LibJS: Convert IfAbruptRejectPromise AO to a GNU statement expression

GNU statement expressions fit the definition of IfAbruptRejectPromise
rather nicely, where we need to reject the failed promise (and return
the failed promise itself) on failure, and otherwise store a value on
success.

Userland/Libraries/LibJS/Runtime/PromiseConstructor.cpp

@@ -35,33 +35,18 @@ static ThrowCompletionOr<Value> get_promise_resolve(GlobalObject& global_object,
 }
 
 // 27.2.1.1.1 IfAbruptRejectPromise ( value, capability ), https://tc39.es/ecma262/#sec-ifabruptrejectpromise
-template<typename ValueType>
-static Optional<Value> if_abrupt_reject_promise(GlobalObject& global_object, ValueType const& value_or_error, PromiseCapability capability)
-{
-    auto& vm = global_object.vm();
-
-    // FIXME: This is temporary multi-type support. When all callers to this method are transformed
-    //        to use ThrowCompletionOr, the 'else' clause (and template) can be dropped.
-    if constexpr (requires { value_or_error.is_throw_completion(); }) {
-        if (value_or_error.is_throw_completion()) {
-            vm.clear_exception();
-            vm.stop_unwind();
-
-            (void)vm.call(*capability.reject, js_undefined(), value_or_error.throw_completion().value());
-            return capability.promise;
-        }
-    } else {
-        if (auto* exception = vm.exception()) {
-            vm.clear_exception();
-            vm.stop_unwind();
-
-            (void)vm.call(*capability.reject, js_undefined(), exception->value());
-            return capability.promise;
-        }
-    }
-
-    return {};
-}
+#define TRY_OR_REJECT(vm, capability, expression)                                                         \
+    ({                                                                                                    \
+        auto _temporary_result = (expression);                                                            \
+        if (_temporary_result.is_error()) {                                                               \
+            vm.clear_exception();                                                                         \
+            vm.stop_unwind();                                                                             \
+                                                                                                          \
+            (void)vm.call(*capability.reject, js_undefined(), _temporary_result.release_error().value()); \
+            return capability.promise;                                                                    \
+        }                                                                                                 \
+        _temporary_result.release_value();                                                                \
+    })
 
 static bool iterator_record_is_complete(GlobalObject& global_object, Object& iterator_record)
 {
@@ -287,15 +272,8 @@ JS_DEFINE_OLD_NATIVE_FUNCTION(PromiseConstructor::all)
     if (vm.exception())
         return {};
 
-    auto promise_resolve_or_error = get_promise_resolve(global_object, constructor);
-    if (auto abrupt = if_abrupt_reject_promise(global_object, promise_resolve_or_error, promise_capability); abrupt.has_value())
-        return abrupt.value();
-    auto promise_resolve = promise_resolve_or_error.release_value();
-
-    auto iterator_record_or_error = get_iterator(global_object, vm.argument(0));
-    if (auto abrupt = if_abrupt_reject_promise(global_object, iterator_record_or_error, promise_capability); abrupt.has_value())
-        return abrupt.value();
-    auto* iterator_record = iterator_record_or_error.release_value();
+    auto promise_resolve = TRY_OR_REJECT(vm, promise_capability, get_promise_resolve(global_object, constructor));
+    auto* iterator_record = TRY_OR_REJECT(vm, promise_capability, get_iterator(global_object, vm.argument(0)));
 
     auto result = perform_promise_all(global_object, *iterator_record, constructor, promise_capability, promise_resolve);
     if (auto* exception = vm.exception()) {
@@ -307,8 +285,7 @@ JS_DEFINE_OLD_NATIVE_FUNCTION(PromiseConstructor::all)
             result_error = iterator_close(*iterator_record, move(result_error));
         }
 
-        auto abrupt = if_abrupt_reject_promise(global_object, result_error, promise_capability);
-        return abrupt.value();
+        TRY_OR_REJECT(vm, promise_capability, result_error);
     }
 
     return result;
@@ -323,15 +300,8 @@ JS_DEFINE_OLD_NATIVE_FUNCTION(PromiseConstructor::all_settled)
     if (vm.exception())
         return {};
 
