Stack overflow calling from generic method to non-generic method. - DOTNET

<=?Utf-8?B?RWQgQ2hhcGVs?= <Ed Chapel@discussions.microsoft.com>>
wrote:
> In the following code (over-simplified, of course), the generic method calls
> itself recursively, quickly resulting in a StackOverflowException:
>
> public T[] GetArray<T>( T value )
> {
> return GetArray( value );
> }
>
> public Array GetArray( object value )
> {
> return return new ArrayList().ToArray();
> }
>
> I assumed the second method would be called because the notation of the call
> (lacking the 'generic' brackets) indicated the non-generic method would be
> called. Why does this behave this way?

It's using type inference to call the generic version without
explicitly stating the type involved. T is more specific than object,
hence the compiler is choosing the generic version over the non-generic
version.

If you cast value to object, your call will go to the non-generic
version.

You'd have to look at the specs in detail for the exact steps the
compiler will take.

--
Jon Skeet - <skeet@pobox.com>
http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
If replying to the group, please do not mail me too

That answers my question. Thank you! I learn something new everyday.

Ed

"Jon Skeet [C# MVP]" wrote:

> <=?Utf-8?B?RWQgQ2hhcGVs?= <Ed Chapel@discussions.microsoft.com>>
> wrote:
> > In the following code (over-simplified, of course), the generic method calls
> > itself recursively, quickly resulting in a StackOverflowException:
> >
> > public T[] GetArray<T>( T value )
> > {
> > return GetArray( value );
> > }
> >
> > public Array GetArray( object value )
> > {
> > return return new ArrayList().ToArray();
> > }
> >
> > I assumed the second method would be called because the notation of the call
> > (lacking the 'generic' brackets) indicated the non-generic method would be
> > called. Why does this behave this way?
>
> It's using type inference to call the generic version without
> explicitly stating the type involved. T is more specific than object,
> hence the compiler is choosing the generic version over the non-generic
> version.
>
> If you cast value to object, your call will go to the non-generic
> version.
>
> You'd have to look at the specs in detail for the exact steps the
> compiler will take.
>
> --
> Jon Skeet - <skeet@pobox.com>
> http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
> If replying to the group, please do not mail me too
>