The current implementation will throw a parser error for tuple structs
that contain a pub tuple field. For example,
```rust
struct Foo(pub (u32, u32));
```
is valid Rust, but rust-analyzer will throw a parser error. This is
because the parens after `pub` is treated as a visibility context.
Allowing a tuple type to follow `pub` in the special case when we are
defining fields in a tuple struct can fix the issue.
The code here is intentionally dense and does exactly what is written.
Explaining semantic difference between Rust 2015 and 2018 doesn't help
with understanding syntax. Better to just add more targeted tests.
7218: Fix typos r=Veykril a=regexident
Apart from the very last commit on this PR (which fixes a public type's name) all changes are non-breaking.
Co-authored-by: Vincent Esche <regexident@gmail.com>
