#include "HsVersions.h"
-import {-# SOURCE #-} DsExpr ( dsExpr, dsLet )
-
import CmdLineOpts ( opt_WarnIncompletePatterns, opt_WarnOverlappingPatterns,
opt_WarnSimplePatterns
)
import DsHsSyn ( outPatType )
import Check ( check, ExhaustivePat )
import CoreSyn
-import CoreUtils ( coreExprType )
+import CoreUtils ( bindNonRec )
import DsMonad
import DsGRHSs ( dsGRHSs )
import DsUtils
import Id ( idType, recordSelectorFieldLabel, Id )
-import DataCon ( dataConFieldLabels, dataConArgTys )
+import DataCon ( dataConFieldLabels, dataConInstOrigArgTys )
import MatchCon ( matchConFamily )
import MatchLit ( matchLiterals )
-import PrelVals ( pAT_ERROR_ID )
-import Type ( isUnLiftedType, splitAlgTyConApp,
- Type
- )
-import TysPrim ( intPrimTy, charPrimTy, floatPrimTy, doublePrimTy,
- addrPrimTy, wordPrimTy
- )
-import TysWiredIn ( nilDataCon, consDataCon, mkTupleTy, mkListTy,
- charTy, charDataCon, intTy, intDataCon,
- floatTy, floatDataCon, doubleTy, tupleCon,
- doubleDataCon, addrTy,
- addrDataCon, wordTy, wordDataCon,
- mkUnboxedTupleTy, unboxedTupleCon
- )
+import PrelInfo ( pAT_ERROR_ID )
+import Type ( splitAlgTyConApp, mkTyVarTys, Type )
+import TysWiredIn ( nilDataCon, consDataCon, mkTupleTy, mkListTy, tupleCon )
+import BasicTypes ( Boxity(..) )
import UniqSet
import ErrUtils ( addErrLocHdrLine, dontAddErrLoc )
import Outputable
eqns_shadow = map (\n -> qs!!(n - 1)) unused_eqns
\end{code}
-This variable shows the maximun number of lines of output generated for warnings.
-It will limit the number of patterns/equations displayed to maximum_output.
+This variable shows the maximum number of lines of output generated for warnings.
+It will limit the number of patterns/equations displayed to@ maximum_output@.
(ToDo: add command-line option?)
maximum_output = 4
\end{code}
-The next two functions creates the warning message.
+The next two functions create the warning message.
\begin{code}
dsShadowWarn :: DsMatchContext -> [EquationInfo] -> DsM ()
, id
)
+ pp_match RecUpdMatch pats
+ = (hang (ptext SLIT("in a record-update construct"))
+ 4 (ppr_pats pats)
+ , id
+ )
+
pp_match PatBindMatch pats
= ( hang (ptext SLIT("in a pattern binding"))
4 (ppr_pats pats)
separator (CaseMatch) = SLIT("->")
separator (LambdaMatch) = SLIT("->")
separator (PatBindMatch) = panic "When is this used?"
+separator (RecUpdMatch) = panic "When is this used?"
separator (DoBindMatch) = SLIT("<-")
separator (ListCompMatch) = SLIT("<-")
separator (LetMatch) = SLIT("=")
sep (map ppr_constraint constraints)]
-ppr_constraint (var,pats) = sep [ppr var, ptext SLIT("`not_elem`"), ppr pats]
+ppr_constraint (var,pats) = sep [ppr var, ptext SLIT("`notElem`"), ppr pats]
ppr_eqn prefixF kind (EqnInfo _ _ pats _) = prefixF (ppr_shadow_pats kind pats)
\end{code}
-- re-express <con-something> as (ConPat ...) [directly]
-tidy1 v (RecPat data_con pat_ty tvs dicts rpats) match_result
- = returnDs (ConPat data_con pat_ty tvs dicts pats, match_result)
+tidy1 v (RecPat data_con pat_ty ex_tvs dicts rpats) match_result
+ | null rpats
+ = -- Special case for C {}, which can be used for
+ -- a constructor that isn't declared to have
+ -- fields at all
+ returnDs (ConPat data_con pat_ty ex_tvs dicts (map WildPat con_arg_tys'), match_result)
+
+ | otherwise
+ = returnDs (ConPat data_con pat_ty ex_tvs dicts pats, match_result)
where
pats = map mk_pat tagged_arg_tys
-- Boring stuff to find the arg-tys of the constructor
(_, inst_tys, _) = splitAlgTyConApp pat_ty
- con_arg_tys' = dataConArgTys data_con inst_tys
+ con_arg_tys' = dataConInstOrigArgTys data_con (inst_tys ++ mkTyVarTys ex_tvs)
tagged_arg_tys = con_arg_tys' `zip` (dataConFieldLabels data_con)
-- mk_pat picks a WildPat of the appropriate type for absent fields,
(ConPat nilDataCon list_ty [] [] [])
pats
-tidy1 v (TuplePat pats True{-boxed-}) match_result
+tidy1 v (TuplePat pats boxity) match_result
= returnDs (tuple_ConPat, match_result)
where
arity = length pats
tuple_ConPat
- = ConPat (tupleCon arity)
- (mkTupleTy arity (map outPatType pats)) [] []
- pats
-
-tidy1 v (TuplePat pats False{-unboxed-}) match_result
- = returnDs (tuple_ConPat, match_result)
- where
- arity = length pats
- tuple_ConPat
- = ConPat (unboxedTupleCon arity)
