title: stack install ghc-mod fails with dependencies conflicts on OSX 10.13.4
body: <p>When I try to install ghc-mod via stack I end up having these depencies conflicts</p>
  
  <pre><code>Error: While constructing the build plan, the following exceptions were encountered:
  
  In the dependencies for ghc-mod-5.8.0.0:
      Cabal-2.0.1.1 from stack configuration does not match &gt;=1.18 &amp;&amp; &lt;1.25  (latest matching version is 1.24.2.0)
      base-4.10.1.0 from stack configuration does not match &gt;=4.6.0.1 &amp;&amp; &lt;4.10  (latest matching version is 4.9.1.0)
      cabal-helper must match &lt;0.8 &amp;&amp; &gt;=0.7.3.0, but the stack configuration has no specified version  (latest matching version is 0.7.3.0)
      extra-1.6.8 from stack configuration does not match &lt;1.6 &amp;&amp; &gt;=1.4  (latest matching version is 1.5.3)
      ghc-8.2.2 from stack configuration does not match &gt;=7.6 &amp;&amp; &lt;8.2
      haskell-src-exts-1.20.2 from stack configuration does not match &lt;1.20 &amp;&amp; &gt;=1.18  (latest matching version is 1.19.1)
      hlint-2.1.6 from stack configuration does not match &lt;2.1 &amp;&amp; &gt;=2.0.8  (latest matching version is 2.0.15)
      monad-journal-0.8.1 from stack configuration does not match &lt;0.8 &amp;&amp; &gt;=0.4  (latest matching version is 0.7.2)
      optparse-applicative-0.14.2.0 from stack configuration does not match &gt;=0.13.0.0 &amp;&amp; &lt;0.14  (latest matching version is 0.13.2.0)
  needed since ghc-mod is a build target.
  
  Some different approaches to resolving this:
  
    * Consider trying 'stack solver', which uses the cabal-install solver to attempt to find some working build configuration. This can be convenient when dealing with many complicated constraint
      errors, but results may be unpredictable.
  
    * Recommended action: try adding the following to your extra-deps in /Users/mo/.stack/global-project/stack.yaml:
  
  - Cabal-1.24.2.0
  - base-4.9.1.0
  - cabal-helper-0.7.3.0
  - extra-1.5.3
  - haskell-src-exts-1.19.1
  - hlint-2.0.15
  - monad-journal-0.7.2
  - optparse-applicative-0.13.2.0
  </code></pre>
  
  <p>if I try to add the suggested extra deps like so</p>
  
  <pre><code>extra-deps:
  - Cabal-1.24.2.0
  - base-4.9.1.0
  - cabal-helper-0.7.3.0
  - extra-1.5.3
  - haskell-src-exts-1.19.1
  - hlint-2.0.15
  - monad-journal-0.7.2
  - optparse-applicative-0.13.2.0
  - process-1.4.3.0
  - either-4.4.1.1
  - free-4.12.4
  </code></pre>
  
  <p>I end up having a loop like this </p>
  
  <pre><code>    Error: While constructing the build plan, the following exceptions were encountered:
  
  In the dependencies for ghc-mod-5.8.0.0:
      base-4.10.1.0 from stack configuration does not match &gt;=4.6.0.1 &amp;&amp; &lt;4.10  (latest matching version is 4.9.1.0)
      ghc-8.2.2 from stack configuration does not match &gt;=7.6 &amp;&amp; &lt;8.2
  needed since ghc-mod is a build target.
  
  In the dependencies for haskell-src-exts-util-0.2.3:
      haskell-src-exts-1.19.1 from stack configuration does not match &gt;=1.20.0  (latest matching version is 1.20.2)
  needed due to ghc-mod-5.8.0.0 -&gt; haskell-src-exts-util-0.2.3
  
  In the dependencies for hlint-2.0.15:
      haskell-src-exts-1.19.1 from stack configuration does not match &gt;=1.20 &amp;&amp; &lt;1.21  (latest matching version is 1.20.2)
  needed due to ghc-mod-5.8.0.0 -&gt; hlint-2.0.15
  
  Some different approaches to resolving this:
  
    * Set 'allow-newer: true' to ignore all version constraints and build anyway.
  
    * Consider trying 'stack solver', which uses the cabal-install solver to attempt to find some working build configuration. This can be convenient when dealing with many complicated constraint
      errors, but results may be unpredictable.
  
    * Recommended action: try adding the following to your extra-deps in /Users/mo/.stack/global-project/stack.yaml:
  
  - base-4.9.1.0
  - haskell-src-exts-1.20.2
  </code></pre>
  
  <p>if i put - haskell-src-exts-1.20.2 they ask me for - haskell-src-exts-1.19.1 back and vice versa I can't figure out what to do about this dependency conflict, and also I tried to run stack resolver but it doesn't get me anywhere </p>