Ensure we are lowering coroutine normal result using proper (callee) context.

Author: asl

lib/IRGen/IRGenSIL.cpp

@@ -4765,19 +4765,23 @@ void IRGenSILFunction::visitEndApply(BeginApplyInst *i, EndApplyInst *ei) {
   const auto &coroutine = getLoweredCoroutine(i->getTokenResult());
   bool isAbort = ei == nullptr;
 
-  auto sig = Signature::forCoroutineContinuation(IGM, i->getOrigCalleeType());
+  // Lower the return value in the callee's generic context.
+  auto origCalleeType = i->getOrigCalleeType();
+  GenericContextScope scope(IGM, origCalleeType->getInvocationGenericSignature());
+
+  auto sig = Signature::forCoroutineContinuation(IGM, origCalleeType);
 
   // Cast the continuation pointer to the right function pointer type.
   auto continuation = coroutine.Continuation;
   continuation = Builder.CreateBitCast(continuation,
                                        sig.getType()->getPointerTo());
 
   auto schemaAndEntity =
-    getCoroutineResumeFunctionPointerAuth(IGM, i->getOrigCalleeType());
+    getCoroutineResumeFunctionPointerAuth(IGM, origCalleeType);
   auto pointerAuth = PointerAuthInfo::emit(*this, schemaAndEntity.first,
                                            coroutine.Buffer.getAddress(),
                                            schemaAndEntity.second);
-  auto callee = FunctionPointer::createSigned(i->getOrigCalleeType(),
+  auto callee = FunctionPointer::createSigned(origCalleeType,
                                               continuation, pointerAuth, sig);
 
   auto *call = Builder.CreateCall(callee, {