11 pub mod internal_lints;
16 pub use self::attrs::*;
17 pub use self::diagnostics::*;
18 pub use self::hir_utils::{SpanlessEq, SpanlessHash};
23 use if_chain::if_chain;
26 use rustc::hir::def::Def;
27 use rustc::hir::def_id::CrateNum;
28 use rustc::hir::def_id::{DefId, CRATE_DEF_INDEX, LOCAL_CRATE};
29 use rustc::hir::intravisit::{NestedVisitorMap, Visitor};
30 use rustc::hir::map::DisambiguatedDefPathData;
33 use rustc::lint::{LateContext, Level, Lint, LintContext};
37 layout::{self, IntegerExt},
41 use rustc_data_structures::sync::Lrc;
42 use rustc_errors::Applicability;
43 use syntax::ast::{self, LitKind};
45 use syntax::source_map::{Span, DUMMY_SP};
46 use syntax::symbol::{keywords, LocalInternedString, Symbol};
48 use crate::reexport::*;
50 /// Returns `true` if the two spans come from differing expansions (i.e., one is
51 /// from a macro and one isn't).
52 pub fn differing_macro_contexts(lhs: Span, rhs: Span) -> bool {
53 rhs.ctxt() != lhs.ctxt()
56 /// Returns `true` if the given `NodeId` is inside a constant context
61 /// if in_constant(cx, expr.id) {
65 pub fn in_constant(cx: &LateContext<'_, '_>, id: HirId) -> bool {
66 let parent_id = cx.tcx.hir().get_parent_item(id);
67 match cx.tcx.hir().get_by_hir_id(parent_id) {
69 node: ItemKind::Const(..),
72 | Node::TraitItem(&TraitItem {
73 node: TraitItemKind::Const(..),
76 | Node::ImplItem(&ImplItem {
77 node: ImplItemKind::Const(..),
82 node: ItemKind::Static(..),
86 node: ItemKind::Fn(_, header, ..),
88 }) => header.constness == Constness::Const,
93 /// Returns `true` if this `expn_info` was expanded by any macro.
94 pub fn in_macro(span: Span) -> bool {
95 span.ctxt().outer().expn_info().is_some()
98 /// Used to store the absolute path to a type.
100 /// See `match_def_path` for usage.
101 pub struct AbsolutePathPrinter<'a, 'tcx> {
102 pub tcx: TyCtxt<'a, 'tcx, 'tcx>,
105 use rustc::ty::print::Printer;
107 #[allow(clippy::diverging_sub_expression)]
108 impl<'tcx> Printer<'tcx, 'tcx> for AbsolutePathPrinter<'_, 'tcx> {
111 type Path = Vec<LocalInternedString>;
114 type DynExistential = ();
116 fn tcx<'a>(&'a self) -> TyCtxt<'a, 'tcx, 'tcx> {
120 fn print_region(self, _region: ty::Region<'_>) -> Result<Self::Region, Self::Error> {
124 fn print_type(self, _ty: Ty<'tcx>) -> Result<Self::Type, Self::Error> {
128 fn print_dyn_existential(
130 _predicates: &'tcx ty::List<ty::ExistentialPredicate<'tcx>>,
131 ) -> Result<Self::DynExistential, Self::Error> {
135 fn path_crate(self, cnum: CrateNum) -> Result<Self::Path, Self::Error> {
136 Ok(vec![self.tcx.original_crate_name(cnum).as_str()])
142 trait_ref: Option<ty::TraitRef<'tcx>>,
143 ) -> Result<Self::Path, Self::Error> {
144 if trait_ref.is_none() {
145 if let ty::Adt(def, substs) = self_ty.sty {
146 return self.print_def_path(def.did, substs);
150 // This shouldn't ever be needed, but just in case:
151 Ok(vec![match trait_ref {
152 Some(trait_ref) => Symbol::intern(&format!("{:?}", trait_ref)).as_str(),
153 None => Symbol::intern(&format!("<{}>", self_ty)).as_str(),
159 print_prefix: impl FnOnce(Self) -> Result<Self::Path, Self::Error>,
160 _disambiguated_data: &DisambiguatedDefPathData,
162 trait_ref: Option<ty::TraitRef<'tcx>>,
163 ) -> Result<Self::Path, Self::Error> {
164 let mut path = print_prefix(self)?;
166 // This shouldn't ever be needed, but just in case:
167 path.push(match trait_ref {
168 Some(trait_ref) => Symbol::intern(&format!("<impl {} for {}>", trait_ref, self_ty)).as_str(),
169 None => Symbol::intern(&format!("<impl {}>", self_ty)).as_str(),
177 print_prefix: impl FnOnce(Self) -> Result<Self::Path, Self::Error>,
178 disambiguated_data: &DisambiguatedDefPathData,
179 ) -> Result<Self::Path, Self::Error> {
180 let mut path = print_prefix(self)?;
181 path.push(disambiguated_data.data.as_interned_str().as_str());
185 fn path_generic_args(
187 print_prefix: impl FnOnce(Self) -> Result<Self::Path, Self::Error>,
188 _args: &[Kind<'tcx>],
189 ) -> Result<Self::Path, Self::Error> {
194 /// Checks if a `DefId`'s path matches the given absolute type path usage.
