Update the tests/ui/explicit-tail-calls/caller_is_track_caller.rs test with a case of a default trait method.

Author: jakubadamw

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

@@ -13,4 +13,13 @@ fn c() {
     become a(); //~ error: a function marked with `#[track_caller]` cannot perform a tail-call
 }
 
+trait Trait {
+    fn d(&self);
+
+    #[track_caller]
+    fn e(&self) {
+        become self.d(); //~ error: a function marked with `#[track_caller]` cannot perform a tail-call
+    }
+}
+
 fn main() {}

tests/ui/explicit-tail-calls/caller_is_track_caller.stderr

@@ -10,5 +10,11 @@ error: a function marked with `#[track_caller]` cannot perform a tail-call
 LL |     become a();
    |     ^^^^^^^^^^
 
-error: aborting due to 2 previous errors
+error: a function marked with `#[track_caller]` cannot perform a tail-call
+  --> $DIR/caller_is_track_caller.rs:21:9
+   |
+LL |         become self.d();
+   |         ^^^^^^^^^^^^^^^
+
+error: aborting due to 3 previous errors