1 files changed, 26 insertions, 0 deletions
diff --git a/tests/ui/extern/extern-const.rs b/tests/ui/extern/extern-const.rs
new file mode 100644
index 00000000000..7cef5b3497b
--- /dev/null
+++ b/tests/ui/extern/extern-const.rs
@@ -0,0 +1,26 @@
+// Check extern items cannot be const + `rustfix` suggests using
+// extern static.
+//
+// #54388: an unused reference to an undefined static may or may not
+// compile. To sidestep this by using one that *is* defined.
+
+// run-rustfix
+// ignore-wasm32-bare no external library to link to.
+// ignore-asmjs wasm2js does not support source maps yet
+// compile-flags: -g
+#![feature(rustc_private)]
+extern crate libc;
+
+#[link(name = "rust_test_helpers", kind = "static")]
+extern "C" {
+    const rust_dbg_static_mut: libc::c_int; //~ ERROR extern items cannot be `const`
+}
+
+fn main() {
+    // We suggest turning the (illegal) extern `const` into an extern `static`,
+    // but this also requires `unsafe` (a deny-by-default lint at comment time,
+    // future error; Issue #36247)
+    unsafe {
+        let _x = rust_dbg_static_mut;
+    }
+}