merge GHC HEAD

[ghc-hetmet.git] / compiler / rename / RnExpr.lhs

diff --git a/compiler/rename/RnExpr.lhs b/compiler/rename/RnExpr.lhs
index b3458db..9b1f08e 100644 (file)
--- a/compiler/rename/RnExpr.lhs
+++ b/compiler/rename/RnExpr.lhs
@@ -25,7 +25,7 @@ import RnBinds   ( rnLocalBindsAndThen, rnLocalValBindsLHS, rnLocalValBindsRHS,
                    rnMatchGroup, makeMiniFixityEnv) 
 import HsSyn
 import TcRnMonad
-import TcEnv           ( thRnBrack )
+import TcEnv           ( thRnBrack, getHetMetLevel )
 import RnEnv
 import RnTypes         ( rnHsTypeFVs, rnSplice, checkTH,
                          mkOpFormRn, mkOpAppRn, mkNegAppRn, checkSectionPrec)
@@ -34,6 +34,7 @@ import DynFlags
 import BasicTypes      ( FixityDirection(..) )
 import PrelNames
 
+import Var              ( TyVar, varName )
 import Name
 import NameSet
 import RdrName
@@ -84,6 +85,13 @@ rnExprs ls = rnExprs' ls emptyUniqSet
 Variables. We look up the variable and return the resulting name. 
 
 \begin{code}
+
+-- during the renamer phase we only care about the length of the
+-- current HetMet level; the actual tyvars don't
+-- matter, so we use bottoms for them
+dummyTyVar :: TyVar
+dummyTyVar = error "tried to force RnExpr.dummyTyVar"
+
 rnLExpr :: LHsExpr RdrName -> RnM (LHsExpr Name, FreeVars)
 rnLExpr = wrapLocFstM rnExpr
 
@@ -157,6 +165,21 @@ rnExpr (NegApp e _)
     mkNegAppRn e' neg_name     `thenM` \ final_e ->
     return (final_e, fv_e `plusFV` fv_neg)
 
+rnExpr (HsHetMetBrak c e)
+  = do { (e', fv_e) <- updLclEnv (\x -> x { tcl_hetMetLevel = dummyTyVar:(tcl_hetMetLevel x) }) $ rnLExpr e
+       ; return (HsHetMetBrak c e', fv_e)
+       }
+rnExpr (HsHetMetEsc c t e)
+  = do { (e', fv_e) <- updLclEnv (\x -> x { tcl_hetMetLevel = tail (tcl_hetMetLevel x) }) $ rnLExpr e
+       ; return (HsHetMetEsc c t e', fv_e)
+       }
+rnExpr (HsHetMetCSP c e)
+  = do { (e', fv_e) <- updLclEnv (\x -> x { tcl_hetMetLevel = tail (tcl_hetMetLevel x) }) $ rnLExpr e
+       ; return (HsHetMetCSP c e', fv_e)
+       }
+
+    
+
 ------------------------------------------
 -- Template Haskell extensions
 -- Don't ifdef-GHCI them because we want to fail gracefully
@@ -694,6 +717,8 @@ rnStmt ctxt (L loc (ExprStmt expr _ _ _)) thing_inside
                               then lookupStmtName ctxt guardMName
                              else return (noSyntaxExpr, emptyFVs)
                              -- Only list/parr/monad comprehensions use 'guard'
+                             -- Also for sub-stmts of same eg [ e | x<-xs, gd | blah ]
+                             -- Here "gd" is a guard
        ; (thing, fvs3)    <- thing_inside []
        ; return (([L loc (ExprStmt expr' then_op guard_op placeHolderType)], thing),
                  fv_expr `plusFV` fvs1 `plusFV` fvs2 `plusFV` fvs3) }
@@ -841,9 +866,24 @@ rnParallelStmts ctxt segs thing_inside
 
 lookupStmtName :: HsStmtContext Name -> Name -> RnM (HsExpr Name, FreeVars)
 -- Like lookupSyntaxName, but ListComp/PArrComp are never rebindable
-lookupStmtName ListComp n = return (HsVar n, emptyFVs)
-lookupStmtName PArrComp n = return (HsVar n, emptyFVs)
-lookupStmtName _        n = lookupSyntaxName n
+-- Neither is ArrowExpr, which has its own desugarer in DsArrows
+lookupStmtName ctxt n 
+  = case ctxt of
+      ListComp        -> not_rebindable
+      PArrComp        -> not_rebindable
+      ArrowExpr       -> not_rebindable
+      PatGuard {}     -> not_rebindable
+
+      DoExpr          -> rebindable
+      MDoExpr         -> rebindable
+      MonadComp       -> rebindable
+      GhciStmt        -> rebindable   -- I suppose?
+
+      ParStmtCtxt   c -> lookupStmtName c n    -- Look inside to
+      TransStmtCtxt c -> lookupStmtName c n    -- the parent context
+  where
+    rebindable     = lookupSyntaxName n
+    not_rebindable = return (HsVar n, emptyFVs)
 \end{code}
 
 Note [Renaming parallel Stmts]