Migrate errors to diagnostics in GHC.Tc.Module

This commit migrates the errors in GHC.Tc.Module to use the new
diagnostic infrastructure.

It required a significant overhaul of the compatibility checks between
an hs-boot or signature module and its implementation; we now use
a Writer monad to accumulate errors; see the BootMismatch datatype
in GHC.Tc.Errors.Types, with its panoply of subtypes.
For the sake of readability, several local functions inside the
'checkBootTyCon' function were split off into top-level functions.

We split off GHC.Types.HscSource into a "boot or sig" vs "normal hs file"
datatype, as this mirrors the logic in several other places where we
want to treat hs-boot and hsig files in a similar fashion.

This commit also refactors the Backpack checks for type synonyms
implementing abstract data, to correctly reject implementations that
contain qualified or quantified types (this fixes #23342 and #23344).

1 files changed, 10 insertions, 10 deletions

diff --git a/testsuite/tests/backpack/should_fail/T19244b.stderr b/testsuite/tests/backpack/should_fail/T19244b.stderr
index 3a50d11079..6c883c2601 100644
--- a/testsuite/tests/backpack/should_fail/T19244b.stderr
+++ b/testsuite/tests/backpack/should_fail/T19244b.stderr
@@ -1,21 +1,21 @@
 [1 of 3] Processing user
-  [1 of 2] Compiling Map[sig]         ( user/Map.hsig, nothing )
-  [2 of 2] Compiling User             ( user/User.hs, nothing )
+  [1 of 2] Compiling Map[sig]         ( user\Map.hsig, nothing )
+  [2 of 2] Compiling User             ( user\User.hs, nothing )
 [2 of 3] Processing ordmap
   Instantiating ordmap
-  [1 of 1] Compiling Map              ( ordmap/Map.hs, T19244b.out/ordmap/Map.o )
+  [1 of 1] Compiling Map              ( ordmap\Map.hs, T19244b.out\ordmap\Map.o )
 [3 of 3] Processing main
   Instantiating main
   [1 of 1] Including user[Map=ordmap:Map]
     Instantiating user[Map=ordmap:Map]
-    [1 of 2] Compiling Map[sig]         ( user/Map.hsig, T19244b.out/user/user-GzloW2NeDdA2M0V8qzN4g2/Map.o )
+    [1 of 2] Compiling Map[sig]         ( user\Map.hsig, T19244b.out\user\user-GzloW2NeDdA2M0V8qzN4g2\Map.o )
 
-T19244b.bkp:11:27: error:
+T19244b.bkp:11:27: error: [GHC-15843]
     • Type constructor ‘Key’ has conflicting definitions in the module
-      and its hsig file
+      and its hsig file.
       Main module: type Key :: * -> Constraint
                    type Key = GHC.Classes.Ord :: * -> Constraint
-      Hsig file:  type Key :: forall {k}. k -> Constraint
-                  class Key k1
-      The types have different kinds
-    • while checking that ordmap:Map implements signature Map in user[Map=ordmap:Map]
+        Hsig file: type Key :: forall {k}. k -> Constraint
+                   class Key k1
+      The types have different kinds.
+    • While checking that ‘ordmap:Map’ implements signature ‘Map’ in ‘user[Map=ordmap:Map]’.