Further information.
6.6.1 will compile it. Also brings down 6.8.1
ghc-6.8.1 -v -c /tmp/Bug.hs
Glasgow Haskell Compiler, Version 6.8.1, for Haskell 98, stage 2 booted by GHC version 6.6.1 Using package config file: /home/tora/lib/ghc-6.8.1/package.conf hiding package X11-1.2.3.1 to avoid conflict with later version X11-1.4.0 wired-in package base mapped to base-3.0.0.0 wired-in package rts mapped to rts-1.0 wired-in package haskell98 mapped to haskell98-1.0.1.0 wired-in package template-haskell mapped to template-haskell-2.2.0.0 wired-in package ndp not found. Hsc static flags: -static Created temporary directory: /tmp/ghc2997_0 *** Checking old interface for main:Bug: *** Parser: *** Renamer/typechecker:
/tmp/Bug.hs:36:24:
GHC internal error: `m' is not in scope In the type `m Safety' In the type `Alt -> m Safety' In the type signature for `isSafeAlt':
- isSafeAlt
- Alt -> m Safety
*** Deleting temp files: Deleting: /tmp/ghc2997_0/ghc2997_0.s Warning: deleting non-existent /tmp/ghc2997_0/ghc2997_0.s *** Deleting temp dirs: Deleting: /tmp/ghc2997_0