Wibbles

[ghc-hetmet.git] / compiler / simplCore / CoreMonad.lhs

diff --git a/compiler/simplCore/CoreMonad.lhs b/compiler/simplCore/CoreMonad.lhs
index 7849d88..8e75a7b 100644 (file)
--- a/compiler/simplCore/CoreMonad.lhs
+++ b/compiler/simplCore/CoreMonad.lhs
@@ -166,6 +166,11 @@ displayLintResults dflags pass warns errs binds
        ; Err.ghcExit dflags 1 }
 
   | not (isEmptyBag warns)
+  , not (case pass of { CoreDesugar -> True; _ -> False })
+       -- Suppress warnings after desugaring pass because some
+       -- are legitimate. Notably, the desugarer generates instance
+       -- methods with INLINE pragmas that form a mutually recursive
+       -- group.  Only afer a round of simplification are they unravelled.
   , not opt_NoDebugOutput
   , showLintWarnings pass
   = printDump (banner "warnings" $$ Err.pprMessageBag warns)
@@ -381,17 +386,11 @@ getCoreToDo dflags
         -- initial simplify: mk specialiser happy: minimum effort please
     simpl_gently = CoreDoSimplify 
                        (SimplGently { sm_rules = True, sm_inline = False })
+                         -- See Note [Gentle mode] and
+                         -- Note [RULEs enabled in SimplGently] in SimplUtils
                        max_iter
                        [
-                        --      Simplify "gently"
-                        -- Don't inline anything till full laziness has bitten
-                        -- In particular, inlining wrappers inhibits floating
-                        -- e.g. ...(case f x of ...)...
-                        --  ==> ...(case (case x of I# x# -> fw x#) of ...)...
-                        --  ==> ...(case x of I# x# -> case fw x# of ...)...
-                        -- and now the redex (f x) isn't floatable any more
-                        -- Similarly, don't apply any rules until after full
-                        -- laziness.  Notably, list fusion can prevent floating.
+
 
             NoCaseOfCase        -- Don't do case-of-case transformations.
                                 -- This makes full laziness work better