Version Used: .NET Core 3.0 preview 3, with Visual Studio 2019 (16.0)

Steps to Reproduce:

In a C# class file:

1. Declare an array: var numbers = Enumerable.Range(0,100).ToArray();
2. Start typing to get a span: Span<int> subRange = numbers[5..25];

Expected Behavior: The editor realizes I'm typing a Range expression.

Actual Behavior: As soon as I type 5., the editor assumes I want to access a member of System.Int32. I end up with numbers[5.CompareTo.25].