error[E0381]: partially assigned binding `x` isn't fully initialized
  --> $DIR/reassignment_immutable_fields_overlapping.rs:12:5
   |
LL |     let x: Foo;
   |         - binding declared here but left uninitialized
LL |     x.a = 1;
   |     ^^^^^^^ `x` partially assigned here but it isn't fully initialized
   |
   = help: partial initialization isn't supported, fully initialize the binding with a default value and mutate it, or use `std::mem::MaybeUninit`

error[E0594]: cannot assign to `x.b`, as `x` is not declared as mutable
  --> $DIR/reassignment_immutable_fields_overlapping.rs:13:5
   |
LL |     x.b = 22;
   |     ^^^^^^^^ cannot assign
   |
help: consider changing this to be mutable
   |
LL |     let mut x: Foo;
   |         +++

error: aborting due to 2 previous errors

Some errors have detailed explanations: E0381, E0594.
For more information about an error, try `rustc --explain E0381`.