#16095: Infinite loop during error reporting (ignores SIGINT/SIGTERM, then OOMs) -------------------------------------+------------------------------------- Reporter: _deepfire | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.6.1 Resolution: | Keywords: Operating System: Linux | Architecture: Type of failure: Compile-time | Unknown/Multiple crash or panic | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Description changed by _deepfire: Old description:

Compiling the repro snippet produces the following incomplete output and hangs GHC: {{{ $ ghc repro.hs [1 of 1] Compiling Main ( repro.hs, repro.o )

repro.hs:16:22: error: }}}

The GHC process ignores SIGINT -- so it must be killed with SIGKILL. The memory usage grows, until it consumes all memory (~30G RAM + swap) and is terminated by the OOM killer.

This minimal snippet depends on `generics-sop` (tested with version `0.4.0.0`). Sadly I didn't find a constraint in `base` to cause this behavior..

{{{#!hs {-# LANGUAGE FlexibleInstances #-} {-# LANGUAGE MultiParamTypeClasses #-} {-# LANGUAGE TypeFamilies #-}

import Generics.SOP (HasDatatypeInfo)

data family TF i a :: * data instance TF i a = R

class C i a where method :: TF i a

instance C i () where

instance HasDatatypeInfo a => C i a where method = undefined function

function :: C i a => TF i a function = method

main = undefined }}}

New description: Compiling the repro snippet produces the following incomplete output and hangs GHC: {{{ $ ghc repro.hs [1 of 1] Compiling Main ( repro.hs, repro.o ) repro.hs:16:22: error: }}} The GHC process ignores SIGINT -- so it must be killed with SIGKILL. The memory usage grows, until it consumes all memory (~30G RAM + swap) and is terminated by the OOM killer. This minimal snippet depends on `generics-sop` (tested with version `0.4.0.0`). Sadly I didn't find a constraint in `base` to cause this behavior.. {{{#!hs {-# LANGUAGE FlexibleInstances #-} {-# LANGUAGE MultiParamTypeClasses #-} {-# LANGUAGE TypeFamilies #-} import Generics.SOP (HasDatatypeInfo) data family TF i a :: * data instance TF i a = R class C i a where method :: TF i a instance C i () where instance HasDatatypeInfo a => C i a where method = undefined function function :: C i a => TF i a function = method main = undefined }}} Affects 8.4.3 and 8.6.1. Not tested on 8.6.2 & 8.6.3. -- -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/16095#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler

#16095: Infinite loop during error reporting (ignores SIGINT/SIGTERM, then OOMs) -------------------------------------+------------------------------------- Reporter: _deepfire | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.6.1 Resolution: | Keywords: Operating System: Linux | Architecture: Type of failure: Compile-time | Unknown/Multiple crash or panic | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by _deepfire): Another, different repro for what seems to be a related problem: {{{#!hs {-# LANGUAGE AllowAmbiguousTypes #-} {-# LANGUAGE DataKinds #-} {-# LANGUAGE GADTs #-} {-# LANGUAGE KindSignatures #-} {-# LANGUAGE ScopedTypeVariables #-} {-# LANGUAGE TypeApplications #-} {-# LANGUAGE TypeOperators #-} module Repro where import Generics.SOP recover :: forall a xs. (Code a ~ '[xs], HasDatatypeInfo a) => a recover = case datatypeInfo (Proxy @a) :: DatatypeInfo '[xs] of Newtype _ _ _ -> let sop :: NP [] xs = (undefined :: forall c xs . All c xs => NP [] xs) in undefined }}} ..once again, dependent on `generics-sop`. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/16095#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler