Add regression test for #455

Author: Veykril

tests/regression_455.rs

@@ -0,0 +1,40 @@
+use salsa::{Database, Setter};
+
+#[salsa::tracked]
+fn memoized(db: &dyn Database, input: MyInput) -> u32 {
+    memoized_a(db, MyTracked::new(db, input.field(db)))
+}
+
+#[salsa::tracked]
+fn memoized_a<'db>(db: &'db dyn Database, tracked: MyTracked<'db>) -> u32 {
+    MyTracked::new(db, 0);
+    memoized_b(db, tracked)
+}
+
+fn recovery_fn<'db>(_db: &'db dyn Database, _cycle: &salsa::Cycle, _input: MyTracked<'db>) -> u32 {
+    0
+}
+
+#[salsa::tracked(recovery_fn=recovery_fn)]
+fn memoized_b<'db>(db: &'db dyn Database, tracked: MyTracked<'db>) -> u32 {
+    tracked.field(db) + memoized_a(db, tracked)
+}
+
+#[salsa::input]
+struct MyInput {
+    field: u32,
+}
+
+#[salsa::tracked]
+struct MyTracked<'db> {
+    field: u32,
+}
+
+#[test]
+fn cycle_memoized() {
+    let mut db = salsa::DatabaseImpl::new();
+    let input = MyInput::new(&db, 2);
+    memoized(&db, input);
+    input.set_field(&mut db).to(3);
+    memoized(&db, input);
+}