Auto merge of #7466 - xFrednet:5393-use-more-diagnostic-items, r=flip…

…1995

Use diagnostic items where possible

Clippy still uses a bunch of paths in places that could easily use already defined diagnostic items. This PR updates all references to such paths and also removes a bunch of them that are no longer needed after this cleanup.

Some paths are also used to construct new paths and can therefore not be removed that easily. I've added a doc comment to those instances that recommends the use of the diagnostic item where possible.

And that's it, cleaning crew signing off 🧹 🗑️

---

changelog: none

(only internal improvements)

cc: #5393

clippy_lints/src/from_over_into.rs

@@ -1,11 +1,11 @@
 use clippy_utils::diagnostics::span_lint_and_help;
-use clippy_utils::paths::INTO;
-use clippy_utils::{match_def_path, meets_msrv, msrvs};
+use clippy_utils::{meets_msrv, msrvs};
 use if_chain::if_chain;
 use rustc_hir as hir;
 use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_semver::RustcVersion;
 use rustc_session::{declare_tool_lint, impl_lint_pass};
+use rustc_span::symbol::sym;
 
 declare_clippy_lint! {
     /// **What it does:** Searches for implementations of the `Into<..>` trait and suggests to implement `From<..>` instead.
@@ -62,7 +62,7 @@ impl LateLintPass<'_> for FromOverInto {
         if_chain! {
             if let hir::ItemKind::Impl{ .. } = &item.kind;
             if let Some(impl_trait_ref) = cx.tcx.impl_trait_ref(item.def_id);
-            if match_def_path(cx, impl_trait_ref.def_id, &INTO);
+            if cx.tcx.is_diagnostic_item(sym::into_trait, impl_trait_ref.def_id);
 
             then {
                 span_lint_and_help(

clippy_lints/src/implicit_hasher.rs

@@ -17,10 +17,9 @@ use rustc_typeck::hir_ty_to_ty;
 use if_chain::if_chain;
 
 use clippy_utils::diagnostics::{multispan_sugg, span_lint_and_then};
-use clippy_utils::paths;
+use clippy_utils::differing_macro_contexts;
 use clippy_utils::source::{snippet, snippet_opt};
 use clippy_utils::ty::is_type_diagnostic_item;
-use clippy_utils::{differing_macro_contexts, match_def_path};
 
 declare_clippy_lint! {
     /// **What it does:** Checks for public `impl` or `fn` missing generalization
@@ -337,7 +336,7 @@ impl<'a, 'b, 'tcx> Visitor<'tcx> for ImplicitHasherConstructorVisitor<'a, 'b, 't
                     return;
                 }
 
-                if match_def_path(self.cx, ty_did, &paths::HASHMAP) {
+                if self.cx.tcx.is_diagnostic_item(sym::hashmap_type, ty_did) {
                     if method.ident.name == sym::new {
                         self.suggestions
                             .insert(e.span, "HashMap::default()".to_string());
@@ -350,7 +349,7 @@ impl<'a, 'b, 'tcx> Visitor<'tcx> for ImplicitHasherConstructorVisitor<'a, 'b, 't
                             ),
                         );
                     }
-                } else if match_def_path(self.cx, ty_did, &paths::HASHSET) {
+                } else if self.cx.tcx.is_diagnostic_item(sym::hashset_type, ty_did) {
                     if method.ident.name == sym::new {
                         self.suggestions
                             .insert(e.span, "HashSet::default()".to_string());

clippy_lints/src/infinite_iter.rs

@@ -1,9 +1,10 @@
 use clippy_utils::diagnostics::span_lint;
-use clippy_utils::ty::{implements_trait, match_type};
+use clippy_utils::ty::{implements_trait, is_type_diagnostic_item};
 use clippy_utils::{get_trait_def_id, higher, is_qpath_def_path, paths};
 use rustc_hir::{BorrowKind, Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
+use rustc_span::symbol::{sym, Symbol};
 
 declare_clippy_lint! {
     /// **What it does:** Checks for iteration that is guaranteed to be infinite.
@@ -202,15 +203,15 @@ const COMPLETING_METHODS: [(&str, usize); 12] = [
 ];
 
