Below are my ghcup config -

I've I've created haskell project using stack with command stack new stack-hls-dbg-demo.

I then updated snapshot.url as below so that it uses ghc-9.10.1-

snapshot:
  url: .yaml

Then I run the command to install haskell-dap and ghci-dap stack install haskell-dap ghci-dap haskell-debug-adapter.

This command failed with below error -

prettyprinter > Building library for prettyprinter-1.7.1...

ghci-dap > [1 of 2] Compiling GHCi.DAP

prettyprinter > [ 1 of 28] Compiling Prettyprinter.Render.Util.Panic

ghci-dap > [2 of 2] Compiling Paths_ghci_dap prettyprinter > [ 2 of 28] Compiling Prettyprinter.Internal

ghci-dap > Preprocessing executable 'ghci-dap' for ghci-dap-0.0.22.0...

ghci-dap > Building executable 'ghci-dap' for ghci-dap-0.0.22.0...

ghci-dap > [1 of 6] Compiling GHCi.DAP.Constant

ghci-dap > [2 of 6] Compiling GHCi.DAP.Type

ghci-dap > /tmp/stack-d3fe2f06db4f403e/ghci-dap-0.0.22.0/app/GHCi/DAP/Type.hs:10:1: error: [GHC-87110]

ghci-dap > Could not find module ‘GHCi.GhcApiCompat’.

ghci-dap > Use -v to see a list of the files searched for.

ghci-dap > |

ghci-dap > 10 | import qualified GHCi.GhcApiCompat as GAC

ghci-dap > | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

ghci-dap >

Error: [S-7282] Stack failed to execute the build plan.
While executing the build plan, Stack encountered the error:
[S-7011] While building package ghci-dap-0.0.22.0 (scroll up to its section tosee the error) using: /home/raj/.stack/setup-exe-cache/x86_64-linux/Cabal-simple_w2MFVN35_3.12.0.0_ghc-9.10.1 --verbose=1 --builddir=.stack-work/dist/x86_64-linux/ghc-9.10.1 build --ghc-options " -fdiagnostics-color=always" Process exited with code: ExitFailure 1

How can I fix this error?

Stack version installed in my machine is -

Ghc version I'm using is 9.10.1

Below are my ghcup config -

I've I've created haskell project using stack with command stack new stack-hls-dbg-demo.

I then updated snapshot.url as below so that it uses ghc-9.10.1-

snapshot:
  url: https://raw.githubusercontent/commercialhaskell/stackage-snapshots/refs/heads/master/nightly/2025/2/15.yaml

Then I run the command to install haskell-dap and ghci-dap stack install haskell-dap ghci-dap haskell-debug-adapter.

This command failed with below error -

prettyprinter > Building library for prettyprinter-1.7.1...

ghci-dap > [1 of 2] Compiling GHCi.DAP

prettyprinter > [ 1 of 28] Compiling Prettyprinter.Render.Util.Panic

ghci-dap > [2 of 2] Compiling Paths_ghci_dap prettyprinter > [ 2 of 28] Compiling Prettyprinter.Internal

ghci-dap > Preprocessing executable 'ghci-dap' for ghci-dap-0.0.22.0...

ghci-dap > Building executable 'ghci-dap' for ghci-dap-0.0.22.0...

ghci-dap > [1 of 6] Compiling GHCi.DAP.Constant

ghci-dap > [2 of 6] Compiling GHCi.DAP.Type

ghci-dap > /tmp/stack-d3fe2f06db4f403e/ghci-dap-0.0.22.0/app/GHCi/DAP/Type.hs:10:1: error: [GHC-87110]

ghci-dap > Could not find module ‘GHCi.GhcApiCompat’.

ghci-dap > Use -v to see a list of the files searched for.

ghci-dap > |

ghci-dap > 10 | import qualified GHCi.GhcApiCompat as GAC

ghci-dap > | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

ghci-dap >

Error: [S-7282] Stack failed to execute the build plan.
While executing the build plan, Stack encountered the error:
[S-7011] While building package ghci-dap-0.0.22.0 (scroll up to its section tosee the error) using: /home/raj/.stack/setup-exe-cache/x86_64-linux/Cabal-simple_w2MFVN35_3.12.0.0_ghc-9.10.1 --verbose=1 --builddir=.stack-work/dist/x86_64-linux/ghc-9.10.1 build --ghc-options " -fdiagnostics-color=always" Process exited with code: ExitFailure 1

How can I fix this error?

Stack version installed in my machine is -

Ghc version I'm using is 9.10.1

• haskell
• ghc
• haskell-stack
• ghci

• I don't have detailed diagnostics for this specific issue, but do you really need to depend on a nightly build rather than something more stable? In most open-source packages, nightlies are quite bleeding-edge, and I would expect to cut myself often if I depended on one unless I were intimately involved with development of that project itself. – amalloy Commented Feb 16 at 4:33

1 Answer 1

It looks like ghci-dap build is somewhat broken in certain versions (issue).

I solved it by pinning ghci-dap to 0.0.24.0 in extra-deps (I did it for global project (global-project\stack.yaml)):

extra-deps:
  - haskell-dap-0.0.16.0
  - ghci-dap-0.0.24.0