[vernac] Warn when using “Require” in a section

2 files changed, 8 insertions, 0 deletions

diff --git a/CHANGES b/CHANGES
index eaceea6da..9dbc73adb 100644
--- a/CHANGES
+++ b/CHANGES
@@ -73,6 +73,7 @@ Vernacular Commands
   was removed. Use Local as a prefix instead.
 - For the Extraction Language command, "OCaml" is spelled correctly.
   The older "Ocaml" is still accepted, but deprecated.
+- Using “Require” inside a section is deprecated.
 
 Universes
 
diff --git a/vernac/vernacentries.ml b/vernac/vernacentries.ml
index 0ff6d9c17..5779c07ab 100644
--- a/vernac/vernacentries.ml
+++ b/vernac/vernacentries.ml
@@ -805,7 +805,14 @@ let vernac_end_segment ({v=id} as lid) =
 
 (* Libraries *)
 
+let warn_require_in_section =
+  let name = "require-in-section" in
+  let category = "deprecated" in
+  CWarnings.create ~name ~category
+    (fun () -> strbrk "Use of “Require” inside a section is deprecated.")
+
 let vernac_require from import qidl =
+  if Lib.sections_are_opened () then warn_require_in_section ();
   let qidl = List.map qualid_of_reference qidl in
   let root = match from with
   | None -> None