fix #36491

src/vs/editor/contrib/suggest/suggestModel.ts

@@ -259,17 +259,14 @@ export class SuggestModel implements IDisposable {
 		this._currentPosition = this._editor.getPosition();
 
 		if (!e.selection.isEmpty()
-			|| e.source !== 'keyboard'
 			|| e.reason !== CursorChangeReason.NotSet
+			|| (e.source !== 'keyboard' && e.source !== 'deleteLeft')
 		) {
-
-			if (this._state === State.Idle) {
-				// Early exit if nothing needs to be done!
-				// Leave some form of early exit check here if you wish to continue being a cursor position change listener ;)
-				return;
+			// Early exit if nothing needs to be done!
+			// Leave some form of early exit check here if you wish to continue being a cursor position change listener ;)
+			if (this._state !== State.Idle) {
+				this.cancel();
 			}
-
-			this.cancel();
 			return;
 		}
 

src/vs/editor/contrib/suggest/test/suggestModel.test.ts

@@ -23,6 +23,7 @@ import { NullTelemetryService } from 'vs/platform/telemetry/common/telemetryUtil
 import { EditOperation } from 'vs/editor/common/core/editOperation';
 import { Range } from 'vs/editor/common/core/range';
 import { ICodeEditor } from 'vs/editor/browser/editorBrowser';
+import { CoreEditingCommands } from 'vs/editor/browser/controller/coreCommands';
 
 function createMockEditor(model: Model): TestCodeEditor {
 	const contextKeyService = new MockContextKeyService();
@@ -534,4 +535,33 @@ suite('SuggestModel - TriggerAndCancelOracle', function () {
 			});
 		});
 	});
+
+	test('Backspace should not always cancel code completion, #36491', function () {
+		disposables.push(SuggestRegistry.register({ scheme: 'test' }, alwaysSomethingSupport));
+
+		return withOracle(async (model, editor) => {
+			await assertEvent(model.onDidSuggest, () => {
+				editor.setPosition({ lineNumber: 1, column: 4 });
+				editor.trigger('keyboard', Handler.Type, { text: 'd' });
+
+			}, event => {
+				assert.equal(event.auto, true);
+				assert.equal(event.completionModel.items.length, 1);
+				const [first] = event.completionModel.items;
+
+				assert.equal(first.support, alwaysSomethingSupport);
+			});
+
+			await assertEvent(model.onDidSuggest, () => {
+				CoreEditingCommands.DeleteLeft.runEditorCommand(null, editor, null);
+
+			}, event => {
+				assert.equal(event.auto, true);
+				assert.equal(event.completionModel.items.length, 1);
+				const [first] = event.completionModel.items;
+
+				assert.equal(first.support, alwaysSomethingSupport);
+			});
+		});
+	});
 });