[project @ 2003-10-29 18:10:14 by simonpj]

Squish bogus warning

diff --git a/ghc/compiler/stranal/DmdAnal.lhs b/ghc/compiler/stranal/DmdAnal.lhs
index fe588f0..2c6f394 100644 (file)
--- a/ghc/compiler/stranal/DmdAnal.lhs
+++ b/ghc/compiler/stranal/DmdAnal.lhs
@@ -17,7 +17,7 @@ import CmdLineOpts    ( DynFlags, DynFlag(..), opt_MaxWorkerArgs )
 import NewDemand       -- All of it
 import CoreSyn
 import PprCore 
-import CoreUtils       ( exprIsValue, exprArity )
+import CoreUtils       ( exprIsValue, exprIsTrivial, exprArity )
 import DataCon         ( dataConTyCon )
 import TyCon           ( isProductTyCon, isRecursiveTyCon )
 import Id              ( Id, idType, idInlinePragma,
@@ -415,7 +415,9 @@ dmdAnalRhs top_lvl rec_flag sigs (id, rhs)
   arity                     = idArity id   -- The idArity should be up to date
                                    -- The simplifier was run just beforehand
   (rhs_dmd_ty, rhs') = dmdAnal sigs (vanillaCall arity) rhs
-  (lazy_fv, sig_ty)  = WARN( arity /= dmdTypeDepth rhs_dmd_ty, ppr id )
+  (lazy_fv, sig_ty)  = WARN( arity /= dmdTypeDepth rhs_dmd_ty && not (exprIsTrivial rhs), ppr id )
+                               -- The RHS can be eta-reduced to just a variable, 
+                               -- in which case we should not complain. 
                       mkSigTy top_lvl rec_flag id rhs rhs_dmd_ty
   id'               = id `setIdNewStrictness` sig_ty
   sigs'                     = extendSigEnv top_lvl sigs id sig_ty