id,summary,reporter,owner,description,type,status,priority,milestone,component,version,resolution,keywords,cc,os,architecture,failure,difficulty,testcase,blockedby,blocking,related
4845,internal error: threadStackUnderflow: not enough space for return values,igloo,simonmar,"With (the type-incorrect) `Foo.hs`:
{{{
module Foo where

import Data.Char
import System.Directory

main :: IO ()
main = do return ()
          return ()
          return ()
          return ()
          return ()
          return ()
          return ()
          return ()
          return ()
          let xs :: [(Int, Bool, Char, Char, Char)]
              xs = undefined
          mapM_ f xs
          return ()
          return ()

f :: (Int, Char, Char, Char) -> IO ()
f _ = return ()

f1 :: IO ()
f1 = return ()

f2 :: IO ()
f2 = return ()

f3 :: IO ()
f3 = return ()

f4 :: IO ()
f4 = return ()
}}}
I get:
{{{
$ ghci Foo.hs
GHCi, version 7.1.20101216: http://www.haskell.org/ghc/  :? for help
Loading package ghc-prim ... linking ... done.
Loading package integer-gmp ... linking ... done.
Loading package base ... linking ... done.
Loading package ffi-1.0 ... linking ... done.
[1 of 1] Compiling Foo              ( Foo.hs, interpreted )
ghc-stage2: internal error: threadStackUnderflow: not enough space for return values
    (GHC version 7.1.20101216 for x86_64_unknown_linux)
    Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug
}}}
",bug,closed,highest,7.4.1,Runtime System,7.1,fixed,,,Unknown/Multiple,Unknown/Multiple,GHCi crash,,,,,