Hi Simon, Earlier today I noticed that the testsuite started failing with f723ba2f3b6d778f903fb1de4a5af93fe65eed10 due to break024 and break011. See https://phabricator.haskell.org/harbormaster/build/16407/ (I've included the output differences below). I've reverted the patch to keep the tree buildable but obviously feel free to commit again when it validates. Cheers, - Ben --- "/tmp/ghctest-zc_e5ng4/test spaces/./ghci.debugger/scripts/break011.run/break011.stdout.normalised" 2016-12-13 01:09:56.868988119 +0000 +++ "/tmp/ghctest-zc_e5ng4/test spaces/./ghci.debugger/scripts/break011.run/break011.run.stdout.normalised" 2016-12-13 01:09:56.868988119 +0000 @@ -40,17 +40,9 @@ CallStack (from HasCallStack): error, called at Test7.hs:<line>:<column> in <package-id>:Main Stopped in <exception thrown>, <unknown> -_exception :: e = SomeException - (ErrorCallWithLocation - "foo" - "CallStack (from HasCallStack): - error, called at Test7.hs:<line>:<column> in <package-id>:Main") +_exception :: e = _ Stopped in <exception thrown>, <unknown> -_exception :: e = SomeException - (ErrorCallWithLocation - "foo" - "CallStack (from HasCallStack): - error, called at Test7.hs:<line>:<column> in <package-id>:Main") +_exception :: e = _ *** Exception: foo CallStack (from HasCallStack): error, called at Test7.hs:<line>:<column> in <package-id>:Main --- "/tmp/ghctest-zc_e5ng4/test spaces/./ghci.debugger/scripts/break024.run/break024.stdout.normalised" 2016-12-13 01:09:57.464988119 +0000 +++ "/tmp/ghctest-zc_e5ng4/test spaces/./ghci.debugger/scripts/break024.run/break024.run.stdout.normalised" 2016-12-13 01:09:57.464988119 +0000 @@ -11,8 +11,7 @@ (GHC.IO.Exception.IOError Nothing GHC.IO.Exception.UserError [] "error" Nothing Nothing) Stopped in <exception thrown>, <unknown> -_exception :: e = SomeException - (GHC.IO.Exception.IOError Nothing GHC.IO.Exception.UserError ....) +_exception :: e = _ Stopped in <exception thrown>, <unknown> _exception :: e = _ _exception = SomeException