title: Property 'disabled' is missing in type 'MatButton' but required in type 'CanDisable'
body: <p>node_modules/@angular/material/core/option/optgroup.d.ts:17:22 - error TS2420: Class '_MatOptgroupBase' incorrectly implements interface 'CanDisable'.
  Property 'disabled' is missing in type '_MatOptgroupBase' but required in type 'CanDisable'.</p>
  <pre><code>17 export declare class _MatOptgroupBase extends _MatOptgroupMixinBase implements CanDisable {
                          ~~~~~~~~~~~~~~~~
  
    node_modules/@angular/material/core/common-behaviors/disabled.d.ts:12:5
      12     disabled: boolean;
             ~~~~~~~~
      'disabled' is declared here.
  node_modules/@angular/material/button/button.d.ts:22:22 - [91merror TS2420: Class 'MatButton' incorrectly implements interface 'CanColor'.
    Type 'MatButton' is missing the following properties from type 'CanColor': color, defaultColor
  
  22 export declare class MatButton extends _MatButtonMixinBase implements AfterViewInit, OnDestroy, CanDisable, CanColor, CanDisableRipple, FocusableOption {
                          ~~~~~~~~~
  node_modules/@angular/material/button/button.d.ts:22:22 - error TS2420: Class 'MatButton' incorrectly implements interface 
  </code></pre>
  <p>'CanDisable'.
  Property 'disabled' is missing in type 'MatButton' but required in type 'CanDisable'.</p>