From 8bc30fae43a34cea9fb938a71a8c532c3e9825a5 Mon Sep 17 00:00:00 2001
From: Tobias Mock <mail@tmock.de>
Date: Thu, 12 Sep 2024 16:49:03 +0200
Subject: [PATCH] Fix detection of recursive calls

---
 lib/monomorph_tree.ml                 |  8 +++-----
 test/functions.t/nested_recursive.smu | 15 +++++++++++++++
 test/functions.t/run.t                |  6 ++++++
 3 files changed, 24 insertions(+), 5 deletions(-)
 create mode 100644 test/functions.t/nested_recursive.smu

diff --git a/lib/monomorph_tree.ml b/lib/monomorph_tree.ml
index 94e45902..0ab1bbc9 100644
--- a/lib/monomorph_tree.ml
+++ b/lib/monomorph_tree.ml
@@ -390,8 +390,8 @@ let set_tailrec p name =
   (* We have to check the name (of the function) here, because a nested function
      could call recursively its parent *)
   | (nm, _) :: tl when String.equal name nm ->
-      { p with recursion_stack = (nm, Rtail) :: tl }
-  | _ :: _ -> p
+      (true, { p with recursion_stack = (nm, Rtail) :: tl })
+  | _ :: _ -> (false, p)
   | [] -> failwith "Internal Error: Recursion stack empty (set)"
 
 let set_upward = function
@@ -1172,9 +1172,7 @@ and morph_app mk p callee args ret_typ =
   let tailrec, p =
     if ret then
       match callee.monomorph with
-      | Recursive name ->
-          let p = set_tailrec p name.nonmono in
-          (true, p)
+      | Recursive name -> set_tailrec p name.nonmono
       | _ -> (false, p)
     else (false, p)
   in
diff --git a/test/functions.t/nested_recursive.smu b/test/functions.t/nested_recursive.smu
new file mode 100644
index 00000000..5e6cb06f
--- /dev/null
+++ b/test/functions.t/nested_recursive.smu
@@ -0,0 +1,15 @@
+let arr = [("heya", 1)]
+
+fun rec consume(storage, opt) {
+  match storage.[opt] {
+    #none: println("none")
+    #some(arr): {
+      array/iter(arr, fun ((str, expr)) {
+        println(str)
+        consume(storage, expr)
+      })
+    }
+  }
+}
+
+consume([#some(copy(arr)), #none], 0)
diff --git a/test/functions.t/run.t b/test/functions.t/run.t
index 89a548ce..afa91568 100644
--- a/test/functions.t/run.t
+++ b/test/functions.t/run.t
@@ -2177,3 +2177,9 @@ Upward closures are moved closures
   on iteration: 7
   on iteration: 8
   on iteration: 9
+
+Only direct recursive calls count as recursive
+  $ schmu nested_recursive.smu
+  $ valgrind -q --leak-check=yes --show-reachable=yes ./nested_recursive
+  heya
+  none