diff options
Diffstat (limited to 'compiler/rename/RnSource.lhs')
| -rw-r--r-- | compiler/rename/RnSource.lhs | 39 |
1 files changed, 28 insertions, 11 deletions
diff --git a/compiler/rename/RnSource.lhs b/compiler/rename/RnSource.lhs index 9a92f84b59..5083044a6f 100644 --- a/compiler/rename/RnSource.lhs +++ b/compiler/rename/RnSource.lhs @@ -333,20 +333,32 @@ rnSrcInstDecl (InstDecl inst_ty mbinds uprags ats) -- to remove the context). \end{code} -Renaming of the associated data definitions requires adding the instance -context, as the rhs of an AT declaration may use ATs from classes in the -context. +Renaming of the associated type definitions in instances. + +* In the case of associated data and newtype definitions we add the instance + context. +* We raise an error if we encounter a kind signature in an instance. \begin{code} rnATDefs :: HsContext RdrName -> [LTyClDecl RdrName] -> RnM ([LTyClDecl Name], FreeVars) rnATDefs ctxt atDecls = - mapFvRn (wrapLocFstM addCtxtAndRename) atDecls + mapFvRn (wrapLocFstM rnAtDef) atDecls where - -- The parser won't accept anything, but a data declaration - addCtxtAndRename ty@TyData {tcdCtxt = L l tyCtxt} = - rnTyClDecl (ty {tcdCtxt = L l (ctxt ++ tyCtxt)}) - -- The source loc is somewhat half hearted... -=chak + rnAtDef tydecl@TyFunction {} = + do + addErr noKindSig + rnTyClDecl tydecl + rnAtDef tydecl@TySynonym {} = rnTyClDecl tydecl + rnAtDef tydecl@TyData {tcdCtxt = L l tyCtxt} = + do + checkM (not . isKindSigDecl $ tydecl) $ addErr noKindSig + rnTyClDecl (tydecl {tcdCtxt = L l (ctxt ++ tyCtxt)}) + -- The source loc is somewhat half hearted... -=chak + rnAtDef _ = + panic "RnSource.rnATDefs: not a type declaration" + +noKindSig = text "Instances cannot have kind signatures" \end{code} For the method bindings in class and instance decls, we extend the @@ -769,15 +781,17 @@ needOneIdx = text "Kind signature requires at least one type index" -- Rename associated type declarations (in classes) -- --- * This can be data declarations, type function signatures, and (default) --- type function equations. +-- * This can be kind signatures and (default) type function equations. -- rnATs :: [LTyClDecl RdrName] -> RnM ([LTyClDecl Name], FreeVars) rnATs ats = mapFvRn (wrapLocFstM rn_at) ats where rn_at (tydecl@TyData {}) = rnTySig tydecl lookupIdxVars rn_at (tydecl@TyFunction {}) = rnTySig tydecl lookupIdxVars - rn_at (tydecl@TySynonym {}) = rnTyClDecl tydecl + rn_at (tydecl@TySynonym {}) = + do + checkM (isNothing (tcdTyPats tydecl)) $ addErr noPatterns + rnTyClDecl tydecl rn_at _ = panic "RnSource.rnATs: invalid TyClDecl" lookupIdxVars _ tyvars cont = mappM lookupIdxVar tyvars >>= cont @@ -789,6 +803,9 @@ rnATs ats = mapFvRn (wrapLocFstM rn_at) ats name' <- lookupOccRn (hsTyVarName tyvar) return $ L l (replaceTyVarName tyvar name') +noPatterns = text "Default definition for an associated synonym cannot have" + <+> text "type pattern" + -- This data decl will parse OK -- data T = a Int -- treating "a" as the constructor. |