X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Ftypecheck%2FTcRnMonad.lhs;h=43232e56b51a43b49ac9147fe9e8ebd807d62ec9;hp=c86b081a2147bc50a213f248b00af27671ac431b;hb=7e95df790b34e11d7308e43dab0a7175b69b70fc;hpb=c0687066474aa4ce4912f31a5c09c1bcd673fb06

diff --git a/compiler/typecheck/TcRnMonad.lhs b/compiler/typecheck/TcRnMonad.lhs
index c86b081..43232e5 100644
--- a/compiler/typecheck/TcRnMonad.lhs
+++ b/compiler/typecheck/TcRnMonad.lhs
@@ -495,9 +495,10 @@ getSrcSpanM :: TcRn SrcSpan
 getSrcSpanM = do { env <- getLclEnv; return (tcl_loc env) }
 
 setSrcSpan :: SrcSpan -> TcRn a -> TcRn a
-setSrcSpan loc thing_inside
-  | isGoodSrcSpan loc = updLclEnv (\env -> env { tcl_loc = loc }) thing_inside
-  | otherwise	      = thing_inside	-- Don't overwrite useful info with useless
+setSrcSpan loc@(RealSrcSpan _) thing_inside
+    = updLclEnv (\env -> env { tcl_loc = loc }) thing_inside
+-- Don't overwrite useful info with useless:
+setSrcSpan (UnhelpfulSpan _) thing_inside = thing_inside
 
 addLocM :: (a -> TcM b) -> Located a -> TcM b
 addLocM fn (L loc a) = setSrcSpan loc $ fn a
@@ -990,10 +991,10 @@ captureConstraints :: TcM a -> TcM (a, WantedConstraints)
 -- (captureConstraints m) runs m, and returns the type constraints it generates
 captureConstraints thing_inside
   = do { lie_var <- newTcRef emptyWC ;
-	 res <- updLclEnv (\ env -> env { tcl_lie = lie_var }) 
-			  thing_inside ;
-	 lie <- readTcRef lie_var ;
-	 return (res, lie) }
+         res <- updLclEnv (\ env -> env { tcl_lie = lie_var }) 
+                          thing_inside ;
+         lie <- readTcRef lie_var ;
+         return (res, lie) }
 
 captureUntouchables :: TcM a -> TcM (a, Untouchables)
 captureUntouchables thing_inside
@@ -1018,14 +1019,21 @@ setLclTypeEnv lcl_env thing_inside
   = updLclEnv upd thing_inside
   where
     upd env = env { tcl_env = tcl_env lcl_env,
-		    tcl_tyvars = tcl_tyvars lcl_env }
+                    tcl_tyvars = tcl_tyvars lcl_env }
+
+traceTcConstraints :: String -> TcM ()
+traceTcConstraints msg
+  = do { lie_var <- getConstraintVar
+       ; lie     <- readTcRef lie_var
+       ; traceTc (msg ++ "LIE:") (ppr lie)
+       }
 \end{code}
 
 
 %************************************************************************
-%*									*
-	     Template Haskell context
-%*									*
+%*                                                                      *
+             Template Haskell context
+%*                                                                      *
 %************************************************************************
 
 \begin{code}