Use ghc versions from stack-*.yaml files

install/src/Env.hs

@@ -43,15 +43,6 @@ existsExecutable executable = liftIO $ isJust <$> findExecutable executable
 isWindowsSystem :: Bool
 isWindowsSystem = os `elem` ["mingw32", "win32"]
 
--- | Defines all different hie versions that are supported.
--- On windows, `8.6.3` is excluded as this version of ghc does not work there
-supportedGhcVersions :: [VersionNumber]
-supportedGhcVersions = sort (commonVersions ++ osVersions)
-  where commonVersions = ["8.4.2", "8.4.3", "8.4.4", "8.6.1", "8.6.2", "8.6.4", "8.6.5"]
-        -- the following lines exclude `8.6.3` on windows systems
-        osVersions | isWindowsSystem = []
-                   | otherwise = ["8.6.3"]
-
 findInstalledGhcs :: IO [(VersionNumber, GhcPath)]
 findInstalledGhcs = do
   hieVersions <- getHieVersions :: IO [VersionNumber]
@@ -62,7 +53,7 @@ findInstalledGhcs = do
     )
     (reverse hieVersions)
   -- filter out not supported ghc versions
-  availableGhcs <- filter ((`elem` supportedGhcVersions) . fst) <$> getGhcPaths
+  availableGhcs <- filter ((`elem` hieVersions) . fst) <$> getGhcPaths
   return
     -- sort by version to make it coherent with getHieVersions
     $ sortBy (comparing fst)
@@ -113,7 +104,8 @@ getHieVersions = do
           & mapMaybe
               (T.stripPrefix stackYamlPrefix >=> T.stripSuffix stackYamlSuffix)
           & map T.unpack
-          & filter (\p -> p `elem` supportedGhcVersions)
+        -- the following line excludes `8.6.3` on windows systems
+          & filter (\p -> not isWindowsSystem || p /= "8.6.3")
           & sort
   return hieVersions