 /// the paths of types that are known to be infinitely allocating
-const INFINITE_COLLECTORS: [&[&str]; 8] = [
-    &paths::BINARY_HEAP,
-    &paths::BTREEMAP,
-    &paths::BTREESET,
-    &paths::HASHMAP,
-    &paths::HASHSET,
-    &paths::LINKED_LIST,
-    &paths::VEC,
-    &paths::VEC_DEQUE,
+const INFINITE_COLLECTORS: &[Symbol] = &[
+    sym::BinaryHeap,
+    sym::BTreeMap,
+    sym::BTreeSet,
+    sym::hashmap_type,
+    sym::hashset_type,
+    sym::LinkedList,
+    sym::vec_type,
+    sym::vecdeque_type,
 ];
 
 fn complete_infinite_iter(cx: &LateContext<'_>, expr: &Expr<'_>) -> Finiteness {
@@ -235,7 +236,10 @@ fn complete_infinite_iter(cx: &LateContext<'_>, expr: &Expr<'_>) -> Finiteness {
                 }
             } else if method.ident.name == sym!(collect) {
                 let ty = cx.typeck_results().expr_ty(expr);
-                if INFINITE_COLLECTORS.iter().any(|path| match_type(cx, ty, path)) {
+                if INFINITE_COLLECTORS
+                    .iter()
+                    .any(|diag_item| is_type_diagnostic_item(cx, ty, *diag_item))
+                {
                     return is_infinite(cx, &args[0]);
                 }
             }

clippy_lints/src/loops/explicit_into_iter_loop.rs

@@ -1,16 +1,17 @@
 use super::EXPLICIT_INTO_ITER_LOOP;
 use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::is_trait_method;
 use clippy_utils::source::snippet_with_applicability;
-use clippy_utils::{match_trait_method, paths};
 use rustc_errors::Applicability;
 use rustc_hir::Expr;
 use rustc_lint::LateContext;
 use rustc_middle::ty::TyS;
+use rustc_span::symbol::sym;
 
 pub(super) fn check(cx: &LateContext<'_>, self_arg: &'hir Expr<'hir>, call_expr: &Expr<'_>) {
     let self_ty = cx.typeck_results().expr_ty(self_arg);
     let self_ty_adjusted = cx.typeck_results().expr_ty_adjusted(self_arg);
-    if !(TyS::same_type(self_ty, self_ty_adjusted) && match_trait_method(cx, call_expr, &paths::INTO_ITERATOR)) {
+    if !(TyS::same_type(self_ty, self_ty_adjusted) && is_trait_method(cx, call_expr, sym::IntoIterator)) {
         return;
     }
 

clippy_lints/src/loops/explicit_iter_loop.rs

@@ -1,8 +1,8 @@
 use super::EXPLICIT_ITER_LOOP;
 use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::is_trait_method;
 use clippy_utils::source::snippet_with_applicability;
-use clippy_utils::ty::{is_type_diagnostic_item, match_type};
-use clippy_utils::{match_trait_method, paths};
+use clippy_utils::ty::is_type_diagnostic_item;
 use rustc_errors::Applicability;
 use rustc_hir::{Expr, Mutability};
 use rustc_lint::LateContext;
@@ -12,7 +12,7 @@ use rustc_span::sym;
 pub(super) fn check(cx: &LateContext<'_>, self_arg: &Expr<'_>, arg: &Expr<'_>, method_name: &str) {
     let should_lint = match method_name {
         "iter" | "iter_mut" => is_ref_iterable_type(cx, self_arg),
-        "into_iter" if match_trait_method(cx, arg, &paths::INTO_ITERATOR) => {
+        "into_iter" if is_trait_method(cx, arg, sym::IntoIterator) => {
             let receiver_ty = cx.typeck_results().expr_ty(self_arg);
             let receiver_ty_adjusted = cx.typeck_results().expr_ty_adjusted(self_arg);
             let ref_receiver_ty = cx.tcx.mk_ref(
@@ -55,13 +55,13 @@ fn is_ref_iterable_type(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
     let ty = cx.typeck_results().expr_ty(e);
     is_iterable_array(ty, cx) ||
     is_type_diagnostic_item(cx, ty, sym::vec_type) ||
-    match_type(cx, ty, &paths::LINKED_LIST) ||
+    is_type_diagnostic_item(cx, ty, sym::LinkedList) ||
     is_type_diagnostic_item(cx, ty, sym::hashmap_type) ||
     is_type_diagnostic_item(cx, ty, sym::hashset_type) ||
     is_type_diagnostic_item(cx, ty, sym::vecdeque_type) ||
-    match_type(cx, ty, &paths::BINARY_HEAP) ||
-    match_type(cx, ty, &paths::BTREEMAP) ||
-    match_type(cx, ty, &paths::BTREESET)
+    is_type_diagnostic_item(cx, ty, sym::BinaryHeap) ||
+    is_type_diagnostic_item(cx, ty, sym::BTreeMap) ||
+    is_type_diagnostic_item(cx, ty, sym::BTreeSet)
 }
 
