Convert interface file loading errors into proper diagnosticswip/interface-loading-errs

This patch converts all the errors to do with loading interface files
into proper structured diagnostics.

* DriverMessage: Sometimes in the driver we attempt to load an interface
  file so we embed the IfaceMessage into the DriverMessage.
* TcRnMessage: Most the time we are loading interface files during
  typechecking, so we embed the IfaceMessage

This patch also removes the TcRnInterfaceLookupError constructor which
is superceded by the IfaceMessage, which is now structured compared to
just storing an SDoc before.

1 files changed, 3 insertions, 4 deletions

diff --git a/compiler/GHC/Driver/MakeFile.hs b/compiler/GHC/Driver/MakeFile.hs
index a770637311..be20bfd89f 100644
--- a/compiler/GHC/Driver/MakeFile.hs
+++ b/compiler/GHC/Driver/MakeFile.hs
@@ -27,7 +27,6 @@ import GHC.Data.Graph.Directed ( SCC(..) )
 import GHC.Utils.Outputable
 import GHC.Utils.Panic
 import GHC.Utils.Panic.Plain
-import GHC.Types.Error (UnknownDiagnostic(..))
 import GHC.Types.SourceError
 import GHC.Types.SrcLoc
 import GHC.Types.PkgQual
@@ -53,6 +52,7 @@ import Control.Monad    ( when, forM_ )
 import Data.Maybe       ( isJust )
 import Data.IORef
 import qualified Data.Set as Set
+import GHC.Iface.Errors.Types
 
 -----------------------------------------------------------------
 --
@@ -307,9 +307,8 @@ findDependency hsc_env srcloc pkg imp is_boot include_pkg_deps = do
     fail ->
         throwOneError $
           mkPlainErrorMsgEnvelope srcloc $
-          GhcDriverMessage $ DriverUnknownMessage $
-             UnknownDiagnostic $ mkPlainError noHints $
-             cannotFindModule hsc_env imp fail
+          GhcDriverMessage $ DriverInterfaceError $
+             (Can'tFindInterface (cannotFindModule hsc_env imp fail) (LookingForModule imp is_boot))
 
 -----------------------------
 writeDependency :: FilePath -> Handle -> [FilePath] -> FilePath -> IO ()