Inclusion of functors with restricted signature is now forbidden (fix #3746)

 The previous behavior was to include the interface of such a functor,
 possibly leading to the creation of unexpected axioms, see bug report #3746.
 In the case of non-functor module with restricted signature, we could
 simply refer to the original objects (strengthening), but for a functor,
 the inner objects have no existence yet. As said in the new error message,
 a simple workaround is hence to first instantiate the functor, then include
 the local instance:

  Module LocalInstance := Funct(Args).
  Include LocalInstance.

 By the way, the mod_type_alg field is now filled more systematically,
 cf new comments in declarations.mli. This way, we could use it to know
 whether a module had been given a restricted signature (via ":"). Earlier,
 some mod_type_alg were None in situations not handled by the extraction
 (MEapply of module type).

 Some code refactoring on the fly.

1 files changed, 4 insertions, 3 deletions

diff --git a/kernel/modops.ml b/kernel/modops.ml
index cbb7963315..341c3993a3 100644
--- a/kernel/modops.ml
+++ b/kernel/modops.ml
@@ -67,15 +67,13 @@ type module_typing_error =
   | IncorrectWithConstraint of Label.t
   | GenerativeModuleExpected of Label.t
   | LabelMissing of Label.t * string
+  | IncludeRestrictedFunctor of module_path
 
 exception ModuleTypingError of module_typing_error
 
 let error_existing_label l =
   raise (ModuleTypingError (LabelAlreadyDeclared l))
 
-let error_application_to_not_path mexpr =
-  raise (ModuleTypingError (ApplicationToNotPath mexpr))
-
 let error_not_a_functor () =
   raise (ModuleTypingError NotAFunctor)
 
@@ -112,6 +110,9 @@ let error_generative_module_expected l =
 let error_no_such_label_sub l l1 =
   raise (ModuleTypingError (LabelMissing (l,l1)))
 
+let error_include_restricted_functor mp =
+  raise (ModuleTypingError (IncludeRestrictedFunctor mp))
+
 (** {6 Operations on functors } *)
 
 let is_functor = function