toplevel: detect recursive definitions in #show

3 files changed, 46 insertions, 13 deletions

diff --git a/testsuite/tests/tool-toplevel/known-bugs/broken_rec_in_show.ml b/testsuite/tests/tool-toplevel/known-bugs/broken_rec_in_show.ml
index d4160db712..688ac53844 100644
--- a/testsuite/tests/tool-toplevel/known-bugs/broken_rec_in_show.ml
+++ b/testsuite/tests/tool-toplevel/known-bugs/broken_rec_in_show.ml
@@ -10,9 +10,9 @@ type t = T of t;;
 type t = T of t
 |}]
 #show t;;
-(* this output is INCORRECT, it should not use nonrec *)
+(* this output is CORRECT, it should not use nonrec *)
 [%%expect{|
-type nonrec t = T of t
+type t = T of t
 |}];;
 
 type nonrec s = Foo of t;;
@@ -20,9 +20,9 @@ type nonrec s = Foo of t;;
 type nonrec s = Foo of t
 |}];;
 #show s;;
-(* this output is CORRECT, it uses nonrec *)
+(* this output is CORRECT, it elides the unnecessary nonrec keyword *)
 [%%expect{|
-type nonrec s = Foo of t
+type s = Foo of t
 |}];;
 
 
@@ -32,8 +32,6 @@ module M : sig type t val x : t end = struct type t = int let x = 0 end;;
 module M : sig type t val x : t end
 |}];;
 (* this output is CORRECT, it does not use 'rec' *)
-[%%expect{|
-|}];;
 
 module rec M : sig type t val x : M.t end = struct type t = int let x = 0 end;;
 (* this output is CORRECT . *)
@@ -41,7 +39,42 @@ module rec M : sig type t val x : M.t end = struct type t = int let x = 0 end;;
 module rec M : sig type t val x : M.t end
 |}];;
 #show_module M;;
-(* this output is INCORRECT, it should use 'rec' *)
+(* this output is CORRECT *)
+[%%expect{|
+module rec M : sig type t val x : M.t end
+|}];;
+
+
+(* Indirect recursion *)
+
+type t
+type f = [ `A of t ]
+type t = X of u | Y of [ f | `B ]  and u = Y of t;;
+
+[%%expect{|
+type t
+type f = [ `A of t ]
+type t = X of u | Y of [ `A of t/1 | `B ]
+and u = Y of t/2
+|}];;
+
+#show t;;
+(* this output is PARTIAL: t is mutually recursive with u *)
+[%%expect{|
+type nonrec t = X of u | Y of [ `A of t/2 | `B ]
+|}];;
+
+
+module rec M: sig type t = X of N.t end = M
+and N: sig type t = X of M.t end = N
+
+[%%expect{|
+module rec M : sig type t = X of N.t end
+and N : sig type t = X of M.t end
+|}];;
+
+(* this output is PARTIAL: M is mutually recursive with N *)
+#show M;;
 [%%expect{|
-module M : sig type t val x : M.t end
+module M : sig type t = X of N.t end
 |}];;
diff --git a/testsuite/tests/tool-toplevel/show.ml b/testsuite/tests/tool-toplevel/show.ml
index 6c000120ec..9dd7dc664b 100644
--- a/testsuite/tests/tool-toplevel/show.ml
+++ b/testsuite/tests/tool-toplevel/show.ml
@@ -40,7 +40,7 @@ type 'a option = None | Some of 'a
 
 #show option;;
 [%%expect {|
-type nonrec 'a option = None | Some of 'a
+type 'a option = None | Some of 'a
 |}];;
 
 #show Open_binary;;
@@ -59,7 +59,7 @@ type Stdlib.open_flag =
 
 #show open_flag;;
 [%%expect {|
-type nonrec open_flag =
+type open_flag =
     Open_rdonly
   | Open_wronly
   | Open_append
@@ -90,7 +90,7 @@ type extensible += B of int
 
 #show extensible;;
 [%%expect {|
-type nonrec extensible = ..
+type extensible = ..
 |}];;
 
 type 'a t = ..;;
diff --git a/testsuite/tests/tool-toplevel/show_short_paths.ml b/testsuite/tests/tool-toplevel/show_short_paths.ml
index c0c50de20c..000e775234 100644
--- a/testsuite/tests/tool-toplevel/show_short_paths.ml
+++ b/testsuite/tests/tool-toplevel/show_short_paths.ml
@@ -8,12 +8,12 @@
 
 #show list;;
 [%%expect {|
-type nonrec 'a list = [] | (::) of 'a * 'a list
+type 'a list = [] | (::) of 'a * 'a list
 |}];;
 
 type 'a t;;
 #show t;;
 [%%expect {|
 type 'a t
-type nonrec 'a t
+type 'a t
 |}];;