add a test

Author: WaffleLapkin

compiler/rustc_mir_build/src/check_tail_calls.rs

@@ -168,7 +168,6 @@ impl<'tcx> TailCallCkVisitor<'_, 'tcx> {
             let cause = ObligationCause::misc(expr.span, self.caller_def_id);
 
             // Erase safety, as it never affects ABI and is thus irrelevant for tail calls
-            // TODO: check if there is a test for this
             let caller_sig = caller_sig.set_safety(Safety::Safe);
             let callee_sig = callee_sig.set_safety(Safety::Safe);
 

tests/ui/explicit-tail-calls/safety.rs

@@ -0,0 +1,19 @@
+// Checks that you can tail call functions with different unsafety
+//
+//@ check-pass
+#![feature(explicit_tail_calls)]
+#![expect(incomplete_features)]
+
+fn a() {
+    unsafe {
+        become b();
+    }
+}
+
+unsafe fn b() {
+    become c();
+}
+
+fn c() {}
+
+fn main() {}