Fixing #11114 (anomaly with Extraction Implicit on records).

This was due to an inconsistency in handling implicit arguments in
the fields and in the constructor of a record.

2 files changed, 24 insertions, 6 deletions

diff --git a/plugins/extraction/extraction.ml b/plugins/extraction/extraction.ml
index 9b30ddd958..71a3dcfef2 100644
--- a/plugins/extraction/extraction.ml
+++ b/plugins/extraction/extraction.ml
@@ -507,21 +507,22 @@ and extract_really_ind env kn mib =
         assert (Int.equal (List.length field_names) (List.length typ));
         let projs = ref Cset.empty in
         let mp = MutInd.modpath kn in
-        let rec select_fields l typs = match l,typs with
+        let implicits = implicits_of_global (GlobRef.ConstructRef (ip,1)) in
+        let rec select_fields i l typs = match l,typs with
           | [],[] -> []
-          | _::l, typ::typs when isTdummy (expand env typ) ->
-              select_fields l typs
+          | _::l, typ::typs when isTdummy (expand env typ) || Int.Set.mem i implicits ->
+              select_fields (i+1) l typs
           | {binder_name=Anonymous}::l, typ::typs ->
-              None :: (select_fields l typs)
+              None :: (select_fields (i+1) l typs)
           | {binder_name=Name id}::l, typ::typs ->
               let knp = Constant.make2 mp (Label.of_id id) in
               (* Is it safe to use [id] for projections [foo.id] ? *)
               if List.for_all ((==) Keep) (type2signature env typ)
               then projs := Cset.add knp !projs;
-              Some (GlobRef.ConstRef knp) :: (select_fields l typs)
+              Some (GlobRef.ConstRef knp) :: (select_fields (i+1) l typs)
           | _ -> assert false
         in
-        let field_glob = select_fields field_names typ
+        let field_glob = select_fields (1+npar) field_names typ
         in
         (* Is this record officially declared with its projections ? *)
         (* If so, we use this information. *)
diff --git a/test-suite/bugs/closed/bug_11114.v b/test-suite/bugs/closed/bug_11114.v
new file mode 100644
index 0000000000..dd981279db
--- /dev/null
+++ b/test-suite/bugs/closed/bug_11114.v
@@ -0,0 +1,17 @@
+Require Extraction.
+
+Inductive t (sig: list nat) :=
+| T (k: nat).
+
+Record pkg :=
+  { _sig: list nat;
+    _t : t _sig }.
+
+Definition map (f: nat -> nat) (p: pkg) :=
+  {| _sig := p.(_sig);
+     _t := match p.(_t) with
+          | T _ k => T p.(_sig) (f k)
+          end |}.
+
+Extraction Implicit Build_pkg [_sig].
+Extraction TestCompile map.