Rollup merge of rust-lang#142787 - samueltardieu:diag-items-for-clippy, r=Manishearth,Urgau

Add diagnostic items for Clippy

Clippy still uses some paths to access items from the standard library. Adding the missing diagnostic items allows removing the last remaining paths.

Closes rust-lang/rust-clippy#5393

Author: matthiaskrgr

compiler/rustc_span/src/symbol.rs

@@ -641,6 +641,7 @@ symbols! {
         cfi_encoding,
         char,
         char_is_ascii,
+        char_to_digit,
         child_id,
         child_kill,
         client,
@@ -1216,6 +1217,8 @@ symbols! {
         intrinsics,
         intrinsics_unaligned_volatile_load,
         intrinsics_unaligned_volatile_store,
+        io_error_new,
+        io_errorkind,
         io_stderr,
         io_stdout,
         irrefutable_let_patterns,
@@ -1305,6 +1308,7 @@ symbols! {
         m68k_target_feature,
         macro_at_most_once_rep,
         macro_attributes_in_derive_output,
+        macro_concat,
         macro_escape,
         macro_export,
         macro_lifetime_matcher,
@@ -1339,6 +1343,7 @@ symbols! {
         maybe_uninit,
         maybe_uninit_uninit,
         maybe_uninit_zeroed,
+        mem_align_of,
         mem_discriminant,
         mem_drop,
         mem_forget,
@@ -1706,6 +1711,7 @@ symbols! {
         question_mark,
         quote,
         range_inclusive_new,
+        range_step,
         raw_dylib,
         raw_dylib_elf,
         raw_eq,
@@ -2022,6 +2028,7 @@ symbols! {
         slice,
         slice_from_raw_parts,
         slice_from_raw_parts_mut,
+        slice_from_ref,
         slice_get_unchecked,
         slice_into_vec,
         slice_iter,

library/core/src/char/methods.rs

@@ -395,6 +395,7 @@ impl char {
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_const_stable(feature = "const_char_convert", since = "1.67.0")]
+    #[rustc_diagnostic_item = "char_to_digit"]
     #[must_use = "this returns the result of the operation, \
                   without modifying the original"]
     #[inline]

library/core/src/iter/range.rs

@@ -20,6 +20,7 @@ unsafe_impl_trusted_step![AsciiChar char i8 i16 i32 i64 i128 isize u8 u16 u32 u6
 ///
 /// The *successor* operation moves towards values that compare greater.
 /// The *predecessor* operation moves towards values that compare lesser.
+#[rustc_diagnostic_item = "range_step"]
 #[unstable(feature = "step_trait", issue = "42168")]
 pub trait Step: Clone + PartialOrd + Sized {
     /// Returns the bounds on the number of *successor* steps required to get from `start` to `end`

library/core/src/macros/mod.rs

@@ -1192,6 +1192,7 @@ pub(crate) mod builtin {
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_builtin_macro]
+    #[rustc_diagnostic_item = "macro_concat"]
     #[macro_export]
     macro_rules! concat {
         ($($e:expr),* $(,)?) => {{ /* compiler built-in */ }};

library/core/src/mem/mod.rs

@@ -481,6 +481,7 @@ pub fn min_align_of_val<T: ?Sized>(val: &T) -> usize {
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_promotable]
 #[rustc_const_stable(feature = "const_align_of", since = "1.24.0")]
+#[rustc_diagnostic_item = "mem_align_of"]
 pub const fn align_of<T>() -> usize {
     intrinsics::align_of::<T>()
 }

library/core/src/slice/raw.rs

@@ -198,6 +198,7 @@ pub const unsafe fn from_raw_parts_mut<'a, T>(data: *mut T, len: usize) -> &'a m
 /// Converts a reference to T into a slice of length 1 (without copying).
 #[stable(feature = "from_ref", since = "1.28.0")]
 #[rustc_const_stable(feature = "const_slice_from_ref_shared", since = "1.63.0")]
+#[rustc_diagnostic_item = "slice_from_ref"]
 #[must_use]
 pub const fn from_ref<T>(s: &T) -> &[T] {
     array::from_ref(s)

