error[E0506]: cannot assign to `*s` because it is borrowed --> $DIR/guarantor-issue-46974.rs:7:5 | LL | let t = &mut *s; // this borrow should last for the entire function | ------- `*s` is borrowed here LL | let x = &t.0; LL | *s = (2,); | ^^^^^^^^^ `*s` is assigned to here but it was already borrowed LL | *x | -- borrow later used here error: lifetime may not live long enough --> $DIR/guarantor-issue-46974.rs:13:5 | LL | fn bar(s: &Box<(i32,)>) -> &'static i32 { | - let's call the lifetime of this reference `'1` LL | // FIXME(#46983): error message should be better LL | &s.0 | ^^^^ returning this value requires that `'1` must outlive `'static` error: aborting due to 2 previous errors For more information about this error, try `rustc --explain E0506`.