1 #![feature(box_patterns)]
2 #![feature(in_band_lifetimes)]
3 #![feature(rustc_private)]
4 #![recursion_limit = "512"]
5 #![allow(clippy::missing_errors_doc, clippy::missing_panics_doc, clippy::must_use_candidate)]
7 // FIXME: switch to something more ergonomic here, once available.
8 // (Currently there is no way to opt into sysroot crates without `extern crate`.)
9 extern crate rustc_ast;
10 extern crate rustc_ast_pretty;
11 extern crate rustc_data_structures;
12 extern crate rustc_errors;
13 extern crate rustc_hir;
14 extern crate rustc_hir_pretty;
15 extern crate rustc_infer;
16 extern crate rustc_lexer;
17 extern crate rustc_lint;
18 extern crate rustc_middle;
19 extern crate rustc_mir;
20 extern crate rustc_session;
21 extern crate rustc_span;
22 extern crate rustc_target;
23 extern crate rustc_trait_selection;
24 extern crate rustc_typeck;
29 #[allow(clippy::module_name_repetitions)]
36 pub mod eager_or_lazy;
39 pub mod numeric_literal;
42 pub mod qualify_min_const_fn;
49 pub use self::attrs::*;
50 pub use self::hir_utils::{both, count_eq, eq_expr_value, over, SpanlessEq, SpanlessHash};
52 use std::collections::hash_map::Entry;
53 use std::hash::BuildHasherDefault;
55 use if_chain::if_chain;
56 use rustc_ast::ast::{self, Attribute, BorrowKind, LitKind};
57 use rustc_data_structures::fx::FxHashMap;
59 use rustc_hir::def::{CtorKind, CtorOf, DefKind, Res};
60 use rustc_hir::def_id::{DefId, LOCAL_CRATE};
61 use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor};
63 def, Arm, BindingAnnotation, Block, Body, Constness, Expr, ExprKind, FnDecl, GenericArgs, HirId, Impl, ImplItem,
64 ImplItemKind, Item, ItemKind, LangItem, MatchSource, Node, Param, Pat, PatKind, Path, PathSegment, QPath,
65 TraitItem, TraitItemKind, TraitRef, TyKind,
67 use rustc_lint::{LateContext, Level, Lint, LintContext};
68 use rustc_middle::hir::exports::Export;
69 use rustc_middle::hir::map::Map;
70 use rustc_middle::ty as rustc_ty;
71 use rustc_middle::ty::{layout::IntegerExt, DefIdTree, Ty, TyCtxt, TypeFoldable};
72 use rustc_semver::RustcVersion;
73 use rustc_session::Session;
74 use rustc_span::hygiene::{ExpnKind, MacroKind};
75 use rustc_span::source_map::original_sp;
77 use rustc_span::symbol::{kw, Symbol};
78 use rustc_span::{Span, DUMMY_SP};
79 use rustc_target::abi::Integer;
81 use crate::consts::{constant, Constant};
82 use crate::ty::is_recursively_primitive_type;
84 pub fn parse_msrv(msrv: &str, sess: Option<&Session>, span: Option<Span>) -> Option<RustcVersion> {
85 if let Ok(version) = RustcVersion::parse(msrv) {
87 } else if let Some(sess) = sess {
88 if let Some(span) = span {
89 sess.span_err(span, &format!("`{}` is not a valid Rust version", msrv));
95 pub fn meets_msrv(msrv: Option<&RustcVersion>, lint_msrv: &RustcVersion) -> bool {
96 msrv.map_or(true, |msrv| msrv.meets(*lint_msrv))
100 macro_rules! extract_msrv_attr {
102 extract_msrv_attr!(@LateContext, ());
105 extract_msrv_attr!(@EarlyContext);
107 (@$context:ident$(, $call:tt)?) => {
108 fn enter_lint_attrs(&mut self, cx: &rustc_lint::$context<'tcx>, attrs: &'tcx [rustc_ast::ast::Attribute]) {
109 use $crate::get_unique_inner_attr;
110 match get_unique_inner_attr(cx.sess$($call)?, attrs, "msrv") {
112 if let Some(msrv) = msrv_attr.value_str() {
113 self.msrv = $crate::parse_msrv(
115 Some(cx.sess$($call)?),
116 Some(msrv_attr.span),
119 cx.sess$($call)?.span_err(msrv_attr.span, "bad clippy attribute");
128 /// Returns `true` if the two spans come from differing expansions (i.e., one is
129 /// from a macro and one isn't).
131 pub fn differing_macro_contexts(lhs: Span, rhs: Span) -> bool {
132 rhs.ctxt() != lhs.ctxt()
135 /// If the given expression is a local binding, find the initializer expression.
136 /// If that initializer expression is another local binding, find its initializer again.
137 /// This process repeats as long as possible (but usually no more than once). Initializer
138 /// expressions with adjustments are ignored. If this is not desired, use [`find_binding_init`]
151 /// let def = abc + 2;
152 /// // ^^^^^^^ output
156 pub fn expr_or_init<'a, 'b, 'tcx: 'b>(cx: &LateContext<'tcx>, mut expr: &'a Expr<'b>) -> &'a Expr<'b> {
157 while let Some(init) = path_to_local(expr)
158 .and_then(|id| find_binding_init(cx, id))
159 .filter(|init| cx.typeck_results().expr_adjustments(init).is_empty())
166 /// Finds the initializer expression for a local binding. Returns `None` if the binding is mutable.
167 /// By only considering immutable bindings, we guarantee that the returned expression represents the
168 /// value of the binding wherever it is referenced.
170 /// Example: For `let x = 1`, if the `HirId` of `x` is provided, the `Expr` `1` is returned.
171 /// Note: If you have an expression that references a binding `x`, use `path_to_local` to get the
172 /// canonical binding `HirId`.
