GHC blocks indefinitely on MVar at shutdown on Windows
Currently the stage2 ghc
fails to compile anything on Windows, dying with a "thread blocked indefinitely in an MVar operation". For instance,
Glasgow Haskell Compiler, Version 8.11.0.20200317, stage 2 booted by GHC version 8.8.3
*** initializing package database:
Using binary package database: C:\msys64\home\ben\ghc\_build\stage1\lib\package.conf.d\package.cache
There is no package.cache in C:\Users\ben\AppData\Roaming\ghc\x86_64-mingw32-8.11.0.20200317\package.conf.d, checking if the database is empty
...
*** CodeGen [Main]:
!!! CodeGen [Main]: finished in 46.88 milliseconds, allocated 35.786 megabytes
writeBinIface: 2 Names
writeBinIface: 128 dict entries
*** Deleting temp files:
Deleting: C:\msys64\tmp\ghc5608_0\ghc_1.s C:\msys64\tmp\ghc5608_0\ghc_2.s C:\msys64\tmp\ghc5608_0\ghc_3.c
Warning: deleting non-existent C:\msys64\tmp\ghc5608_0\ghc_1.s
Warning: deleting non-existent C:\msys64\tmp\ghc5608_0\ghc_3.c
*** Deleting temp dirs:
Deleting: C:\msys64\tmp\ghc5608_0
ghc.exe: panic! (the 'impossible' happened)
(GHC version 8.11.0.20200317:
thread blocked indefinitely in an MVar operation
Please report this as a GHC bug: https://www.haskell.org/ghc/reportabug