From 6398dff6628baedec8646500177ccb8074fe2dcd Mon Sep 17 00:00:00 2001
From: Oliver Medhurst <honk@goose.icu>
Date: Thu, 27 Aug 2026 09:26:20 +0100
Subject: [PATCH] codegen: unwrap async Promise return types

---
 compiler/codegen.js | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/compiler/codegen.js b/compiler/codegen.js
index 29f8a126..e4e6c496 100644
--- a/compiler/codegen.js
+++ b/compiler/codegen.js
@@ -2352,9 +2352,11 @@ const typeAnnoToIrType = x => {
   return null;
 };
 
-const extractTypeAnnotation = decl => {
+const extractTypeAnnotation = (decl, unwrapPromise = false) => {
   let a = decl;
   while (a.typeAnnotation) a = a.typeAnnotation;
+  if (unwrapPromise && a.type === 'TSTypeReference' && a.typeName?.name === 'Promise') a = a.typeParameters?.params?.[0];
+  if (!a) return {};
 
   let types = null, type = null, elementType = null, irType = null;
   if (a.typeName) {
@@ -4808,7 +4810,8 @@ const generateFunc = (scope, decl, forceNoExpr = false) => {
   funcsByIndex[func.index] = func;
 
   if (typedInput && decl.returnType) {
-    const { type, types, irType } = extractTypeAnnotation(decl.returnType);
+    // unwrap Promise<T> for async functions
+    const { type, types, irType } = extractTypeAnnotation(decl.returnType, func.async && !func.generator);
     if (irType != null) func.retType = irType;
     if (type != null) { typeUsed(func, type); func.returnType = type; }
     else if (types != null) { func.returnTypes = types; for (const x of types) typeUsed(func, x); }
-- 
2.51.2