loc    <- getSrcSpanM

     name_ppr_ctx <- getNamePprCtx

     let sty = case msg_class of

                 MCDump             -> dump_sty

                 _                  -> user_sty

         err_sty  = mkErrStyle name_ppr_ctx

       logJsonMsg logger messageClass jsonMessage

   where

     logflags :: LogFlags

     logflags = logFlags logger

     doc = updSDocContext (\_ -> ctx) (messageWithHints diagnostic)

     messageClass :: MessageClass

     style :: PprStyle

     style = mkErrStyle (errMsgContext message)

     diagnostic :: a

     diagnostic = errMsgDiagnostic message

     sourceSpans :: NonEmpty SrcSpan

     severity :: Severity

     severity = errMsgSeverity message

     messageWithHints :: a -> SDoc

     messageWithHints e =

       let main_msg = formatBulleted $ diagnosticMessage msg_opts e

     let deferDiagnostics _dflags !msgClass !srcSpan !msg = do

           let action = logMsg logger msgClass srcSpan msg

           case msgClass of

               -> atomicModifyIORef' warnings $ \(!i) -> (action: i, ())

               -> atomicModifyIORef' errors   $ \(!i) -> (action: i, ())

             MCFatal

               -> atomicModifyIORef' fatals   $ \(!i) -> (action: i, ())

     -- ^ Log messages intended for end users.

     -- No file\/line\/column stuff.

     -- ^ Diagnostics from the compiler. This constructor is very powerful as

     -- it allows the construction of a 'MessageClass' with a completely

     -- arbitrary permutation of 'Severity' and 'DiagnosticReason'. As such,

     -- this diagnostic. If you are creating a message not tied to any

     -- error-message type, then use Nothing. In the long run, this really

     -- should always have a 'DiagnosticCode'. See Note [Diagnostic codes].

 {-

 Note [Suppressing Messages]

   json MCInteractive = JSString "MCInteractive"

   json MCDump = JSString "MCDump"

   json MCInfo = JSString "MCInfo"

     JSString $ renderWithContext defaultSDocContext (ppr $ text "MCDiagnostic" <+> ppr sev <+> ppr reason <+> ppr code)

 instance ToJson DiagnosticCode where

   -> SDoc

 mkLocMessageWarningGroups show_warn_groups msg_class locn msg

   = case msg_class of

     _ -> sdocOption sdocColScheme $ \col_scheme ->

       let

           msg_colour = getMessageClassColour msg_class col_scheme

                         msg)

 getMessageClassColour :: MessageClass -> Col.Scheme -> Col.PprColour

 getMessageClassColour MCFatal                                 = Col.sFatal

 getMessageClassColour _                                       = const mempty

   | MCInteractive

   | MCDump

   | MCInfo

 data Severity

   = SevIgnore

                                     , errMsgReason     = reason })

   = withErrStyle name_ppr_ctx $

       mkLocMessage

         s

         (formatBulleted $ diagnosticMessage opts e)

       MCInteractive                -> putStrSDoc msg

       MCInfo                       -> printErrs msg

       MCFatal                      -> printErrs msg

   where

     printOut   = defaultLogActionHPrintDoc  logflags False stdout

     printErrs  = defaultLogActionHPrintDoc  logflags False stderr

 -- See Note [JSON Error Messages]

 -- this is to be removed

 jsonLogActionWithHandle :: Handle {-^ Standard out -} -> LogAction

 jsonLogActionWithHandle out logflags msg_class srcSpan msg

   =

     defaultLogActionHPutStrDoc logflags True out

       MCInteractive                -> putStrSDoc msg

       MCInfo                       -> printErrs msg

       MCFatal                      -> printErrs msg

     where

       printOut   = defaultLogActionHPrintDoc  logflags False out

       printErrs  = defaultLogActionHPrintDoc  logflags False err

               dflags msg_class srcSpan msg = do

     old_log_action dflags msg_class srcSpan msg

     case msg_class of

             RealSrcSpan rsp _ -> modifyIORef lastErrLocations

                 (++ [(srcLocFile (realSrcSpanStart rsp), srcLocLine (realSrcSpanStart rsp))])

             _ -> return ()