lsp: Simplifier phase 0/"main" not found

[unhammer]

When I turn this on, haskell-language-server just says Simplifier phase 0/"main" not found and gives none of the other hints. Is there some additional setup required to get this to work with lsp or should I just turn it off in .cabal while developing?

[harendra-kumar]

This happens because fusion-plugin requires optimization to be turned on. When you use it with ghci or with lsp which is the same thing, then you will get this error. Maybe we can add a workaround in the fusion-plugin so that it does nothing in this case. But for now you can put fusion-plugin under a build flag. When that flag is on makes sure optimization is on. Like in streamly-examples.cabal.

[unhammer]

OK, thanks, the workaround seems to do the trick :)