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is superceded by the IfaceMessage, which is now structured compared to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.

2 files changed, 15 insertions, 12 deletions

diff --git a/compiler/GHC/Driver/Errors/Ppr.hs b/compiler/GHC/Driver/Errors/Ppr.hs
index 9e3822e460..a89e7992b1 100644
--- a/compiler/GHC/Driver/Errors/Ppr.hs
+++ b/compiler/GHC/Driver/Errors/Ppr.hs
@@ -16,7 +16,6 @@ import GHC.Driver.Flags
 import GHC.Driver.Session
 import GHC.HsToCore.Errors.Ppr ()
 import GHC.Parser.Errors.Ppr ()
-import GHC.Tc.Errors.Ppr ()
 import GHC.Types.Error
 import GHC.Types.Error.Codes ( constructorCode )
 import GHC.Unit.Types
@@ -30,6 +29,9 @@ import Data.Version
 import Language.Haskell.Syntax.Decls (RuleDecl(..))
 import GHC.Tc.Errors.Types (TcRnMessage)
 import GHC.HsToCore.Errors.Types (DsMessage)
+import GHC.Iface.Errors.Types
+import GHC.Tc.Errors.Ppr ()
+import GHC.Iface.Errors.Ppr ()
 
 --
 -- Suggestions
@@ -86,7 +88,7 @@ instance Diagnostic GhcMessage where
 
 instance Diagnostic DriverMessage where
   type DiagnosticOpts DriverMessage = DriverMessageOpts
-  defaultDiagnosticOpts = DriverMessageOpts (defaultDiagnosticOpts @PsMessage)
+  defaultDiagnosticOpts = DriverMessageOpts (defaultDiagnosticOpts @PsMessage) (defaultDiagnosticOpts @IfaceMessage)
   diagnosticMessage opts = \case
     DriverUnknownMessage (UnknownDiagnostic @e m)
       -> diagnosticMessage (defaultDiagnosticOpts @e) m
@@ -218,6 +220,7 @@ instance Diagnostic DriverMessage where
       -> mkSimpleDecorated $ vcat ([text "Home units are not closed."
                                   , text "It is necessary to also load the following units:" ]
                                   ++ map (\uid -> text "-" <+> ppr uid) needed_unit_ids)
+    DriverInterfaceError reason -> diagnosticMessage (ifaceDiagnosticOpts opts) reason
 
   diagnosticReason = \case
     DriverUnknownMessage m
@@ -272,6 +275,7 @@ instance Diagnostic DriverMessage where
       -> ErrorWithoutFlag
     DriverHomePackagesNotClosed {}
       -> ErrorWithoutFlag
+    DriverInterfaceError reason -> diagnosticReason reason
 
   diagnosticHints = \case
     DriverUnknownMessage m
@@ -328,5 +332,6 @@ instance Diagnostic DriverMessage where
       -> noHints
     DriverHomePackagesNotClosed {}
       -> noHints
+    DriverInterfaceError reason -> diagnosticHints reason
 
   diagnosticCode = constructorCode
diff --git a/compiler/GHC/Driver/Errors/Types.hs b/compiler/GHC/Driver/Errors/Types.hs
index c2ec9cbb0c..cbf0622025 100644
--- a/compiler/GHC/Driver/Errors/Types.hs
+++ b/compiler/GHC/Driver/Errors/Types.hs
@@ -8,7 +8,6 @@ module GHC.Driver.Errors.Types (
   , DriverMessage(..)
   , DriverMessageOpts(..)
   , DriverMessages, PsMessage(PsHeaderMessage)
-  , BuildingCabalPackage(..)
   , WarningMessages
   , ErrorMessages
   , WarnMsg
@@ -32,7 +31,6 @@ import GHC.Unit.Module
 import GHC.Unit.State
 
 import GHC.Parser.Errors.Types ( PsMessage(PsHeaderMessage) )
-import GHC.Tc.Errors.Types     ( TcRnMessage )
 import GHC.HsToCore.Errors.Types ( DsMessage )
 import GHC.Hs.Extension          (GhcTc)
 
@@ -40,6 +38,9 @@ import Language.Haskell.Syntax.Decls (RuleDecl)
 
 import GHC.Generics ( Generic )
 
+import GHC.Tc.Errors.Types
+import GHC.Iface.Errors.Types
+
 -- | A collection of warning messages.
 -- /INVARIANT/: Each 'GhcMessage' in the collection should have 'SevWarning' severity.
 type WarningMessages = Messages GhcMessage
@@ -369,21 +370,18 @@ data DriverMessage where
 
   DriverHomePackagesNotClosed :: ![UnitId] -> DriverMessage
 
+  DriverInterfaceError :: !IfaceMessage -> DriverMessage
+
 deriving instance Generic DriverMessage
 
 data DriverMessageOpts =
-  DriverMessageOpts { psDiagnosticOpts :: DiagnosticOpts PsMessage }
+  DriverMessageOpts { psDiagnosticOpts :: DiagnosticOpts PsMessage
+                    , ifaceDiagnosticOpts :: DiagnosticOpts IfaceMessage }
 
--- | Pass to a 'DriverMessage' the information whether or not the
--- '-fbuilding-cabal-package' flag is set.
-data BuildingCabalPackage
-  = YesBuildingCabalPackage
-  | NoBuildingCabalPackage
-  deriving Eq
 
 -- | Checks if we are building a cabal package by consulting the 'DynFlags'.
 checkBuildingCabalPackage :: DynFlags -> BuildingCabalPackage
 checkBuildingCabalPackage dflags =
   if gopt Opt_BuildingCabalPackage dflags
      then YesBuildingCabalPackage
-     else NoBuildingCabalPackage
+     else NoBuildingCabalPackage
\ No newline at end of file