Rendering templates fails for a project opened using Package.swift in Xcode 11

[kylebshr]

This seems a little bizarre, but if I open my project using Package.swift in Xcode 11, routes rendering stencil templates fail to render with the error unableToRenderContext. If I generate an Xcode project with swift package generate-xcodeproj, and build and run using the Xcode project, the template renders with no issues.

I can reproduce this on my project here in Xcode 11.2.1, on both Catalina and Mojave: https://github.com/kylebshr/mustache.cc