cabal vs ghc-mod part 2

cabal

alan@alan-haskell01:~/tmp-ghc-mod$ cat tmp-ghc-mod.cabal 
-- Initial tmp-ghc-mod.cabal generated by cabal init.  For further 
-- documentation, see http://haskell.org/cabal/users-guide/

name:                tmp-ghc-mod
version:             0.1.0.0
-- synopsis:            
-- description:         
-- license:             
license-file:        LICENSE
-- author:              
-- maintainer:          
-- copyright:           
-- category:            
build-type:          Simple
cabal-version:       >=1.10

library
  exposed-modules:   Test
  -- other-modules:       
  --build-depends:       base ==4.6.*
  build-depends:       base 
  default-language: Haskell2010

################################################################################
alan@alan-haskell01:~/tmp-ghc-mod$ ghc-mod debug
Root directory:      /home/alan/tmp-ghc-mod
Current directory:   /home/alan/tmp-ghc-mod
Cabal file:          Just "/home/alan/tmp-ghc-mod/tmp-ghc-mod.cabal"
GHC options:         -global-package-db -user-package-db -XHaskell2010
Include directories: /home/alan/tmp-ghc-mod /home/alan/tmp-ghc-mod/dist/build /home/alan/tmp-ghc-mod/dist/build/autogen
Dependent packages:  
System libraries:    /usr/lib/ghc

################################################################################



And here's another example with an obviously incorrect haskell file.

alan@alan-haskell01:~/tmp-ghc-mod$ cat Test.hs
module Test where

broken :: Int -> Int
broken a = a ++ " some text"


With cabal  file I get:
alan@alan-haskell01:~/tmp-ghc-mod$ ghc-mod check Test.hs 
Test.hs:1:1:Could not find module `Prelude'It is a member of the hidden package `base'.Perhaps you need to add `base' to the build-depends in your .cabal file.It is a member of the hidden package `haskell98-2.0.0.2'.Perhaps you need to add `haskell98' to the build-depends in your .cabal file.It is a member of the hidden package `haskell2010-1.1.1.0'.Perhaps you need to add `haskell2010' to the build-depends in your .cabal file.Use -v to see a list of the files searched for.


Without cabal file I get:
alan@alan-haskell01:~/tmp-ghc-mod$ ghc-mod check Test.hs 
Test.hs:4:12:Couldn't match expected type `[GHC.Types.Char]'            with actual type `GHC.Types.Int'In the first argument of `(GHC.Base.++)', namely `a'In the expression: a GHC.Base.++ " some text"In an equation for `broken': broken a = a GHC.Base.++ " some text"
Test.hs:4:12:Couldn't match expected type `GHC.Types.Int'            with actual type `[GHC.Types.Char]'In the expression: a GHC.Base.++ " some text"In an equation for `broken': broken a = a GHC.Base.++ " some text"


So better... but horribly verbose


###############################################################################################
ghc-mod debug output with cabal file

alan2@alan-haskell01:~/test1$ ghc-mod debug
Root directory:      /home/alan2/test1
Current directory:   /home/alan2/test1
Cabal file:          Just "/home/alan2/test1/test1.cabal"
GHC options:         -global-package-db -user-package-db -XHaskell98
Include directories: /home/alan2/test1 /home/alan2/test1/dist/build /home/alan2/test1/dist/build/autogen
Dependent packages:  
System libraries:    /usr/lib/ghc

without cabal file
alan2@alan-haskell01:~/test1$ ghc-mod debug
Root directory:      /home/alan2/test1
Current directory:   /home/alan2/test1
Cabal file:          Nothing
GHC options:         
Include directories: 
Dependent packages:  
System libraries:    /usr/lib/ghc