Sub DoSomething(foo As Integer)
        DoSomethingElse foo
    End Sub

    Sub DoSomethingElse(ByRef bar As Integer)
        bar = 42
    End Sub

var procedureCalls = parameter.References.Select(s => s.ParentScoping);

var procedureCalls = items.Where(item => item.DeclarationType.HasFlag(DeclarationType.Member))
    .SelectMany(member => member.References.Where(reference => reference.ParentScoping.Equals(parameter.ParentScopeDeclaration)))
    .GroupBy(call => call.Declaration)
    .ToList();

    Sub DoSomething(foo As Integer)
        DoSomethingElse foo
    End Sub

    Sub DoSomethingElse(ByRef bar As Integer)
        bar = 42
    End Sub

    Sub DoSomething(foo As Integer)
        DoSomethingElse foo
    End Sub

    Sub DoSomethingElse(ByVal bar As Integer)

    End Sub

    Sub DoSomething(foo As Integer)
        DoSomethingElse foo
    End Sub

    Sub DoSomethingElse(ByVal bar As Integer)
        bar = 42
    End Sub

foreach (var reference in item.References)
{
    if (!(reference.Context is VBAParser.ArgContext))
    {
        continue;
    }
    var context = ((dynamic)reference.Context.Parent).argsCall() as VBAParser.ArgContext;
    if (context == null)
    {
        continue;
    }
    if (parameter.IdentifierName == context.GetText())
    {
        return true;
    }
}