173 pub fn find_binding_init<'tcx>(cx: &LateContext<'tcx>, hir_id: HirId) -> Option<&'tcx Expr<'tcx>> {
174 let hir = cx.tcx.hir();
176 if let Some(Node::Binding(pat)) = hir.find(hir_id);
177 if matches!(pat.kind, PatKind::Binding(BindingAnnotation::Unannotated, ..));
178 let parent = hir.get_parent_node(hir_id);
179 if let Some(Node::Local(local)) = hir.find(parent);
187 /// Returns `true` if the given `NodeId` is inside a constant context
192 /// if in_constant(cx, expr.hir_id) {
196 pub fn in_constant(cx: &LateContext<'_>, id: HirId) -> bool {
197 let parent_id = cx.tcx.hir().get_parent_item(id);
198 match cx.tcx.hir().get(parent_id) {
200 kind: ItemKind::Const(..) | ItemKind::Static(..),
203 | Node::TraitItem(&TraitItem {
204 kind: TraitItemKind::Const(..),
207 | Node::ImplItem(&ImplItem {
208 kind: ImplItemKind::Const(..),
211 | Node::AnonConst(_) => true,
213 kind: ItemKind::Fn(ref sig, ..),
216 | Node::ImplItem(&ImplItem {
217 kind: ImplItemKind::Fn(ref sig, _),
219 }) => sig.header.constness == Constness::Const,
224 /// Returns `true` if this `span` was expanded by any macro.
226 pub fn in_macro(span: Span) -> bool {
227 if span.from_expansion() {
228 !matches!(span.ctxt().outer_expn_data().kind, ExpnKind::Desugaring(..))
234 /// Checks if given pattern is a wildcard (`_`)
235 pub fn is_wild<'tcx>(pat: &impl std::ops::Deref<Target = Pat<'tcx>>) -> bool {
236 matches!(pat.kind, PatKind::Wild)
239 /// Checks if the first type parameter is a lang item.
240 pub fn is_ty_param_lang_item(cx: &LateContext<'_>, qpath: &QPath<'tcx>, item: LangItem) -> Option<&'tcx hir::Ty<'tcx>> {
241 let ty = get_qpath_generic_tys(qpath).next()?;
243 if let TyKind::Path(qpath) = &ty.kind {
244 cx.qpath_res(qpath, ty.hir_id)
246 .map_or(false, |id| {
247 cx.tcx.lang_items().require(item).map_or(false, |lang_id| id == lang_id)
255 /// Checks if the first type parameter is a diagnostic item.
256 pub fn is_ty_param_diagnostic_item(
257 cx: &LateContext<'_>,
260 ) -> Option<&'tcx hir::Ty<'tcx>> {
261 let ty = get_qpath_generic_tys(qpath).next()?;
263 if let TyKind::Path(qpath) = &ty.kind {
264 cx.qpath_res(qpath, ty.hir_id)
266 .map_or(false, |id| cx.tcx.is_diagnostic_item(item, id))
273 /// Checks if the method call given in `expr` belongs to the given trait.
274 /// This is a deprecated function, consider using [`is_trait_method`].
275 pub fn match_trait_method(cx: &LateContext<'_>, expr: &Expr<'_>, path: &[&str]) -> bool {
276 let def_id = cx.typeck_results().type_dependent_def_id(expr.hir_id).unwrap();
277 let trt_id = cx.tcx.trait_of_item(def_id);
278 trt_id.map_or(false, |trt_id| match_def_path(cx, trt_id, path))
281 /// Checks if the method call given in `def_id` belongs to a trait or other container with a given
283 pub fn is_diagnostic_assoc_item(cx: &LateContext<'_>, def_id: DefId, diag_item: Symbol) -> bool {
285 .opt_associated_item(def_id)
286 .and_then(|associated_item| match associated_item.container {
287 rustc_ty::TraitContainer(assoc_def_id) => Some(assoc_def_id),
288 rustc_ty::ImplContainer(assoc_def_id) => match cx.tcx.type_of(assoc_def_id).kind() {
289 rustc_ty::Adt(adt, _) => Some(adt.did),
290 rustc_ty::Slice(_) => cx.tcx.get_diagnostic_item(sym::slice), // this isn't perfect but it works
294 .map_or(false, |assoc_def_id| cx.tcx.is_diagnostic_item(diag_item, assoc_def_id))
297 /// Checks if the method call given in `expr` belongs to the given trait.
298 pub fn is_trait_method(cx: &LateContext<'_>, expr: &Expr<'_>, diag_item: Symbol) -> bool {
300 .type_dependent_def_id(expr.hir_id)
301 .map_or(false, |did| is_diagnostic_assoc_item(cx, did, diag_item))
304 /// Checks if an expression references a variable of the given name.
305 pub fn match_var(expr: &Expr<'_>, var: Symbol) -> bool {
306 if let ExprKind::Path(QPath::Resolved(None, ref path)) = expr.kind {
307 if let [p] = path.segments {
308 return p.ident.name == var;
314 pub fn last_path_segment<'tcx>(path: &QPath<'tcx>) -> &'tcx PathSegment<'tcx> {
316 QPath::Resolved(_, ref path) => path.segments.last().expect("A path must have at least one segment"),
317 QPath::TypeRelative(_, ref seg) => seg,
318 QPath::LangItem(..) => panic!("last_path_segment: lang item has no path segments"),
322 pub fn get_qpath_generics(path: &QPath<'tcx>) -> Option<&'tcx GenericArgs<'tcx>> {
324 QPath::Resolved(_, p) => p.segments.last().and_then(|s| s.args),
325 QPath::TypeRelative(_, s) => s.args,
326 QPath::LangItem(..) => None,
330 pub fn get_qpath_generic_tys(path: &QPath<'tcx>) -> impl Iterator<Item = &'tcx hir::Ty<'tcx>> {
331 get_qpath_generics(path)
332 .map_or([].as_ref(), |a| a.args)
335 if let hir::GenericArg::Type(ty) = a {
343 pub fn single_segment_path<'tcx>(path: &QPath<'tcx>) -> Option<&'tcx PathSegment<'tcx>> {
345 QPath::Resolved(_, ref path) => path.segments.get(0),
346 QPath::TypeRelative(_, ref seg) => Some(seg),
347 QPath::LangItem(..) => None,
351 /// THIS METHOD IS DEPRECATED and will eventually be removed since it does not match against the
352 /// entire path or resolved `DefId`. Prefer using `match_def_path`. Consider getting a `DefId` from
353 /// `QPath::Resolved.1.res.opt_def_id()`.
355 /// Matches a `QPath` against a slice of segment string literals.
357 /// There is also `match_path` if you are dealing with a `rustc_hir::Path` instead of a
358 /// `rustc_hir::QPath`.