library/std/src/io/error.rs

@@ -219,6 +219,7 @@ struct Custom {
 /// the recognized error kinds and fail in those cases.
 #[derive(Clone, Copy, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
 #[stable(feature = "rust1", since = "1.0.0")]
+#[cfg_attr(not(test), rustc_diagnostic_item = "io_errorkind")]
 #[allow(deprecated)]
 #[non_exhaustive]
 pub enum ErrorKind {
@@ -562,6 +563,7 @@ impl Error {
     /// let eof_error = Error::from(ErrorKind::UnexpectedEof);
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[cfg_attr(not(test), rustc_diagnostic_item = "io_error_new")]
     #[inline(never)]
     pub fn new<E>(kind: ErrorKind, error: E) -> Error
     where

src/tools/clippy/clippy_lints/src/casts/manual_dangling_ptr.rs

@@ -1,6 +1,6 @@
 use clippy_utils::diagnostics::span_lint_and_sugg;
 use clippy_utils::source::SpanRangeExt;
-use clippy_utils::{expr_or_init, path_def_id, paths, std_or_core};
+use clippy_utils::{expr_or_init, is_path_diagnostic_item, std_or_core, sym};
 use rustc_ast::LitKind;
 use rustc_errors::Applicability;
 use rustc_hir::{Expr, ExprKind, GenericArg, Mutability, QPath, Ty, TyKind};
@@ -53,8 +53,7 @@ fn is_expr_const_aligned(cx: &LateContext<'_>, expr: &Expr<'_>, to: &Ty<'_>) ->
 
 fn is_align_of_call(cx: &LateContext<'_>, fun: &Expr<'_>, to: &Ty<'_>) -> bool {
     if let ExprKind::Path(QPath::Resolved(_, path)) = fun.kind
-        && let Some(fun_id) = path_def_id(cx, fun)
-        && paths::ALIGN_OF.matches(cx, fun_id)
+        && is_path_diagnostic_item(cx, fun, sym::mem_align_of)
         && let Some(args) = path.segments.last().and_then(|seg| seg.args)
         && let [GenericArg::Type(generic_ty)] = args.args
     {

src/tools/clippy/clippy_lints/src/manual_option_as_slice.rs

@@ -1,7 +1,7 @@
 use clippy_config::Conf;
 use clippy_utils::diagnostics::{span_lint, span_lint_and_sugg};
 use clippy_utils::msrvs::Msrv;
-use clippy_utils::{is_none_arm, msrvs, paths, peel_hir_expr_refs, sym};
+use clippy_utils::{is_none_arm, msrvs, peel_hir_expr_refs, sym};
 use rustc_errors::Applicability;
 use rustc_hir::def::{DefKind, Res};
 use rustc_hir::{Arm, Expr, ExprKind, LangItem, Pat, PatKind, QPath, is_range_literal};
@@ -220,5 +220,5 @@ fn is_empty_slice(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
 }
 
 fn is_slice_from_ref(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
-    paths::SLICE_FROM_REF.matches_path(cx, expr)
+    clippy_utils::is_path_diagnostic_item(cx, expr, sym::slice_from_ref)
 }

src/tools/clippy/clippy_lints/src/methods/io_other_error.rs

@@ -1,6 +1,6 @@
 use clippy_utils::diagnostics::span_lint_and_then;
 use clippy_utils::msrvs::{self, Msrv};
-use clippy_utils::{expr_or_init, paths};
+use clippy_utils::{expr_or_init, is_path_diagnostic_item, sym};
 use rustc_errors::Applicability;
 use rustc_hir::{Expr, ExprKind, QPath};
 use rustc_lint::LateContext;
@@ -10,8 +10,11 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>, path: &Expr<'_>, args
         && !expr.span.from_expansion()
         && !error_kind.span.from_expansion()
         && let ExprKind::Path(QPath::TypeRelative(_, new_segment)) = path.kind
-        && paths::IO_ERROR_NEW.matches_path(cx, path)
-        && paths::IO_ERRORKIND_OTHER_CTOR.matches_path(cx, expr_or_init(cx, error_kind))
+        && is_path_diagnostic_item(cx, path, sym::io_error_new)
+        && let ExprKind::Path(QPath::Resolved(_, init_path)) = &expr_or_init(cx, error_kind).kind
+        && let [.., error_kind_ty, error_kind_variant] = init_path.segments
+        && cx.tcx.is_diagnostic_item(sym::io_errorkind, error_kind_ty.res.def_id())
+        && error_kind_variant.ident.name == sym::Other
         && msrv.meets(cx, msrvs::IO_ERROR_OTHER)
     {
         span_lint_and_then(