Show error early on invalid rename in js/ts

Fixes #58393

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

@@ -14,15 +14,49 @@ class TypeScriptRenameProvider implements vscode.RenameProvider {
 		private readonly client: ITypeScriptServiceClient
 	) { }
 
+	public async prepareRename(
+		document: vscode.TextDocument,
+		position: vscode.Position,
+		token: vscode.CancellationToken
+	): Promise<vscode.Range | null> {
+		const body = await this.execRename(document, position, token);
+		if (!body) {
+			return null;
+		}
+
+		const renameInfo = body.info;
+		if (!renameInfo.canRename) {
+			return Promise.reject<vscode.Range>(new Error(renameInfo.localizedErrorMessage));
+		}
+		return null;
+	}
+
 	public async provideRenameEdits(
 		document: vscode.TextDocument,
 		position: vscode.Position,
 		newName: string,
 		token: vscode.CancellationToken
 	): Promise<vscode.WorkspaceEdit | null> {
+		const body = await this.execRename(document, position, token);
+		if (!body) {
+			return null;
+		}
+
+		const renameInfo = body.info;
+		if (!renameInfo.canRename) {
+			return Promise.reject<vscode.WorkspaceEdit>(renameInfo.localizedErrorMessage);
+		}
+		return this.toWorkspaceEdit(body.locs, newName);
+	}
+
+	public async execRename(
+		document: vscode.TextDocument,
+		position: vscode.Position,
+		token: vscode.CancellationToken
+	): Promise<Proto.RenameResponseBody | undefined> {
 		const file = this.client.toPath(document.uri);
 		if (!file) {
-			return null;
+			return undefined;
 		}
 
 		const args: Proto.RenameRequestArgs = {
@@ -31,22 +65,12 @@ class TypeScriptRenameProvider implements vscode.RenameProvider {
 			findInComments: false
 		};
 
-		let body: Proto.RenameResponseBody | undefined;
 		try {
-			body = (await this.client.execute('rename', args, token)).body;
-			if (!body) {
-				return null;
-			}
+			return (await this.client.execute('rename', args, token)).body;
 		} catch {
 			// noop
-			return null;
-		}
-
-		const renameInfo = body.info;
-		if (!renameInfo.canRename) {
-			return Promise.reject<vscode.WorkspaceEdit>(renameInfo.localizedErrorMessage);
+			return undefined;
 		}
-		return this.toWorkspaceEdit(body.locs, newName);
 	}
 
 	private toWorkspaceEdit(