Commit ba6308ec authored by eir@cis.upenn.edu's avatar eir@cis.upenn.edu

Refine fix for #7667.

Now, we allow types that do not begin with ':', but we retain other
checks on variable names.
parent f122291c
......@@ -1053,9 +1053,10 @@ tName n = cvtName OccName.tvName n
tconNameL n = wrapL (tconName n)
tconName n = cvtName OccName.tcClsName n
-- See Note [Checking name spaces]
cvtName :: OccName.NameSpace -> TH.Name -> CvtM RdrName
cvtName ctxt_ns (TH.Name occ flavour)
| not (okOcc ctxt_ns occ_str) = failWith (badOcc ctxt_ns occ_str)
| otherwise
= do { loc <- getL
; let rdr_name = thRdrName loc ctxt_ns occ_str flavour
; force rdr_name
......@@ -1063,6 +1064,15 @@ cvtName ctxt_ns (TH.Name occ flavour)
where
occ_str = TH.occString occ
okOcc :: OccName.NameSpace -> String -> Bool
okOcc _ [] = False
okOcc ns str@(c:_)
| OccName.isVarNameSpace ns = startsVarId c || startsVarSym c
| OccName.isDataConNameSpace ns = startsConId c || startsConSym c || str == "[]"
| otherwise = startsConId c || startsConSym c ||
startsVarSym c || str == "[]" || str == "->"
-- allow type operators like "+"
-- Determine the name space of a name in a type
--
isVarName :: TH.Name -> Bool
......@@ -1071,6 +1081,11 @@ isVarName (TH.Name occ _)
"" -> False
(c:_) -> startsVarId c || startsVarSym c
badOcc :: OccName.NameSpace -> String -> SDoc
badOcc ctxt_ns occ
= ptext (sLit "Illegal") <+> pprNameSpace ctxt_ns
<+> ptext (sLit "name:") <+> quotes (text occ)
thRdrName :: SrcSpan -> OccName.NameSpace -> String -> TH.NameFlavour -> RdrName
-- This turns a TH Name into a RdrName; used for both binders and occurrences
-- See Note [Binders in Template Haskell]
......@@ -1205,14 +1220,3 @@ the way System Names are printed.
There's a small complication of course; see Note [Looking up Exact
RdrNames] in RnEnv.
Note [Checking name spaces]
~~~~~~~~~~~~~~~~~~~~~~~~~~~
In cvtName, it's possible that the name we are converting doesn't
match the namespace requested. For example, we might have a data
constructor "foo" or a variable "Bar". We could check for these cases,
but it seems difficult to guarantee identical behavior to the parser.
Furthermore, a TH user might (somewhat dirtily) want to violate Haskell's
naming expectations, and to use a name that couldn't be used in source
code. So, according to the discussion in #7667, we just don't check.
If you're thinking of changing this behavior, also please do see #7484,
which is closely related.
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