-    auto promise_resolve_or_error = get_promise_resolve(global_object, constructor);
-    if (auto abrupt = if_abrupt_reject_promise(global_object, promise_resolve_or_error, promise_capability); abrupt.has_value())
-        return abrupt.value();
-    auto promise_resolve = promise_resolve_or_error.release_value();
-
-    auto iterator_record_or_error = get_iterator(global_object, vm.argument(0));
-    if (auto abrupt = if_abrupt_reject_promise(global_object, iterator_record_or_error, promise_capability); abrupt.has_value())
-        return abrupt.value();
-    auto* iterator_record = iterator_record_or_error.release_value();
+    auto promise_resolve = TRY_OR_REJECT(vm, promise_capability, get_promise_resolve(global_object, constructor));
+    auto* iterator_record = TRY_OR_REJECT(vm, promise_capability, get_iterator(global_object, vm.argument(0)));
 
     auto result = perform_promise_all_settled(global_object, *iterator_record, constructor, promise_capability, promise_resolve);
     if (auto* exception = vm.exception()) {
@@ -343,8 +313,7 @@ JS_DEFINE_OLD_NATIVE_FUNCTION(PromiseConstructor::all_settled)
             result_error = iterator_close(*iterator_record, move(result_error));
         }
 
-        auto abrupt = if_abrupt_reject_promise(global_object, result_error, promise_capability);
-        return abrupt.value();
+        TRY_OR_REJECT(vm, promise_capability, result_error);
     }
 
     return result;
@@ -359,15 +328,8 @@ JS_DEFINE_OLD_NATIVE_FUNCTION(PromiseConstructor::any)
     if (vm.exception())
         return {};
 
-    auto promise_resolve_or_error = get_promise_resolve(global_object, constructor);
-    if (auto abrupt = if_abrupt_reject_promise(global_object, promise_resolve_or_error, promise_capability); abrupt.has_value())
-        return abrupt.value();
-    auto promise_resolve = promise_resolve_or_error.release_value();
-
-    auto iterator_record_or_error = get_iterator(global_object, vm.argument(0));
-    if (auto abrupt = if_abrupt_reject_promise(global_object, iterator_record_or_error, promise_capability); abrupt.has_value())
-        return abrupt.value();
-    auto* iterator_record = iterator_record_or_error.release_value();
+    auto promise_resolve = TRY_OR_REJECT(vm, promise_capability, get_promise_resolve(global_object, constructor));
+    auto* iterator_record = TRY_OR_REJECT(vm, promise_capability, get_iterator(global_object, vm.argument(0)));
 
     auto result = perform_promise_any(global_object, *iterator_record, constructor, promise_capability, promise_resolve);
     if (auto* exception = vm.exception()) {
@@ -379,8 +341,7 @@ JS_DEFINE_OLD_NATIVE_FUNCTION(PromiseConstructor::any)
             result_error = iterator_close(*iterator_record, move(result_error));
         }
 
-        auto abrupt = if_abrupt_reject_promise(global_object, result_error, promise_capability);
-        return abrupt.value();
+        TRY_OR_REJECT(vm, promise_capability, result_error);
     }
 
     return result;
@@ -395,15 +356,8 @@ JS_DEFINE_OLD_NATIVE_FUNCTION(PromiseConstructor::race)
     if (vm.exception())
         return {};
 
-    auto promise_resolve_or_error = get_promise_resolve(global_object, constructor);
-    if (auto abrupt = if_abrupt_reject_promise(global_object, promise_resolve_or_error, promise_capability); abrupt.has_value())
-        return abrupt.value();
-    auto promise_resolve = promise_resolve_or_error.release_value();
-
-    auto iterator_record_or_error = get_iterator(global_object, vm.argument(0));
-    if (auto abrupt = if_abrupt_reject_promise(global_object, iterator_record_or_error, promise_capability); abrupt.has_value())
-        return abrupt.value();
-    auto* iterator_record = iterator_record_or_error.release_value();
+    auto promise_resolve = TRY_OR_REJECT(vm, promise_capability, get_promise_resolve(global_object, constructor));
+    auto* iterator_record = TRY_OR_REJECT(vm, promise_capability, get_iterator(global_object, vm.argument(0)));
 
     auto result = perform_promise_race(global_object, *iterator_record, constructor, promise_capability, promise_resolve);
     if (auto* exception = vm.exception()) {
@@ -415,8 +369,7 @@ JS_DEFINE_OLD_NATIVE_FUNCTION(PromiseConstructor::race)
             result_error = iterator_close(*iterator_record, move(result_error)); // iterator_close() may invoke vm.call(), which VERIFYs no exception.
         }
 
-        auto abrupt = if_abrupt_reject_promise(global_object, result_error, promise_capability);
-        return abrupt.value();
+        TRY_OR_REJECT(vm, promise_capability, result_error);
     }
 
     return result;