plusLIEs, mkLIE, isEmptyLIE, lieToList, listToLIE,
-- Misc other types
- TcId, TcIdSet, TcDictBinds,
+ TcId, TcIdSet, TcDictBinds, TcTyVarBind(..), TcTyVarBinds
) where
import ListSetOps
import FastString
-import Data.Maybe
-import Data.List
+import Data.Set (Set)
\end{code}
type TcM a = TcRn a -- Historical
\end{code}
+Representation of type bindings to uninstantiated meta variables used during
+constraint solving.
+
+\begin{code}
+data TcTyVarBind = TcTyVarBind TcTyVar TcType
+
+type TcTyVarBinds = Bag TcTyVarBind
+
+instance Outputable TcTyVarBind where
+ ppr (TcTyVarBind tv ty) = ppr tv <+> text ":=" <+> ppr ty
+\end{code}
+
%************************************************************************
%* *
-- reference is implicit rather than explicit, so we have to zap a
-- mutable variable.
- tcg_dfun_n :: TcRef Int,
- -- ^ Allows us to number off the names of DFuns.
- --
- -- It's convenient to allocate an External Name for a DFun, with
- -- a permanently-fixed unique, just like other top-level functions
- -- defined in this module. But that means we need a canonical
- -- occurrence name, distinct from all other dfuns in this module,
- -- and this name supply serves that purpose (df1, df2, etc).
+ tcg_dfun_n :: TcRef OccSet,
+ -- ^ Allows us to choose unique DFun names.
-- The next fields accumulate the payload of the module
-- The binds, rules and foreign-decl fiels are collected
-- initially in un-zonked form and are finally zonked in tcRnSrcDecls
- tcg_rn_imports :: Maybe [LImportDecl Name],
tcg_rn_exports :: Maybe [Located (IE Name)],
+ tcg_rn_imports :: [LImportDecl Name],
+ -- Keep the renamed imports regardless. They are not
+ -- voluminous and are needed if you want to report unused imports
+ tcg_used_rdrnames :: TcRef (Set RdrName),
tcg_rn_decls :: Maybe (HsGroup Name),
-- ^ Renamed decls, maybe. @Nothing@ <=> Don't retain renamed
-- decls.
-- Discarded after typecheck/rename; not passed on to desugarer
= TcLclEnv {
tcl_loc :: SrcSpan, -- Source span
- tcl_ctxt :: ErrCtxt, -- Error context
+ tcl_ctxt :: [ErrCtxt], -- Error context, innermost on top
tcl_errs :: TcRef Messages, -- Place to accumulate errors
tcl_th_ctxt :: ThStage, -- Template Haskell context
-- We still need the unsullied global name env so that
-- we can look up record field names
- tcl_env :: NameEnv TcTyThing, -- The local type environment: Ids and TyVars
- -- defined in this module
+ tcl_env :: NameEnv TcTyThing, -- The local type environment: Ids and
+ -- TyVars defined in this module
tcl_tyvars :: TcRef TcTyVarSet, -- The "global tyvars"
-- Namely, the in-scope TyVars bound in tcl_env,
- -- plus the tyvars mentioned in the types of Ids bound in tcl_lenv
- -- Why mutable? see notes with tcGetGlobalTyVars
+ -- plus the tyvars mentioned in the types of Ids bound
+ -- in tcl_lenv.
+ -- Why mutable? see notes with tcGetGlobalTyVars
- tcl_lie :: TcRef LIE -- Place to accumulate type constraints
+ tcl_lie :: TcRef LIE, -- Place to accumulate type constraints
+
+ tcl_tybinds :: TcRef TcTyVarBinds -- Meta and coercion type variable
+ -- bindings accumulated during
+ -- constraint solving
}
\end{code}
\begin{code}
-type ErrCtxt = [TidyEnv -> TcM (TidyEnv, Message)]
- -- Innermost first. Monadic so that we have a chance
- -- to deal with bound type variables just before error
- -- message construction
+type ErrCtxt = (Bool, TidyEnv -> TcM (TidyEnv, Message))
+ -- Monadic so that we have a chance
+ -- to deal with bound type variables just before error
+ -- message construction
+
+ -- Bool: True <=> this is a landmark context; do not
+ -- discard it when trimming for display
\end{code}
\begin{code}
-------------------------------------------
-data InstLoc = InstLoc InstOrigin SrcSpan ErrCtxt
+data InstLoc = InstLoc InstOrigin SrcSpan [ErrCtxt]
instLoc :: Inst -> InstLoc
instLoc inst = tci_loc inst