 fn is_iterable_array<'tcx>(ty: Ty<'tcx>, cx: &LateContext<'tcx>) -> bool {

clippy_lints/src/loops/for_kv_map.rs

@@ -1,9 +1,9 @@
 use super::FOR_KV_MAP;
 use clippy_utils::diagnostics::{multispan_sugg, span_lint_and_then};
 use clippy_utils::source::snippet;
-use clippy_utils::ty::{is_type_diagnostic_item, match_type};
+use clippy_utils::sugg;
+use clippy_utils::ty::is_type_diagnostic_item;
 use clippy_utils::visitors::LocalUsedVisitor;
-use clippy_utils::{paths, sugg};
 use rustc_hir::{BorrowKind, Expr, ExprKind, Mutability, Pat, PatKind};
 use rustc_lint::LateContext;
 use rustc_middle::ty;
@@ -39,7 +39,7 @@ pub(super) fn check<'tcx>(
                 _ => arg,
             };
 
-            if is_type_diagnostic_item(cx, ty, sym::hashmap_type) || match_type(cx, ty, &paths::BTREEMAP) {
+            if is_type_diagnostic_item(cx, ty, sym::hashmap_type) || is_type_diagnostic_item(cx, ty, sym::BTreeMap) {
                 span_lint_and_then(
                     cx,
                     FOR_KV_MAP,

clippy_lints/src/matches.rs

@@ -1793,8 +1793,8 @@ mod redundant_pattern_match {
             || is_type_diagnostic_item(cx, ty, sym::Rc)
             || is_type_diagnostic_item(cx, ty, sym::Arc)
             || is_type_diagnostic_item(cx, ty, sym::cstring_type)
-            || match_type(cx, ty, &paths::BTREEMAP)
-            || match_type(cx, ty, &paths::LINKED_LIST)
+            || is_type_diagnostic_item(cx, ty, sym::BTreeMap)
+            || is_type_diagnostic_item(cx, ty, sym::LinkedList)
             || match_type(cx, ty, &paths::WEAK_RC)
             || match_type(cx, ty, &paths::WEAK_ARC)
         {

clippy_lints/src/methods/get_unwrap.rs

@@ -1,8 +1,8 @@
 use super::utils::derefs_to_slice;
 use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::get_parent_expr;
 use clippy_utils::source::snippet_with_applicability;
-use clippy_utils::ty::{is_type_diagnostic_item, match_type};
-use clippy_utils::{get_parent_expr, paths};
+use clippy_utils::ty::is_type_diagnostic_item;
 use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir as hir;
@@ -36,7 +36,7 @@ pub(super) fn check<'tcx>(
     } else if !is_mut && is_type_diagnostic_item(cx, expr_ty, sym::hashmap_type) {
         needs_ref = true;
         "HashMap"
-    } else if !is_mut && match_type(cx, expr_ty, &paths::BTREEMAP) {
+    } else if !is_mut && is_type_diagnostic_item(cx, expr_ty, sym::BTreeMap) {
         needs_ref = true;
         "BTreeMap"
     } else {

clippy_lints/src/methods/iter_count.rs

@@ -1,8 +1,7 @@
 use super::utils::derefs_to_slice;
 use clippy_utils::diagnostics::span_lint_and_sugg;
-use clippy_utils::paths;
 use clippy_utils::source::snippet_with_applicability;
-use clippy_utils::ty::{is_type_diagnostic_item, match_type};
+use clippy_utils::ty::is_type_diagnostic_item;
 use rustc_errors::Applicability;
 use rustc_hir::Expr;
 use rustc_lint::LateContext;
@@ -22,13 +21,13 @@ pub(crate) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &Expr<'_>, recv: &'tcx E
         "HashSet"
     } else if is_type_diagnostic_item(cx, ty, sym::hashmap_type) {
         "HashMap"
-    } else if match_type(cx, ty, &paths::BTREEMAP) {
+    } else if is_type_diagnostic_item(cx, ty, sym::BTreeMap) {
         "BTreeMap"
-    } else if match_type(cx, ty, &paths::BTREESET) {
+    } else if is_type_diagnostic_item(cx, ty, sym::BTreeSet) {
         "BTreeSet"
-    } else if match_type(cx, ty, &paths::LINKED_LIST) {
+    } else if is_type_diagnostic_item(cx, ty, sym::LinkedList) {
         "LinkedList"
-    } else if match_type(cx, ty, &paths::BINARY_HEAP) {
+    } else if is_type_diagnostic_item(cx, ty, sym::BinaryHeap) {
         "BinaryHeap"
     } else {
         return;

