C#: upgrade Roslyn dependencies to version 3.7

[tamasvajk]

No description provided.

[tamasvajk]

I think this is expected to fail, because the tests can't build a new codeql CLI without the new dependencies.

[tamasvajk]

Tuple<T1,T2,T3,T4,T5,T6,T7,TRest> and similar are IsTupleType == true, but TupleUnderlyingType == null

[tamasvajk]

this might be null see, below.

[tamasvajk]

TupleUnderlyingType is not a NamedType, but a TupleType.

[tamasvajk]

With these changes the extracted data changed too. I found the following

#  | [InstanceConstructor] ValueTuple
#--|   2: (Parameters)

in the print ast expected files.

@hvitved Didn't you fix something similar during the assembly prefix PR?

[tamasvajk]

I'm not sure I understand the case covered by the quoted comment. Is it the following:

using System;

interface IA
{
	int Prop
	{
		get;
	}
}

interface IB : IA
{
}

class C : IB
{
	int IA.Prop // Does this property explicitly implement both IA and IB?
	{
		get
		{
			return 1;
		}
	}

	public int Prop
	{
		get
		{
			return 2;
		}
	}
}

public class Program
{
	public static void Main()
	{
		var c = new C();
		Console.WriteLine(c.Prop); // 2
		Console.WriteLine(((IA)c).Prop); // 1
		Console.WriteLine(((IB)c).Prop); // 1
	}
}