Allow direct casting between type parameters and all types

[ekolis]

Let's say I have this:

public string DoStuff<T>(T t)
{
	if (t is decimal)
	{
		decimal d = (decimal)t;
		Console.WriteLine("the number is: " + d);
	}
}

This code does not compile because T cannot be cast directly to decimal; I have to do an intermediate cast to object (void* much?!):

decimal d = (decimal)(object)t;

Seems rather unnecessary to me... why can't I cast the type parameter instance directly to whatever type I want?

[HaloFour]

The compiler can't validate the cast. The fact that you did an is check on the previous line does not impact the analysis of the compiler.

In this case you can use pattern matching and eliminate the need for the cast:

public string DoStuff<T>(T t)
{
	if (t is decimal d)
	{
		Console.WriteLine("the number is: " + d);
	}
}

[IS4Code]

Interestingly enough, is decimal d boxes the value, so it is in essence equivalent to obtaining (object)t as decimal. I can see now why the runtime specifically tries to optimize this situation and get rid of actual boxing.