error[E0716]: temporary value dropped while borrowed
  --> $DIR/let_underscore_temporary.rs:10:14
   |
LL |       let _ = if let Some(s) = &mut num {
   |  _____________-
LL | |         *s += 1;
LL | |         s
LL | |     } else {
LL | |         &mut 0
   | |              ^ creates a temporary value which is freed while still in use
LL | |
LL | |     };
   | |     -
   | |     |
   | |_____temporary value is freed at the end of this statement
   |       borrow later used here
   |
   = note: consider using a `let` binding to create a longer lived value

error[E0716]: temporary value dropped while borrowed
  --> $DIR/let_underscore_temporary.rs:24:14
   |
LL |       let _ = if let Some(ref mut s) = num {
   |  _____________-
LL | |         *s += 1;
LL | |         s
LL | |     } else {
LL | |         &mut 0
   | |              ^ creates a temporary value which is freed while still in use
LL | |
LL | |     };
   | |     -
   | |     |
   | |_____temporary value is freed at the end of this statement
   |       borrow later used here
   |
   = note: consider using a `let` binding to create a longer lived value

error[E0716]: temporary value dropped while borrowed
  --> $DIR/let_underscore_temporary.rs:36:14
   |
LL |       let _: _ = if let Some(s) = &mut num {
   |  ________________-
LL | |         *s += 1;
LL | |         s
LL | |     } else {
LL | |         &mut 0
   | |              ^ creates a temporary value which is freed while still in use
LL | |
LL | |     };
   | |     -
   | |     |
   | |_____temporary value is freed at the end of this statement
   |       borrow later used here
   |
   = note: consider using a `let` binding to create a longer lived value

error[E0716]: temporary value dropped while borrowed
  --> $DIR/let_underscore_temporary.rs:50:14
   |
LL |       let _: _ = if let Some(ref mut s) = num {
   |  ________________-
LL | |         *s += 1;
LL | |         s
LL | |     } else {
LL | |         &mut 0
   | |              ^ creates a temporary value which is freed while still in use
LL | |
LL | |     };
   | |     -
   | |     |
   | |_____temporary value is freed at the end of this statement
   |       borrow later used here
   |
   = note: consider using a `let` binding to create a longer lived value

error[E0716]: temporary value dropped while borrowed
  --> $DIR/let_underscore_temporary.rs:66:14
   |
LL |       match if let Some(s) = &mut num {
   |  ___________-
LL | |         *s += 1;
LL | |         s
LL | |     } else {
LL | |         &mut 0
   | |              ^ creates a temporary value which is freed while still in use
LL | |
LL | |     } {
   | |     -
   | |     |
   | |_____temporary value is freed at the end of this statement
   |       borrow later used here
   |
   = note: consider using a `let` binding to create a longer lived value

error[E0716]: temporary value dropped while borrowed
  --> $DIR/let_underscore_temporary.rs:86:14
   |
LL |       match if let Some(ref mut s) = num {
   |  ___________-
LL | |         *s += 1;
LL | |         s
LL | |     } else {
LL | |         &mut 0
   | |              ^ creates a temporary value which is freed while still in use
LL | |
LL | |     } {
   | |     -
   | |     |
   | |_____temporary value is freed at the end of this statement
   |       borrow later used here
   |
   = note: consider using a `let` binding to create a longer lived value

error: aborting due to 6 previous errors

For more information about this error, try `rustc --explain E0716`.