Marge Bot pushed to branch master at Glasgow Haskell Compiler / GHC

Commits:

• 4bf040c6
  by sheaf at 2026-04-05T14:56:29-04:00

  Add utility pprTrace_ function
  
  This function is useful for quick debugging, as it can be added to a
  where clause to pretty-print debugging information:
  
    fooBar x y
      | cond      = body1
      | otherwise = body2
      where
        !_ = pprTrace_ "fooBar" $
             vcat [ text "x:" <+> ppr x
                  , text "y:" <+> ppr y
                  , text "cond:" <+> ppr cond
                  ]
  

1 changed file:

• compiler/GHC/Utils/Trace.hs

Changes:

 -- | Tracing utilities

 module GHC.Utils.Trace

   ( pprTrace

+  , pprTrace_

   , pprTraceM

   , pprTraceDebug

   , pprTraceIt

   | unsafeHasNoDebugOutput = x

   | otherwise              = pprDebugAndThen traceSDocContext trace (text str) doc x

+-- | A version of 'pprTrace' that is useful for quick debugging:

+--

+-- @

+-- fooBar x y

+--   | cond      = body1

+--   | otherwise = body2

+--   where

+--     !_ = pprTrace_ "fooBar" $

+--          vcat [ text "x:" <+> ppr x

+--               , text "y:" <+> ppr y

+--               , text "cond:" <+> ppr cond

+--               ]

+-- @

+pprTrace_ :: String -> SDoc -> ()

+pprTrace_ str doc = pprTrace str doc ()

+

 pprTraceM :: Applicative f => String -> SDoc -> f ()

 pprTraceM str doc = pprTrace str doc (pure ())