add test for stack overflow with recursive type #98842

Fixes #98842

1 files changed, 15 insertions, 0 deletions

diff --git a/tests/ui/sized/stack-overflow-trait-infer-98842.rs b/tests/ui/sized/stack-overflow-trait-infer-98842.rs
new file mode 100644
index 00000000000..2bba0777be4
--- /dev/null
+++ b/tests/ui/sized/stack-overflow-trait-infer-98842.rs
@@ -0,0 +1,15 @@
+// #98842 stack overflow in trait inference
+//@ check-fail
+//@ edition:2021
+//~^^^ ERROR cycle detected when computing layout of `Foo`
+
+// If the inner `Foo` is named through an associated type,
+// the "infinite size" error does not occur.
+struct Foo(<&'static Foo as ::core::ops::Deref>::Target);
+// But Rust will be unable to know whether `Foo` is sized or not,
+// and it will infinitely recurse somewhere trying to figure out the
+// size of this pointer (is my guess):
+const _: *const Foo = 0 as _;
+//~^ ERROR it is undefined behavior to use this value
+
+pub fn main() {}