1 files changed, 18 insertions, 0 deletions
diff --git a/tests/ui/thread-local-mutation.rs b/tests/ui/thread-local-mutation.rs
new file mode 100644
index 000000000..e738225ce
--- /dev/null
+++ b/tests/ui/thread-local-mutation.rs
@@ -0,0 +1,18 @@
+// Regression test for #54901: immutable thread locals could be mutated. See:
+// https://github.com/rust-lang/rust/issues/29594#issuecomment-328177697
+// https://github.com/rust-lang/rust/issues/54901
+
+#![feature(thread_local)]
+
+#[thread_local]
+static S: &str = "before";
+
+fn set_s() {
+    S = "after"; //~ ERROR cannot assign to immutable
+}
+
+fn main() {
+    println!("{}", S);
+    set_s();
+    println!("{}", S);
+}