platform-browser": "~8.2.14",
    "@angular/platform-browser-dynamic": "~8.2.14",
    "@angular/router": "~8.2.14",
    "hammerjs": "^2.0.8",
    "rxjs": "~6.4.0",
    "tslib": "^1.10.0",
    "zone.js": "~0.9.1"
  },
  "devDependencies": {
    "@angular-devkit/build-angular": "~0.803.21",
    "@angular/cli": "~8.3.21",
    "@angular/compiler-cli": "~8.2.14",
    "@angular/language-service": "~8.2.14",
    "@types/node": "~8.9.4",
    "@types/jasmine": "~3.3.8",
    "@types/jasminewd2": "~2.0.3",
    "codelyzer": "^5.0.0",
    "jasmine-core": "~3.4.0",
    "jasmine-spec-reporter": "~4.2.1",
    "karma": "~4.1.0",
    "karma-chrome-launcher": "~2.2.0",
    "karma-coverage-istanbul-reporter": "~2.0.1",
    "karma-jasmine": "~2.0.1",
    "karma-jasmine-html-reporter": "^1.4.0",
    "protractor": "~5.4.0",
    "ts-node": "~7.0.0",
    "tslint": "~5.15.0",
    "typescript": "~3.5.3"
  }
}

According to your package.json, you're using Angular 8.3, but you've imported angular/cdk v9. You can downgrade your angular/cdk version or you can upgrade your Angular version to v9 by running:

ng update @angular/core @angular/cli

That will update your local angular version to 9. Then, just to sync material, run: ng update @angular/material

Adding skipLibCheck: true in compilerOptions inside tsconfig.json file fixed my issue.

"compilerOptions": {
   "skipLibCheck": true,
},

These issue arise generally due to mismatch between @ngx-translate/core version and Angular .Before installing check compatible version of corresponding ngx_trnalsate/Core, @ngx-translate/http-loader and Angular at https://www.npmjs.com/package/@ngx-translate/core

Eg: For Angular 6.X versions,

npm install @ngx-translate/core@10 @ngx-translate/http-loader@3 rxjs --save

Like as above, follow below command and rest of code part is common for all versions(Note: Version can obtain from( https://www.npmjs.com/package/@ngx-translate/core)

npm install @ngx-translate/core@version @ngx-translate/http-loader@version rxjs --save

npm i @ionic/storage@2.2.0

this is install to degrade your storage package

First please check in module.ts file that in @NgModule all properties are only one time. If any of are more than one time then also this error come. Because I had also occur this error but in module.ts file entryComponents property were two time that's why I was getting this error. I resolved this error by removing one time entryComponents from @NgModule. So, I recommend that first you check it properly.

I had this problem but didn't have a version conflict in my package.json.

My package-lock.json was somehow out of sync with package json though. Deleting and regenerating it worked for me.

I solved the same issue by following steps:

Check the angular version: Using command: ng version My angular version is: Angular CLI: 7.3.10

After that I have support version of ngx bootstrap from the link: https://www.npmjs.com/package/ngx-bootstrap

In package.json file update the version: "bootstrap": "^4.5.3", "@ng-bootstrap/ng-bootstrap": "^4.2.2",

Now after updating package.json, use the command npm update

After this use command ng serve and my error got resolved