Add recursion limit to FFI safety lint

Fixes stack overflow in the case of recursive types

3 files changed, 31 insertions, 15 deletions

diff --git a/tests/crashes/130310.rs b/tests/crashes/130310.rs
deleted file mode 100644
index d59dd39983c..00000000000
--- a/tests/crashes/130310.rs
+++ /dev/null
@@ -1,15 +0,0 @@
-//@ known-bug: rust-lang/rust#130310
-
-use std::marker::PhantomData;
-
-#[repr(C)]
-struct A<T> {
-    a: *const A<A<T>>,
-    p: PhantomData<T>,
-}
-
-extern "C" {
-    fn f(a: *const A<()>);
-}
-
-fn main() {}
diff --git a/tests/ui/lint/improper-types-stack-overflow-130310.rs b/tests/ui/lint/improper-types-stack-overflow-130310.rs
new file mode 100644
index 00000000000..60eb8739817
--- /dev/null
+++ b/tests/ui/lint/improper-types-stack-overflow-130310.rs
@@ -0,0 +1,20 @@
+// Regression test for #130310
+// Tests that we do not fall into infinite
+// recursion while checking FFI safety of
+// recursive types like `A<T>` below
+
+//@ build-pass
+use std::marker::PhantomData;
+
+#[repr(C)]
+struct A<T> {
+    a: *const A<A<T>>, // Recursive because of this field
+    p: PhantomData<T>,
+}
+
+extern "C" {
+    fn f(a: *const A<()>);
+    //~^ WARN `extern` block uses type `*const A<()>`, which is not FFI-safe
+}
+
+fn main() {}
diff --git a/tests/ui/lint/improper-types-stack-overflow-130310.stderr b/tests/ui/lint/improper-types-stack-overflow-130310.stderr
new file mode 100644
index 00000000000..6981bb25755
--- /dev/null
+++ b/tests/ui/lint/improper-types-stack-overflow-130310.stderr
@@ -0,0 +1,11 @@
+warning: `extern` block uses type `*const A<()>`, which is not FFI-safe
+  --> $DIR/improper-types-stack-overflow-130310.rs:16:13
+   |
+LL |     fn f(a: *const A<()>);
+   |             ^^^^^^^^^^^^ not FFI-safe
+   |
+   = note: type is infinitely recursive
+   = note: `#[warn(improper_ctypes)]` on by default
+
+warning: 1 warning emitted
+