This is the same problem ashaskell/haskell-language-server#4579. I believe the "bug" is in the vscode extension so I opened this. Also, I can reproduce on linux with recent enough ghc versions, i.e starting with ghc-9.8.4.

The crux is that HLS is sending the URIs for the locally stored docs, e.g.

[Documentation](file:///home/vscode/.ghcup/ghc/9.8.4/share/doc/ghc-9.8.4/html/libraries/base-4.19.2.0-9fbd/System-IO.html#v:putStrLn)[Source](file:///home/vscode/.ghcup/ghc/9.8.4/share/doc/ghc-9.8.4/html/libraries/base-4.19.2.0-9fbd/src/System.IO.html#putStrLn)

andvscode-haskell does some mangling to point them to Hackage instead. Since ghc-9.8.4 the mangling is insufficient, as it keeps the-9fbd suffix in the URI, which is not correct.

The package directories are named$pkg_name-$pkg_ver-$hex where $hex is 4 hex digits. We want to drop the-$hex suffix, and since$pkg_ver cannot contain- it's actually unambiguous.