diff options
Diffstat (limited to 'compiler/typecheck/TcWarnings.hs')
| -rw-r--r-- | compiler/typecheck/TcWarnings.hs | 29 |
1 files changed, 28 insertions, 1 deletions
diff --git a/compiler/typecheck/TcWarnings.hs b/compiler/typecheck/TcWarnings.hs index f0d1a21acc..2c89ead806 100644 --- a/compiler/typecheck/TcWarnings.hs +++ b/compiler/typecheck/TcWarnings.hs @@ -9,7 +9,10 @@ module TcWarnings ( warnAboutEmptyEnumerations, -- * Discarded do bindings - warnDiscardedDoBindings + warnDiscardedDoBindings, + + -- * Useless pragmas + warnUselessSpecialisePragma ) where import GhcPrelude @@ -274,3 +277,27 @@ badMonadBind rhs elt_ty , hang (text "Suppress this warning by saying") 2 (quotes $ text "_ <-" <+> ppr rhs) ] + +warnUselessSpecialisePragma :: LTcSpecPrag -> TcM () +warnUselessSpecialisePragma (dL->L loc (SpecPrag id _ spec_inl)) + | Just _ <- isClassOpId_maybe id + = setSrcSpan loc (warn_useless "class method selector") + | no_act_spec && isNeverActive id_rule_act + -- Function is NOINLINE, and the specialisation inherits that + -- See Note [Activation pragmas for SPECIALISE] in DsBinds + = setSrcSpan loc (warn_useless "NOINLINE function") + | otherwise + = return () + where + warn_useless what = warnTc NoReason True $ hsep + [ text "Ignoring useless SPECIALISE pragma for" + , ppr what + , quotes (ppr id) + ] + -- See Note [Activation pragmas for SPECIALISE] in DsBinds + -- no_act_spec is True if the user didn't write an explicit + -- phase specification in the SPECIALISE pragma + no_act_spec = case inlinePragmaSpec spec_inl of + NoInline -> isNeverActive (inlinePragmaActivation spec_inl) + _ -> isAlwaysActive (inlinePragmaActivation spec_inl) + id_rule_act = inlinePragmaActivation (idInlinePragma id) |