[project @ 2003-10-30 10:14:59 by simonpj]

1.  When desugaring a [d| ... |], do not gensym the method names of
    an instance declaration, else we get very confused!

2.  We don't need to make fresh Names in DsMeta.mkGenSym, because
    the existing Name will do, I believe.  We'll do the genSym when
    we *run* the splice.  (This stuff makes my head hurt.)

    Assuming this is so, we can simplify the mkGenSym stuff still more.

diff --git a/ghc/compiler/deSugar/DsMeta.hs b/ghc/compiler/deSugar/DsMeta.hs
index 061c367..9ab3bf7 100644 (file)
--- a/ghc/compiler/deSugar/DsMeta.hs
+++ b/ghc/compiler/deSugar/DsMeta.hs
@@ -37,7 +37,8 @@ import HsSyn            ( Pat(..), HsExpr(..), Stmt(..), HsLit(..), HsOverLit(..),
                    InstDecl(..), ConDecl(..), BangType(..),
                    PendingSplice, splitHsInstDeclTy,
                    placeHolderType, tyClDeclNames,
-                   collectHsBinders, collectPatBinders, collectPatsBinders,
+                   collectHsBinders, collectPatBinders, 
+                   collectMonoBinders, collectPatsBinders,
                    hsTyVarName, hsConArgs
                  )
 
@@ -51,7 +52,7 @@ import OccName          ( isDataOcc, isTvOcc, occNameUserString )
 import qualified OccName( varName, tcName )
 
 import Module    ( Module, mkModule, moduleUserString )
-import Id         ( Id, idType )
+import Id         ( Id, idType, mkLocalId )
 import Name      ( mkExternalName )
 import OccName   ( mkOccFS )
 import NameEnv
@@ -267,10 +268,10 @@ repInstD' (InstDecl ty binds _ loc)
        ; let ss = mkGenSyms (collectMonoBinders binds)
        ; binds1 <- addBinds ss (rep_monobind binds)
        ; decls1 <- coreList decQTyConName binds1
-       ; i <- repInst cxt1 inst_ty1 
-                      (wrapNonGenSyms ss decls1)
+       ; decls2 <- wrapNongenSyms ss decls1
                -- wrapNonGenSyms: do not clone the class op names!
                -- They must be called 'op' etc, not 'op34'
+       ; i <- repInst cxt1 inst_ty1 decls2
        ; return (loc, i)}
  where
    (tvs, cxt, cls, tys) = splitHsInstDeclTy ty
@@ -802,6 +803,14 @@ type GenSymBind = (Name, Id)       -- Gensym the string and bind it to the Id
 -- Generate a fresh name for a locally bound entity
 
 mkGenSym :: Name -> GenSymBind
+-- Does not need to be monadic, becuase we can use the
+-- existing name.  For example:
+--     [| \x_77 -> x_77 + x_77 |]
+-- desugars to
+--     do { x_77 <- genSym "x"; .... }
+-- We use the same x_77 in the desugared program, but with the type Bndr
+-- instead of Int
+
 mkGenSym nm = (nm, mkLocalId nm stringTy)
 
 -- Ditto for a list of names