[project @ 2001-06-28 08:36:30 by simonpj]

Comment and import wibbles

3 files changed, 10 insertions, 9 deletions

diff --git a/ghc/compiler/coreSyn/CoreUtils.lhs b/ghc/compiler/coreSyn/CoreUtils.lhs
index b3cab6699d..bea8316a26 100644
--- a/ghc/compiler/coreSyn/CoreUtils.lhs
+++ b/ghc/compiler/coreSyn/CoreUtils.lhs
@@ -512,7 +512,7 @@ idAppIsBottom id n_val_args = appIsBottom (idStrictness id) n_val_args
 \end{code}
 
 @exprIsValue@ returns true for expressions that are certainly *already* 
-evaluated to WHNF.  This is used to decide wether it's ok to change
+evaluated to WHNF.  This is used to decide whether it's ok to change
 	case x of _ -> e   ===>   e
 
 and to decide whether it's safe to discard a `seq`
diff --git a/ghc/compiler/coreSyn/Subst.lhs b/ghc/compiler/coreSyn/Subst.lhs
index 0b88ea00d7..1633362611 100644
--- a/ghc/compiler/coreSyn/Subst.lhs
+++ b/ghc/compiler/coreSyn/Subst.lhs
@@ -544,10 +544,9 @@ substExpr subst expr
 simplBndr :: Subst -> Var -> (Subst, Var)
 -- Used for lambda and case-bound variables
 -- Clone Id if necessary, substitute type
--- Return with IdInfo already substituted, 
--- but occurrence info zapped
+-- Return with IdInfo already substituted, but (fragile) occurrence info zapped
 -- The substitution is extended only if the variable is cloned, because
--- we don't need to use it to track occurrence info.
+-- we *don't* need to use it to track occurrence info.
 simplBndr subst bndr
   | isTyVar bndr  = substTyVar subst bndr
   | otherwise     = subst_id isFragileOcc subst subst bndr
@@ -559,9 +558,11 @@ simplLetId :: Subst -> Id -> (Subst, Id)
 -- Clone Id if necessary
 -- Substitute its type
 -- Return an Id with completely zapped IdInfo
--- Augment the subtitution if the unique changed or if there's
--- 	interesting occurrence info
--- [A subsequent substIdInfo will restore its IdInfo]
+-- 	[A subsequent substIdInfo will restore its IdInfo]
+-- Augment the subtitution 
+--	if the unique changed, *or* 
+--	if there's interesting occurrence info
+
 simplLetId subst@(Subst in_scope env) old_id
   = (Subst (in_scope `extendInScopeSet` new_id) new_env, new_id)
   where
@@ -590,7 +591,7 @@ simplIdInfo subst old_info bndr
 
 \begin{code}
 -- substBndr and friends are used when doing expression substitution only
--- In this case we can preserve occurrence information, and indeed we want
+-- In this case we can *preserve* occurrence information, and indeed we *want*
 -- to do so else lose useful occ info in rules.  Hence the calls to 
 -- simpl_id with keepOccInfo
 
diff --git a/ghc/compiler/stranal/StrictAnal.lhs b/ghc/compiler/stranal/StrictAnal.lhs
index aeb1c3fe50..bac6b14ac8 100644
--- a/ghc/compiler/stranal/StrictAnal.lhs
+++ b/ghc/compiler/stranal/StrictAnal.lhs
@@ -11,7 +11,7 @@ module StrictAnal ( saBinds ) where
 
 #include "HsVersions.h"
 
-import CmdLineOpts	( DynFlags, DynFlag(..), dopt )
+import CmdLineOpts	( DynFlags, DynFlag(..) )
 import CoreSyn
 import Id		( setIdStrictness, setInlinePragma, 
 			  idDemandInfo, setIdDemandInfo, isBottomingId,