Cancel backup promises on save and dispose

Fixes #15748

src/vs/workbench/services/textfile/common/textFileEditorModel.ts

@@ -108,9 +108,10 @@ export class TextFileEditorModel extends BaseTextEditorModel implements ITextFil
 		this.toDispose.push(this.textFileService.onFilesAssociationChange(e => this.onFilesAssociationChange()));
 		this.toDispose.push(this.onDidStateChange(e => {
 			if (e === StateChange.REVERTED) {
-				// Refire reverted events as content change events, cancelling any content change
-				// promises that are in flight.
+				// Cancel any content change event promises as they are no longer valid.
 				this.contentChangeEventScheduler.cancel();
+
+				// Refire state change reverted events as content change events
 				this._onDidContentChange.fire(StateChange.REVERTED);
 			}
 		}));
@@ -544,6 +545,9 @@ export class TextFileEditorModel extends BaseTextEditorModel implements ITextFil
 				// Updated resolved stat with updated stat, and keep old for event
 				this.updateVersionOnDiskStat(stat);
 
+				// Cancel any content change event promises as they are no longer valid
+				this.contentChangeEventScheduler.cancel();
+
 				// Emit File Saved Event
 				this._onDidStateChange.fire(StateChange.SAVED);
 			}, (error) => {
@@ -765,6 +769,7 @@ export class TextFileEditorModel extends BaseTextEditorModel implements ITextFil
 		this.createTextEditorModelPromise = null;
 
 		this.cancelAutoSavePromises();
+		this.contentChangeEventScheduler.cancel();
 
 		super.dispose();
 	}