test: unsupported melange primitives in OCaml 5

jscomp/core/lam_convert.ml

@@ -414,8 +414,8 @@ let lam_prim ~primitive:(p : Lambda.primitive) ~args loc : Lam.t =
   | Prunstack | Pperform | Presume | Preperform | Patomic_exchange | Patomic_cas
   | Patomic_fetch_add | Pdls_get | Patomic_load _ ->
       Location.raise_errorf ~loc
-        "OCaml 5 multicore primitives (Effect, Domain, Condition, Mutex, \
-         Semaphore) are not supported in Melange"
+        "OCaml 5 multicore primitives (Effect, Condition, Semaphore) are not \
+         currently supported in Melange"
 
 (* Does not exist since we compile array in js backend unlike native backend *)
 

test/blackbox-tests/unsupported-ocaml5-primitives.t

@@ -0,0 +1,18 @@
+Demonstrate OCaml 5 primitives that are currently unsupported in Melange
+
+  $ . ./setup.sh
+
+%perform is an Effects primitive in OCaml 5
+
+  $ cat > x.ml <<EOF
+  > type 'a t
+  > external perform : 'a t -> 'a = "%perform"
+  > let () = perform (Obj.magic ())
+  > EOF
+
+  $ melc x.ml
+  File "x.ml", line 3, characters 9-31:
+  3 | let () = perform (Obj.magic ())
+               ^^^^^^^^^^^^^^^^^^^^^^
+  Error: OCaml 5 multicore primitives (Effect, Condition, Semaphore) are not currently supported in Melange
+  [2]