Why a comparison of a value type with null is a warning?

re: Why a comparison of a value type with null is a warning?

ysweet — Tue, 09 Sep 2008 21:46:17 GMT

if you have a generic with unconstrained T type parameter, it is really useful that C# allows comparison to null even if T can be value type. I even used default(T) == null as a test whether T is reference type.

re: Why a comparison of a value type with null is a warning?

Kirill Osenkov — Fri, 12 Sep 2008 00:43:48 GMT

That's a good point, by the way!

re: Why a comparison of a value type with null is a warning?

madduck — Thu, 25 Sep 2008 10:31:45 GMT

If we all did the right thing and compiled with warnings-as-errors, this point would be moot.

Of course, generated code would probably want to compile without it.

re: Why a comparison of a value type with null is a warning?

Lucas — Wed, 29 Jul 2009 18:33:09 GMT

@ysweet Be careful with that check for reference type. For nullable types it will return true but they are still value types, not reference types.