Oh yeah

lib/GHCup.hs

@@ -556,6 +556,7 @@ installTool :: ( MonadThrow m
                , MonadLogger m
                , MonadCatch m
                , MonadIO m
+               , MonadFail m
                )
             => ToolRequest
             -> Maybe PlatformRequest -- ^ if Nothing, looks up current host platform
@@ -570,6 +571,7 @@ installTool :: ( MonadThrow m
                   , NoDownload
                   , NoCompatibleArch
                   , DistroNotFound
+                  , NotInstalled
                   ]
                  m
                  ()
@@ -607,7 +609,9 @@ installTool treq mpfReq urlSource = do
 
   -- TODO: test if tool is already installed
   case treq of
-    (ToolRequest GHC   ver) -> liftE $ installGHC archiveSubdir ghcdir
+    (ToolRequest GHC   ver) -> do
+      liftE $ installGHC archiveSubdir ghcdir
+      liftE $ setGHC ver SetGHCOnly
     (ToolRequest Cabal ver) -> liftE $ installCabal archiveSubdir bindir
   pure ()
 
@@ -619,7 +623,7 @@ toolAlreadyInstalled ToolRequest {..} = case _tool of
 
 
 
--- | Install an unpacked GHC distribution.
+-- | Install an unpacked GHC distribution. This only deals with the GHC build system and nothing else.
 installGHC :: (MonadLogger m, MonadIO m)
            => Path Abs      -- ^ Path to the unpacked GHC bindist (where the configure script resides)
            -> Path Abs      -- ^ Path to install to
@@ -642,6 +646,7 @@ installCabal :: (MonadLogger m, MonadCatch m, MonadIO m)
 installCabal path inst = do
   lift $ $(logInfo) ([s|Installing cabal|])
   let cabalFile = [rel|cabal|] :: Path Rel
+  liftIO $ createDirIfMissing newDirPerms inst
   handleIO (throwE . CopyError . show) $ liftIO $ copyFile
     (path </> cabalFile)
     (inst </> cabalFile)
@@ -667,6 +672,7 @@ setGHC ver sghc = do
 
   -- symlink destination
   destdir  <- liftIO $ ghcupBinDir
+  liftIO $ createDirIfMissing newDirPerms destdir
 
   -- for ghc tools (ghc, ghci, haddock, ...)
   verfiles <- ghcToolFiles ghcdir