anchor.diff:    # https://github.com/josefs/STMonadTrans/issues/4
     STMonadTrans = dontCheck super.STMonadTrans;
   
  -  socket_0_7_0_0 = super.socket_0_7_0_0.overrideScope (self: super: { QuickCheck = self.QuickCheck_2_9_2; });
  -
  -  # requires most recent vty
  -  brick = super.brick.overrideScope (self: super: { vty = self.vty_5_15; });
  -
  -  turtle_1_3_1 = super.turtle_1_3_1.overrideScope (self: super: {
  -    optparse-applicative = self.optparse-applicative_0_13_0_0;
  -  });
  -
     # No upstream issue tracker
     hspec-expectations-pretty-diff = dontCheck super.hspec-expectations-pretty-diff;
   
     lentil = super.lentil.overrideScope (self: super: {
       pipes = self.pipes_4_3_2;
  -    optparse-applicative = self.optparse-applicative_0_13_0_0;
       # https://github.com/roelvandijk/terminal-progress-bar/issues/14
       terminal-progress-bar = doJailbreak self.terminal-progress-bar_0_1_1;
     });
  
positive.code:   # Needs new version.
    haskell-src-exts-simple = super.haskell-src-exts-simple.override { haskell-src-exts = self.haskell-src-exts_1_19_1; };
  
    # Test suite fails a QuickCheck property.
    optparse-applicative_0_13_0_0 = dontCheck super.optparse-applicative_0_13_0_0;
  
    # https://github.com/Philonous/hs-stun/pull/1
    # Remove if a version > 0.1.0.1 ever gets released.
    stunclient = overrideCabal super.stunclient (drv: {
  
negative.code: 
    # https://github.com/bos/math-functions/issues/25
    math-functions = dontCheck super.math-functions;
  
    # Fix build for latest versions of servant and servant-client.
    servant_0_10 = super.servant_0_10.overrideScope (self: super: {
  