1 files changed, 23 insertions, 0 deletions
diff --git a/testsuite/tests/typing-modules/nongen.ml b/testsuite/tests/typing-modules/nongen.ml
new file mode 100644
index 0000000000..9aca5a1f88
--- /dev/null
+++ b/testsuite/tests/typing-modules/nongen.ml
@@ -0,0 +1,23 @@
+(* TEST
+ expect;
+*)
+
+module X = struct
+  let t = ref None
+end
+
+module type X' = module type of X
+[%%expect{|
+module X : sig val t : '_weak1 option ref end
+Line 5, characters 32-33:
+5 | module type X' = module type of X
+                                    ^
+Error: The type of this module, sig val t : '_weak1 option ref end,
+       contains non-generalizable type variable(s).
+       (see manual section 6.1.2)
+Line 2, characters 6-7:
+2 |   let t = ref None
+          ^
+  The type of this value, '_weak1 option ref,
+  contains the non-generalizable type variable(s) '_weak1.
+|}]