title: Tried to overwrite @angular/cdk/stepper/step-header.d.ts.__ivy_ngcc_bak with an ngcc back up file, which is disallowed
body: <p>After upgrading <code>@angular/core</code> and <code>@angular/material</code> using <code>ng update</code> command, the <code>ngcc</code> command fails with below error</p>
  
  <p><strong>command used:</strong></p>
  
  <p><code>ngcc --properties es2015 browser module main --first-only --create-ivy-entry-points</code></p>
  
  <p><strong>Error:</strong></p>
  
  <pre><code>&gt; Compiling @angular/cdk/stepper : es2015 as esm2015
  &gt; Compiling @angular/cdk/drag-drop : es2015 as esm2015
  &gt; Error: Error on worker #3: Error: Tried to overwrite node_modules/@angular/cdk/stepper/step-header.d.ts.__ivy_ngcc_bak with an ngcc back up file, which is disallowed.
  &gt;     at NewEntryPointFileWriter.InPlaceFileWriter.writeFileAndBackup (node_modules/@angular/compiler-cli/ngcc/src/writing/in_place_file_writer.js:37:23)
  &gt;     at NewEntryPointFileWriter.writeFile (node_modules/@angular/compiler-cli/ngcc/src/writing/new_entry_point_file_writer.js:64:53)
  &gt;     at node_modules/@angular/compiler-cli/ngcc/src/writing/new_entry_point_file_writer.js:46:69
  &gt;     at Array.forEach (&lt;anonymous&gt;)
  &gt;     at NewEntryPointFileWriter.writeBundle (node_modules/@angular/compiler-cli/ngcc/src/writing/new_entry_point_file_writer.js:46:30)
  &gt;     at ClusterWorker.compile (node_modules/@angular/compiler-cli/ngcc/src/main.js:173:32)
  &gt;     at Worker.&lt;anonymous&gt; (node_modules/@angular/compiler-cli/ngcc/src/execution/cluster/worker.js:44:42)
  &gt;     at Worker.emit (events.js:321:20)
  &gt;     at process.&lt;anonymous&gt; (internal/cluster/worker.js:32:12)
  &gt;     at process.emit (events.js:321:20)
  &gt;     at ClusterMaster.onWorkerMessage (node_modules/@angular/compiler-cli/ngcc/src/execution/cluster/master.js:158:27)
  &gt;     at node_modules/@angular/compiler-cli/ngcc/src/execution/cluster/master.js:46:95
  &gt;     at ClusterMaster.&lt;anonymous&gt; (node_modules/@angular/compiler-cli/ngcc/src/execution/cluster/master.js:238:57)
  &gt;     at step (node_modules/tslib/tslib.js:136:27)
  &gt;     at Object.next (node_modules/tslib/tslib.js:117:57)
  &gt;     at node_modules/tslib/tslib.js:110:75
  &gt;     at new Promise (&lt;anonymous&gt;)
  &gt;     at Object.__awaiter (node_modules/tslib/tslib.js:106:16)
  &gt;     at EventEmitter.&lt;anonymous&gt; (node_modules/@angular/compiler-cli/ngcc/src/execution/cluster/master.js:232:32)
  &gt;     at EventEmitter.emit (events.js:321:20)
  </code></pre>