362 /// match_qpath(path, &["std", "rt", "begin_unwind"])
364 pub fn match_qpath(path: &QPath<'_>, segments: &[&str]) -> bool {
366 QPath::Resolved(_, ref path) => match_path(path, segments),
367 QPath::TypeRelative(ref ty, ref segment) => match ty.kind {
368 TyKind::Path(ref inner_path) => {
369 if let [prefix @ .., end] = segments {
370 if match_qpath(inner_path, prefix) {
371 return segment.ident.name.as_str() == *end;
378 QPath::LangItem(..) => false,
382 /// THIS METHOD IS DEPRECATED and will eventually be removed since it does not match against the
383 /// entire path or resolved `DefId`. Prefer using `match_def_path`. Consider getting a `DefId` from
384 /// `QPath::Resolved.1.res.opt_def_id()`.
386 /// Matches a `Path` against a slice of segment string literals.
388 /// There is also `match_qpath` if you are dealing with a `rustc_hir::QPath` instead of a
389 /// `rustc_hir::Path`.
394 /// if match_path(&trait_ref.path, &paths::HASH) {
395 /// // This is the `std::hash::Hash` trait.
398 /// if match_path(ty_path, &["rustc", "lint", "Lint"]) {
399 /// // This is a `rustc_middle::lint::Lint`.
402 pub fn match_path(path: &Path<'_>, segments: &[&str]) -> bool {
406 .zip(segments.iter().rev())
407 .all(|(a, b)| a.ident.name.as_str() == *b)
410 /// Matches a `Path` against a slice of segment string literals, e.g.
414 /// match_path_ast(path, &["std", "rt", "begin_unwind"])
416 pub fn match_path_ast(path: &ast::Path, segments: &[&str]) -> bool {
420 .zip(segments.iter().rev())
421 .all(|(a, b)| a.ident.name.as_str() == *b)
424 /// If the expression is a path to a local, returns the canonical `HirId` of the local.
425 pub fn path_to_local(expr: &Expr<'_>) -> Option<HirId> {
426 if let ExprKind::Path(QPath::Resolved(None, ref path)) = expr.kind {
427 if let Res::Local(id) = path.res {
434 /// Returns true if the expression is a path to a local with the specified `HirId`.
435 /// Use this function to see if an expression matches a function argument or a match binding.
436 pub fn path_to_local_id(expr: &Expr<'_>, id: HirId) -> bool {
437 path_to_local(expr) == Some(id)
440 /// Gets the definition associated to a path.
441 #[allow(clippy::shadow_unrelated)] // false positive #6563
442 pub fn path_to_res(cx: &LateContext<'_>, path: &[&str]) -> Res {
443 macro_rules! try_res {
447 None => return Res::Err,
451 fn item_child_by_name<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId, name: &str) -> Option<&'tcx Export<HirId>> {
452 tcx.item_children(def_id)
454 .find(|item| item.ident.name.as_str() == name)
457 let (krate, first, path) = match *path {
458 [krate, first, ref path @ ..] => (krate, first, path),
459 _ => return Res::Err,
462 let crates = tcx.crates();
463 let krate = try_res!(crates.iter().find(|&&num| tcx.crate_name(num).as_str() == krate));
464 let first = try_res!(item_child_by_name(tcx, krate.as_def_id(), first));
468 // `get_def_path` seems to generate these empty segments for extern blocks.
469 // We can just ignore them.
470 .filter(|segment| !segment.is_empty())
471 // for each segment, find the child item
472 .try_fold(first, |item, segment| {
473 let def_id = item.res.def_id();
474 if let Some(item) = item_child_by_name(tcx, def_id, segment) {
476 } else if matches!(item.res, Res::Def(DefKind::Enum | DefKind::Struct, _)) {
477 // it is not a child item so check inherent impl items
478 tcx.inherent_impls(def_id)
480 .find_map(|&impl_def_id| item_child_by_name(tcx, impl_def_id, segment))
488 /// Convenience function to get the `DefId` of a trait by path.
489 /// It could be a trait or trait alias.
490 pub fn get_trait_def_id(cx: &LateContext<'_>, path: &[&str]) -> Option<DefId> {
491 match path_to_res(cx, path) {
492 Res::Def(DefKind::Trait | DefKind::TraitAlias, trait_id) => Some(trait_id),
497 /// Gets the `hir::TraitRef` of the trait the given method is implemented for.
499 /// Use this if you want to find the `TraitRef` of the `Add` trait in this example:
502 /// struct Point(isize, isize);
504 /// impl std::ops::Add for Point {
505 /// type Output = Self;
507 /// fn add(self, other: Self) -> Self {
512 pub fn trait_ref_of_method<'tcx>(cx: &LateContext<'tcx>, hir_id: HirId) -> Option<&'tcx TraitRef<'tcx>> {
513 // Get the implemented trait for the current function
514 let parent_impl = cx.tcx.hir().get_parent_item(hir_id);
516 if parent_impl != hir::CRATE_HIR_ID;
517 if let hir::Node::Item(item) = cx.tcx.hir().get(parent_impl);
518 if let hir::ItemKind::Impl(impl_) = &item.kind;
519 then { return impl_.of_trait.as_ref(); }
524 /// Returns the method names and argument list of nested method call expressions that make up
525 /// `expr`. method/span lists are sorted with the most recent call first.
526 pub fn method_calls<'tcx>(
527 expr: &'tcx Expr<'tcx>,
529 ) -> (Vec<Symbol>, Vec<&'tcx [Expr<'tcx>]>, Vec<Span>) {
530 let mut method_names = Vec::with_capacity(max_depth);
531 let mut arg_lists = Vec::with_capacity(max_depth);
532 let mut spans = Vec::with_capacity(max_depth);
534 let mut current = expr;
535 for _ in 0..max_depth {
536 if let ExprKind::MethodCall(path, span, args, _) = ¤t.kind {
537 if args.iter().any(|e| e.span.from_expansion()) {
540 method_names.push(path.ident.name);
541 arg_lists.push(&**args);
549 (method_names, arg_lists, spans)
552 /// Matches an `Expr` against a chain of methods, and return the matched `Expr`s.
