From b0eb55a092506aa4cfe34969c56adfeca9616750 Mon Sep 17 00:00:00 2001
From: jumbatm <30644300+jumbatm@users.noreply.github.com>
Date: Sat, 15 Aug 2020 13:18:54 +1000
Subject: [PATCH] Add test demonstrating the issue.

---
 .../ui/lint/clashing-extern-fn-recursion.rs   | 117 ++++++++++++++++++
 1 file changed, 117 insertions(+)
 create mode 100644 src/test/ui/lint/clashing-extern-fn-recursion.rs

diff --git a/src/test/ui/lint/clashing-extern-fn-recursion.rs b/src/test/ui/lint/clashing-extern-fn-recursion.rs
new file mode 100644
index 000000000000..51bfd2032838
--- /dev/null
+++ b/src/test/ui/lint/clashing-extern-fn-recursion.rs
@@ -0,0 +1,117 @@
+// check-pass
+//
+// This tests checks that clashing_extern_declarations handles types that are recursive through a
+// pointer or ref argument. See #75512.
+
+#![crate_type = "lib"]
+
+mod raw_ptr_recursion {
+    mod a {
+        #[repr(C)]
+        struct Pointy {
+            pointy: *const Pointy,
+        }
+
+        extern "C" {
+            fn run_pointy(pointy: Pointy);
+        }
+    }
+    mod b {
+        #[repr(C)]
+        struct Pointy {
+            pointy: *const Pointy,
+        }
+
+        extern "C" {
+            fn run_pointy(pointy: Pointy);
+        }
+    }
+}
+
+mod raw_ptr_recursion_once_removed {
+    mod a {
+        #[repr(C)]
+        struct Pointy1 {
+            pointy_two: *const Pointy2,
+        }
+
+        #[repr(C)]
+        struct Pointy2 {
+            pointy_one: *const Pointy1,
+        }
+
+        extern "C" {
+            fn run_pointy2(pointy: Pointy2);
+        }
+    }
+
+    mod b {
+        #[repr(C)]
+        struct Pointy1 {
+            pointy_two: *const Pointy2,
+        }
+
+        #[repr(C)]
+        struct Pointy2 {
+            pointy_one: *const Pointy1,
+        }
+
+        extern "C" {
+            fn run_pointy2(pointy: Pointy2);
+        }
+    }
+}
+
+mod ref_recursion {
+    mod a {
+        #[repr(C)]
+        struct Reffy<'a> {
+            reffy: &'a Reffy<'a>,
+        }
+
+        extern "C" {
+            fn reffy_recursion(reffy: Reffy);
+        }
+    }
+    mod b {
+        #[repr(C)]
+        struct Reffy<'a> {
+            reffy: &'a Reffy<'a>,
+        }
+
+        extern "C" {
+            fn reffy_recursion(reffy: Reffy);
+        }
+    }
+}
+
+mod ref_recursion_once_removed {
+    mod a {
+        #[repr(C)]
+        struct Reffy1<'a> {
+            reffy: &'a Reffy1<'a>,
+        }
+
+        struct Reffy2<'a> {
+            reffy: &'a Reffy2<'a>,
+        }
+
+        extern "C" {
+            fn reffy_once_removed(reffy: Reffy1);
+        }
+    }
+    mod b {
+        #[repr(C)]
+        struct Reffy1<'a> {
+            reffy: &'a Reffy1<'a>,
+        }
+
+        struct Reffy2<'a> {
+            reffy: &'a Reffy2<'a>,
+        }
+
+        extern "C" {
+            fn reffy_once_removed(reffy: Reffy1);
+        }
+    }
+}