198 /// match_def_path(cx.tcx, id, &["core", "option", "Option"])
201 /// See also the `paths` module.
202 pub fn match_def_path<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId, path: &[&str]) -> bool {
203 let names = get_def_path(tcx, def_id);
205 names.len() == path.len() && names.into_iter().zip(path.iter()).all(|(a, &b)| *a == *b)
208 /// Gets the absolute path of `def_id` as a vector of `&str`.
212 /// let def_path = get_def_path(tcx, def_id);
213 /// if let &["core", "option", "Option"] = &def_path[..] {
214 /// // The given `def_id` is that of an `Option` type
217 pub fn get_def_path<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Vec<&'static str> {
218 AbsolutePathPrinter { tcx }
219 .print_def_path(def_id, &[])
222 .map(LocalInternedString::get)
226 /// Checks if type is struct, enum or union type with the given def path.
227 pub fn match_type(cx: &LateContext<'_, '_>, ty: Ty<'_>, path: &[&str]) -> bool {
229 ty::Adt(adt, _) => match_def_path(cx.tcx, adt.did, path),
234 /// Checks if the method call given in `expr` belongs to the given trait.
235 pub fn match_trait_method(cx: &LateContext<'_, '_>, expr: &Expr, path: &[&str]) -> bool {
236 let method_call = cx.tables.type_dependent_defs()[expr.hir_id];
237 let trt_id = cx.tcx.trait_of_item(method_call.def_id());
238 if let Some(trt_id) = trt_id {
239 match_def_path(cx.tcx, trt_id, path)
245 /// Checks if an expression references a variable of the given name.
246 pub fn match_var(expr: &Expr, var: Name) -> bool {
247 if let ExprKind::Path(QPath::Resolved(None, ref path)) = expr.node {
248 if path.segments.len() == 1 && path.segments[0].ident.name == var {
255 pub fn last_path_segment(path: &QPath) -> &PathSegment {
257 QPath::Resolved(_, ref path) => path.segments.last().expect("A path must have at least one segment"),
258 QPath::TypeRelative(_, ref seg) => seg,
262 pub fn single_segment_path(path: &QPath) -> Option<&PathSegment> {
264 QPath::Resolved(_, ref path) if path.segments.len() == 1 => Some(&path.segments[0]),
265 QPath::Resolved(..) => None,
266 QPath::TypeRelative(_, ref seg) => Some(seg),
270 /// Matches a `QPath` against a slice of segment string literals.
272 /// There is also `match_path` if you are dealing with a `rustc::hir::Path` instead of a
273 /// `rustc::hir::QPath`.
277 /// match_qpath(path, &["std", "rt", "begin_unwind"])
279 pub fn match_qpath(path: &QPath, segments: &[&str]) -> bool {
281 QPath::Resolved(_, ref path) => match_path(path, segments),
282 QPath::TypeRelative(ref ty, ref segment) => match ty.node {
283 TyKind::Path(ref inner_path) => {
285 && match_qpath(inner_path, &segments[..(segments.len() - 1)])
286 && segment.ident.name == segments[segments.len() - 1]
293 /// Matches a `Path` against a slice of segment string literals.
295 /// There is also `match_qpath` if you are dealing with a `rustc::hir::QPath` instead of a
296 /// `rustc::hir::Path`.
301 /// if match_path(&trait_ref.path, &paths::HASH) {
302 /// // This is the `std::hash::Hash` trait.
305 /// if match_path(ty_path, &["rustc", "lint", "Lint"]) {
306 /// // This is a `rustc::lint::Lint`.
309 pub fn match_path(path: &Path, segments: &[&str]) -> bool {
313 .zip(segments.iter().rev())
314 .all(|(a, b)| a.ident.name == *b)
317 /// Matches a `Path` against a slice of segment string literals, e.g.
