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POOpen instance delegates to value types
 

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    <p>Delegate.CreateDelegate fails when I try to create open instance delegates to value type methods that implement interfaces. Because the instance method is on a value type, the first argument must be a ref, so let's define a general delegate type for this:</p> <pre><code>delegate T2 VF&lt;T0, T1, T2&gt;(ref T0 arg0, T1 arg1); </code></pre> <p>Now here's a program that succeeds in creating an open instance delegate to int.ToString(string), but fails to create an open instance delegate to int.Equals(int):</p> <pre><code>class Program { static void Main(string[] args) { var tos = typeof(int).GetMethod("ToString", new[] { typeof(string) }); var tosopen = Delegate.CreateDelegate( typeof(VF&lt;int, string, string&gt;), null, tos); // success! var eq = typeof(int).GetMethod("Equals", new[] { typeof(int) }); var eqopen = Delegate.CreateDelegate( typeof(VF&lt;int, int, bool&gt;), null, eq); // previous line fails with "Error binding to target method" } } </code></pre> <p>This seems to be due to the fact that int.Equals(int) implements <code>IEquatable&lt;int&gt;</code>. Note that the following <em>does</em> work:</p> <pre><code>var x = typeof(IEquatable&lt;int&gt;).GetMethod("Equals", new Type[] { typeof(int) }); var xopen = Delegate.CreateDelegate( typeof(Func&lt;IEquatable&lt;int&gt;, int, bool&gt;), null, x); xopen(1,1); // returns true </code></pre> <p>But this isn't exactly what I want, since this would seem to box any integers passed as the first argument. I also don't want to compare any <code>IEquatable&lt;int&gt;</code>, I want to specifically call the method to compare two ints.</p> <p>Any thoughts on what's wrong here?</p> <p>A Microsoft Connect bug was <a href="https://stackoverflow.com/a/4326917/144873">mentioned here</a> that seems directly related, but that link no longer works for me, and I can't find that bug by searching.</p> <p>Edit: note that the same problem occurs when trying to create open instance delegates to overridden methods, so it's not just interface methods.</p>
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