Add test file about visib in section in module

We needed to test when locality attributes in a section in a module
affect the visibility outside the module.

test-suite/success/locality_attributes_sections_in_modules.v

@@ -0,0 +1,163 @@
+(** This file tests how locality attributes affect usual vernacular commands.
+    PLEASE, when this file fails to compute following a voluntary change in
+    Coq's behaviour, modify accordingly the tables in [sections.rst] and
+    [modules.rst] in [doc/sphinx/language/core] *)
+
+(** This structure is used to test availability or not of a
+    [Canonical Structure]. *)
+Structure PointedType : Type := { Carrier :> Set; point : Carrier }.
+
+(** ** Tests of visibility attributes in a section inside a module *)
+
+(** We only test [Definition], [Coercion], [Canonical] and [Set], the other
+    commands only support the [local] attribute in sections, which is also
+    the default visibility, making them unavailable outside the section. *)
+
+(** *** Without attribute (default) *)
+
+Module InSectionDefault.
+
+Module M.
+Section Bar.
+  (* A definition: *)
+  Definition foo := 42.
+  (* A Coercion: *)
+  Coercion to_nat (b : bool) := if b then 1 else 0.
+  (* A Canonical Structure: *)
+  Canonical natPointed : PointedType := {| Carrier := nat; point := 42 |}.
+  (* A Setting: *)
+  Set Universe Polymorphism.
+End Bar.
+End M.
+
+Module M_not_imported.
+(** First, we do not import M. *)
+(* Availability of the definition *)
+Fail Check foo. (* not imported *)
+(* Availability of the coercion *)
+Fail Check (true + 2). (* not imported *)
+(* Availability of the canonical structure *)
+Fail Check (point nat). (* not imported *)
+(* Availability of [Set Universe Polymorphism] *)
+Definition foo_i@{u} := nat.
+Fail Check foo_i@{_}.
+End M_not_imported.
+
+Module M_imported.
+(** Now we import M. *)
+Import M.
+(* Availability of the definition *)
+Check foo.
+(* Availability of the coercion *)
+Check (true + 2).
+(* Availability of the canonical structure *)
+Check (point nat).
+(* Availability of [Set Universe Polymorphism] *)
+Definition foo_i@{u} := nat.
+Fail Check foo_i@{_}.
+End M_imported.
+
+End InSectionDefault.
+
+(** *** With the [local] attribute *)
+(** We only need to test a definition, we know the other commands have no effect
+    outside the section (hence outside the module containing the section). *)
+Module InSectionLocal.
+
+Module M.
+Section Bar.
+  (* A definition: *)
+  #[local]
+  Definition foo := 42.
+End Bar.
+End M.
+
+Module M_not_imported.
+(** First, we do not import M. *)
+(* Availability of the definition *)
+Fail Check foo. (* not imported *)
+Check M.foo.
+End M_not_imported.
+
+Module M_imported.
+(** Now we import M. *)
+Import M.
+(* Availability of the definition *)
+Fail Check foo.
+(* /!\ notice the local attribute has been passed to the module! *)
+Check M.foo.
+End M_imported.
+
+End InSectionLocal.
+
+(** *** With the [export] attribute *)
+(** We only need to test a setting, it is the only command for which [export]
+    is supported inside a [Section]. *)
+Module InSectionExport.
+
+Module M.
+Section Bar.
+  (* A Setting *)
+  #[export]
+  Set Universe Polymorphism.
+End Bar.
+End M.
+
+Module M_not_imported.
+(** **** Without importing: *)
+(* Availability of [Set Universe Polymorphism] *)
+Definition foo_ni@{u} := nat.
+Fail Check foo_ni@{_}.
+End M_not_imported.
+
+Module M_imported.
+Import M.
+(* Availability of [Set Universe Polymorphism] *)
+Definition foo_ni@{u} := nat.
+Check foo_ni@{_}.
+End M_imported.
+End InSectionExport.
+
+(** *** With the [export] attribute *)
+(** We only need to test [Coercion], [Canonical] and [Set]. *)
+
+Module InSectionGlobal.
+
+Module M.
+Section Bar.
+  (* A Coercion: *)
+  #[global]
+  Coercion to_nat (b : bool) := if b then 1 else 0.
+  (* A Canonical Structure: *)
+  #[global]
+  Canonical natPointed : PointedType := {| Carrier := nat; point := 42 |}.
+  (* A Setting: *)
+  #[global]
+  Set Universe Polymorphism.
+End Bar.
+End M.
+
+Module M_not_imported.
+(** First, we do not import M. *)
+(* Availability of the coercion *)
+Fail Check (true + 2). (* not imported *)
+(* Availability of the canonical structure *)
+Fail Check (point nat). (* not imported *)
+(* Availability of [Set Universe Polymorphism] *)
+Definition foo_i@{u} := nat.
+Check foo_i@{_}. (* available *)
+End M_not_imported.
+
+Module M_imported.
+(** Now we import M. *)
+Import M.
+(* Availability of the coercion *)
+Check (true + 2).
+(* Availability of the canonical structure *)
+Check (point nat).
+(* Availability of [Set Universe Polymorphism] *)
+Definition foo_i@{u} := nat.
+Check foo_i@{_}.
+End M_imported.
+
+End InSectionGlobal.