clippy_lints/src/methods/or_fun_call.rs

@@ -2,7 +2,7 @@ use clippy_utils::diagnostics::span_lint_and_sugg;
 use clippy_utils::eager_or_lazy::is_lazyness_candidate;
 use clippy_utils::source::{snippet, snippet_with_applicability, snippet_with_macro_callsite};
 use clippy_utils::ty::{implements_trait, is_type_diagnostic_item, match_type};
-use clippy_utils::{contains_return, get_trait_def_id, last_path_segment, paths};
+use clippy_utils::{contains_return, last_path_segment, paths};
 use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir as hir;
@@ -41,7 +41,7 @@ pub(super) fn check<'tcx>(
             let path = last_path_segment(qpath).ident.name;
             if matches!(path, kw::Default | sym::new);
             let arg_ty = cx.typeck_results().expr_ty(arg);
-            if let Some(default_trait_id) = get_trait_def_id(cx, &paths::DEFAULT_TRAIT);
+            if let Some(default_trait_id) = cx.tcx.get_diagnostic_item(sym::Default);
             if implements_trait(cx, arg_ty, default_trait_id, &[]);
 
             then {

clippy_lints/src/mut_key.rs

@@ -1,11 +1,12 @@
 use clippy_utils::diagnostics::span_lint;
-use clippy_utils::{match_def_path, paths, trait_ref_of_method};
+use clippy_utils::trait_ref_of_method;
 use rustc_hir as hir;
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::ty::TypeFoldable;
 use rustc_middle::ty::{Adt, Array, RawPtr, Ref, Slice, Tuple, Ty, TypeAndMut};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::source_map::Span;
+use rustc_span::symbol::sym;
 use std::iter;
 
 declare_clippy_lint! {
@@ -99,9 +100,9 @@ fn check_sig<'tcx>(cx: &LateContext<'tcx>, item_hir_id: hir::HirId, decl: &hir::
 fn check_ty<'tcx>(cx: &LateContext<'tcx>, span: Span, ty: Ty<'tcx>) {
     let ty = ty.peel_refs();
     if let Adt(def, substs) = ty.kind() {
-        if [&paths::HASHMAP, &paths::BTREEMAP, &paths::HASHSET, &paths::BTREESET]
+        if [sym::hashmap_type, sym::BTreeMap, sym::hashset_type, sym::BTreeMap]
             .iter()
-            .any(|path| match_def_path(cx, def.did, &**path))
+            .any(|diag_item| cx.tcx.is_diagnostic_item(*diag_item, def.did))
             && is_mutable_type(cx, substs.type_at(0), span)
         {
             span_lint(cx, MUTABLE_KEY_TYPE, span, "mutable key type");

clippy_lints/src/needless_pass_by_value.rs

@@ -103,7 +103,6 @@ impl<'tcx> LateLintPass<'tcx> for NeedlessPassByValue {
         }
 
         // Allow `Borrow` or functions to be taken by value
-        let borrow_trait = need!(get_trait_def_id(cx, &paths::BORROW_TRAIT));
         let allowed_traits = [
             need!(cx.tcx.lang_items().fn_trait()),
             need!(cx.tcx.lang_items().fn_once_trait()),
@@ -167,7 +166,7 @@ impl<'tcx> LateLintPass<'tcx> for NeedlessPassByValue {
                 let preds = preds.iter().filter(|t| t.self_ty() == ty).collect::<Vec<_>>();
 
