I have problems installing ghc-mod on my linux machine. cabal worries about "happy" not being available in versione >= 1.17:

$ cabal install ghc-mod
Resolving dependencies...
[1 of 1] Compiling Main             ( /tmp/haskell-src-exts-1.14.0-1357/haskell-src-exts-1.14.0/Setup.hs, /tmp/haskell-src-exts-1.14.0-1357/haskell-src-exts-1.14.0/dist/setup/Main.o )
Linking /tmp/haskell-src-exts-1.14.0-1357/haskell-src-exts-1.14.0/dist/setup/setup ...
Configuring haskell-src-exts-1.14.0...
setup: The program happy version >=1.17 is required but it could not be found.
Failed to install haskell-src-exts-1.14.0
cabal: Error: some packages failed to install:
ghc-mod-3.1.3 depends on haskell-src-exts-1.14.0 which failed to install.
haskell-src-exts-1.14.0 failed during the configure step. The exception was:
ExitFailure 1
hlint-1.8.53 depends on haskell-src-exts-1.14.0 which failed to install.

However, it even is installed in v. 1.19, as you can see here:

$ cabal install happy
Resolving dependencies...
[1 of 1] Compiling Main             ( /tmp/happy-1.19.0-1124/happy-1.19.0/Setup.lhs, /tmp/happy-1.19.0-1124/happy-1.19.0/dist/setup/Main.o )
Linking /tmp/happy-1.19.0-1124/happy-1.19.0/dist/setup/setup ...
Configuring happy-1.19.0...
Building happy-1.19.0...
Preprocessing executable 'happy' for happy-1.19.0...
[ 1 of 18] Compiling NameSet          ( src/NameSet.hs, dist/build/happy/happy-tmp/NameSet.o )
[ 2 of 18] Compiling Target           ( src/Target.lhs, dist/build/happy/happy-tmp/Target.o )
[ 3 of 18] Compiling AbsSyn           ( src/AbsSyn.lhs, dist/build/happy/happy-tmp/AbsSyn.o )
[ 4 of 18] Compiling ParamRules       ( src/ParamRules.hs, dist/build/happy/happy-tmp/ParamRules.o )
[ 5 of 18] Compiling GenUtils         ( src/GenUtils.lhs, dist/build/happy/happy-tmp/GenUtils.o )
[ 6 of 18] Compiling ParseMonad       ( src/ParseMonad.lhs, dist/build/happy/happy-tmp/ParseMonad.o )
[ 7 of 18] Compiling Lexer            ( src/Lexer.lhs, dist/build/happy/happy-tmp/Lexer.o )
[ 8 of 18] Compiling Parser           ( dist/build/happy/happy-tmp/Parser.hs, dist/build/happy/happy-tmp/Parser.o )
[ 9 of 18] Compiling AttrGrammar      ( src/AttrGrammar.lhs, dist/build/happy/happy-tmp/AttrGrammar.o )
[10 of 18] Compiling AttrGrammarParser ( dist/build/happy/happy-tmp/AttrGrammarParser.hs, dist/build/happy/happy-tmp/AttrGrammarParser.o )
[11 of 18] Compiling Grammar          ( src/Grammar.lhs, dist/build/happy/happy-tmp/Grammar.o )
[12 of 18] Compiling First            ( src/First.lhs, dist/build/happy/happy-tmp/First.o )
[13 of 18] Compiling LALR             ( src/LALR.lhs, dist/build/happy/happy-tmp/LALR.o )
[14 of 18] Compiling Paths_happy      ( dist/build/autogen/Paths_happy.hs, dist/build/happy/happy-tmp/Paths_happy.o )
[15 of 18] Compiling ProduceCode      ( src/ProduceCode.lhs, dist/build/happy/happy-tmp/ProduceCode.o )
[16 of 18] Compiling ProduceGLRCode   ( src/ProduceGLRCode.lhs, dist/build/happy/happy-tmp/ProduceGLRCode.o )
[17 of 18] Compiling Info             ( src/Info.lhs, dist/build/happy/happy-tmp/Info.o )
[18 of 18] Compiling Main             ( src/Main.lhs, dist/build/happy/happy-tmp/Main.o )
Linking dist/build/happy/happy ...
Installing executable(s) in /home/hope/.cabal/bin
Installed happy-1.19.0

Any ideas?

cabal-install version 1.16.0.2
using version 1.16.0 of the Cabal library