What It Means & How to Fix It

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🧠 Why You’re Seeing This Error

The C2243 error means you’re trying to convert one type to another, and technically that conversion does exist, but the compiler isn’t allowed to use it — because it’s marked as private or protected, or it’s inside a class you can’t access directly.

In UE5, this often happens when:

• You’re working with custom classes or structs that define private conversion operators
• You try to implicitly cast between types (especially UObject-based ones)
• You forget to use Cast<>, or you attempt a direct assignment that isn’t allowed

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💥 Example Error Message

error C2243: 'type conversion': conversion from 'FMyStruct' to 'int32' exists, but is inaccessible

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🛠️ Example Code

struct FMyStruct
{
private:
    operator int32() const { return 42; } // ❌ Private conversion
};

FMyStruct MyValue;
int32 Num = MyValue; // ❌ C2243: conversion exists but is inaccessible

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✅ How to Fix C2243 in UE5 – Step-by-Step

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✔️ 1. Make the Conversion Operator Public

If you control the class/struct and want to allow this conversion, make the operator public.

Fix:

struct FMyStruct
{
public:
    operator int32() const { return 42; } // ✅ Now it's accessible
};

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✔️ 2. Avoid Implicit Conversions – Use an Explicit Method Instead

If you don’t want implicit conversion, expose a getter or function.

Fix:

int32 GetValue() const { return 42; }

int32 Num = MyValue.GetValue(); // ✅ Clean and explicit

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✔️ 3. Use Cast<>() for UObject-Based Types

If this error comes from trying to assign between classes like AActor* and AEnemy*, remember that UE5 requires Cast<>.

Wrong:

AActor* Base = EnemyPointer; // ❌ C2243

Fix:

AEnemy* Enemy = Cast(SomeActor); // ✅ Safe UE5 casting

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✅ Summary: How to Fix C2243 in UE5

Cause	Fix Example
Conversion operator is private/protected	Make it public or use a method instead
Implicit casting between custom types	Use explicit functions like GetValue()
Casting between Unreal object types	Use Cast<> instead of direct assignment