                 (
-                    preds.iter().any(|t| t.def_id() == borrow_trait),
+                    preds.iter().any(|t| cx.tcx.is_diagnostic_item(sym::Borrow, t.def_id())),
                     !preds.is_empty() && {
                         let ty_empty_region = cx.tcx.mk_imm_ref(cx.tcx.lifetimes.re_root_empty, ty);
                         preds.iter().all(|t| {

clippy_lints/src/new_without_default.rs

@@ -1,8 +1,7 @@
 use clippy_utils::diagnostics::span_lint_hir_and_then;
-use clippy_utils::paths;
+use clippy_utils::return_ty;
 use clippy_utils::source::snippet;
 use clippy_utils::sugg::DiagnosticBuilderExt;
-use clippy_utils::{get_trait_def_id, return_ty};
 use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir as hir;
@@ -105,7 +104,7 @@ impl<'tcx> LateLintPass<'tcx> for NewWithoutDefault {
                             let self_def_id = cx.tcx.hir().local_def_id(cx.tcx.hir().get_parent_item(id));
                             let self_ty = cx.tcx.type_of(self_def_id);
                             if TyS::same_type(self_ty, return_ty(cx, id));
-                            if let Some(default_trait_id) = get_trait_def_id(cx, &paths::DEFAULT_TRAIT);
+                            if let Some(default_trait_id) = cx.tcx.get_diagnostic_item(sym::Default);
                             then {
                                 if self.impling_types.is_none() {
                                     let mut impls = HirIdSet::default();

clippy_lints/src/ptr.rs

@@ -4,7 +4,7 @@ use clippy_utils::diagnostics::{span_lint, span_lint_and_sugg, span_lint_and_the
 use clippy_utils::ptr::get_spans;
 use clippy_utils::source::snippet_opt;
 use clippy_utils::ty::{is_type_diagnostic_item, match_type, walk_ptrs_hir_ty};
-use clippy_utils::{expr_path_res, is_lint_allowed, match_any_def_paths, paths};
+use clippy_utils::{expr_path_res, is_lint_allowed, match_any_diagnostic_items, paths};
 use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir::{
@@ -419,7 +419,7 @@ fn get_rptr_lm<'tcx>(ty: &'tcx Ty<'tcx>) -> Option<(&'tcx Lifetime, Mutability,
 fn is_null_path(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
     if let ExprKind::Call(pathexp, []) = expr.kind {
         expr_path_res(cx, pathexp).opt_def_id().map_or(false, |id| {
-            match_any_def_paths(cx, id, &[&paths::PTR_NULL, &paths::PTR_NULL_MUT]).is_some()
+            match_any_diagnostic_items(cx, id, &[sym::ptr_null, sym::ptr_null_mut]).is_some()
         })
     } else {
         false

clippy_lints/src/size_of_in_element_count.rs

@@ -67,7 +67,7 @@ fn get_pointee_ty_and_count_expr(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -
     const FUNCTIONS: [&[&str]; 8] = [
         &paths::PTR_COPY_NONOVERLAPPING,
         &paths::PTR_COPY,
-        &paths::WRITE_BYTES,
+        &paths::PTR_WRITE_BYTES,
         &paths::PTR_SWAP_NONOVERLAPPING,
         &paths::PTR_SLICE_FROM_RAW_PARTS,
         &paths::PTR_SLICE_FROM_RAW_PARTS_MUT,

clippy_lints/src/transmute/mod.rs

@@ -12,11 +12,12 @@ mod useless_transmute;
 mod utils;
 mod wrong_transmute;
 
-use clippy_utils::{in_constant, match_def_path, paths};
+use clippy_utils::in_constant;
 use if_chain::if_chain;
 use rustc_hir::{Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
+use rustc_span::symbol::sym;
 
 declare_clippy_lint! {
     /// **What it does:** Checks for transmutes that can't ever be correct on any
@@ -328,7 +329,7 @@ impl<'tcx> LateLintPass<'tcx> for Transmute {
             if let ExprKind::Call(path_expr, args) = e.kind;
             if let ExprKind::Path(ref qpath) = path_expr.kind;
             if let Some(def_id) = cx.qpath_res(qpath, path_expr.hir_id).opt_def_id();
-            if match_def_path(cx, def_id, &paths::TRANSMUTE);
+            if cx.tcx.is_diagnostic_item(sym::transmute, def_id);
             then {
                 // Avoid suggesting from/to bits and dereferencing raw pointers in const contexts.
                 // See https://github.com/rust-lang/rust/issues/73736 for progress on making them `const fn`.