I just downloaded a fresh installation of the Haskell platform on Mac El Capitàn: brew cask install haskell-platform and a fresh installation of the Haskell layer for spacemacs: dotspacemacs-configuration-layers '( ;;; lots of other layers haskell)
However, I get errors on almost every keystroke in emacs
Try installing a more recent version of haskell-stack-ghc, and please open a bug report if the issue persists in the latest release. Thanks! Suspicious state from syntax checker haskell-stack-ghc: Flycheck checker haskell-stack-ghc returned non-zero exit code 1, but its output contained no errors: Downloading lts-10.0 build plan ... Downloaded lts-10.0 build plan. AesonException "Error in $.packages.cassava.constraints.flags['bytestring--lt-0_10_4']: Invalid flag name: \"bytestring--lt-0_10_4\""
This results in very slow operation as it (apparently) redownloads
lts-10.0 build plan on almost every keystroke.
The rest of the interface to the
ghci interpreter seems to work. The defect only affects my editing in Haskell mode.
I'd be grateful even for hacky workarounds not including just disabling Haskell-mode.