import HsSyn ( HsDecl(..), InstDecl(..), TyClDecl(..), HsType(..),
MonoBinds(..), HsExpr(..), HsLit(..), Sig(..),
- andMonoBindList, collectMonoBinders, isClassDecl
+ andMonoBindList, collectMonoBinders, isClassDecl, toHsType
)
import RnHsSyn ( RenamedHsBinds, RenamedInstDecl, RenamedHsDecl,
RenamedMonoBinds, RenamedTyClDecl, RenamedHsType,
tcInstDecl2 (InstInfo { iDFunId = dfun_id,
iBinds = monobinds, iPrags = uprags })
= -- Prime error recovery
- recoverNF_Tc (returnNF_Tc (emptyLIE, EmptyMonoBinds)) $
- tcAddSrcLoc (getSrcLoc dfun_id) $
+ recoverNF_Tc (returnNF_Tc (emptyLIE, EmptyMonoBinds)) $
+ tcAddSrcLoc (getSrcLoc dfun_id) $
+ tcAddErrCtxt (instDeclCtxt (toHsType (idType dfun_id))) $
-- Instantiate the instance decl with tc-style type variables
tcInstType (idType dfun_id) `thenNF_Tc` \ (inst_tyvars', dfun_theta', dict_ty') ->
scs_and_meths = map instToId (sc_dicts ++ meth_insts)
this_dict_id = instToId this_dict
inlines = unitNameSet (idName dfun_id)
+ -- Always inline the dfun; this is an experimental decision
+ -- because it makes a big performance difference sometimes.
+ -- Often it means we can do the method selection, and then
+ -- inline the method as well. Marcin's idea.
dict_rhs
| null scs_and_meths