Resl1021 Multi Argument Ierror Constructor Warning

title: RESL1021 — Multi-Argument IError Constructor [Warning]

---

Warns when an IError or IReason implementation has a public constructor with 2+ required parameters. Multi-parameter public constructors prevent [CallerMemberName] capture at the factory call site and make the API ambiguous.

Allowed: (), (string), (string, Exception), [Obsolete]-marked ctors, non-public ctors, and ctors where all extra params are optional (e.g., [CallerMemberName] string? = null).

// ⚠️ RESL1021: 'MyError' has a public constructor with 2+ required parameters
public class MyError : IError
{
    public MyError(string entity, string field) { ... }   // ← RESL1021
    public string Message { get; }
}

// ✅ use a static factory instead:
public class MyError : IError
{
    public MyError(string message) { ... }                // single-string ctor — allowed

    public static MyError For(string entity, string field,
        [CallerMemberName] string? callerMember = null, ...) => ...;  // ← CallerMember captured here
}