+deSugar :: HscEnv -> TcGblEnv -> IO (Bag WarnMsg, Maybe ModGuts)
+-- Can modify PCS by faulting in more declarations
+
+deSugar hsc_env
+ tcg_env@(TcGblEnv { tcg_mod = mod,
+ tcg_type_env = type_env,
+ tcg_imports = imports,
+ tcg_exports = exports,
+ tcg_dus = dus,
+ tcg_inst_uses = dfun_uses_var,
+ tcg_th_used = th_var,
+ tcg_rdr_env = rdr_env,
+ tcg_fix_env = fix_env,
+ tcg_deprecs = deprecs,
+ tcg_insts = insts })
+ = do { showPass dflags "Desugar"
+
+ -- Do desugaring
+ ; (results, warnings) <- initDs hsc_env mod type_env $
+ dsProgram ghci_mode tcg_env
+
+ ; let { (ds_binds, ds_rules, ds_fords) = results
+ ; warns = mapBag mk_warn warnings
+ }
+
+ -- If warnings are considered errors, leave.
+ ; if errorsFound dflags (warns, emptyBag)
+ then return (warns, Nothing)
+ else do
+
+ -- Lint result if necessary
+ { endPass dflags "Desugar" Opt_D_dump_ds ds_binds
+
+ -- Dump output
+ ; doIfSet (dopt Opt_D_dump_ds dflags)
+ (printDump (ppr_ds_rules ds_rules))
+
+ ; dfun_uses <- readIORef dfun_uses_var -- What dfuns are used
+ ; let used_names = allUses dus `unionNameSets` dfun_uses
+ ; usages <- mkUsageInfo hsc_env imports used_names
+
+ ; th_used <- readIORef th_var
+ ; let
+ pkgs | th_used = insertList thPackage (imp_dep_pkgs imports)
+ | otherwise = imp_dep_pkgs imports
+
+ mods = moduleEnvElts (delModuleEnv (imp_dep_mods imports) mod)
+ -- M.hi-boot can be in the imp_dep_mods, but we must remove
+ -- it before recording the modules on which this one depends!
+
+ -- ModuleNames don't compare lexicographically usually,
+ -- but we want them to do so here.
+ le_mod :: ModuleName -> ModuleName -> Bool
+ le_mod m1 m2 = moduleNameFS m1 <= moduleNameFS m2
+ le_dep_mod :: (ModuleName, IsBootInterface) -> (ModuleName, IsBootInterface) -> Bool
+ le_dep_mod (m1,_) (m2,_) = m1 `le_mod` m2
+
+ deps = Deps { dep_mods = sortLe le_dep_mod mods,
+ dep_pkgs = sortLe (<=) pkgs,
+ dep_orphs = sortLe le_mod (imp_orphs imports) }
+ -- sort to get into canonical order
+
+ mod_guts = ModGuts {
+ mg_module = mod,
+ mg_exports = exports,
+ mg_deps = deps,
+ mg_usages = usages,
+ mg_dir_imps = [m | (m,_,_) <- moduleEnvElts (imp_mods imports)],
+ mg_rdr_env = rdr_env,
+ mg_fix_env = fix_env,
+ mg_deprecs = deprecs,
+ mg_types = type_env,
+ mg_insts = insts,
+ mg_rules = ds_rules,
+ mg_binds = ds_binds,
+ mg_foreign = ds_fords }
+
+ ; return (warns, Just mod_guts)
+ }}
+
+ where
+ dflags = hsc_dflags hsc_env
+ ghci_mode = hsc_mode hsc_env
+ print_unqual = unQualInScope rdr_env
+
+ -- Desugarer warnings are SDocs; here we
+ -- add the info about whether or not to print unqualified
+ mk_warn :: (SrcSpan,SDoc) -> WarnMsg
+ mk_warn (loc, sdoc) = mkWarnMsg loc print_unqual sdoc
+
+
+deSugarExpr :: HscEnv
+ -> Module -> GlobalRdrEnv -> TypeEnv
+ -> LHsExpr Id
+ -> IO CoreExpr
+deSugarExpr hsc_env this_mod rdr_env type_env tc_expr
+ = do { showPass dflags "Desugar"
+ ; us <- mkSplitUniqSupply 'd'
+
+ -- Do desugaring
+ ; (core_expr, ds_warns) <- initDs hsc_env this_mod type_env $
+ dsLExpr tc_expr
+
+ -- Display any warnings
+ -- Note: if -Werror is used, we don't signal an error here.
+ ; doIfSet (not (isEmptyBag ds_warns))
+ (printErrs (pprBagOfWarnings (mapBag mk_warn ds_warns)))
+
+ -- Dump output
+ ; dumpIfSet_dyn dflags Opt_D_dump_ds "Desugared" (pprCoreExpr core_expr)
+
+ ; return core_expr
+ }
+ where
+ dflags = hsc_dflags hsc_env
+ print_unqual = unQualInScope rdr_env