-- Template Haskell
ThStage(..), topStage, topAnnStage, topSpliceStage,
- ThLevel, impLevel, topLevel,
+ ThLevel, impLevel, outerLevel, thLevel,
-- Arrows
ArrowCtxt(NoArrowCtxt), newArrowScope, escapeArrowScope,
import ListSetOps
import FastString
-import Data.Maybe
-import Data.List
+import Data.Set (Set)
\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),
+ -- The set of used *imported* (not locally-defined) RdrNames
+ -- Used only to report unused import declarations
+
tcg_rn_decls :: Maybe (HsGroup Name),
-- ^ Renamed decls, maybe. @Nothing@ <=> Don't retain renamed
-- decls.
tcg_rules :: [LRuleDecl Id], -- ...Rules
tcg_fords :: [LForeignDecl Id], -- ...Foreign import & exports
- tcg_doc :: Maybe (HsDoc Name), -- ^ Maybe Haddock documentation
- tcg_hmi :: HaddockModInfo Name, -- ^ Haddock module information
- tcg_hpc :: AnyHpcUsage -- ^ @True@ if any part of the prog uses hpc
- -- instrumentation.
+ tcg_doc_hdr :: Maybe LHsDocString, -- ^ Maybe Haddock header docs
+ tcg_hpc :: AnyHpcUsage, -- ^ @True@ if any part of the
+ -- prog uses hpc instrumentation.
+
+ tcg_main :: Maybe Name -- ^ The Name of the main
+ -- function, if this module is
+ -- the main module.
}
data RecFieldEnv
-- 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
-}
---------------------------
--- Template Haskell levels
+-- Template Haskell stages and levels
---------------------------
+data ThStage -- See Note [Template Haskell state diagram] in TcSplice
+ = Splice -- Top-level splicing
+ -- This code will be run *at compile time*;
+ -- the result replaces the splice
+ -- Binding level = 0
+
+ | Comp -- Ordinary Haskell code
+ -- Binding level = 1
+
+ | Brack -- Inside brackets
+ ThStage -- Binding level = level(stage) + 1
+ (TcRef [PendingSplice]) -- Accumulate pending splices here
+ (TcRef LIE) -- and type constraints here
+
+topStage, topAnnStage, topSpliceStage :: ThStage
+topStage = Comp
+topAnnStage = Splice
+topSpliceStage = Splice
+
+instance Outputable ThStage where
+ ppr Splice = text "Splice"
+ ppr Comp = text "Comp"
+ ppr (Brack s _ _) = text "Brack" <> parens (ppr s)
+
type ThLevel = Int
- -- Indicates how many levels of brackets we are inside
- -- (always >= 0)
+ -- See Note [Template Haskell levels] in TcSplice
-- Incremented when going inside a bracket,
-- decremented when going inside a splice
-- NB: ThLevel is one greater than the 'n' in Fig 2 of the
-- original "Template meta-programming for Haskell" paper
-impLevel, topLevel :: ThLevel
-topLevel = 1 -- Things defined at top level of this module
+impLevel, outerLevel :: ThLevel
impLevel = 0 -- Imported things; they can be used inside a top level splice
+outerLevel = 1 -- Things defined outside brackets
+-- NB: Things at level 0 are not *necessarily* imported.
+-- eg $( \b -> ... ) here b is bound at level 0
--
-- For example:
-- f = ...
-- g1 = $(map ...) is OK
-- g2 = $(f ...) is not OK; because we havn't compiled f yet
-
-data ThStage
- = Comp ThLevel -- Ordinary compiling, usually at level topLevel but annotations use a lower level
- | Splice ThLevel -- Inside a splice
- | Brack ThLevel -- Inside brackets;
- (TcRef [PendingSplice]) -- accumulate pending splices here
- (TcRef LIE) -- and type constraints here
-topStage, topAnnStage, topSpliceStage :: ThStage
-topStage = Comp topLevel
-topAnnStage = Comp (topLevel - 1)
-topSpliceStage = Splice (topLevel - 1) -- Stage for the body of a top-level splice
+thLevel :: ThStage -> ThLevel
+thLevel Splice = 0
+thLevel Comp = 1
+thLevel (Brack s _ _) = thLevel s + 1
---------------------------
-- Arrow-notation context
\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
projects / ghc-hetmet.git / blobdiff