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is superceded by the IfaceMessage, which is now structured compared to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, 12 insertions, 3 deletions

diff --git a/compiler/GHC/Runtime/Loader.hs b/compiler/GHC/Runtime/Loader.hs
index ebfa7875e5..cbe376b9cd 100644
--- a/compiler/GHC/Runtime/Loader.hs
+++ b/compiler/GHC/Runtime/Loader.hs
@@ -45,16 +45,20 @@ import GHC.Core.Type        ( Type, mkTyConTy )
 import GHC.Core.TyCo.Compare( eqType )
 import GHC.Core.TyCon       ( TyCon )
 
+
 import GHC.Types.SrcLoc        ( noSrcSpan )
 import GHC.Types.Name    ( Name, nameModule_maybe )
 import GHC.Types.Id      ( idType )
 import GHC.Types.TyThing
 import GHC.Types.Name.Occurrence ( OccName, mkVarOccFS )
 import GHC.Types.Name.Reader
+import GHC.Types.Unique.DFM
+
 import GHC.Unit.Finder         ( findPluginModule, FindResult(..) )
 import GHC.Driver.Config.Finder ( initFinderOpts )
+import GHC.Driver.Config.Diagnostic ( initIfaceMessageOpts )
 import GHC.Unit.Module   ( Module, ModuleName )
-import GHC.Unit.Module.ModIface
+import GHC.Unit.Module.ModIface ( ModIface_(mi_exports), ModIface )
 import GHC.Unit.Env
 
 import GHC.Utils.Panic
@@ -68,8 +72,9 @@ import Control.Monad     ( unless )
 import Data.Maybe        ( mapMaybe )
 import Unsafe.Coerce     ( unsafeCoerce )
 import GHC.Linker.Types
-import GHC.Types.Unique.DFM
 import Data.List (unzip4)
+import GHC.Iface.Errors.Ppr
+
 
 -- | Loads the plugins specified in the pluginModNames field of the dynamic
 -- flags. Should be called after command line arguments are parsed, but before
@@ -329,7 +334,11 @@ lookupRdrNameInModuleForPlugins hsc_env mod_name rdr_name = do
                         _     -> panic "lookupRdrNameInModule"
 
                 Nothing -> throwCmdLineErrorS dflags $ hsep [text "Could not determine the exports of the module", ppr mod_name]
-        err -> throwCmdLineErrorS dflags $ cannotFindModule hsc_env mod_name err
+        err ->
+          let opts   = initIfaceMessageOpts dflags
+              err_txt = missingInterfaceErrorDiagnostic opts
+                      $ cannotFindModule hsc_env mod_name err
+          in throwCmdLineErrorS dflags err_txt
   where
     doc = text "contains a name used in an invocation of lookupRdrNameInModule"