Re: Strange behavior with method overload resolution

make that:

static void DoStuff(Type type, string input)
{
 object value;
 if (TryParse(input, out value))
 {
   // ...
 }
}

On 4/11/08, Sébastien Lorion <sebastien.loriongmail.com> wrote:
> Well, in my code I have another method similar to:
>
>  void DoStuff(Type type, string input)
>  {
>   object value;
>   if (TryParse(input, out value)
>   {
>     // ...
>   }
>  }
>
>  I made a mistake and forgot to pass "type"
to TryParse. I discovered
>  the bug only at runtime when testing my code. I can
understand the
>  compiler behavior, but it is not what I expect since I
think in most
>  case, the programmer did not intend to do that. A
warning would be
>  nice here IMO.
>
>  Sébastien
>
>
>  On 4/11/08, Greg Young <gregoryyoung1gmail.com> wrote:
>  >      object value;
>  >      Parser.TryParse(typeof(int), "1",
out value);
>  >
>  >
>  > is a valid call to the second (non-generic
method).
>  >
>  >
>  >  It would seem to me that it is then inferring T
as object here ...
>  >
>  >
>  >  return TryParse(input, out value);
>  >
>  >
>  > because if
>  >
>  >    public static bool TryParse<T>(string
input, out T value) value is
>  >  an object ... (and its a T) T must be an
object.
>  >
>  >
>  >  What were you expecting to be the error and
why?
>  >
>  >  Cheers,
>  >
>  >  Greg
>  >
>  >
>  >  On Fri, Apr 11, 2008 at 5:06 PM, Sébastien
Lorion
>  >  <sebastien.loriongmail.com> wrote:
>  >  > The following program outputs:
>  >  >
>  >  >  in Parse, type='System.Int32'
>  >  >  in Parse<T>, T='System.Object'
>  >  >
>  >  >  Is this behavior intended and if yes, why
? I would expect a compile error.
>  >  >
>  >  >
>  >  >
>  >  >  using System;
>  >  >
>  >  >  namespace ConsoleApplication1
>  >  >  {
>  >  >   class Program
>  >  >   {
>  >  >     static void Main(string[] args)
>  >  >     {
>  >  >       object value;
>  >  >       Parser.TryParse(typeof(int),
"1", out value);
>  >  >
>  >  >       Console.ReadLine();
>  >  >     }
>  >  >   }
>  >  >
>  >  >   class Parser
>  >  >   {
>  >  >     public static bool
TryParse<T>(string input, out T value)
>  >  >     {
>  >  >       Console.WriteLine("in
Parse<T>, T=''", typeof(T));
>  >  >
>  >  >       value = default(T);
>  >  >       return true;
>  >  >     }
>  >  >
>  >  >     public static bool TryParse(Type type,
string input, out object value)
>  >  >     {
>  >  >       Console.WriteLine("in Parse,
type=''", type);
>  >  >
>  >  >       return TryParse(input, out value);
>  >  >     }
>  >  >   }
>  >  >  }
>  >  >
>  >  >  --
>  >  >  Sébastien
>  >  >  www.sebastienlorion.com
>  >  >
>  >
>  > >  ===================================
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>  >  >
>  >
>  >
>  >
>  >
>  >  --
>  >  Studying for the Turing test
>  >
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>  >
>
>
>  --
>
> Sébastien
>  www.sebastienlorion.com
>


-- 
Sébastien
www.sebastienlorion.com

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