Add TcRnSimplifierTooManyIterations to TcRnMessage

2 files changed, 25 insertions, 0 deletions

diff --git a/compiler/GHC/Tc/Errors/Ppr.hs b/compiler/GHC/Tc/Errors/Ppr.hs
index 9953971c24..fc69df5379 100644
--- a/compiler/GHC/Tc/Errors/Ppr.hs
+++ b/compiler/GHC/Tc/Errors/Ppr.hs
@@ -62,6 +62,11 @@ instance Diagnostic TcRnMessage where
       -> mkSimpleDecorated $
            vcat [text "Multiple warning declarations for" <+> quotes (ppr rdr_name),
                  text "also at " <+> ppr (getLocA d)]
+    TcRnSimplifierTooManyIterations limit wc
+      -> mkSimpleDecorated $
+           hang (text "solveWanteds: too many iterations"
+                   <+> parens (text "limit =" <+> ppr limit))
+                2 (text "Unsolved:" <+> ppr wc)
 
   diagnosticReason = \case
     TcRnUnknownMessage m
@@ -89,6 +94,8 @@ instance Diagnostic TcRnMessage where
       -> WarningWithFlag Opt_WarnNameShadowing
     TcRnDuplicateWarningDecls{}
       -> ErrorWithoutFlag
+    TcRnSimplifierTooManyIterations{}
+      -> ErrorWithoutFlag
 
   diagnosticHints = \case
     TcRnUnknownMessage m
@@ -116,6 +123,8 @@ instance Diagnostic TcRnMessage where
       -> noHints
     TcRnDuplicateWarningDecls{}
       -> noHints
+    TcRnSimplifierTooManyIterations{}
+      -> [SuggestIncreaseSimplifierIterations]
 
 messageWithInfoDiagnosticMessage :: UnitState
                                  -> ErrInfo
diff --git a/compiler/GHC/Tc/Errors/Types.hs b/compiler/GHC/Tc/Errors/Types.hs
index f76ac52727..1e8a18a8a0 100644
--- a/compiler/GHC/Tc/Errors/Types.hs
+++ b/compiler/GHC/Tc/Errors/Types.hs
@@ -10,6 +10,7 @@ module GHC.Tc.Errors.Types (
   ) where
 
 import GHC.Hs
+import GHC.Tc.Types.Constraint
 import GHC.Types.Error
 import GHC.Types.Name (Name, OccName)
 import GHC.Types.Name.Reader
@@ -19,6 +20,7 @@ import GHC.Utils.Outputable
 import Data.Typeable
 import GHC.Core.Type (Type, Var)
 import GHC.Unit.State (UnitState)
+import GHC.Types.Basic
 
 {-
 Note [Migrating TcM Messages]
@@ -196,6 +198,20 @@ data TcRnMessage where
   -}
   TcRnDuplicateWarningDecls :: !(LocatedN RdrName) -> !RdrName -> TcRnMessage
 
+  {-| TcRnDuplicateWarningDecls is an error that occurs whenever
+      the constraint solver in the simplifier hits the iterations' limit.
+
+      Examples(s):
+        None.
+
+     Test cases:
+        None.
+  -}
+  TcRnSimplifierTooManyIterations :: !IntWithInf
+                                  -- ^ The limit.
+                                  -> WantedConstraints
+                                  -> TcRnMessage
+
 
 -- | Where a shadowed name comes from
 data ShadowedNameProvenance