This is a new problem I've never seen before. It's occurring in an open source wrapper for LibCURL.NET:
http://sourceforge.net/projects/libcurl-net/
I am getting an ambiguous reference "warning as error", but the odd part is that it's happening due to a CREF reference in one of the LibCURL source files (see below). There are indeed several different overloads for for the method named Easy.GetInfo(), but I have no idea how to fix this since the offending code isn't a method call to Easy.GetInfo(), in fact it isn't code at all, but instead it's a CREF element in the comments for an Enum. Does anyone know how to fix this?
/// <summary>
/// This enumeration is used to extract information associated with an
/// <see cref="Easy"/> transfer. Specifically, a member of this
/// enumeration is passed as the first argument to
/// <see cref="Easy.GetInfo"/> specifying the item to retrieve in the
/// second argument, which is a reference to an <c>int</c>, a
/// <c>double</c>, a <c>string</c>, a <c>DateTime</c> or an <c>object</c>.
/// </summary>
public enum CURLINFO
{
...
Note: I re-targeted LibCURL.NET for the .NET framework version 4.5.1. I am mentioning this in case it might be related.