Parse error when using LambdaCase pragma

[jdnavarro]

It seems they are not supported yet by hlint, which is fine, but the the parse error makes hlint not to report any other suggestions for the file.

https://www.haskell.org/ghc/docs/latest/html/users_guide/syntax-extns.html#lambda-case

[ndmitchell]

This is a bug in the underlying haskell-src-exts library, tracked here: haskell-suite/haskell-src-exts#33

Unfortunately once there is a single parse error nothing else works, as that is by design of haskell-src-exts.

[nh2]

This is now implemented in HSE.

[ndmitchell]

The latest version of HLint, in conjunction with haskell-src-exts 1.15.0.1 should now work. (Thanks @nh2 for spotting this bug)

[robstewart57]

@ndmitchell Would it be worth setting haskell-src-exts-1.15.0.1 as a minimum version dependency within hlint?

[ndmitchell]

@robstewart57 In the past I've very much supported HSE versions as far back as could be reasonably done without C pre processor. The main reason is that people might have other things on their system that require the older haskell-src-exts, and thus it's better for HLint to be a bit more accommodating. That said, it's a popular request, and while it now works, it's not at all obvious that you need to upgrade HSE to get it working in HLint. I'm on the fence, so welcome other opinions.