Rollup merge of #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

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
     {

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)
 }

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(

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

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

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:

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);