If anyone is running into the "mirrors.json is expired" issue, please see this issue for explanation and workaround:
Also, please feel free to weigh in with a vote on that issue.
Compiler thinks a type is different depending on where it is referenced
core:testas a separate target from
core:lib, so the arrow should look like
core:lib -> testlib:lib -> core:test
core:testthe same target in some way?
stack installbegins downloading some old ghc version
✗ stack install Preparing to install GHC to an isolated location. This will not interfere with any system-level installation. ghc-8.6.4: 406.53 KiB / 215.76 MiB ( 0.18%) downloaded...^C ➜ ptghci git:(master) ✗ cat ~/.stack/config.yaml # This file contains default non-project-specific settings for 'stack', used # in all projects. For more information about stack's configuration, see # http://docs.haskellstack.org/en/stable/yaml_configuration/ # system-ghc: true