[project @ 2003-10-29 18:14:27 by simonpj]

[ghc-hetmet.git] / ghc / compiler / typecheck / TcRnTypes.lhs

diff --git a/ghc/compiler/typecheck/TcRnTypes.lhs b/ghc/compiler/typecheck/TcRnTypes.lhs
index 01dbce1..8b5bc3b 100644 (file)
--- a/ghc/compiler/typecheck/TcRnTypes.lhs
+++ b/ghc/compiler/typecheck/TcRnTypes.lhs
@@ -163,12 +163,19 @@ data TcGblEnv
        tcg_imports :: ImportAvails,            -- Information about what was imported 
                                                --    from where, including things bound
                                                --    in this module
+
        tcg_dus :: DefUses,     -- What is defined in this module and what is used.
                                -- The latter is used to generate 
                                --      (a) version tracking; no need to recompile if these
                                --              things have not changed version stamp
                                --      (b) unused-import info
 
+       tcg_keep :: NameSet,    -- Set of names to keep alive, and to expose in the 
+                               -- interface file (but not to export to the user).
+                               -- These are typically extra definitions generated from
+                               -- data type declarations which would otherwise be
+                               -- dropped as dead code.  
+
                -- 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