diff --git a/Changes b/Changes
index b7445c556..baad6dee5 100644
--- a/Changes
+++ b/Changes
@@ -47,6 +47,7 @@ OCaml 4.01.1:
 
 Bug fixes:
 - PR#6173: Typing error message is worse that before
+- PR#6174: OCaml compiler loops on an example using GADTs (non -rectypes)
 
 OCaml 4.01.0:
 -------------
diff --git a/testsuite/tests/typing-gadts/pr6174.ml b/testsuite/tests/typing-gadts/pr6174.ml
new file mode 100644
index 000000000..84f79ba0e
--- /dev/null
+++ b/testsuite/tests/typing-gadts/pr6174.ml
@@ -0,0 +1,3 @@
+type _ t = C : ((('a -> 'o) -> 'o) -> ('b -> 'o) -> 'o) t
+let f : type a o. ((a -> o) -> o) t -> (a -> o) -> o =
+ fun C k -> k (fun x -> x);;
diff --git a/testsuite/tests/typing-gadts/pr6174.ml.principal.reference b/testsuite/tests/typing-gadts/pr6174.ml.principal.reference
new file mode 100644
index 000000000..647015c36
--- /dev/null
+++ b/testsuite/tests/typing-gadts/pr6174.ml.principal.reference
@@ -0,0 +1,8 @@
+
+#     Characters 118-119:
+   fun C k -> k (fun x -> x);;
+       ^
+Error: Recursive local constraint when unifying
+         (((ex#0 -> ex#1) -> ex#1) -> (ex#2 -> ex#1) -> ex#1) t
+       with ((a -> o) -> o) t
+# 
diff --git a/testsuite/tests/typing-gadts/pr6174.ml.reference b/testsuite/tests/typing-gadts/pr6174.ml.reference
new file mode 100644
index 000000000..647015c36
--- /dev/null
+++ b/testsuite/tests/typing-gadts/pr6174.ml.reference
@@ -0,0 +1,8 @@
+
+#     Characters 118-119:
+   fun C k -> k (fun x -> x);;
+       ^
+Error: Recursive local constraint when unifying
+         (((ex#0 -> ex#1) -> ex#1) -> (ex#2 -> ex#1) -> ex#1) t
+       with ((a -> o) -> o) t
+# 
diff --git a/typing/ctype.ml b/typing/ctype.ml
index aa67a9181..1bf4872ef 100644
--- a/typing/ctype.ml
+++ b/typing/ctype.ml
@@ -1660,7 +1660,8 @@ let rec local_non_recursive_abbrev visited env p ty =
         iter_type_expr (local_non_recursive_abbrev visited env p) ty
   end
 
-let local_non_recursive_abbrev = local_non_recursive_abbrev (ref [])
+let local_non_recursive_abbrev env p =
+  local_non_recursive_abbrev (ref []) env p
 
                    (*****************************)
                    (*  Polymorphic Unification  *)