Collect all unreachable fields in a single struct literal struct and emit a single error, instead of one error per private field.
```
error[E0451]: fields `beta` and `gamma` of struct `Alpha` are private
--> $DIR/visibility.rs:18:13
|
LL | let _x = Alpha {
| ----- in this type
LL | beta: 0,
| ^^^^^^^ private field
LL | ..
| ^^ field `gamma` is private
```
|
||
|---|---|---|
| .. | ||
| auxiliary | ||
| lookup-ignores-private.rs | ||
| private-in-public.rs | ||
| relative-2018.rs | ||
| relative-2018.stderr | ||
| struct-literal-field.rs | ||
| struct-literal-field.stderr | ||
| test.rs | ||
| test.stderr | ||