554 /// For example, if `expr` represents the `.baz()` in `foo.bar().baz()`,
555 /// `method_chain_args(expr, &["bar", "baz"])` will return a `Vec`
556 /// containing the `Expr`s for
557 /// `.bar()` and `.baz()`
558 pub fn method_chain_args<'a>(expr: &'a Expr<'_>, methods: &[&str]) -> Option<Vec<&'a [Expr<'a>]>> {
559 let mut current = expr;
560 let mut matched = Vec::with_capacity(methods.len());
561 for method_name in methods.iter().rev() {
562 // method chains are stored last -> first
563 if let ExprKind::MethodCall(ref path, _, ref args, _) = current.kind {
564 if path.ident.name.as_str() == *method_name {
565 if args.iter().any(|e| e.span.from_expansion()) {
568 matched.push(&**args); // build up `matched` backwards
569 current = &args[0] // go to parent expression
577 // Reverse `matched` so that it is in the same order as `methods`.
582 /// Returns `true` if the provided `def_id` is an entrypoint to a program.
583 pub fn is_entrypoint_fn(cx: &LateContext<'_>, def_id: DefId) -> bool {
585 .entry_fn(LOCAL_CRATE)
586 .map_or(false, |(entry_fn_def_id, _)| def_id == entry_fn_def_id.to_def_id())
589 /// Returns `true` if the expression is in the program's `#[panic_handler]`.
590 pub fn is_in_panic_handler(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
591 let parent = cx.tcx.hir().get_parent_item(e.hir_id);
592 let def_id = cx.tcx.hir().local_def_id(parent).to_def_id();
593 Some(def_id) == cx.tcx.lang_items().panic_impl()
596 /// Gets the name of the item the expression is in, if available.
597 pub fn get_item_name(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<Symbol> {
598 let parent_id = cx.tcx.hir().get_parent_item(expr.hir_id);
599 match cx.tcx.hir().find(parent_id) {
601 Node::Item(Item { ident, .. })
602 | Node::TraitItem(TraitItem { ident, .. })
603 | Node::ImplItem(ImplItem { ident, .. }),
604 ) => Some(ident.name),
609 /// Gets the name of a `Pat`, if any.
610 pub fn get_pat_name(pat: &Pat<'_>) -> Option<Symbol> {
612 PatKind::Binding(.., ref spname, _) => Some(spname.name),
613 PatKind::Path(ref qpath) => single_segment_path(qpath).map(|ps| ps.ident.name),
614 PatKind::Box(ref p) | PatKind::Ref(ref p, _) => get_pat_name(&*p),
619 pub struct ContainsName {
624 impl<'tcx> Visitor<'tcx> for ContainsName {
625 type Map = Map<'tcx>;
627 fn visit_name(&mut self, _: Span, name: Symbol) {
628 if self.name == name {
632 fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
633 NestedVisitorMap::None
637 /// Checks if an `Expr` contains a certain name.
638 pub fn contains_name(name: Symbol, expr: &Expr<'_>) -> bool {
639 let mut cn = ContainsName { name, result: false };
644 /// Returns `true` if `expr` contains a return expression
645 pub fn contains_return(expr: &hir::Expr<'_>) -> bool {
646 struct RetCallFinder {
650 impl<'tcx> hir::intravisit::Visitor<'tcx> for RetCallFinder {
651 type Map = Map<'tcx>;
653 fn visit_expr(&mut self, expr: &'tcx hir::Expr<'_>) {
657 if let hir::ExprKind::Ret(..) = &expr.kind {
660 hir::intravisit::walk_expr(self, expr);
664 fn nested_visit_map(&mut self) -> hir::intravisit::NestedVisitorMap<Self::Map> {
665 hir::intravisit::NestedVisitorMap::None
669 let mut visitor = RetCallFinder { found: false };
670 visitor.visit_expr(expr);
674 struct FindMacroCalls<'a, 'b> {
675 names: &'a [&'b str],
679 impl<'a, 'b, 'tcx> Visitor<'tcx> for FindMacroCalls<'a, 'b> {
680 type Map = Map<'tcx>;
682 fn visit_expr(&mut self, expr: &'tcx Expr<'_>) {
683 if self.names.iter().any(|fun| is_expn_of(expr.span, fun).is_some()) {
684 self.result.push(expr.span);
686 // and check sub-expressions
687 intravisit::walk_expr(self, expr);
690 fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
691 NestedVisitorMap::None
695 /// Finds calls of the specified macros in a function body.
696 pub fn find_macro_calls(names: &[&str], body: &Body<'_>) -> Vec<Span> {
697 let mut fmc = FindMacroCalls {
701 fmc.visit_expr(&body.value);
705 /// Extends the span to the beginning of the spans line, incl. whitespaces.
710 /// // will be converted to
712 /// // ^^^^^^^^^^^^^^
714 fn line_span<T: LintContext>(cx: &T, span: Span) -> Span {
715 let span = original_sp(span, DUMMY_SP);
716 let source_map_and_line = cx.sess().source_map().lookup_line(span.lo()).unwrap();
717 let line_no = source_map_and_line.line;
718 let line_start = source_map_and_line.sf.lines[line_no];
719 Span::new(line_start, span.hi(), span.ctxt())
722 /// Gets the parent node, if any.
723 pub fn get_parent_node(tcx: TyCtxt<'_>, id: HirId) -> Option<Node<'_>> {
724 tcx.hir().parent_iter(id).next().map(|(_, node)| node)
727 /// Gets the parent expression, if any –- this is useful to constrain a lint.
728 pub fn get_parent_expr<'tcx>(cx: &LateContext<'tcx>, e: &Expr<'_>) -> Option<&'tcx Expr<'tcx>> {
729 match get_parent_node(cx.tcx, e.hir_id) {
730 Some(Node::Expr(parent)) => Some(parent),
735 pub fn get_enclosing_block<'tcx>(cx: &LateContext<'tcx>, hir_id: HirId) -> Option<&'tcx Block<'tcx>> {
736 let map = &cx.tcx.hir();
737 let enclosing_node = map
738 .get_enclosing_scope(hir_id)
739 .and_then(|enclosing_id| map.find(enclosing_id));
740 enclosing_node.and_then(|node| match node {
741 Node::Block(block) => Some(block),
743 kind: ItemKind::Fn(_, _, eid),
746 | Node::ImplItem(&ImplItem {
747 kind: ImplItemKind::Fn(_, eid),
749 }) => match cx.tcx.hir().body(eid).value.kind {
750 ExprKind::Block(ref block, _) => Some(block),
757 /// Gets the parent node if it's an impl block.
