Added PhantomPinned diagnostic item and prevented dead field warning on PhantomPinned

Author: asder8215

compiler/rustc_span/src/symbol.rs

@@ -267,6 +267,7 @@ symbols! {
         PartialEq,
         PartialOrd,
         Pending,
+        PhantomPinned,
         PinDerefMutHelper,
         Pointer,
         Poll,

library/core/src/marker.rs

@@ -1023,6 +1023,7 @@ pub auto trait Unpin {}
 // will likely eventually be deprecated, and all new code should be using `UnsafePinned` instead.
 #[stable(feature = "pin", since = "1.33.0")]
 #[derive(Debug, Default, Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)]
+#[rustc_diagnostic_item = "PhantomPinned"]
 pub struct PhantomPinned;
 
 #[stable(feature = "pin", since = "1.33.0")]

src/tools/clippy/clippy_lints/src/missing_fields_in_debug.rs

@@ -185,6 +185,7 @@ fn check_struct<'tcx>(
         .filter_map(|field| {
             if field_accesses.contains(&field.ident.name)
                 || field.ty.basic_res().is_lang_item(cx, LangItem::PhantomData)
+                || field.ty.basic_res().is_diag_item(cx, sym::PhantomPinned)
             {
                 None
             } else {

src/tools/clippy/clippy_lints/src/pub_underscore_fields.rs

@@ -6,6 +6,7 @@ use clippy_utils::res::{MaybeDef, MaybeResPath};
 use rustc_hir::{FieldDef, Item, ItemKind, LangItem};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::impl_lint_pass;
+use rustc_span::sym;
 
 declare_clippy_lint! {
     /// ### What it does
@@ -77,6 +78,7 @@ impl<'tcx> LateLintPass<'tcx> for PubUnderscoreFields {
                 && !is_doc_hidden(cx.tcx.hir_attrs(field.hir_id))
                 // We ignore fields that are `PhantomData`.
                 && !field.ty.basic_res().is_lang_item(cx, LangItem::PhantomData)
+                && !field.ty.basic_res().is_diag_item(cx, sym::PhantomPinned)
             {
                 span_lint_hir_and_then(
                     cx,

src/tools/clippy/tests/ui-toml/pub_underscore_fields/pub_underscore_fields.all_pub_fields.stderr

@@ -9,47 +9,47 @@ LL |         pub _b: u8,
    = help: to override `-D warnings` add `#[allow(clippy::pub_underscore_fields)]`
 
 error: field marked as public but also inferred as unused because it's prefixed with `_`
-  --> tests/ui-toml/pub_underscore_fields/pub_underscore_fields.rs:24:13
+  --> tests/ui-toml/pub_underscore_fields/pub_underscore_fields.rs:25:13
    |
 LL |             pub(in crate::inner) _f: Option<()>,
    |             ^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: consider removing the underscore, or making the field private
 
 error: field marked as public but also inferred as unused because it's prefixed with `_`
-  --> tests/ui-toml/pub_underscore_fields/pub_underscore_fields.rs:29:13
+  --> tests/ui-toml/pub_underscore_fields/pub_underscore_fields.rs:30:13
    |
 LL |             pub _g: String,
    |             ^^^^^^
    |
    = help: consider removing the underscore, or making the field private
 
 error: field marked as public but also inferred as unused because it's prefixed with `_`
-  --> tests/ui-toml/pub_underscore_fields/pub_underscore_fields.rs:37:9
+  --> tests/ui-toml/pub_underscore_fields/pub_underscore_fields.rs:38:9
    |
 LL |         pub _a: usize,
    |         ^^^^^^
    |
    = help: consider removing the underscore, or making the field private
 
 error: field marked as public but also inferred as unused because it's prefixed with `_`
-  --> tests/ui-toml/pub_underscore_fields/pub_underscore_fields.rs:45:9
+  --> tests/ui-toml/pub_underscore_fields/pub_underscore_fields.rs:46:9
    |
 LL |         pub _c: i64,
    |         ^^^^^^
    |
    = help: consider removing the underscore, or making the field private
 
 error: field marked as public but also inferred as unused because it's prefixed with `_`
-  --> tests/ui-toml/pub_underscore_fields/pub_underscore_fields.rs:49:9
+  --> tests/ui-toml/pub_underscore_fields/pub_underscore_fields.rs:50:9
    |
 LL |         pub _e: Option<u8>,
    |         ^^^^^^
    |
    = help: consider removing the underscore, or making the field private
 
 error: field marked as public but also inferred as unused because it's prefixed with `_`
-  --> tests/ui-toml/pub_underscore_fields/pub_underscore_fields.rs:63:9
+  --> tests/ui-toml/pub_underscore_fields/pub_underscore_fields.rs:64:9
    |
 LL |         pub(crate) _b: Option<String>,
    |         ^^^^^^^^^^^^^

src/tools/clippy/tests/ui-toml/pub_underscore_fields/pub_underscore_fields.rs

@@ -5,7 +5,7 @@
 #![allow(unused)]
 #![warn(clippy::pub_underscore_fields)]
 
-use std::marker::PhantomData;
+use std::marker::{PhantomData, PhantomPinned};
 
 pub mod inner {
     use std::marker;
@@ -16,6 +16,7 @@ pub mod inner {
         //~^ pub_underscore_fields
         _c: i32,
         pub _mark: marker::PhantomData<u8>,
+        pub _pinned: marker::PhantomPinned,
     }
 
     mod inner2 {
@@ -69,6 +70,7 @@ fn main() {
         r#pub: bool,
         _pub: String,
         pub(crate) _mark: PhantomData<u8>,
+        pub(crate) _pinned: PhantomPinned,
     }
 
     // shouldn't warn when `#[allow]` is used on field level

src/tools/clippy/tests/ui/missing_fields_in_debug.rs

@@ -2,7 +2,7 @@
 #![warn(clippy::missing_fields_in_debug)]
 
 use std::fmt;
-use std::marker::PhantomData;
+use std::marker::{PhantomData, PhantomPinned};
 use std::ops::Deref;
 use std::thread::LocalKey;
 
@@ -179,14 +179,15 @@ mod comment1175473620 {
 }
 
 // https://github.com/rust-lang/rust-clippy/pull/10616#discussion_r1175488757
-// PhantomData is an exception and does not need to be included
-struct WithPD {
+// PhantomData & PhantomPinned is an exception and does not need to be included
+struct WithPDPP {
     a: u8,
     b: u8,
     c: PhantomData<String>,
+    d: PhantomPinned,
 }
 
-impl fmt::Debug for WithPD {
+impl fmt::Debug for WithPDPP {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_struct("WithPD")
             .field("a", &self.a)