flambda-backend: Revert "Semaphore without probes: dummy notes (#142)" (#242)

This reverts commit 8c9bf5e.

Author: gretay-js

typing/typecore.ml

@@ -124,6 +124,7 @@ type error =
   | Probe_format
   | Probe_name_too_long of string
   | Probe_name_format of string
+  | Probe_name_undefined of string
   | Probe_is_enabled_format
   | Literal_overflow of string
   | Unknown_literal of string * char
@@ -3752,6 +3753,10 @@ and type_expect_
                        _ } ,
                       _)}]) ->
         check_probe_name name name_loc env;
+        add_delayed_check
+          (fun () ->
+             if not (Env.has_probe name) then
+               raise(Error(name_loc, env, (Probe_name_undefined name))));
         rue {
           exp_desc = Texp_probe_is_enabled {name};
           exp_loc = loc; exp_extra = [];
@@ -5601,6 +5606,11 @@ let report_error ~loc env = function
          Probe names may only contain alphanumeric characters or \
          underscores."
         name
+  | Probe_name_undefined name ->
+      Location.errorf ~loc
+        "Undefined probe name `%s' used in %%probe_is_enabled. \
+         Not found [%%probe \"%s\" ...] in the same compilation unit."
+        name name
   | Probe_format ->
       Location.errorf ~loc
         "Probe points must consist of a name, as a string \

typing/typecore.mli

@@ -181,6 +181,7 @@ type error =
   | Probe_format
   | Probe_name_too_long of string
   | Probe_name_format of string
+  | Probe_name_undefined of string
   (* CR-soon mshinwell: Use an inlined record *)
   | Probe_is_enabled_format
   | Literal_overflow of string