- (mkUnboxedTupleTy arity (map outPatType pats)) [] []
+ = ConPat (tupleCon boxity arity)
+ (mkTupleTy boxity arity (map outPatType pats)) [] []
pats
tidy1 v (DictPat dicts methods) match_result
= case num_of_d_and_ms of
- 0 -> tidy1 v (TuplePat [] True) match_result
+ 0 -> tidy1 v (TuplePat [] Boxed) match_result
1 -> tidy1 v (head dict_and_method_pats) match_result
- _ -> tidy1 v (TuplePat dict_and_method_pats True) match_result
+ _ -> tidy1 v (TuplePat dict_and_method_pats Boxed) match_result
where
num_of_d_and_ms = length dicts + length methods
dict_and_method_pats = map VarPat (dicts ++ methods)
-- LitPats: the desugarer only sees these at well-known types
tidy1 v pat@(LitPat lit lit_ty) match_result
- | isUnLiftedType lit_ty
- = returnDs (pat, match_result)
-
- | lit_ty == charTy
- = returnDs (ConPat charDataCon charTy [] [] [LitPat (mk_char lit) charPrimTy],
- match_result)
-
- | otherwise = pprPanic "tidy1:LitPat:" (ppr pat)
- where
- mk_char (HsChar c) = HsCharPrim c
+ = returnDs (tidyLitPat lit lit_ty pat, match_result)
-- NPats: we *might* be able to replace these w/ a simpler form
-
-
tidy1 v pat@(NPat lit lit_ty _) match_result
- = returnDs (better_pat, match_result)
- where
- better_pat
- | lit_ty == charTy = ConPat charDataCon lit_ty [] [] [LitPat (mk_char lit) charPrimTy]
- | lit_ty == intTy = ConPat intDataCon lit_ty [] [] [LitPat (mk_int lit) intPrimTy]
- | lit_ty == wordTy = ConPat wordDataCon lit_ty [] [] [LitPat (mk_word lit) wordPrimTy]
- | lit_ty == addrTy = ConPat addrDataCon lit_ty [] [] [LitPat (mk_addr lit) addrPrimTy]
- | lit_ty == floatTy = ConPat floatDataCon lit_ty [] [] [LitPat (mk_float lit) floatPrimTy]
- | lit_ty == doubleTy = ConPat doubleDataCon lit_ty [] [] [LitPat (mk_double lit) doublePrimTy]
-
- -- Convert the literal pattern "" to the constructor pattern [].
- | null_str_lit lit = ConPat nilDataCon lit_ty [] [] []
-
- | otherwise = pat
-
- mk_int (HsInt i) = HsIntPrim i
- mk_int l@(HsLitLit s) = l
-
- mk_char (HsChar c) = HsCharPrim c
- mk_char l@(HsLitLit s) = l
-
- mk_word l@(HsLitLit s) = l
-
- mk_addr l@(HsLitLit s) = l
-
- mk_float (HsInt i) = HsFloatPrim (fromInteger i)
- mk_float (HsFrac f) = HsFloatPrim f
- mk_float l@(HsLitLit s) = l
-
- mk_double (HsInt i) = HsDoublePrim (fromInteger i)
- mk_double (HsFrac f) = HsDoublePrim f
- mk_double l@(HsLitLit s) = l
-
- null_str_lit (HsString s) = _NULL_ s
- null_str_lit other_lit = False
+ = returnDs (tidyLitPat lit lit_ty pat, match_result)
-- and everything else goes through unchanged...
= returnDs (non_interesting_pat, match_result)
\end{code}
-PREVIOUS matchTwiddled STUFF:
+\noindent
+{\bf Previous @matchTwiddled@ stuff:}
Now we get to the only interesting part; note: there are choices for
translation [from Simon's notes]; translation~1:
There is one small problem with the Lambda Patterns, when somebody
writes something similar to:
+\begin{verbatim}
(\ (x:xs) -> ...)
+\end{verbatim}
he/she don't want a warning about incomplete patterns, that is done with
- the flag opt_WarnSimplePatterns.
- This problem also appears in the :
- do patterns, but if the do can fail it creates another equation if the match can
- fail (see DsExpr.doDo function)
- let patterns, are treated by matchSimply
- List Comprension Patterns, are treated by matchSimply also
-
-We can't call matchSimply with Lambda patterns, due to lambda patterns can have more than
+ the flag @opt_WarnSimplePatterns@.
+ This problem also appears in the:
+\begin{itemize}
+\item @do@ patterns, but if the @do@ can fail
+ it creates another equation if the match can fail
+ (see @DsExpr.doDo@ function)
+\item @let@ patterns, are treated by @matchSimply@
+ List Comprension Patterns, are treated by @matchSimply@ also
+\end{itemize}
+
+We can't call @matchSimply@ with Lambda patterns,
+due to the fact that lambda patterns can have more than
one pattern, and match simply only accepts one pattern.
JJQC 30-Nov-1997
-
+
\begin{code}
matchWrapper kind matches error_string
- = flattenMatches kind matches `thenDs` \ (result_ty, eqns_info) ->
+ = flattenMatches kind matches `thenDs` \ (result_ty, eqns_info) ->
let
EqnInfo _ _ arg_pats _ : _ = eqns_info
in
projects / ghc-hetmet.git / blobdiff