Background

This issue tracks one of the BuildCheck analyzers we would like to ship in-box with MSBuild.

Goal

Implement an analyzer with the following rule: Properties whose name starts with an underscore should not be set in project files that are part of the project (as opposed to SDK project files).

Notes

By convention, the leading underscore is used to mark properties as internal to common targets or SDK, and not expected to be modified by the user.