Don't send @ as trigger character for ts 3.1

Fixes #59165

Workaround for https://github.com/Microsoft/TypeScript/issues/27321

extensions/typescript-language-features/src/features/completions.ts

@@ -316,7 +316,7 @@ class TypeScriptCompletionItemProvider implements vscode.CompletionItemProvider
 			...typeConverters.Position.toFileLocationRequestArgs(file, position),
 			includeExternalModuleExports: completionConfiguration.autoImportSuggestions,
 			includeInsertTextCompletions: true,
-			triggerCharacter: context.triggerCharacter as Proto.CompletionsTriggerCharacter
+			triggerCharacter: this.getTsTriggerCharacter(context)
 		};
 
 		let isNewIdentifierLocation = true;
@@ -347,6 +347,17 @@ class TypeScriptCompletionItemProvider implements vscode.CompletionItemProvider
 			}));
 	}
 
+	private getTsTriggerCharacter(context: vscode.CompletionContext): Proto.CompletionsTriggerCharacter | undefined {
+		// Workaround for https://github.com/Microsoft/TypeScript/issues/27321
+		if (context.triggerCharacter === '@'
+			&& this.client.apiVersion.gte(API.v310) && !this.client.apiVersion.gte(API.v320)
+		) {
+			return undefined;
+		}
+
+		return context.triggerCharacter as Proto.CompletionsTriggerCharacter;
+	}
+
 	public async resolveCompletionItem(
 		item: vscode.CompletionItem,
 		token: vscode.CancellationToken

extensions/typescript-language-features/src/utils/api.ts

@@ -31,6 +31,7 @@ export default class API {
 	public static readonly v292 = API.fromSimpleString('2.9.2');
 	public static readonly v300 = API.fromSimpleString('3.0.0');
 	public static readonly v310 = API.fromSimpleString('3.1.0');
+	public static readonly v320 = API.fromSimpleString('3.2.0');
 
 
 	public static fromVersionString(versionString: string): API {