Avoid type checking private_constants (side_eff) again during Qed (#4357).

Side effects are now an opaque data type, called private_constant, you can
only obtain from safe_typing.  When add_constant is called on a
definition_entry that contains private constants, they are either
- inlined in the main proof term but not re-checked
- declared globally without re-checking them
As a safety measure, the opaque data type contains a pointer to the
revstruct (an internal field of safe_env that changes every time a new
constant is added), and such pointer is compared with the current value
store in safe_env when the private_constant is inlined.  Only when the
comparison is successful the private_constant is not re-checked.  Otherwise
else it is.  In short, we accept into the kernel private constant only
when they arrive in the very same order and on top of the very same env
they arrived when we fist checked them.

Note: private_constants produced by workers never pass the safety
measure (the revstruct pointer is an Ephemeron).  Sending back the
entire revstruct is possible but: 1. we lack a way to quickly compare
two revstructs, 2. it can be large.

1 files changed, 0 insertions, 6 deletions

diff --git a/kernel/declarations.mli b/kernel/declarations.mli
index 7def963e73..dc5c17a75b 100644
--- a/kernel/declarations.mli
+++ b/kernel/declarations.mli
@@ -79,12 +79,6 @@ type constant_body = {
     const_proj : projection_body option;
     const_inline_code : bool }
 
-type seff_env = [ `Nothing | `Opaque of Constr.t * Univ.universe_context_set ]
-
-type side_effect =
-  | SEsubproof of constant * constant_body * seff_env
-  | SEscheme of (inductive * constant * constant_body * seff_env) list * string
-    
 (** {6 Representation of mutual inductive types in the kernel } *)
 
 type recarg =