758 pub fn get_parent_as_impl(tcx: TyCtxt<'_>, id: HirId) -> Option<&Impl<'_>> {
760 match map.parent_iter(id).next() {
764 kind: ItemKind::Impl(imp),
772 /// Checks if the given expression is the else clause of either an `if` or `if let` expression.
773 pub fn is_else_clause(tcx: TyCtxt<'_>, expr: &Expr<'_>) -> bool {
775 let mut iter = map.parent_iter(expr.hir_id);
777 Some((arm_id, Node::Arm(..))) => matches!(
782 kind: ExprKind::Match(_, [_, else_arm], MatchSource::IfLetDesugar { .. }),
786 if else_arm.hir_id == arm_id
791 kind: ExprKind::If(_, _, Some(else_expr)),
794 )) => else_expr.hir_id == expr.hir_id,
799 /// Checks whether the given expression is a constant integer of the given value.
800 /// unlike `is_integer_literal`, this version does const folding
801 pub fn is_integer_const(cx: &LateContext<'_>, e: &Expr<'_>, value: u128) -> bool {
802 if is_integer_literal(e, value) {
805 let map = cx.tcx.hir();
806 let parent_item = map.get_parent_item(e.hir_id);
807 if let Some((Constant::Int(v), _)) = map
808 .maybe_body_owned_by(parent_item)
809 .and_then(|body_id| constant(cx, cx.tcx.typeck_body(body_id), e))
817 /// Checks whether the given expression is a constant literal of the given value.
818 pub fn is_integer_literal(expr: &Expr<'_>, value: u128) -> bool {
819 // FIXME: use constant folding
820 if let ExprKind::Lit(ref spanned) = expr.kind {
821 if let LitKind::Int(v, _) = spanned.node {
828 /// Returns `true` if the given `Expr` has been coerced before.
830 /// Examples of coercions can be found in the Nomicon at
831 /// <https://doc.rust-lang.org/nomicon/coercions.html>.
833 /// See `rustc_middle::ty::adjustment::Adjustment` and `rustc_typeck::check::coercion` for more
834 /// information on adjustments and coercions.
835 pub fn is_adjusted(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
836 cx.typeck_results().adjustments().get(e.hir_id).is_some()
839 /// Returns the pre-expansion span if is this comes from an expansion of the
841 /// See also `is_direct_expn_of`.
843 pub fn is_expn_of(mut span: Span, name: &str) -> Option<Span> {
845 if span.from_expansion() {
846 let data = span.ctxt().outer_expn_data();
847 let new_span = data.call_site;
849 if let ExpnKind::Macro(MacroKind::Bang, mac_name) = data.kind {
850 if mac_name.as_str() == name {
851 return Some(new_span);
862 /// Returns the pre-expansion span if the span directly comes from an expansion
863 /// of the macro `name`.
864 /// The difference with `is_expn_of` is that in
868 /// `42` is considered expanded from `foo!` and `bar!` by `is_expn_of` but only
870 /// `is_direct_expn_of`.
872 pub fn is_direct_expn_of(span: Span, name: &str) -> Option<Span> {
873 if span.from_expansion() {
874 let data = span.ctxt().outer_expn_data();
875 let new_span = data.call_site;
877 if let ExpnKind::Macro(MacroKind::Bang, mac_name) = data.kind {
878 if mac_name.as_str() == name {
879 return Some(new_span);
887 /// Convenience function to get the return type of a function.
888 pub fn return_ty<'tcx>(cx: &LateContext<'tcx>, fn_item: hir::HirId) -> Ty<'tcx> {
889 let fn_def_id = cx.tcx.hir().local_def_id(fn_item);
890 let ret_ty = cx.tcx.fn_sig(fn_def_id).output();
891 cx.tcx.erase_late_bound_regions(ret_ty)
894 /// Checks if an expression is constructing a tuple-like enum variant or struct
895 pub fn is_ctor_or_promotable_const_function(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
896 if let ExprKind::Call(ref fun, _) = expr.kind {
897 if let ExprKind::Path(ref qp) = fun.kind {
898 let res = cx.qpath_res(qp, fun.hir_id);
900 def::Res::Def(DefKind::Variant | DefKind::Ctor(..), ..) => true,
901 def::Res::Def(_, def_id) => cx.tcx.is_promotable_const_fn(def_id),
909 /// Returns `true` if a pattern is refutable.
910 // TODO: should be implemented using rustc/mir_build/thir machinery
911 pub fn is_refutable(cx: &LateContext<'_>, pat: &Pat<'_>) -> bool {
912 fn is_enum_variant(cx: &LateContext<'_>, qpath: &QPath<'_>, id: HirId) -> bool {
914 cx.qpath_res(qpath, id),
915 def::Res::Def(DefKind::Variant, ..) | Res::Def(DefKind::Ctor(def::CtorOf::Variant, _), _)
919 fn are_refutable<'a, I: Iterator<Item = &'a Pat<'a>>>(cx: &LateContext<'_>, mut i: I) -> bool {
920 i.any(|pat| is_refutable(cx, pat))
924 PatKind::Wild => false,
925 PatKind::Binding(_, _, _, pat) => pat.map_or(false, |pat| is_refutable(cx, pat)),
926 PatKind::Box(ref pat) | PatKind::Ref(ref pat, _) => is_refutable(cx, pat),
927 PatKind::Lit(..) | PatKind::Range(..) => true,
928 PatKind::Path(ref qpath) => is_enum_variant(cx, qpath, pat.hir_id),
929 PatKind::Or(ref pats) => {
930 // TODO: should be the honest check, that pats is exhaustive set
931 are_refutable(cx, pats.iter().map(|pat| &**pat))
933 PatKind::Tuple(ref pats, _) => are_refutable(cx, pats.iter().map(|pat| &**pat)),
934 PatKind::Struct(ref qpath, ref fields, _) => {
935 is_enum_variant(cx, qpath, pat.hir_id) || are_refutable(cx, fields.iter().map(|field| &*field.pat))
937 PatKind::TupleStruct(ref qpath, ref pats, _) => {
938 is_enum_variant(cx, qpath, pat.hir_id) || are_refutable(cx, pats.iter().map(|pat| &**pat))
940 PatKind::Slice(ref head, ref middle, ref tail) => {
941 match &cx.typeck_results().node_type(pat.hir_id).kind() {
942 rustc_ty::Slice(..) => {
943 // [..] is the only irrefutable slice pattern.
