[project @ 2003-06-27 21:17:24 by simonpj]

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

diff --git a/ghc/compiler/typecheck/TcRules.lhs b/ghc/compiler/typecheck/TcRules.lhs
index 3cc7770..a26faa8 100644 (file)
--- a/ghc/compiler/typecheck/TcRules.lhs
+++ b/ghc/compiler/typecheck/TcRules.lhs
@@ -15,11 +15,12 @@ import TcHsSyn              ( TypecheckedRuleDecl, mkHsLet )
 import TcRnMonad
 import TcSimplify      ( tcSimplifyToDicts, tcSimplifyInferCheck )
 import TcMType         ( newTyVarTy )
+import TcUnify         ( Expected(..) )
 import TcType          ( tyVarsOfTypes, openTypeKind )
 import TcIfaceSig      ( tcCoreExpr, tcCoreLamBndrs )
 import TcMonoType      ( tcHsSigType, UserTypeCtxt(..), tcAddScopedTyVars )
-import TcExpr          ( tcMonoExpr )
-import TcEnv           ( tcExtendLocalValEnv, tcLookupGlobalId )
+import TcExpr          ( tcCheckRho )
+import TcEnv           ( tcExtendLocalValEnv, tcLookupGlobalId, tcLookupId )
 import Inst            ( instToId )
 import Id              ( idType, mkLocalId )
 import Outputable
@@ -39,8 +40,15 @@ tcRule (IfaceRule name act vars fun args rhs src_loc)
     tcCoreExpr rhs                     `thenM` \ rhs' ->
     returnM (IfaceRuleOut fun' (Rule name act vars' args' rhs'))
 
-tcRule (IfaceRuleOut fun rule) -- Built-in rules come this way
-  = tcLookupGlobalId fun               `thenM` \ fun' ->
+tcRule (IfaceRuleOut fun rule) -- Built-in rules, and only built-in rules, 
+                               -- come this way.  Usually IfaceRuleOut is only
+                               -- used for the *output* of the type checker
+  = tcLookupId fun             `thenM` \ fun' ->
+       -- NB: tcLookupId, not tcLookupGlobalId
+       -- Reason: when compiling GHC.Base, where eqString is defined,
+       --         we'll get the builtin rule for eqString, but eqString
+       --         will be in the *local* type environment.
+       -- Seems like a bit of a hack
     returnM (IfaceRuleOut fun' rule)   
 
 tcRule (HsRule name act vars lhs rhs src_loc)
@@ -56,8 +64,8 @@ tcRule (HsRule name act vars lhs rhs src_loc)
        tcExtendLocalValEnv ids                 $
        
                -- Now LHS and RHS
-       getLIE (tcMonoExpr lhs rule_ty)         `thenM` \ (lhs', lhs_lie) ->
-       getLIE (tcMonoExpr rhs rule_ty)         `thenM` \ (rhs', rhs_lie) ->
+       getLIE (tcCheckRho lhs rule_ty) `thenM` \ (lhs', lhs_lie) ->
+       getLIE (tcCheckRho rhs rule_ty) `thenM` \ (rhs', rhs_lie) ->
        
        returnM (ids, lhs', rhs', lhs_lie, rhs_lie)
     )                          `thenM` \ (ids, lhs', rhs', lhs_lie, rhs_lie) ->