From b9312affa20dfd82bfd27129c291df40730be1c2 Mon Sep 17 00:00:00 2001
From: Thomas Refis <thomas.refis@gmail.com>
Date: Mon, 6 Aug 2018 18:32:29 +0100
Subject: [PATCH] generalize_expansive: test that we treat missing types as
 abstract types

---
 testsuite/tests/typing-missing-cmi-2/bar.mli      |  1 +
 testsuite/tests/typing-missing-cmi-2/baz.ml       |  1 +
 testsuite/tests/typing-missing-cmi-2/foo.mli      |  1 +
 testsuite/tests/typing-missing-cmi-2/ocamltests   |  1 +
 .../typing-missing-cmi-2/test.compilers.reference |  1 +
 testsuite/tests/typing-missing-cmi-2/test.ml      | 15 +++++++++++++++
 typing/ctype.ml                                   |  5 ++++-
 7 files changed, 24 insertions(+), 1 deletion(-)
 create mode 100644 testsuite/tests/typing-missing-cmi-2/bar.mli
 create mode 100644 testsuite/tests/typing-missing-cmi-2/baz.ml
 create mode 100644 testsuite/tests/typing-missing-cmi-2/foo.mli
 create mode 100644 testsuite/tests/typing-missing-cmi-2/ocamltests
 create mode 100644 testsuite/tests/typing-missing-cmi-2/test.compilers.reference
 create mode 100644 testsuite/tests/typing-missing-cmi-2/test.ml

diff --git a/testsuite/tests/typing-missing-cmi-2/bar.mli b/testsuite/tests/typing-missing-cmi-2/bar.mli
new file mode 100644
index 000000000..752ac028f
--- /dev/null
+++ b/testsuite/tests/typing-missing-cmi-2/bar.mli
@@ -0,0 +1 @@
+val foo : unit -> 'a Foo.t
diff --git a/testsuite/tests/typing-missing-cmi-2/baz.ml b/testsuite/tests/typing-missing-cmi-2/baz.ml
new file mode 100644
index 000000000..2dd4482aa
--- /dev/null
+++ b/testsuite/tests/typing-missing-cmi-2/baz.ml
@@ -0,0 +1 @@
+let x = Bar.foo ()
diff --git a/testsuite/tests/typing-missing-cmi-2/foo.mli b/testsuite/tests/typing-missing-cmi-2/foo.mli
new file mode 100644
index 000000000..cbc4635f6
--- /dev/null
+++ b/testsuite/tests/typing-missing-cmi-2/foo.mli
@@ -0,0 +1 @@
+type 'a t
diff --git a/testsuite/tests/typing-missing-cmi-2/ocamltests b/testsuite/tests/typing-missing-cmi-2/ocamltests
new file mode 100644
index 000000000..31c13b443
--- /dev/null
+++ b/testsuite/tests/typing-missing-cmi-2/ocamltests
@@ -0,0 +1 @@
+test.ml
diff --git a/testsuite/tests/typing-missing-cmi-2/test.compilers.reference b/testsuite/tests/typing-missing-cmi-2/test.compilers.reference
new file mode 100644
index 000000000..0927ee4b0
--- /dev/null
+++ b/testsuite/tests/typing-missing-cmi-2/test.compilers.reference
@@ -0,0 +1 @@
+val x : '_weak1 Foo.t
diff --git a/testsuite/tests/typing-missing-cmi-2/test.ml b/testsuite/tests/typing-missing-cmi-2/test.ml
new file mode 100644
index 000000000..2ef1c6d38
--- /dev/null
+++ b/testsuite/tests/typing-missing-cmi-2/test.ml
@@ -0,0 +1,15 @@
+(* TEST
+files = "foo.mli bar.mli baz.ml"
+* setup-ocamlc.byte-build-env
+** ocamlc.byte
+module = "foo.mli"
+*** ocamlc.byte
+module = "bar.mli"
+**** script
+script = "rm foo.cmi"
+***** ocamlc.byte
+flags = "-c -i"
+module = "baz.ml"
+ocamlc_byte_exit_status = "0"
+****** check-ocamlc.byte-output
+*)
diff --git a/typing/ctype.ml b/typing/ctype.ml
index 097d63ed2..dacbacae5 100644
--- a/typing/ctype.ml
+++ b/typing/ctype.ml
@@ -795,7 +795,10 @@ let rec generalize_expansive env var_level visited ty =
       Tconstr (path, tyl, abbrev) ->
         let variance =
           try (Env.find_type path env).type_variance
-          with Not_found -> List.map (fun _ -> Variance.may_inv) tyl in
+          with Not_found ->
+            (* See testsuite/tests/typing-missing-cmi-2 for an example *)
+            List.map (fun _ -> Variance.may_inv) tyl
+        in
         abbrev := Mnil;
         List.iter2
           (fun v t ->