1 files changed, 50 insertions, 0 deletions
diff --git a/tests/incremental/auxiliary/issue-54059.rs b/tests/incremental/auxiliary/issue-54059.rs
new file mode 100644
index 000000000..fa2814a77
--- /dev/null
+++ b/tests/incremental/auxiliary/issue-54059.rs
@@ -0,0 +1,50 @@
+// force-host
+// no-prefer-dynamic
+
+// check that having extern "C" functions in a proc macro doesn't crash.
+
+#![crate_type="proc-macro"]
+#![allow(non_snake_case)]
+
+extern crate proc_macro;
+
+macro_rules! proc_macro_tokenstream {
+    () => {
+        ::proc_macro::TokenStream
+    };
+}
+
+macro_rules! proc_macro_expr_impl {
+    ($(
+        $( #[$attr:meta] )*
+        pub fn $func:ident($input:ident: &str) -> String $body:block
+    )+) => {
+        $(
+            // Parses an input that looks like:
+            //
+            // ```
+            // #[allow(unused)]
+            // enum ProcMacroHack {
+            //     Input = (stringify!(ARGS), 0).1,
+            // }
+            // ```
+            $( #[$attr] )*
+            #[proc_macro_derive($func)]
+            pub fn $func(input: proc_macro_tokenstream!()) -> proc_macro_tokenstream!() {
+                unsafe { rust_dbg_extern_identity_u64(0); }
+                panic!()
+            }
+        )+
+    };
+}
+
+proc_macro_expr_impl! {
+    pub fn base2_impl(input: &str) -> String {
+        panic!()
+    }
+}
+
+#[link(name="rust_test_helpers")]
+extern "C" {
+    pub fn rust_dbg_extern_identity_u64(v: u64) -> u64;
+}