From 38e36784d0d40aaa8822011d504af2c71872657f Mon Sep 17 00:00:00 2001
From: Dario Rexin <drexin@apple.com>
Date: Wed, 4 Dec 2024 13:57:48 -1000
Subject: [PATCH] [IRGen] Check if type is empty instead of void in
 CallEmission::emitToUnmappedExplosionWithDirectTypedError

rdar://140573912

This caused assertions to fail when using other empty types, like `Never` as the result type on typed throwing functions.
---
 lib/IRGen/GenCall.cpp         |  2 +-
 test/IRGen/typed_throws.swift | 13 +++++++++++++
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/lib/IRGen/GenCall.cpp b/lib/IRGen/GenCall.cpp
index 7a3b664def6c6..3294ccc821307 100644
--- a/lib/IRGen/GenCall.cpp
+++ b/lib/IRGen/GenCall.cpp
@@ -4564,7 +4564,7 @@ void CallEmission::emitToUnmappedExplosionWithDirectTypedError(
   }
 
   // If the regular result type is void, there is nothing to explode
-  if (!resultType.isVoid()) {
+  if (!nativeSchema.empty()) {
     Explosion resultExplosion;
     if (auto *structTy =
             dyn_cast<llvm::StructType>(nativeSchema.getExpandedType(IGF.IGM))) {
diff --git a/test/IRGen/typed_throws.swift b/test/IRGen/typed_throws.swift
index dff2c604c77f7..2951cf5a015c7 100644
--- a/test/IRGen/typed_throws.swift
+++ b/test/IRGen/typed_throws.swift
@@ -252,3 +252,16 @@ public func reabstractAsyncVoidThrowsNever() async {
 struct LoadableGeneric<E>: Error {}
 
 func throwsLoadableGeneric<E>(_: E) throws(LoadableGeneric<E>) {}
+
+@inline(never)
+func throwError() throws(SmallError) -> Never {
+  throw SmallError(x: 1)
+}
+
+func conditionallyCallsThrowError(b: Bool) throws(SmallError) -> Int {
+  if b {
+    try throwError()
+  } else {
+    return 0
+  }
+}