constructor having Enum default value with generics, cause error

ConstructorHasEnumDefaultValue.cs

public enum SampleEnum
{
	None,
	Hoge,
	Huga,
	Hiyo
}
public class ConstructorHasEnumDefaultValue<T>
{
	public SampleEnum Flag { get; private set; }

	public T Value { get; private set; }
	public ConstructorHasEnumDefaultValue(T value, SampleEnum e = SampleEnum.None)
	{
		//Error: The name `Value' does not exist in the current context
		Value = value;
		//Error: The name `Flag' does not exist in the current context
		Flag = e;
	}
}
	
public class ConstructorHasEnumDefaultValue
{
	public SampleEnum Flag {get; private set;}

	public int Value { get; private set; }
	public ConstructorHasEnumDefaultValue(int value, SampleEnum e = SampleEnum.None)
	{
		//OK.
		Value = value;
		//OK.
		Flag = e;
	}
}

public class ConstructorHasEnumDefaultValueWithSpecificNamespace<T>
{
	public global::SampleEnum Flag { get; private set; }
 
	public T Value { get; private set; }
	public ConstructorHasEnumDefaultValueWithSpecificNamespace(T value, global::SampleEnum e = global::SampleEnum.None)
	{
		//OK.
		Value = value;
		//OK.
		Flag = e;
	}
}