diff options
Diffstat (limited to 'compiler/rename/RnSource.hs')
| -rw-r--r-- | compiler/rename/RnSource.hs | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/compiler/rename/RnSource.hs b/compiler/rename/RnSource.hs index 5ec4e05cd1..ca35e941fb 100644 --- a/compiler/rename/RnSource.hs +++ b/compiler/rename/RnSource.hs @@ -1004,6 +1004,7 @@ rnSrcDerivDecl (DerivDecl _ ty mds overlap) <- rnLDerivStrategy DerivDeclCtx mds $ \strat_tvs ppr_via_ty -> rnAndReportFloatingViaTvs strat_tvs loc ppr_via_ty "instance" $ rnHsSigWcType BindUnlessForall DerivDeclCtx ty + ; warnNoDerivStrat mds' loc ; return (DerivDecl noExt ty' mds' overlap, fvs) } where loc = getLoc $ hsib_body $ hswc_body ty @@ -1705,6 +1706,29 @@ rnDataDefn doc (HsDataDefn { dd_ND = new_or_data, dd_cType = cType ; return (cL loc ds', fvs) } rnDataDefn _ (XHsDataDefn _) = panic "rnDataDefn" +warnNoDerivStrat :: Maybe (LDerivStrategy GhcRn) + -> SrcSpan + -> RnM () +warnNoDerivStrat mds loc + = do { dyn_flags <- getDynFlags + ; when (wopt Opt_WarnMissingDerivingStrategies dyn_flags) $ + case mds of + Nothing -> addWarnAt + (Reason Opt_WarnMissingDerivingStrategies) + loc + (if xopt LangExt.DerivingStrategies dyn_flags + then no_strat_warning + else no_strat_warning $+$ deriv_strat_nenabled + ) + _ -> pure () + } + where + no_strat_warning :: SDoc + no_strat_warning = text "No deriving strategy specified. Did you want stock" + <> text ", newtype, or anyclass?" + deriv_strat_nenabled :: SDoc + deriv_strat_nenabled = text "Use DerivingStrategies to specify a strategy." + rnLHsDerivingClause :: HsDocContext -> LHsDerivingClause GhcPs -> RnM (LHsDerivingClause GhcRn, FreeVars) rnLHsDerivingClause doc @@ -1715,6 +1739,7 @@ rnLHsDerivingClause doc = do { (dcs', dct', fvs) <- rnLDerivStrategy doc dcs $ \strat_tvs ppr_via_ty -> mapFvRn (rn_deriv_ty strat_tvs ppr_via_ty) dct + ; warnNoDerivStrat dcs' loc ; pure ( cL loc (HsDerivingClause { deriv_clause_ext = noExt , deriv_clause_strategy = dcs' , deriv_clause_tys = cL loc' dct' }) |