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is superceded by the IfaceMessage, which is now structured compared to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, 16 insertions, 13 deletions

diff --git a/compiler/GHC/Driver/Config/Diagnostic.hs b/compiler/GHC/Driver/Config/Diagnostic.hs
index f4b709301b..1e8b5a1e67 100644
--- a/compiler/GHC/Driver/Config/Diagnostic.hs
+++ b/compiler/GHC/Driver/Config/Diagnostic.hs
@@ -8,11 +8,13 @@ module GHC.Driver.Config.Diagnostic
   , initDsMessageOpts
   , initTcMessageOpts
   , initDriverMessageOpts
+  , initIfaceMessageOpts
   )
 where
 
 import GHC.Driver.Flags
 import GHC.Driver.Session
+import GHC.Prelude
 
 import GHC.Utils.Outputable
 import GHC.Utils.Error (DiagOpts (..))
@@ -22,6 +24,8 @@ import GHC.Tc.Errors.Types
 import GHC.HsToCore.Errors.Types
 import GHC.Types.Error
 import GHC.Tc.Errors.Ppr
+import GHC.Iface.Errors.Types
+import GHC.Iface.Errors.Ppr
 
 -- | Initialise the general configuration for printing diagnostic messages
 -- For example, this configuration controls things like whether warnings are
@@ -50,11 +54,17 @@ initPsMessageOpts :: DynFlags -> DiagnosticOpts PsMessage
 initPsMessageOpts _ = NoDiagnosticOpts
 
 initTcMessageOpts :: DynFlags -> DiagnosticOpts TcRnMessage
-initTcMessageOpts dflags = TcRnMessageOpts { tcOptsShowContext = gopt Opt_ShowErrorContext dflags }
+initTcMessageOpts dflags =
+  TcRnMessageOpts { tcOptsShowContext    = gopt Opt_ShowErrorContext dflags
+                  , tcOptsIfaceOpts      = initIfaceMessageOpts dflags }
 
 initDsMessageOpts :: DynFlags -> DiagnosticOpts DsMessage
 initDsMessageOpts _ = NoDiagnosticOpts
 
+initIfaceMessageOpts :: DynFlags -> DiagnosticOpts IfaceMessage
+initIfaceMessageOpts dflags =
+                  IfaceMessageOpts { ifaceShowTriedFiles = verbosity dflags >= 3 }
+
 initDriverMessageOpts :: DynFlags -> DiagnosticOpts DriverMessage
-initDriverMessageOpts dflags = DriverMessageOpts (initPsMessageOpts dflags)
+initDriverMessageOpts dflags = DriverMessageOpts (initPsMessageOpts dflags) (initIfaceMessageOpts dflags)
 
diff --git a/compiler/GHC/Driver/Config/Tidy.hs b/compiler/GHC/Driver/Config/Tidy.hs
index 89bdf31b2c..a02321ab78 100644
--- a/compiler/GHC/Driver/Config/Tidy.hs
+++ b/compiler/GHC/Driver/Config/Tidy.hs
@@ -17,11 +17,8 @@ import GHC.Driver.Env
 import GHC.Driver.Backend
 
 import GHC.Core.Make (getMkStringIds)
-import GHC.Data.Maybe
-import GHC.Utils.Panic
-import GHC.Utils.Outputable
 import GHC.Builtin.Names
-import GHC.Tc.Utils.Env (lookupGlobal_maybe)
+import GHC.Tc.Utils.Env (lookupGlobal)
 import GHC.Types.TyThing
 import GHC.Platform.Ways
 
@@ -49,13 +46,9 @@ initStaticPtrOpts :: HscEnv -> IO StaticPtrOpts
 initStaticPtrOpts hsc_env = do
   let dflags = hsc_dflags hsc_env
 
-  let lookupM n = lookupGlobal_maybe hsc_env n >>= \case
-        Succeeded r -> pure r
-        Failed err  -> pprPanic "initStaticPtrOpts: couldn't find" (ppr (err,n))
-
-  mk_string <- getMkStringIds (fmap tyThingId . lookupM)
-  static_ptr_info_datacon <- tyThingDataCon <$> lookupM staticPtrInfoDataConName
-  static_ptr_datacon      <- tyThingDataCon <$> lookupM staticPtrDataConName
+  mk_string <- getMkStringIds (fmap tyThingId . lookupGlobal hsc_env )
+  static_ptr_info_datacon <- tyThingDataCon <$> lookupGlobal hsc_env staticPtrInfoDataConName
+  static_ptr_datacon      <- tyThingDataCon <$> lookupGlobal hsc_env staticPtrDataConName
 
   pure $ StaticPtrOpts
     { opt_platform = targetPlatform dflags