'available fields are' message in diagnostic lists unstable/hidden fields.

[m-ou-se]

With this patch to std:

diff --git a/library/core/src/pin.rs b/library/core/src/pin.rs
index ce5ed40940ec6..b8511eb664cb5 100644
--- a/library/core/src/pin.rs
+++ b/library/core/src/pin.rs
@@ -406,7 +406,9 @@ use crate::ops::{CoerceUnsized, Deref, DerefMut, DispatchFromDyn, Receiver};
 #[repr(transparent)]
 #[derive(Copy, Clone)]
 pub struct Pin<P> {
-    pointer: P,
+    #[unstable(feature = "pin_internals", issue = "none")]
+    #[doc(hidden)]
+    pub pointer: P,
 }

The hidden .pointer field appears as a suggestion in a diagnostic:

---- [ui] ui/async-await/suggest-switching-edition-on-await.rs stdout ----
diff of stderr:

24	LL |     x.await;
25	   |       ^^^^^ unknown field
26	   |
+	   = note: available fields are: `pointer`
27	   = note: to `.await` a `Future`, switch to Rust 2018 or later
28	   = help: set `edition = "2021"` in `Cargo.toml`
Some tests failed in compiletest suite=ui mode=ui host=x86_64-unknown-linux-gnu target=x86_64-unknown-linux-gnu
29	   = note: for more on editions, read https://doc.rust-lang.org/edition-guide

(https://github.com/rust-lang/rust/runs/4908271178?check_suite_focus=true)

[m-ou-se]

Easier reproduction of this issue:

lib.rs:

#[derive(Default)]
pub struct A {
    #[doc(hidden)]
    pub hello: i32,
}

main.rs:

fn main() {
    lib::A::default().hey;
}

output:

$ rustc lib.rs --crate-type=lib && rustc --extern lib=liblib.rlib main.rs --edition=2021 
error[E0609]: no field `hey` on type `A`
 --> main.rs:2:23
  |
2 |     lib::A::default().hey;
  |                       ^^^ unknown field
  |
  = note: available fields are: `hello`

[ibraheemdev]

@rustbot claim