title: Material Angular - Compile error - Class 'MatStepper' incorrectly extends base class 'CdkStepper'
body: <p>I have problems with compiling my angular website. I have installed all necessary dependencies via npm, but it is not working. I use Material Angular too. And this is the problem, without it works.</p>
  
  <p>Log:</p>
  
  <pre><code>webpack: Compiling...
  Date: 2017-11-05T13:02:47.880Z
  Hash: a4f6320620f5d2e9766f
  Time: 665ms
  chunk {inline} inline.bundle.js (inline) 5.79 kB [entry]
  chunk {main} main.bundle.js (main) 1.85 MB [initial]
  chunk {polyfills} polyfills.bundle.js (polyfills) 551 kB [initial]
  chunk {styles} styles.bundle.js (styles) 150 kB [initial]
  chunk {vendor} vendor.bundle.js (vendor) 12.8 MB [initial]
  
  
  ERROR in C:/Users/Erik/node_modules/@angular/core/@angular/core.es5.js
  Module build failed: Error: ENOENT: no such file or directory, open 'C:\Users\Erik\node_modules\@angular\core\@angular\core.es5.js'
   @ C:/Users/Erik/node_modules/@angular/cdk/esm5/a11y.es5.js 17:0-168
   @ ./node_modules/@angular/material/esm5/autocomplete.es5.js
   @ ./node_modules/@angular/material/esm5/material.es5.js
   @ ./src/app/app.module.ts
   @ ./src/main.ts
   @ multi webpack-dev-server/client?http://0.0.0.0:0 ./src/main.ts
  
  webpack: Failed to compile.
  ERROR in node_modules/@angular/material/stepper/typings/stepper.d.ts(17,22): error TS2415: Class 'MatStepper' incorrectly extends base class 'CdkStepper'.
    Types of property '_steps' are incompatible.
      Type 'QueryList&lt;MatStep&gt;' is not assignable to type 'QueryList&lt;CdkStep&gt;'.
        Property '_dirty' is missing in type 'QueryList&lt;MatStep&gt;'.
  ../../node_modules/@angular/cdk/a11y/typings/focus-monitor.d.ts(10,28): error TS2307: Cannot find module 'rxjs/Observable'.
  ../../node_modules/@angular/cdk/a11y/typings/list-key-manager.d.ts(9,25): error TS2307: Cannot find module 'rxjs/Subject'.
  ../../node_modules/@angular/cdk/collections/typings/collection-viewer.d.ts(8,28): error TS2307: Cannot find module 'rxjs/Observable'.
  ../../node_modules/@angular/cdk/collections/typings/data-source.d.ts(8,28): error TS2307: Cannot find module 'rxjs/Observable'.
  ../../node_modules/@angular/cdk/collections/typings/selection.d.ts(8,25): error TS2307: Cannot find module 'rxjs/Subject'.
  ../../node_modules/@angular/cdk/layout/typings/breakpoints-observer.d.ts(10,28): error TS2307: Cannot find module 'rxjs/Observable'.
  ../../node_modules/@angular/cdk/overlay/typings/overlay-ref.d.ts(12,28): error TS2307: Cannot find module 'rxjs/Observable'.
  ../../node_modules/@angular/cdk/overlay/typings/overlay-ref.d.ts(13,25): error TS2307: Cannot find module 'rxjs/Subject'.
  ../../node_modules/@angular/cdk/overlay/typings/position/connected-position-strategy.d.ts(12,25): error TS2307: Cannot find module 'rxjs/Subject'.
  ../../node_modules/@angular/cdk/overlay/typings/position/connected-position-strategy.d.ts(13,28): error TS2307: Cannot find module 'rxjs/Observable'.
  ../../node_modules/@angular/cdk/scrolling/typings/scroll-dispatcher.d.ts(10,30): error TS2307: Cannot find module 'rxjs/Subscription'.
  ../../node_modules/@angular/cdk/scrolling/typings/scroll-dispatcher.d.ts(11,28): error TS2307: Cannot find module 'rxjs/Observable'.
  ../../node_modules/@angular/cdk/scrolling/typings/scrollable.d.ts(9,28): error TS2307: Cannot find module 'rxjs/Observable'.
  ../../node_modules/@angular/cdk/scrolling/typings/viewport-ruler.d.ts(10,28): error TS2307: Cannot find module 'rxjs/Observable'.
  ../../node_modules/@angular/cdk/stepper/typings/stepper.d.ts(10,33): error TS2307: Cannot find module '@angular/forms'.
  ../../node_modules/@angular/cdk/table/typings/table.d.ts(11,33): error TS2307: Cannot find module 'rxjs/BehaviorSubject'.
  ../../node_modules/@angular/core/src/application_ref.d.ts(8,28): error TS2307: Cannot find module 'rxjs/Observable'.
  ../../node_modules/@angular/core/src/event_emitter.d.ts(8,25): error TS2307: Cannot find module 'rxjs/Subject'.
  ../../node_modules/@angular/core/src/linker/query_list.d.ts(8,28): error TS2307: Cannot find module 'rxjs/Observable'.
  ../../node_modules/@angular/core/src/util/lang.d.ts(8,28): error TS2307: Cannot find module 'rxjs/Observable'.
  </code></pre>
  
  <p>Can you help me ? Have I installed bad dependencies or I forget something ?</p>