CSHARP

c# check value at design time

public static class PositiveInt32Extensions
{
    public static Boolean IsPositive( this Int32 candidate, out PositiveInt32 value ) => PositiveInt32.TryCreate( candidate, out value );
}

public readonly struct PositiveInt32
{
    public static Boolean TryCreate( Int32 candidate, out PositiveInt32  value )
    {
        if( candidate > 0 )
        {
            value = new PositiveInt32( candidate );
            return true;
        }
        else
        {
            value = default;
            return false;
        }
    }

    private readonly Int32 value;

    public PositiveInt32( Int32 value )
    {
        if( value < 1 ) throw new ArgumentOutOfRangeException( nameof(value), actualValue: value, message: "Value must be positive." );
        this.value = value;
    }

    public static implicit operator Int32( PositiveInt32 self ) => self.value;

    // NOTE: This implicit conversion will fail when `unsignedValue  > UInt32.MaxValue / 2`, but I assume that will never happen.
    public static implicit operator PositiveInt32 ( UInt32 unsignedValue ) => new PositiveInt32( (Int32)unsignedValue );
}