(Also reported in https://github.com/dotnet/csharp-tmLanguage/tree/master/test)

• VSCode Version: Code 1.19.1 (0759f77, 2017-12-19T09:46:23.884Z)
• OS Version: Windows_NT x64 10.0.16299
• Extensions: none

Steps to Reproduce:

1. Create or open a C# file
2. Write a lambda expression in a LINQ Where clause where the variable name for the element starts with "ref". Example:

var refObjectsToKeep = allRefObjects.Where(refObject => refObject.ShouldKeep);

In Code, you will see that the C# syntax highlighting highlights the "ref" in "refObject" as if the first three characters were a reserved word. This does not seem to happen for other reserved words. For example, these highlight fine:

var intObjectsToKeep = allIntObjects.Where(intObject => intObject.ShouldKeep);
var outObjectsToKeep = allOutObjects.Where(outObject => outObject.ShouldKeep);

Reproduces without extensions: Yes