944 !head.is_empty() || middle.is_none() || !tail.is_empty()
946 rustc_ty::Array(..) => {
947 are_refutable(cx, head.iter().chain(middle).chain(tail.iter()).map(|pat| &**pat))
958 /// If the pattern is an `or` pattern, call the function once for each sub pattern. Otherwise, call
959 /// the function once on the given pattern.
960 pub fn recurse_or_patterns<'tcx, F: FnMut(&'tcx Pat<'tcx>)>(pat: &'tcx Pat<'tcx>, mut f: F) {
961 if let PatKind::Or(pats) = pat.kind {
962 pats.iter().cloned().for_each(f)
968 /// Checks for the `#[automatically_derived]` attribute all `#[derive]`d
969 /// implementations have.
970 pub fn is_automatically_derived(attrs: &[ast::Attribute]) -> bool {
971 attrs.iter().any(|attr| attr.has_name(sym::automatically_derived))
974 /// Remove blocks around an expression.
976 /// Ie. `x`, `{ x }` and `{{{{ x }}}}` all give `x`. `{ x; y }` and `{}` return
978 pub fn remove_blocks<'tcx>(mut expr: &'tcx Expr<'tcx>) -> &'tcx Expr<'tcx> {
979 while let ExprKind::Block(ref block, ..) = expr.kind {
980 match (block.stmts.is_empty(), block.expr.as_ref()) {
981 (true, Some(e)) => expr = e,
988 pub fn is_self(slf: &Param<'_>) -> bool {
989 if let PatKind::Binding(.., name, _) = slf.pat.kind {
990 name.name == kw::SelfLower
996 pub fn is_self_ty(slf: &hir::Ty<'_>) -> bool {
998 if let TyKind::Path(QPath::Resolved(None, ref path)) = slf.kind;
999 if let Res::SelfTy(..) = path.res;
1007 pub fn iter_input_pats<'tcx>(decl: &FnDecl<'_>, body: &'tcx Body<'_>) -> impl Iterator<Item = &'tcx Param<'tcx>> {
1008 (0..decl.inputs.len()).map(move |i| &body.params[i])
1011 /// Checks if a given expression is a match expression expanded from the `?`
1012 /// operator or the `try` macro.
1013 pub fn is_try<'tcx>(expr: &'tcx Expr<'tcx>) -> Option<&'tcx Expr<'tcx>> {
1014 fn is_ok(arm: &Arm<'_>) -> bool {
1016 if let PatKind::TupleStruct(ref path, ref pat, None) = arm.pat.kind;
1017 if match_qpath(path, &paths::RESULT_OK[1..]);
1018 if let PatKind::Binding(_, hir_id, _, None) = pat[0].kind;
1019 if path_to_local_id(arm.body, hir_id);
1027 fn is_err(arm: &Arm<'_>) -> bool {
1028 if let PatKind::TupleStruct(ref path, _, _) = arm.pat.kind {
1029 match_qpath(path, &paths::RESULT_ERR[1..])
1035 if let ExprKind::Match(_, ref arms, ref source) = expr.kind {
1036 // desugared from a `?` operator
1037 if let MatchSource::TryDesugar = *source {
1043 if arms[0].guard.is_none();
1044 if arms[1].guard.is_none();
1045 if (is_ok(&arms[0]) && is_err(&arms[1])) ||
1046 (is_ok(&arms[1]) && is_err(&arms[0]));
1056 /// Returns `true` if the lint is allowed in the current context
1058 /// Useful for skipping long running code when it's unnecessary
1059 pub fn is_allowed(cx: &LateContext<'_>, lint: &'static Lint, id: HirId) -> bool {
1060 cx.tcx.lint_level_at_node(lint, id).0 == Level::Allow
1063 pub fn strip_pat_refs<'hir>(mut pat: &'hir Pat<'hir>) -> &'hir Pat<'hir> {
1064 while let PatKind::Ref(subpat, _) = pat.kind {
1070 pub fn int_bits(tcx: TyCtxt<'_>, ity: rustc_ty::IntTy) -> u64 {
1071 Integer::from_int_ty(&tcx, ity).size().bits()
1074 #[allow(clippy::cast_possible_wrap)]
1075 /// Turn a constant int byte representation into an i128
1076 pub fn sext(tcx: TyCtxt<'_>, u: u128, ity: rustc_ty::IntTy) -> i128 {
1077 let amt = 128 - int_bits(tcx, ity);
1078 ((u as i128) << amt) >> amt
1081 #[allow(clippy::cast_sign_loss)]
1082 /// clip unused bytes
1083 pub fn unsext(tcx: TyCtxt<'_>, u: i128, ity: rustc_ty::IntTy) -> u128 {
1084 let amt = 128 - int_bits(tcx, ity);
1085 ((u as u128) << amt) >> amt
1088 /// clip unused bytes
1089 pub fn clip(tcx: TyCtxt<'_>, u: u128, ity: rustc_ty::UintTy) -> u128 {
1090 let bits = Integer::from_uint_ty(&tcx, ity).size().bits();
1091 let amt = 128 - bits;
1095 pub fn any_parent_is_automatically_derived(tcx: TyCtxt<'_>, node: HirId) -> bool {
1096 let map = &tcx.hir();
1097 let mut prev_enclosing_node = None;
1098 let mut enclosing_node = node;
1099 while Some(enclosing_node) != prev_enclosing_node {
1100 if is_automatically_derived(map.attrs(enclosing_node)) {
1103 prev_enclosing_node = Some(enclosing_node);
1104 enclosing_node = map.get_parent_item(enclosing_node);
1109 /// Matches a function call with the given path and returns the arguments.
1114 /// if let Some(args) = match_function_call(cx, cmp_max_call, &paths::CMP_MAX);
1116 pub fn match_function_call<'tcx>(
1117 cx: &LateContext<'tcx>,
1118 expr: &'tcx Expr<'_>,
1120 ) -> Option<&'tcx [Expr<'tcx>]> {
1122 if let ExprKind::Call(ref fun, ref args) = expr.kind;
1123 if let ExprKind::Path(ref qpath) = fun.kind;
1124 if let Some(fun_def_id) = cx.qpath_res(qpath, fun.hir_id).opt_def_id();
1125 if match_def_path(cx, fun_def_id, path);
1133 pub fn match_def_path<'tcx>(cx: &LateContext<'tcx>, did: DefId, syms: &[&str]) -> bool {
1134 // We have to convert `syms` to `&[Symbol]` here because rustc's `match_def_path`
1135 // accepts only that. We should probably move to Symbols in Clippy as well.
