[project @ 2001-12-13 10:47:28 by sewardj]

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

diff --git a/ghc/compiler/typecheck/TcExpr.lhs b/ghc/compiler/typecheck/TcExpr.lhs
index b66730a..6039559 100644 (file)
--- a/ghc/compiler/typecheck/TcExpr.lhs
+++ b/ghc/compiler/typecheck/TcExpr.lhs
@@ -593,16 +593,18 @@ tcApp fun args res_ty
        split_fun_ty fun_ty (length args)
     )                                          `thenTc` \ (expected_arg_tys, actual_result_ty) ->
 
-       -- Unify with expected result before type-checking the args
-       -- so that the info from res_ty percolates to expected_arg_tys
-       -- This is when we might detect a too-few args situation
-    tcAddErrCtxtM (checkArgsCtxt fun args res_ty actual_result_ty)
-                 (tcSub res_ty actual_result_ty)       `thenTc` \ (co_fn, lie_res) ->
-
        -- Now typecheck the args
     mapAndUnzipTc (tcArg fun)
          (zip3 args expected_arg_tys [1..])    `thenTc` \ (args', lie_args_s) ->
 
+       -- Unify with expected result after type-checking the args
+       -- so that the info from args percolates to actual_result_ty.
+       -- This is when we might detect a too-few args situation.
+       -- (One can think of cases when the opposite order would give
+       -- a better error message.)
+    tcAddErrCtxtM (checkArgsCtxt fun args res_ty actual_result_ty)
+                 (tcSub res_ty actual_result_ty)       `thenTc` \ (co_fn, lie_res) ->
+
     returnTc (co_fn <$> foldl HsApp fun' args', 
              lie_res `plusLIE` lie_fun `plusLIE` plusLIEs lie_args_s)
 
@@ -674,7 +676,7 @@ Typecheck expression which in most cases will be an Id.
 tcExpr_id :: RenamedHsExpr -> TcM (TcExpr, LIE, TcType)
 tcExpr_id (HsVar name) = tcId name
 tcExpr_id expr         = newTyVarTy openTypeKind       `thenNF_Tc` \ id_ty ->
-                        tcMonoExpr expr id_ty  `thenTc`    \ (expr', lie_id) ->
+                        tcMonoExpr expr id_ty          `thenTc`    \ (expr', lie_id) ->
                         returnTc (expr', lie_id, id_ty) 
 \end{code}