ghci leaks memory

The following script spawns ghci, and that spawned ghci then goes on to leak memory:

import Control.Concurrent
import Control.Monad
import System.IO
import System.Process

main = do
    (Just hin, Nothing, Nothing, pid) <- createProcess (proc "ghci" ["+RTS","-S"]){std_in=CreatePipe}
    forever $ do
        threadDelay 100000 -- 0.1s
        hPutStrLn hin "\"this is a test of outputting stuff\""
        hFlush hin

This script just writes a string to GHCi, which then echos it back. The +RTS -S is useful to watch the live memory tick up in realtime, but it leaks without it, and the leak can be seen in process explorer (87Mb to 700Mb over about 30 minutes).

While repeatedly writing commands may not be a standard usage of ghci, it is when driven by tools such as ghcid (https://hackage.haskell.org/package/ghcid) and other IDE-like uses.

Trac metadata

Trac field	Value
Version	8.2.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	GHCi
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