TSubclassOf::UE_REQUIRES (constrained conversion constructor)

function CoreUObject Since 5.0

#include "Templates/SubclassOf.h"

Access: public Specifiers: inline

Description

Constrained conversion constructor that allows a TSubclassOf<Derived> to be implicitly converted to a TSubclassOf<Base> only when Derived* is convertible to Base*. This enforces type-safe upcasting at compile time.

Caveats & Gotchas

• Only upcast conversions (derived-to-base) are permitted by this constructor — there is no corresponding downcasting constructor; to narrow a TSubclassOf<Base> to TSubclassOf<Derived> you must manually check IsChildOf and assign a UClass* directly.
• This constraint replaced the older unconstrained conversion in UE 5.0; code that relied on implicit cross-hierarchy class conversions will fail to compile without explicit casts.

Signature

template < typename OtherT UE_REQUIRES(std::is_convertible_v<OtherT*, T*>) > [[nodiscard]] inline TSubclassOf(const TSubclassOf<OtherT>& Other)

Parameters

Name	Type	Description	Default
Other	const TSubclassOf<OtherT>&	The source TSubclassOf whose type OtherT must be a subtype of T.	—

Example

Implicit upcast between TSubclassOf types C++

TSubclassOf<AMyEnemy> EnemyClass = AMyBossEnemy::StaticClass();
// Safe: AMyBossEnemy* is convertible to APawn*
TSubclassOf<APawn> PawnClass = EnemyClass; // constrained constructor selected

Version History

Introduced in: 5.0

Version	Status	Notes
5.6	stable	—

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