1136 let syms = syms.iter().map(|p| Symbol::intern(p)).collect::<Vec<Symbol>>();
1137 cx.match_def_path(did, &syms)
1140 pub fn match_panic_call<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> Option<&'tcx [Expr<'tcx>]> {
1141 match_function_call(cx, expr, &paths::BEGIN_PANIC)
1142 .or_else(|| match_function_call(cx, expr, &paths::BEGIN_PANIC_FMT))
1143 .or_else(|| match_function_call(cx, expr, &paths::PANIC_ANY))
1144 .or_else(|| match_function_call(cx, expr, &paths::PANICKING_PANIC))
1145 .or_else(|| match_function_call(cx, expr, &paths::PANICKING_PANIC_FMT))
1146 .or_else(|| match_function_call(cx, expr, &paths::PANICKING_PANIC_STR))
1149 pub fn match_panic_def_id(cx: &LateContext<'_>, did: DefId) -> bool {
1150 match_def_path(cx, did, &paths::BEGIN_PANIC)
1151 || match_def_path(cx, did, &paths::BEGIN_PANIC_FMT)
1152 || match_def_path(cx, did, &paths::PANIC_ANY)
1153 || match_def_path(cx, did, &paths::PANICKING_PANIC)
1154 || match_def_path(cx, did, &paths::PANICKING_PANIC_FMT)
1155 || match_def_path(cx, did, &paths::PANICKING_PANIC_STR)
1158 /// Returns the list of condition expressions and the list of blocks in a
1159 /// sequence of `if/else`.
1160 /// E.g., this returns `([a, b], [c, d, e])` for the expression
1161 /// `if a { c } else if b { d } else { e }`.
1162 pub fn if_sequence<'tcx>(mut expr: &'tcx Expr<'tcx>) -> (Vec<&'tcx Expr<'tcx>>, Vec<&'tcx Block<'tcx>>) {
1163 let mut conds = Vec::new();
1164 let mut blocks: Vec<&Block<'_>> = Vec::new();
1166 while let ExprKind::If(ref cond, ref then_expr, ref else_expr) = expr.kind {
1167 conds.push(&**cond);
1168 if let ExprKind::Block(ref block, _) = then_expr.kind {
1171 panic!("ExprKind::If node is not an ExprKind::Block");
1174 if let Some(ref else_expr) = *else_expr {
1181 // final `else {..}`
1182 if !blocks.is_empty() {
1183 if let ExprKind::Block(ref block, _) = expr.kind {
1184 blocks.push(&**block);
1191 /// This function returns true if the given expression is the `else` or `if else` part of an if
1193 pub fn parent_node_is_if_expr(expr: &Expr<'_>, cx: &LateContext<'_>) -> bool {
1194 let map = cx.tcx.hir();
1195 let parent_id = map.get_parent_node(expr.hir_id);
1196 let parent_node = map.get(parent_id);
1200 kind: ExprKind::If(_, _, _),
1206 // Finds the `#[must_use]` attribute, if any
1207 pub fn must_use_attr(attrs: &[Attribute]) -> Option<&Attribute> {
1208 attrs.iter().find(|a| a.has_name(sym::must_use))
1211 // check if expr is calling method or function with #[must_use] attribute
1212 pub fn is_must_use_func_call(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
1213 let did = match expr.kind {
1214 ExprKind::Call(ref path, _) => if_chain! {
1215 if let ExprKind::Path(ref qpath) = path.kind;
1216 if let def::Res::Def(_, did) = cx.qpath_res(qpath, path.hir_id);
1223 ExprKind::MethodCall(_, _, _, _) => cx.typeck_results().type_dependent_def_id(expr.hir_id),
1227 did.map_or(false, |did| must_use_attr(&cx.tcx.get_attrs(did)).is_some())
1230 pub fn is_no_std_crate(cx: &LateContext<'_>) -> bool {
1231 cx.tcx.hir().attrs(hir::CRATE_HIR_ID).iter().any(|attr| {
1232 if let ast::AttrKind::Normal(ref attr, _) = attr.kind {
1233 attr.path == sym::no_std
1240 /// Check if parent of a hir node is a trait implementation block.
1241 /// For example, `f` in
1243 /// impl Trait for S {
1247 pub fn is_trait_impl_item(cx: &LateContext<'_>, hir_id: HirId) -> bool {
1248 if let Some(Node::Item(item)) = cx.tcx.hir().find(cx.tcx.hir().get_parent_node(hir_id)) {
1249 matches!(item.kind, ItemKind::Impl(hir::Impl { of_trait: Some(_), .. }))
1255 /// Check if it's even possible to satisfy the `where` clause for the item.
1257 /// `trivial_bounds` feature allows functions with unsatisfiable bounds, for example:
1260 /// fn foo() where i32: Iterator {
1261 /// for _ in 2i32 {}
1264 pub fn fn_has_unsatisfiable_preds(cx: &LateContext<'_>, did: DefId) -> bool {
1265 use rustc_trait_selection::traits;
1271 .filter_map(|(p, _)| if p.is_global() { Some(*p) } else { None });
1272 traits::impossible_predicates(
1274 traits::elaborate_predicates(cx.tcx, predicates)
1275 .map(|o| o.predicate)
1276 .collect::<Vec<_>>(),
1280 /// Returns the `DefId` of the callee if the given expression is a function or method call.
1281 pub fn fn_def_id(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<DefId> {
1283 ExprKind::MethodCall(..) => cx.typeck_results().type_dependent_def_id(expr.hir_id),
1286 kind: ExprKind::Path(qpath),
1287 hir_id: path_hir_id,
1291 ) => cx.typeck_results().qpath_res(qpath, *path_hir_id).opt_def_id(),
1296 /// This function checks if any of the lints in the slice is enabled for the provided `HirId`.
