# HG changeset patch
# User Adam Chlipala <adam@chlipala.net>
# Date 1419976951 18000
# Node ID 8efba492c48bf6f08fb39c8c4788fec0ecf65638
# Parent  b7cb53affc08b3975d9acace3355524cc13166bf
Fix a bug in subsignature checking for submodules

diff -r b7cb53affc08 -r 8efba492c48b src/elaborate.sml
--- a/src/elaborate.sml	Fri Dec 26 12:30:22 2014 -0500
+++ b/src/elaborate.sml	Tue Dec 30 17:02:31 2014 -0500
@@ -3345,7 +3345,12 @@
                                      L'.SgiStr (x', n1, sgn1) =>
                                      if x = x' then
                                          let
+                                             (* Don't forget to save & restore the
+                                              * counterparts map around recursive calls!
+                                              * Otherwise, all sorts of mayhem may result. *)
+                                             val saved = !counterparts
                                              val () = subSgn' counterparts env loc sgn1 sgn2
+                                             val () = counterparts := saved
                                              val env = E.pushStrNamedAs env x n1 sgn1
                                              val env = if n1 = n2 then
                                                            env