Add a few extra guards for GT/GWorld access

Plugins/UE5Coro/Source/UE5Coro/Private/LatentAwaiter.cpp

@@ -98,6 +98,8 @@ void FLatentAwaiter::Suspend(FAsyncPromise& Promise)
 {
 	checkf(IsInGameThread(),
 	       TEXT("Latent awaiters may only be used on the game thread"));
+	checkf(GWorld,
+	       TEXT("Awaiting this can only be done in the context of a world"));
 
 	// Prepare a latent action on the subsystem and transfer ownership to that
 	auto* Sys = GWorld->GetSubsystem<UUE5CoroSubsystem>();

Plugins/UE5Coro/Source/UE5Coro/Private/LatentAwaiters_Wait.cpp

@@ -53,6 +53,7 @@ bool WaitUntilTime(void* State, bool bCleanup)
 	static_assert(sizeof(void*) >= sizeof(double),
 	              "32-bit platforms are not supported");
 	auto& TargetTime = reinterpret_cast<double&>(State);
+	checkf(GWorld, TEXT("Internal error: Latent poll outside of a world"));
 	return (GWorld->*GetTime)() >= TargetTime;
 }
 
@@ -77,6 +78,10 @@ FLatentAwaiter GenericUntil(double Time)
 		logOrEnsureNanError(TEXT("Latent wait started with NaN time"));
 	}
 #endif
+	checkf(IsInGameThread(),
+	       TEXT("Latent awaiters may only be used on the game thread"));
+	checkf(GWorld,
+	       TEXT("This function may only be used in the context of a world"));
 
 	if constexpr (bTimeIsOffset)
 		Time += (GWorld->*GetTime)();

Plugins/UE5Coro/Source/UE5Coro/Private/LatentChain.cpp

@@ -37,6 +37,7 @@ using namespace UE5Coro::Private;
 
 std::tuple<FLatentActionInfo, FTwoLives*> Private::MakeLatentInfo()
 {
+	checkf(GWorld, TEXT("Internal error: Unguarded world access"));
 	auto* Sys = GWorld->GetSubsystem<UUE5CoroSubsystem>();
 	// Will be Released by the FLatentAwaiter from the caller
 	// and UUE5CoroSubsystem on the latent action's completion.

Plugins/UE5Coro/Source/UE5Coro/Private/LatentTimeline.cpp

@@ -61,6 +61,9 @@ TCoroutine<> CommonTimeline(double From, double To, double Length,
 
 	checkf(IsInGameThread(),
 	       TEXT("Latent coroutines may only be started on the game thread"));
+	checkf(GWorld,
+	       TEXT("This function may only be used in the context of a world"));
+
 	double Start = (GWorld->*GetTime)();
 	for (;;)
 	{

Plugins/UE5Coro/Source/UE5Coro/Public/UE5Coro/LatentChain.inl

@@ -90,6 +90,7 @@ struct FLatentChain<true, bInfo, Type, Types...>
 {
 	static void Call(auto&& Fn, FLatentActionInfo LatentInfo, auto&&... Args)
 	{
+		checkf(GWorld, TEXT("Could not chain latent action: no world found"));
 		FLatentChain<false, bInfo, Types...>::Call(
 			std::bind_front(std::move(Fn), &*GWorld),
 			LatentInfo,
@@ -150,6 +151,8 @@ template<typename... FnParams>
 UE5CORO_PRIVATE_LATENT_CHAIN_BUG_MSG
 Private::FLatentChainAwaiter Chain(auto (*Function)(FnParams...), auto&&... Args)
 {
+	checkf(IsInGameThread(),
+	       TEXT("Latent awaiters may only be used on the game thread"));
 	auto [LatentInfo, Done] = Private::MakeLatentInfo();
 	Private::FLatentChain<true, true, FnParams...>::Call(
 		Function,
@@ -163,6 +166,8 @@ UE5CORO_PRIVATE_LATENT_CHAIN_BUG_MSG
 Private::FLatentChainAwaiter Chain(auto (Class::*Function)(FnParams...),
                                    Class* Object, auto&&... Args)
 {
+	checkf(IsInGameThread(),
+	       TEXT("Latent awaiters may only be used on the game thread"));
 	auto [LatentInfo, Done] = Private::MakeLatentInfo();
 	Private::FLatentChain<true, true, FnParams...>::Call(
 		std::bind_front(Function, Object),
@@ -178,6 +183,11 @@ Private::FLatentChainAwaiter Chain(auto (Class::*Function)(FnParams...),
 template<typename F, typename... A>
 Private::FLatentChainAwaiter ChainEx(F&& Function, A&&... Args)
 {
+	checkf(IsInGameThread(),
+	       TEXT("Latent awaiters may only be used on the game thread"));
+	if constexpr ((... || (std::is_placeholder_v<std::decay_t<A>> == 1)))
+		checkf(GWorld,
+		       TEXT("Could not chain latent action: no world found for _1"));
 	static_assert((... || (std::is_placeholder_v<std::decay_t<A>> == 2)),
 	              "The _2 parameter for LatentInfo is mandatory");