1297 /// A lint counts as enabled with any of the levels: `Level::Forbid` | `Level::Deny` | `Level::Warn`
1300 /// #[deny(clippy::YOUR_AWESOME_LINT)]
1301 /// println!("Hello, World!"); // <- Clippy code: run_lints(cx, &[YOUR_AWESOME_LINT], id) == true
1303 /// #[allow(clippy::YOUR_AWESOME_LINT)]
1304 /// println!("See you soon!"); // <- Clippy code: run_lints(cx, &[YOUR_AWESOME_LINT], id) == false
1306 pub fn run_lints(cx: &LateContext<'_>, lints: &[&'static Lint], id: HirId) -> bool {
1307 lints.iter().any(|lint| {
1309 cx.tcx.lint_level_at_node(lint, id),
1310 (Level::Forbid | Level::Deny | Level::Warn, _)
1315 /// Returns Option<String> where String is a textual representation of the type encapsulated in the
1316 /// slice iff the given expression is a slice of primitives (as defined in the
1317 /// `is_recursively_primitive_type` function) and None otherwise.
1318 pub fn is_slice_of_primitives(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<String> {
1319 let expr_type = cx.typeck_results().expr_ty_adjusted(expr);
1320 let expr_kind = expr_type.kind();
1321 let is_primitive = match expr_kind {
1322 rustc_ty::Slice(element_type) => is_recursively_primitive_type(element_type),
1323 rustc_ty::Ref(_, inner_ty, _) if matches!(inner_ty.kind(), &rustc_ty::Slice(_)) => {
1324 if let rustc_ty::Slice(element_type) = inner_ty.kind() {
1325 is_recursively_primitive_type(element_type)
1334 // if we have wrappers like Array, Slice or Tuple, print these
1335 // and get the type enclosed in the slice ref
1336 match expr_type.peel_refs().walk().nth(1).unwrap().expect_ty().kind() {
1337 rustc_ty::Slice(..) => return Some("slice".into()),
1338 rustc_ty::Array(..) => return Some("array".into()),
1339 rustc_ty::Tuple(..) => return Some("tuple".into()),
1341 // is_recursively_primitive_type() should have taken care
1342 // of the rest and we can rely on the type that is found
1343 let refs_peeled = expr_type.peel_refs();
1344 return Some(refs_peeled.walk().last().unwrap().to_string());
1351 /// returns list of all pairs (a, b) from `exprs` such that `eq(a, b)`
1352 /// `hash` must be comformed with `eq`
1353 pub fn search_same<T, Hash, Eq>(exprs: &[T], hash: Hash, eq: Eq) -> Vec<(&T, &T)>
1355 Hash: Fn(&T) -> u64,
1356 Eq: Fn(&T, &T) -> bool,
1358 if exprs.len() == 2 && eq(&exprs[0], &exprs[1]) {
1359 return vec![(&exprs[0], &exprs[1])];
1362 let mut match_expr_list: Vec<(&T, &T)> = Vec::new();
1364 let mut map: FxHashMap<_, Vec<&_>> =
1365 FxHashMap::with_capacity_and_hasher(exprs.len(), BuildHasherDefault::default());
1368 match map.entry(hash(expr)) {
1369 Entry::Occupied(mut o) => {
1372 match_expr_list.push((o, expr));
1375 o.get_mut().push(expr);
1377 Entry::Vacant(v) => {
1378 v.insert(vec![expr]);
1386 /// Peels off all references on the pattern. Returns the underlying pattern and the number of
1387 /// references removed.
1388 pub fn peel_hir_pat_refs(pat: &'a Pat<'a>) -> (&'a Pat<'a>, usize) {
1389 fn peel(pat: &'a Pat<'a>, count: usize) -> (&'a Pat<'a>, usize) {
1390 if let PatKind::Ref(pat, _) = pat.kind {
1391 peel(pat, count + 1)
1399 /// Peels off up to the given number of references on the expression. Returns the underlying
1400 /// expression and the number of references removed.
1401 pub fn peel_n_hir_expr_refs(expr: &'a Expr<'a>, count: usize) -> (&'a Expr<'a>, usize) {
1402 fn f(expr: &'a Expr<'a>, count: usize, target: usize) -> (&'a Expr<'a>, usize) {
1404 ExprKind::AddrOf(_, _, expr) if count != target => f(expr, count + 1, target),
1411 /// Peels off all references on the expression. Returns the underlying expression and the number of
1412 /// references removed.
1413 pub fn peel_hir_expr_refs(expr: &'a Expr<'a>) -> (&'a Expr<'a>, usize) {
1414 fn f(expr: &'a Expr<'a>, count: usize) -> (&'a Expr<'a>, usize) {
1416 ExprKind::AddrOf(BorrowKind::Ref, _, expr) => f(expr, count + 1),
1424 macro_rules! unwrap_cargo_metadata {
1425 ($cx: ident, $lint: ident, $deps: expr) => {{
1426 let mut command = cargo_metadata::MetadataCommand::new();
1431 match command.exec() {
1432 Ok(metadata) => metadata,
1434 span_lint($cx, $lint, DUMMY_SP, &format!("could not read cargo metadata: {}", err));
1441 pub fn is_hir_ty_cfg_dependant(cx: &LateContext<'_>, ty: &hir::Ty<'_>) -> bool {
1443 if let TyKind::Path(QPath::Resolved(_, path)) = ty.kind;
1444 if let Res::Def(_, def_id) = path.res;
1446 cx.tcx.has_attr(def_id, sym::cfg) || cx.tcx.has_attr(def_id, sym::cfg_attr)
1453 /// Check if the resolution of a given path is an `Ok` variant of `Result`.
1454 pub fn is_ok_ctor(cx: &LateContext<'_>, res: Res) -> bool {
1455 if let Some(ok_id) = cx.tcx.lang_items().result_ok_variant() {
1456 if let Res::Def(DefKind::Ctor(CtorOf::Variant, CtorKind::Fn), id) = res {
1457 if let Some(variant_id) = cx.tcx.parent(id) {
1458 return variant_id == ok_id;
1465 /// Check if the resolution of a given path is a `Some` variant of `Option`.
1466 pub fn is_some_ctor(cx: &LateContext<'_>, res: Res) -> bool {
1467 if let Some(some_id) = cx.tcx.lang_items().option_some_variant() {
1468 if let Res::Def(DefKind::Ctor(CtorOf::Variant, CtorKind::Fn), id) = res {
1469 if let Some(variant_id) = cx.tcx.parent(id) {
1470 return variant_id == some_id;