IntelliSense does not understand lambda parameter type, when overloaded with defaultValue

[Suchiman]

Version Used: VS2015.2

Steps to Reproduce:

using System;
using System.Collections.Generic;

public static class Program
{
    public static void Main()
    {
        var parameter = new List<string>();
        var result = parameter.FirstOrDefault(x => x$);
    }
}

public static class Enumerable
{
    public static TSource FirstOrDefault<TSource>(this IEnumerable<TSource> source, TSource defaultValue)
    {
        return default(TSource);
    }

    public static TSource FirstOrDefault<TSource>(this IEnumerable<TSource> source, Func<TSource, bool> predicate, TSource defaultValue)
    {
        return default(TSource);
    }
}

1. Set cursor to $
2. Type . and get no IntelliSense

Expected Behavior:
IntelliSense picks the correct overload and suggests that the type of x is string, providing member completion.

Actual Behavior:

If you change the FirstOrDefault<TSource>(this IEnumerable<TSource> source, Func<TSource, bool> predicate, TSource defaultValue) overload to FirstOrDefault<TSource>(this IEnumerable<TSource> source, Func<TSource, bool> predicate), then it works as expected

[Pilchie]

I suspect that this is an issue with SemanticModel.LookupSymbols, but can you double-check and move to compiler if so?

[rchande]

@cston I debugged this and it looks like GetSymbolInfo/GetTypeInfo on the reference to x both return nothing after you type ..

The relevant IDE code is here

[rchande]

Moving to compiler.

[jaredpar]

@Pilchie, @DustinCampbell is this just another instance of #11619?