haskell / haskell/haskell-language-server

BadDependency "GetLinkable"

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#4,721 7 comments 3 reactions 0 assignees View on GitHub
component: hls-eval-plugin type: bug
Dominant language
Haskell
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Description

This is a weird error/bug that is maybe related to my local setup.

Usually, the `eval` plugin works just fine, but there is a specific project where it does not, and instead reports `BadDependency "GeLinkable"`. The specific error I get in the editor console is
```
LSP :: Error condition, please check your setup and/or the [issue tracker](https://github.com/haskell/haskell-language-server/issues):
eval: Internal Error: BadDependency "GetLinkable"
lsp-workspace-command-execute: ‘workspace/executeCommand’ with ‘16405:eval:evalCommand’ failed.

(error "eval: Internal Error: BadDependency \"GetLinkable\"")
```

The HLS debug output is not informative at all (see below).

```
2025-09-04T04:40:51.338332Z | Debug | Restarting build session due to Eval
Action Queue: []
Keys: [ IsEvaluating; /home/dominik/work/hs-bindgen/hs-bindgen/src-internal/HsBindgen/Frontend/AST/PrettyPrinter.hs ]
Aborting previous build session took 0.00s
toIfaceIdDetails [ClassOp]
toIfaceIdDetails [ClassOp]
toIfaceIdDetails [DataConWrapper]
toIfaceIdDetails [DataConWrapper]
toIfaceIdDetails [ClassOp]
toIfaceIdDetails [ClassOp]
toIfaceIdDetails [DataConWrapper]
toIfaceIdDetails [DataConWrapper]
toIfaceIdDetails [ClassOp]
toIfaceIdDetails [ClassOp]
toIfaceIdDetails [ClassOp]
... (MANY MORE)
... THEN AGAIN:
2025-09-04T04:40:53.881170Z | Debug | Finished build session
AsyncCancelled
2025-09-04T04:40:53.881322Z | Debug | Restarting build session due to Eval
Action Queue: []
Keys: [ IsEvaluating; /home/dominik/work/hs-bindgen/hs-bindgen/src-internal/HsBindgen/Frontend/AST/PrettyPrinter.hs ]
Aborting previous build session took 0.00s
2025-09-04T04:40:53.881665Z | Error | eval: Internal Error: BadDependency "GetLinkable"
```

Is there anything I can do to debug this issue a bit more methodologically? I do not really know where to start :-).

### Your environment

#### Which OS do you use?
- NixOS

#### Which version of GHC do you use and how did you install it?

- The Glorious Glasgow Haskell Compilation System, version 9.12.2
- Installed via Nix Flake

#### How is your project built (alternative: link to the project)?

- cabal-install version 3.14.2.0
- compiled using version 3.14.2.0 of the Cabal library
- https://github.com/well-typed/hs-bindgen

#### Which LSP client (editor/plugin) do you use?

Emacs with `lsp-mode` with `lsp-haskell`

#### Have you configured HLS in any way (especially: a `hie.yaml` file)?

No

### Steps to reproduce

Open a file in the project, try to evaluate a declaration

Contributor guide

No contributing guide indexed for this repository

Research direction

Reproduce the failure in hs-bindgen using GHC 9.12.2, Cabal 3.14.2.0, Emacs with lsp-mode, and the eval action on HsBindgen/Frontend/AST/PrettyPrinter.hs. Start with the HLS debug output and the eval plugin path; done means the BadDependency "GetLinkable" failure is explained and a diagnostic or fix is identified.

Written by the indexing model from the issue text.

Assessment

Tech stack
emacs, haskell
Domain
developer-experience, tooling
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Quiet
Clarity
Needs clarification
Newbie friendliness
35/100

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