diff options
Diffstat (limited to 'compiler/GHC/Tc/Errors.hs')
| -rw-r--r-- | compiler/GHC/Tc/Errors.hs | 32 |
1 files changed, 18 insertions, 14 deletions
diff --git a/compiler/GHC/Tc/Errors.hs b/compiler/GHC/Tc/Errors.hs index ed102d9bb5..66f0cf118a 100644 --- a/compiler/GHC/Tc/Errors.hs +++ b/compiler/GHC/Tc/Errors.hs @@ -462,8 +462,8 @@ mkErrorItem ct ; (suppress, m_evdest) <- case ctEvidence ct of CtGiven {} -> return (False, Nothing) CtWanted { ctev_rewriters = rewriters, ctev_dest = dest } - -> do { supp <- anyUnfilledCoercionHoles rewriters - ; return (supp, Just dest) } + -> do { rewriters' <- zonkRewriterSet rewriters + ; return (not (isEmptyRewriterSet rewriters'), Just dest) } ; let m_reason = case ct of CIrredCan { cc_reason = reason } -> Just reason _ -> Nothing @@ -492,20 +492,24 @@ reportWanteds ctxt tc_lvl wc@(WC { wc_simple = simples, wc_impl = implics , text "tidy_items1 =" <+> ppr tidy_items1 , text "tidy_errs =" <+> ppr tidy_errs ]) - -- Catch an awkward case in which /all/ errors are suppressed: - -- see Wrinkle at end of Note [Wanteds rewrite Wanteds] in GHC.Tc.Types.Constraint - -- Unless we are sure that an error will be reported some other way (details - -- in the defn of tidy_items) un-suppress the lot. This makes sure we don't forget to - -- report an error at all, which is catastrophic: GHC proceeds to desguar and optimise - -- the program, even though it is full of type errors (#22702, #22793) + -- Catch an awkward (and probably rare) case in which /all/ errors are + -- suppressed: see Wrinkle (WRW2) in Note [Prioritise Wanteds with empty + -- RewriterSet] in GHC.Tc.Types.Constraint. + -- + -- Unless we are sure that an error will be reported some other way + -- (details in the defn of tidy_items) un-suppress the lot. This makes + -- sure we don't forget to report an error at all, which is + -- catastrophic: GHC proceeds to desguar and optimise the program, even + -- though it is full of type errors (#22702, #22793) ; errs_already <- ifErrsM (return True) (return False) ; let tidy_items | not errs_already -- Have not already reported an error (perhaps -- from an outer implication); see #21405 , not (any ignoreConstraint simples) -- No error is ignorable (is reported elsewhere) , all ei_suppress tidy_items1 -- All errors are suppressed - = map unsuppressErrorItem tidy_items1 - | otherwise = tidy_items1 + = map unsuppressErrorItem tidy_items1 + | otherwise + = tidy_items1 -- First, deal with any out-of-scope errors: ; let (out_of_scope, other_holes, not_conc_errs) = partition_errors tidy_errs @@ -1804,8 +1808,8 @@ mkTyVarEqErr' ctxt item (tv1, co1) ty2 return (main_msg, []) -- Incompatible kinds - -- This is wrinkle (4) in Note [Equalities with incompatible kinds] in - -- GHC.Tc.Solver.Canonical + -- This is wrinkle (EIK2) in Note [Equalities with incompatible kinds] + -- in GHC.Tc.Solver.Equality | hasCoercionHoleCo co1 || hasCoercionHoleTy ty2 = return (mkBlockedEqErr item, []) @@ -1987,8 +1991,8 @@ misMatchOrCND insoluble_occurs_check ctxt item ty1 ty2 -- Keep only UserGivens that have some equalities. -- See Note [Suppress redundant givens during error reporting] --- These are for the "blocked" equalities, as described in TcCanonical --- Note [Equalities with incompatible kinds], wrinkle (2). There should +-- These are for the "blocked" equalities, as described in GHC.Tc.Solver.Equality +-- Note [Equalities with incompatible kinds], wrinkle (EIK2). There should -- always be another unsolved wanted around, which will ordinarily suppress -- this message. But this can still be printed out with -fdefer-type-errors -- (sigh), so we must produce a message. |