The PathMap compiler switch can be specified in a project file (or a Directory.Build.props) file to normalize directory names in the compiler-produced outputs (specifically PDBs and assemblies that utilize the CallerFileNameAttribute). See
https://github.com/dotnet/roslyn/issues/949 for details.
In projects that utilize this feature, NCrunch does not display line markers, and links to the source code stop working in test stack traces if the expected file does not exist at the rewritten path.