Adding `{-# OPTIONS_GHC -Wno-all #-}` at the top of the file makes HLS cease to report errors, not only warnings.

### Your environment

Which OS do you use? ArchLinux.

Which version of GHC do you use and how did you install it? 9.4.8, via `ghcup`.

How is your project built (alternative: link to the project)? With Cabal.

Which LSP client (editor/plugin) do you use? `emacs` and `lsp-mode`.

Which version of HLS do you use and how did you install it? 2.5.0.0, 2.7.0.0, 2.9.0.1, via `ghcup`.

Have you configured HLS in any way (especially: a `hie.yaml` file)? No. `gen-hie > hie.yaml` has no effect.

### Steps to reproduce

Create a file like so:

```ghc
{-# OPTIONS_GHC -Wno-all #-}

module Example where

f :: Int
f = g
```

Run `haskell-language-server-wrapper Example.hs`.

### Expected behaviour

`g` is not in scope; GHC could not compile this file. HLS should show this error to me in the editor and when running from the command line.

### Actual behaviour

HLS does not report the error.

### Debug information

Reproduce the issue with the Example.hs contents and run haskell-language-server-wrapper Example.hs, then inspect the debug information in the linked gist. Trace why the `-Wno-all` option suppresses the out-of-scope error, and verify that HLS reports `g` as not in scope both in the editor and on the command line.

Written by the indexing model from the issue text.