[project @ 2003-07-29 10:14:57 by simonpj]

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

diff --git a/ghc/compiler/typecheck/TcDeriv.lhs b/ghc/compiler/typecheck/TcDeriv.lhs
index 9ea0190..60b7b2f 100644 (file)
--- a/ghc/compiler/typecheck/TcDeriv.lhs
+++ b/ghc/compiler/typecheck/TcDeriv.lhs
@@ -497,6 +497,11 @@ makeDerivEqns tycl_decls
                                                -- Don't want
                                                --      instance Eq [A] => Eq A !!
 
+                       -- Here's a recursive newtype that's actually OK
+                       --      newtype S1 = S1 [T1 ()]
+                       --      newtype T1 a = T1 (StateT S1 IO a ) deriving( Monad )
+                       -- It's currently rejected.  Oh well.
+
        -- Check that eta reduction is OK
        --      (a) the dropped-off args are identical
        --      (b) the remaining type args mention