merge changes from ocaml3110 to ocaml3111rc0

git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@9270 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02

1 files changed, 9 insertions, 0 deletions

diff --git a/typing/subst.ml b/typing/subst.ml
index 6b1282697..833b3634a 100644
--- a/typing/subst.ml
+++ b/typing/subst.ml
@@ -294,3 +294,12 @@ and signature_component s comp newid =
 and modtype_declaration s = function
     Tmodtype_abstract -> Tmodtype_abstract
   | Tmodtype_manifest mty -> Tmodtype_manifest(modtype s mty)
+
+(* Composition of substitutions:  
+     apply (compose s1 s2) x = apply s2 (apply s1 x) *)
+
+let compose s1 s2 =
+  { types = Tbl.map (fun id p -> type_path s2 p) s1.types;
+    modules = Tbl.map (fun id p -> module_path s2 p) s1.modules;
+    modtypes = Tbl.map (fun id mty -> modtype s2 mty) s1.modtypes;
+    for_saving = false }