Fix bug in await using transformer (#1579)

Perryvw · web-flow · commit a2d31c95122c · 2024-09-21T17:44:07.000+02:00
diff --git a/src/transformation/pre-transformers/using-transformer.ts b/src/transformation/pre-transformers/using-transformer.ts
@@ -18,7 +18,7 @@ export function usingTransformer(context: TransformationContext): ts.Transformer
                         ts.setParent(node2, parent[parent.length - 1]);
                         parent.push(node2);
                         ts.visitEachChild(node2, setParent, ctx);
-                        parent.push();
+                        parent.pop();
                         return node2;
                     }
                     ts.visitEachChild(updatedBlock, setParent, ctx);
@@ -74,12 +74,13 @@ function transformBlockWithUsing(
             );
 
             const callback = ts.factory.createFunctionExpression(
-                undefined,
+                // Put async keyword in front of callback when we are in an async using
+                isAwaitUsing ? [ts.factory.createModifier(ts.SyntaxKind.AsyncKeyword)] : undefined,
                 undefined,
                 undefined,
                 undefined,
                 variableNames,
-                undefined,
+                ts.factory.createKeywordTypeNode(ts.SyntaxKind.AnyKeyword), // Required for TS to not freak out trying to infer the type of synthetic nodes
                 callbackBody
             );
 
diff --git a/test/unit/using.spec.ts b/test/unit/using.spec.ts
@@ -175,3 +175,21 @@ test("await using can handle non-async disposables", () => {
         .setTsHeader(usingTestLib)
         .expectToEqual({ logs: ["Creating a", "function content", "Disposing a"] });
 });
+
+// https://github.com/TypeScriptToLua/TypeScriptToLua/issues/1571
+test("await using no extra diagnostics (#1571)", () => {
+    util.testModule`
+        async function getResource(): Promise<AsyncDisposable> {
+            return {
+                [Symbol.asyncDispose]: async () => {}
+            };
+        }
+
+        async function someOtherAsync() {}
+
+        async function main() {
+            await using resource = await getResource();
+            await someOtherAsync();
+        }
+    `.expectToHaveNoDiagnostics();
+});
