stack ghci at global level missing base

[MarcelineVQ]

Something recent, possibly the 5b58500 commit, is causing errors such as:

 <interactive>:1:19: error:
    Not in scope: ‘System.IO.hSetBuffering’
    No module named ‘System.IO’ is imported.

<interactive>:1:43: error:
    Not in scope: ‘System.IO.stdin’
    No module named ‘System.IO’ is imported.

<interactive>:1:60: error:
    Not in scope: data constructor ‘System.IO.NoBuffering’
    No module named ‘System.IO’ is imported.

When stack ghci is ran outside of any project's scope. These are resolved by specifying
stack ghci --package base

[snoyberg]

I think this is affecting intero as well, which recently stopped working for me. CC @mgsloan

[mgsloan]

Fixed in 196bdba thanks for the report @MarcelineVQ !

[effectfully]

I did stack upgrade --git, but I still see those errors about System.IO.

Here is how you can reproduce:

stack.yaml:

resolver: lts-9.13

nobase-bug.cabal:

name:                nobase-bug
version:             0.1.0.0
build-type:          Simple
cabal-version:       >= 1.2

executable nobase-bug
  hs-source-dirs:      src
  main-is:             Main.hs
  default-language:    Haskell2010
  default-extensions:  NoImplicitPrelude
  build-depends:       rerebase

src/Main.hs:

module Main where

import Prelude

main = return ()

Then run stack ghci inside the project.

[mgsloan]

@effectfully Are you sure that the stack binary written by upgrade is on your path? Ensure that stack --version reports 1.7.0

[effectfully]

@mgsloan, I checked it before reporting. Here is the output of stack --version:

Version 1.7.0, Git revision 6b9da26bf17c682a5db583f1a5484d4762467a82 x86_64 hpack-0.20.0

[mgsloan]

Huh! For me NoImplicitPrelude works with ghci 8.0.2 . I don't suppose stack ghc -- --version reports something else?

You might try switching to lts-10 (ghc 8.2). I can't find it now but IIRC there was a bug in ghc's tracker about NoImplicitPrelude + ghci. There is still a bug there for ghci + -XSafe

[effectfully]

stack ghc -- --version reports GHC is 8.0.2. NoImplicitPrelude + GHC-8.0.2 has been working just fine for me for month.

The funny thing is that if you comment out build-depends: rerebase, then stack ghci runs without any problems. Sorry, should have said this. So that dependency is crucial somehow. Do you have any ideas? A bug in GHC?

[snoyberg]

Sounds like ghci is getting confused about which System.IO to use, since rerebase is providing its own.

[effectfully]

@snoyberg, the errors would be different then:

<interactive>:1:6: error:
    Not in scope: ‘System.IO.hSetBuffering’
    No module named ‘System.IO’ is imported.

<interactive>:1:30: error:
    Not in scope: ‘System.IO.stdin’
    No module named ‘System.IO’ is imported.

<interactive>:1:46: error:
    Not in scope: data constructor ‘System.IO.NoBuffering’
    No module named ‘System.IO’ is imported.

<interactive>:1:70: error:
    Not in scope: ‘System.IO.hSetBuffering’
    No module named ‘System.IO’ is imported.

<interactive>:1:94: error:
    Not in scope: ‘System.IO.stdout’
    No module named ‘System.IO’ is imported.

<interactive>:1:111: error:
    Not in scope: data constructor ‘System.IO.NoBuffering’
    No module named ‘System.IO’ is imported.

<interactive>:1:135: error:
    Not in scope: ‘System.IO.hSetBuffering’
    No module named ‘System.IO’ is imported.

<interactive>:1:159: error:
    Not in scope: ‘System.IO.stderr’
    No module named ‘System.IO’ is imported.

<interactive>:1:176: error:
    Not in scope: data constructor ‘System.IO.NoBuffering’
    No module named ‘System.IO’ is imported.

[effectfully]

When I start intero and write import Prelude, I get Ambiguous interface for 'Prelude', so there is indeed some confusion, but :load in plain ghci works just fine.

I'm currently using intero as a text editor rather than an IDE and it's extremely annoying, I don't want to switch back to the cabal ecosystem just because there is a single bug, but this bug is total show stopper for me. Could you at least reopen the issue?

[mgsloan]

Sure.

What do you get for stack ghci -v? It will tell you how it is invoking ghci, please try to figure out how the invocation needs to change.

What do you get for stack exec -- ghc-pkg describe base ?

[effectfully]

I get

Run process: /home/effectfully/.stack/programs/x86_64-linux/ghc-8.0.2/bin/ghc --interactive -i -odir=/home/effectfully/code/nobase-bug/.stack-work/odir -hidir=/home/effectfully/code/nobase-bug/.stack-work/odir -hide-all-packages -package base -XNoImplicitPrelude -i/home/effectfully/code/nobase-bug/src -i/home/effectfully/code/nobase-bug/.stack-work/dist/x86_64-linux/Cabal-1.24.2.0/build/autogen -i/home/effectfully/code/nobase-bug/.stack-work/dist/x86_64-linux/Cabal-1.24.2.0/build -i/home/effectfully/code/nobase-bug/.stack-work/dist/x86_64-linux/Cabal-1.24.2.0/build/nobase-bug/nobase-bug-tmp -stubdir=/home/effectfully/code/nobase-bug/.stack-work/dist/x86_64-linux/Cabal-1.24.2.0/build -package-id=rerebase-1.0.3-GUoprUfp95pIfBD9KsEXFK -optP-include -optP/tmp/ghci26488/cabal_macros.h -ghci-script=/tmp/ghci26488/ghci-script

for stack ghci -v. I see -package base there, can this be a culprit?

stack exec -- ghc-pkg describe base results in

name: base
version: 4.9.1.0
...

Here is the full output.

I started to use -XPackageImports to disambiguate Prelude and even though intero "exits abnormally with code 1", type checking, go-to-definition and other tools except ghci work, so it's not a show stopper for me anymore. Still would be nice to get ghci working ofc.

[mgsloan]

Ah, this is indeed caused by 196bdbae9

The reason for -package base was that ghci doesn't start unless something providing these System.IO functions is in scope.

I fixed it! 99950cf

[effectfully]

I've checked, it works. Thank you.

[mgsloan]

Welcome! Thanks for verifying