Revert "Classic mode: partially lift the restrictions on inlining fun…

…ctions containing closures" (ocaml-flambda#2546)

Revert "Classic mode: partially lift the restrictions on inlining functions c…"

This reverts commit 2384937.

middle_end/flambda2/from_lambda/closure_conversion.ml

@@ -2136,22 +2136,19 @@ let close_one_function acc ~code_id ~external_env ~by_function_slot
   let contains_subfunctions = Acc.seen_a_function acc in
   let cost_metrics = Acc.cost_metrics acc in
   let inline : Inline_attribute.t =
-    match Inline_attribute.from_lambda (Function_decl.inline decl) with
-    | (Always_inline | Available_inline | Never_inline) as attr -> attr
-    | (Unroll _ | Default_inline) as attr ->
-      (* We make a decision based on [fallback_inlining_heuristic] here to try
-         to mimic Closure's behaviour as closely as possible, particularly when
-         there are functions involving constant closures, which are not lifted
-         during Closure (but will prevent inlining) but will likely have been
-         lifted by our other check in [Inlining_cost] (thus preventing us seeing
-         they were originally there). Note that while Closure never marks as
-         inlinable functions in a set a recursive definitions with more than one
-         function, we do not try to reproduce this particular property and can
-         mark as inlinable such functions. *)
-      if contains_subfunctions
-         && Flambda_features.Expert.fallback_inlining_heuristic ()
-      then (* CR vlaviron: Store reason *) Never_inline
-      else attr
+    (* We make a decision based on [fallback_inlining_heuristic] here to try to
+       mimic Closure's behaviour as closely as possible, particularly when there
+       are functions involving constant closures, which are not lifted during
+       Closure (but will prevent inlining) but will likely have been lifted by
+       our other check in [Inlining_cost] (thus preventing us seeing they were
+       originally there). Note that while Closure never marks as inlinable
+       functions in a set a recursive definitions with more than one function,
+       we do not try to reproduce this particular property and can mark as
+       inlinable such functions. *)
+    if contains_subfunctions
+       && Flambda_features.Expert.fallback_inlining_heuristic ()
+    then Never_inline
+    else Inline_attribute.from_lambda (Function_decl.inline decl)
   in
   let free_names_of_body = Acc.free_names acc in
   let params_and_body =
@@ -2259,9 +2256,7 @@ let close_one_function acc ~code_id ~external_env ~by_function_slot
     else meta
   in
   let acc = Acc.add_code ~code_id ~code acc in
-  let acc =
-    if has_lifted_closure then acc else Acc.with_seen_a_function acc true
-  in
+  let acc = Acc.with_seen_a_function acc true in
   ( acc,
     ( Function_slot.Map.add function_slot approx by_function_slot,
       function_code_ids ) )