diff --git a/src/vs/workbench/api/common/extHostLanguageFeatures.ts b/src/vs/workbench/api/common/extHostLanguageFeatures.ts
index a438b79f332..e5ca7469fb0 100644
--- a/src/vs/workbench/api/common/extHostLanguageFeatures.ts
+++ b/src/vs/workbench/api/common/extHostLanguageFeatures.ts
@@ -1024,7 +1024,13 @@ class SuggestAdapter {
 	}
 }
 
-class InlineCompletionAdapter {
+class InlineCompletionAdapterBase {
+	public async provideInlineCompletions(resource: URI, position: IPosition, context: languages.InlineCompletionContext, token: CancellationToken): Promise<extHostProtocol.IdentifiableInlineCompletions | undefined> {
+		return undefined;
+	}
+}
+
+class InlineCompletionAdapter extends InlineCompletionAdapterBase {
 	private readonly _cache = new Cache<vscode.InlineCompletionItem>('InlineCompletionItem');
 	private readonly _disposables = new Map<number, DisposableStore>();
 
@@ -1032,9 +1038,11 @@ class InlineCompletionAdapter {
 		private readonly _documents: ExtHostDocuments,
 		private readonly _provider: vscode.InlineCompletionItemProvider,
 		private readonly _commands: CommandsConverter,
-	) { }
+	) {
+		super();
+	}
 
-	public async provideInlineCompletions(resource: URI, position: IPosition, context: languages.InlineCompletionContext, token: CancellationToken): Promise<extHostProtocol.IdentifiableInlineCompletions | undefined> {
+	public override async provideInlineCompletions(resource: URI, position: IPosition, context: languages.InlineCompletionContext, token: CancellationToken): Promise<extHostProtocol.IdentifiableInlineCompletions | undefined> {
 		const doc = this._documents.getDocument(resource);
 		const pos = typeConvert.Position.to(position);
 
@@ -1113,7 +1121,7 @@ class InlineCompletionAdapter {
 	}
 }
 
-class InlineCompletionAdapterNew {
+class InlineCompletionAdapterNew extends InlineCompletionAdapterBase {
 	private readonly _cache = new Cache<vscode.InlineCompletionItemNew>('InlineCompletionItemNew');
 	private readonly _disposables = new Map<number, DisposableStore>();
 
@@ -1124,14 +1132,16 @@ class InlineCompletionAdapterNew {
 		private readonly _documents: ExtHostDocuments,
 		private readonly _provider: vscode.InlineCompletionItemProviderNew,
 		private readonly _commands: CommandsConverter,
-	) { }
+	) {
+		super();
+	}
 
 	private readonly languageTriggerKindToVSCodeTriggerKind: Record<languages.InlineCompletionTriggerKind, vscode.InlineCompletionTriggerKindNew> = {
 		[languages.InlineCompletionTriggerKind.Automatic]: InlineCompletionTriggerKindNew.Automatic,
 		[languages.InlineCompletionTriggerKind.Explicit]: InlineCompletionTriggerKindNew.Invoke,
 	};
 
-	public async provideInlineCompletions(resource: URI, position: IPosition, context: languages.InlineCompletionContext, token: CancellationToken): Promise<extHostProtocol.IdentifiableInlineCompletions | undefined> {
+	public override async provideInlineCompletions(resource: URI, position: IPosition, context: languages.InlineCompletionContext, token: CancellationToken): Promise<extHostProtocol.IdentifiableInlineCompletions | undefined> {
 		const doc = this._documents.getDocument(resource);
 		const pos = typeConvert.Position.to(position);
 
@@ -2156,7 +2166,7 @@ export class ExtHostLanguageFeatures implements extHostProtocol.ExtHostLanguageF
 	}
 
 	$provideInlineCompletions(handle: number, resource: UriComponents, position: IPosition, context: languages.InlineCompletionContext, token: CancellationToken): Promise<extHostProtocol.IdentifiableInlineCompletions | undefined> {
-		return this._withAdapter(handle, InlineCompletionAdapter, adapter => adapter.provideInlineCompletions(URI.revive(resource), position, context, token), undefined, token);
+		return this._withAdapter(handle, InlineCompletionAdapterBase, adapter => adapter.provideInlineCompletions(URI.revive(resource), position, context, token), undefined, token);
 	}
 
 	$handleInlineCompletionDidShow(handle: number, pid: number, idx: number): void {