clippy: replace path uses by diagnostic items

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(

src/tools/clippy/clippy_lints/src/single_range_in_vec_init.rs

@@ -3,7 +3,7 @@ use clippy_utils::higher::VecArgs;
 use clippy_utils::macros::root_macro_call_first_node;
 use clippy_utils::source::SpanRangeExt;
 use clippy_utils::ty::implements_trait;
-use clippy_utils::{is_no_std_crate, paths};
+use clippy_utils::{is_no_std_crate, sym};
 use rustc_ast::{LitIntType, LitKind, UintTy};
 use rustc_errors::Applicability;
 use rustc_hir::{Expr, ExprKind, LangItem, QPath, StructTailExpr};
@@ -100,7 +100,7 @@ impl LateLintPass<'_> for SingleRangeInVecInit {
             && let Some(start_snippet) = start.span.get_source_text(cx)
             && let Some(end_snippet) = end.span.get_source_text(cx)
         {
-            let should_emit_every_value = if let Some(step_def_id) = paths::ITER_STEP.only(cx)
+            let should_emit_every_value = if let Some(step_def_id) = cx.tcx.get_diagnostic_item(sym::range_step)
                 && implements_trait(cx, ty, step_def_id, &[])
             {
                 true

src/tools/clippy/clippy_lints/src/to_digit_is_some.rs

@@ -2,7 +2,7 @@ use clippy_config::Conf;
 use clippy_utils::diagnostics::span_lint_and_sugg;
 use clippy_utils::msrvs::{self, Msrv};
 use clippy_utils::source::snippet_with_applicability;
-use clippy_utils::{is_in_const_context, paths, sym};
+use clippy_utils::{is_in_const_context, is_path_diagnostic_item, sym};
 use rustc_errors::Applicability;
 use rustc_hir as hir;
 use rustc_lint::{LateContext, LateLintPass};
@@ -62,7 +62,7 @@ impl<'tcx> LateLintPass<'tcx> for ToDigitIsSome {
                     }
                 },
                 hir::ExprKind::Call(to_digits_call, [char_arg, radix_arg]) => {
-                    if paths::CHAR_TO_DIGIT.matches_path(cx, to_digits_call) {
+                    if is_path_diagnostic_item(cx, to_digits_call, sym::char_to_digit) {
                         Some((false, char_arg, radix_arg))
                     } else {
                         None

src/tools/clippy/clippy_lints/src/useless_concat.rs

@@ -1,8 +1,7 @@
 use clippy_utils::diagnostics::span_lint_and_sugg;
 use clippy_utils::macros::macro_backtrace;
-use clippy_utils::paths::CONCAT;
 use clippy_utils::source::snippet_opt;
-use clippy_utils::tokenize_with_text;
+use clippy_utils::{sym, tokenize_with_text};
 use rustc_ast::LitKind;
 use rustc_errors::Applicability;
 use rustc_hir::{Expr, ExprKind};
@@ -43,7 +42,7 @@ impl LateLintPass<'_> for UselessConcat {
             // Get the direct parent of the expression.
             && let Some(macro_call) = macro_backtrace(expr.span).next()
             // Check if the `concat` macro from the `core` library.
-            && CONCAT.matches(cx, macro_call.def_id)
+            && cx.tcx.is_diagnostic_item(sym::macro_concat, macro_call.def_id)
             // We get the original code to parse it.
             && let Some(original_code) = snippet_opt(cx, macro_call.span)
             // This check allows us to ensure that the code snippet:

src/tools/clippy/clippy_utils/src/paths.rs

@@ -126,15 +126,6 @@ path_macros! {
     macro_path: PathNS::Macro,
 }
 
-// Paths in `core`/`alloc`/`std`. This should be avoided and cleaned up by adding diagnostic items.
-pub static ALIGN_OF: PathLookup = value_path!(core::mem::align_of);
-pub static CHAR_TO_DIGIT: PathLookup = value_path!(char::to_digit);
-pub static CONCAT: PathLookup = macro_path!(core::concat);
-pub static IO_ERROR_NEW: PathLookup = value_path!(std::io::Error::new);
-pub static IO_ERRORKIND_OTHER_CTOR: PathLookup = value_path!(std::io::ErrorKind::Other);
-pub static ITER_STEP: PathLookup = type_path!(core::iter::Step);
-pub static SLICE_FROM_REF: PathLookup = value_path!(core::slice::from_ref);
-
 // Paths in external crates
 pub static FUTURES_IO_ASYNCREADEXT: PathLookup = type_path!(futures_util::AsyncReadExt);
 pub static FUTURES_IO_ASYNCWRITEEXT: PathLookup = type_path!(futures_util::AsyncWriteExt);