hsc2hs-fail

This is a repro to show 2 problems

hsc2hs shipped with GHC 8.8.x reports wrong version

Set lts-15.5 as a resolver in stack.yaml this will give you

$ stack exec -- hsc2hs --version
hsc2hs version 0.68.5

At the same time stack build will finish with success while it should fail because only 0.68.6 includes the fix for quotes in *.hsc files

And uncommenting the lines

#build-tools:
#- hsc2hs >= 0.68.6

in package.yaml results in stack build ending up in an error from Cabal saying that 0.68.5 doesn't match the constraint >= 0.68.6.

Stack doesn't manage build-tools constraints

It appears that lts-14.27 includes hsc2hs-0.68.6 and with the lines

#build-tools:
#- hsc2hs >= 0.68.6

commented out we get a build failure because the version 0.68.5 from GHC-8.6.5 gets used. Uncommenting the constraint above gives a unsatisfied version failure from Cabal.

One could build hsc2hs manually with stack build hsc2hs and that adds the version 0.68.6 into the Stack's path:

$ stack exec -- hsc2hs --version
hsc2hs version 0.68.6

But it appears that stack build could only use hsc2hs shipped with GHC.