[project @ 2003-07-02 14:59:00 by simonpj]

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

diff --git a/ghc/compiler/typecheck/TcSplice.lhs b/ghc/compiler/typecheck/TcSplice.lhs
index 6a2c4d7..53586be 100644 (file)
--- a/ghc/compiler/typecheck/TcSplice.lhs
+++ b/ghc/compiler/typecheck/TcSplice.lhs
@@ -15,26 +15,26 @@ import TcRnDriver   ( importSupportingDecls, tcTopSrcDecls )
 
 import qualified Language.Haskell.THSyntax as Meta
 
-import HscTypes                ( HscEnv(..), GhciMode(..), PersistentCompilerState(..), unQualInScope )
+import HscTypes                ( HscEnv(..), PersistentCompilerState(..) )
 import HsSyn           ( HsBracket(..), HsExpr(..) )
 import Convert         ( convertToHsExpr, convertToHsDecls )
 import RnExpr          ( rnExpr )
 import RdrHsSyn                ( RdrNameHsExpr, RdrNameHsDecl )
 import RnHsSyn         ( RenamedHsExpr )
-import TcExpr          ( tcCheckRho )
+import TcExpr          ( tcCheckRho, tcMonoExpr )
 import TcHsSyn         ( TcExpr, TypecheckedHsExpr, mkHsLet, zonkTopExpr )
 import TcSimplify      ( tcSimplifyTop, tcSimplifyBracket )
-import TcUnify         ( unifyTauTy )
+import TcUnify         ( Expected, zapExpectedTo, zapExpectedType )
 import TcType          ( TcType, openTypeKind, mkAppTy )
 import TcEnv           ( spliceOK, tcMetaTy, tcWithTempInstEnv, bracketOK )
 import TcRnTypes       ( TopEnv(..) )
-import TcMType         ( newTyVarTy, zapToType, UserTypeCtxt(ExprSigCtxt) )
+import TcMType         ( newTyVarTy, UserTypeCtxt(ExprSigCtxt) )
 import TcMonoType      ( tcHsSigType )
 import Name            ( Name )
 import TcRnMonad
 
 import TysWiredIn      ( mkListTy )
-import DsMeta          ( exprTyConName, declTyConName, typeTyConName, decTyConName, qTyConName )
+import DsMeta          ( expQTyConName, typeQTyConName, decTyConName, qTyConName )
 import ErrUtils (Message)
 import Outputable
 import Panic           ( showException )
@@ -54,7 +54,7 @@ tcSpliceDecls :: RenamedHsExpr -> TcM [RdrNameHsDecl]
 
 tcSpliceExpr :: Name 
             -> RenamedHsExpr
-            -> TcType
+            -> Expected TcType
             -> TcM TcExpr
 
 #ifndef GHCI
@@ -70,7 +70,7 @@ tcSpliceDecls e     = pprPanic "Cant do tcSpliceDecls without GHCi" (ppr e)
 %************************************************************************
 
 \begin{code}
-tcBracket :: HsBracket Name -> TcType -> TcM TcExpr
+tcBracket :: HsBracket Name -> Expected TcType -> TcM TcExpr
 tcBracket brack res_ty
   = getStage                           `thenM` \ level ->
     case bracketOK level of {
@@ -88,7 +88,8 @@ tcBracket brack res_ty
     )                                  `thenM` \ (meta_ty, lie) ->
     tcSimplifyBracket lie              `thenM_`  
 
-    unifyTauTy res_ty meta_ty          `thenM_`
+       -- Make the expected type have the right shape
+    zapExpectedTo res_ty meta_ty       `thenM_`
 
        -- Return the original expression, not the type-decorated one
     readMutVar pending_splices         `thenM` \ pendings ->
@@ -99,12 +100,12 @@ tc_bracket :: HsBracket Name -> TcM TcType
 tc_bracket (ExpBr expr) 
   = newTyVarTy openTypeKind    `thenM` \ any_ty ->
     tcCheckRho expr any_ty     `thenM_`
-    tcMetaTy exprTyConName
+    tcMetaTy expQTyConName
        -- Result type is Expr (= Q Exp)
 
 tc_bracket (TypBr typ) 
   = tcHsSigType ExprSigCtxt typ                `thenM_`
-    tcMetaTy typeTyConName
+    tcMetaTy typeQTyConName
        -- Result type is Type (= Q Typ)
 
 tc_bracket (DecBr decls)
@@ -144,8 +145,8 @@ tcSpliceExpr name expr res_ty
        -- Here (h 4) :: Q Exp
        -- but $(h 4) :: forall a.a     i.e. anything!
 
-    zapToType res_ty                           `thenM_`
-    tcMetaTy exprTyConName                     `thenM` \ meta_exp_ty ->
+    zapExpectedType res_ty                     `thenM_`
+    tcMetaTy expQTyConName                     `thenM` \ meta_exp_ty ->
     setStage (Splice next_level) (
        setLIEVar lie_var          $
        tcCheckRho expr meta_exp_ty
@@ -162,11 +163,11 @@ tcSpliceExpr name expr res_ty
 -- Note that we do not decrement the level (to -1) before 
 -- typechecking the expression.  For example:
 --     f x = $( ...$(g 3) ... )
--- The recursive call to tcCheckRho will simply expand the 
+-- The recursive call to tcMonoExpr will simply expand the 
 -- inner escape before dealing with the outer one
 
 tcTopSplice expr res_ty
-  = tcMetaTy exprTyConName             `thenM` \ meta_exp_ty ->
+  = tcMetaTy expQTyConName             `thenM` \ meta_exp_ty ->
 
        -- Typecheck the expression
     tcTopSpliceExpr expr meta_exp_ty   `thenM` \ zonked_q_expr ->
@@ -188,7 +189,7 @@ tcTopSplice expr res_ty
     initRn SourceMode (rnExpr expr2)           `thenM` \ (exp3, fvs) ->
     importSupportingDecls fvs                  `thenM` \ env ->
 
-    setGblEnv env (tcCheckRho exp3 res_ty)
+    setGblEnv env (tcMonoExpr exp3 res_ty)
 
 
 tcTopSpliceExpr :: RenamedHsExpr -> TcType -> TcM TypecheckedHsExpr