Distribution.Solver.Modular.Index

An index contains information about package instances. This is a nested dictionary. Package names are mapped to instances, which in turn is mapped to info.

Info associated with a package instance. Currently, dependencies, component names, flags and failure reasons. The component map records whether any components are unbuildable in the current environment (compiler, os, arch, and global flag constraints). Packages that have a failure reason recorded for them are disabled globally, for reasons external to the solver. We currently use this for shadowing which essentially is a GHC limitation, and for installed packages that are broken.

Info associated with each library and executable in a package instance.

Whether a component is visible in the current environment.

Whether a component is made unbuildable by a "buildable: False" field.