-%
-For each constructor we match on, we might need to re-pack some
-of the strict fields if they are unpacked in the constructor.
-%
-\begin{code}
-rebuildConArgs
- :: DataCon -- the con we're matching on
- -> [Id] -- the source-level args
- -> [StrictnessMark] -- the strictness annotations (per-arg)
- -> CoreExpr -- the body
- -> DsM (CoreExpr, [Id])
-
-rebuildConArgs con [] stricts body = returnDs (body, [])
-rebuildConArgs con (arg:args) stricts body | isTyVar arg
- = rebuildConArgs con args stricts body `thenDs` \ (body', args') ->
- returnDs (body',arg:args')
-rebuildConArgs con (arg:args) (str:stricts) body
- = rebuildConArgs con args stricts body `thenDs` \ (body', real_args) ->
- case maybeMarkedUnboxed str of
- Just (pack_con1, _) ->
- case splitProductType_maybe (idType arg) of
- Just (_, tycon_args, pack_con, con_arg_tys) ->
- ASSERT( pack_con == pack_con1 )
- newSysLocalsDs con_arg_tys `thenDs` \ unpacked_args ->
- returnDs (
- mkDsLet (NonRec arg (mkConApp pack_con
- (map Type tycon_args ++
- map Var unpacked_args))) body',
- unpacked_args ++ real_args
- )
-
- _ -> returnDs (body', arg:real_args)
-\end{code}