Unexpected conflict generic extension method signature mapping

[Thaina]

I made extension method with signature like this

public static T ConvertFromPath<T>(this DateTimeOffset date,params string[] paths) where T : class => throw new NotImplementedException();
public static T ConvertFromPath<T>(this DateTimeOffset date,string path,T defaultValue) where T : struct => throw new NotImplementedException();

// then use it like this

var intConvert	= DateTimeOffset.Now.ConvertFromPath("",0);
var string1Convert	= DateTimeOffset.Now.ConvertFromPath<string>("");

// above work fine but below got error

var string2Convert	= DateTimeOffset.Now.ConvertFromPath<string>("","");

// The type 'string' must be a non-nullable value type
// in order to use it as parameter 'T' in the generic type or method
// 'Ext.ConvertFromPath<T>(DateTimeOffset, string, T)'

Which I expect that when I put generic type as string it should map with the function with where T : class which just treat it as params string[] but it not. I think this is unexpected behavior of compiler

ps. The actual code is converter from database
ps2. should this be on roslyn?

[HaloFour]

Generic constraints aren't currently part of overload resolution. I believe that this would be covered by the existing championed proposal #98.

[gafter]

Constraints cannot be used to disambiguate methods. Yet. As @HaloFour points out, #98 is an open proposal that should make this work.