public static void IsNullCheck(string check)
{
var code = @"
namespace N
{
using System;
class C
{
bool M(string text) => text == null;
}
}".AssertReplace("text == null", check);
var syntaxTree = CSharpSyntaxTree.ParseText(code);
var expression = syntaxTree.Find <ExpressionSyntax>(check);
Assert.AreEqual(true, NullCheck.IsNullCheck(expression, default, default, out var value));
