error: expected one of `:`, `;`, `=`, `@`, or `|`, found `{`
  --> $DIR/mut-patterns.rs:5:17
   |
LL |     let mut Foo { x: x } = Foo { x: 3 };
   |                 ^ expected one of `:`, `;`, `=`, `@`, or `|` here

error: aborting due to previous error