321 /// match_qpath(path, &["std", "rt", "begin_unwind"])
323 pub fn match_path_ast(path: &ast::Path, segments: &[&str]) -> bool {
327 .zip(segments.iter().rev())
328 .all(|(a, b)| a.ident.name == *b)
331 /// Gets the definition associated to a path.
332 pub fn path_to_def(cx: &LateContext<'_, '_>, path: &[&str]) -> Option<def::Def> {
333 let crates = cx.tcx.crates();
334 let krate = crates.iter().find(|&&krate| cx.tcx.crate_name(krate) == path[0]);
335 if let Some(krate) = krate {
338 index: CRATE_DEF_INDEX,
340 let mut items = cx.tcx.item_children(krate);
341 let mut path_it = path.iter().skip(1).peekable();
344 let segment = match path_it.next() {
345 Some(segment) => segment,
349 for item in mem::replace(&mut items, Lrc::new(vec![])).iter() {
350 if item.ident.name == *segment {
351 if path_it.peek().is_none() {
352 return Some(item.def);
355 items = cx.tcx.item_children(item.def.def_id());
365 /// Convenience function to get the `DefId` of a trait by path.
366 pub fn get_trait_def_id(cx: &LateContext<'_, '_>, path: &[&str]) -> Option<DefId> {
367 let def = match path_to_def(cx, path) {
373 def::Def::Trait(trait_id) => Some(trait_id),
378 /// Checks whether a type implements a trait.
379 /// See also `get_trait_def_id`.
380 pub fn implements_trait<'a, 'tcx>(
381 cx: &LateContext<'a, 'tcx>,
384 ty_params: &[Kind<'tcx>],
386 let ty = cx.tcx.erase_regions(&ty);
387 let obligation = cx.tcx.predicate_for_trait_def(
389 traits::ObligationCause::dummy(),
397 .enter(|infcx| infcx.predicate_must_hold_modulo_regions(&obligation))
400 /// Gets the `hir::TraitRef` of the trait the given method is implemented for.
402 /// Use this if you want to find the `TraitRef` of the `Add` trait in this example:
405 /// struct Point(isize, isize);
407 /// impl std::ops::Add for Point {
408 /// type Output = Self;
410 /// fn add(self, other: Self) -> Self {
415 pub fn trait_ref_of_method(cx: &LateContext<'_, '_>, hir_id: HirId) -> Option<TraitRef> {
416 // Get the implemented trait for the current function
417 let parent_impl = cx.tcx.hir().get_parent_item(hir_id);
419 if parent_impl != hir::CRATE_HIR_ID;
420 if let hir::Node::Item(item) = cx.tcx.hir().get_by_hir_id(parent_impl);
421 if let hir::ItemKind::Impl(_, _, _, _, trait_ref, _, _) = &item.node;
422 then { return trait_ref.clone(); }
427 /// Checks whether this type implements `Drop`.
428 pub fn has_drop<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
429 match ty.ty_adt_def() {
430 Some(def) => def.has_dtor(cx.tcx),
435 /// Resolves the definition of a node from its `HirId`.
436 pub fn resolve_node(cx: &LateContext<'_, '_>, qpath: &QPath, id: HirId) -> def::Def {
437 cx.tables.qpath_def(qpath, id)
440 /// Returns the method names and argument list of nested method call expressions that make up
442 pub fn method_calls<'a>(expr: &'a Expr, max_depth: usize) -> (Vec<Symbol>, Vec<&'a [Expr]>) {
443 let mut method_names = Vec::with_capacity(max_depth);
444 let mut arg_lists = Vec::with_capacity(max_depth);
446 let mut current = expr;
447 for _ in 0..max_depth {
448 if let ExprKind::MethodCall(path, _, args) = ¤t.node {
449 if args.iter().any(|e| in_macro(e.span)) {
452 method_names.push(path.ident.name);
453 arg_lists.push(&**args);
460 (method_names, arg_lists)
463 /// Matches an `Expr` against a chain of methods, and return the matched `Expr`s.
465 /// For example, if `expr` represents the `.baz()` in `foo.bar().baz()`,
466 /// `matched_method_chain(expr, &["bar", "baz"])` will return a `Vec`
467 /// containing the `Expr`s for
468 /// `.bar()` and `.baz()`
469 pub fn method_chain_args<'a>(expr: &'a Expr, methods: &[&str]) -> Option<Vec<&'a [Expr]>> {
470 let mut current = expr;
471 let mut matched = Vec::with_capacity(methods.len());
472 for method_name in methods.iter().rev() {
473 // method chains are stored last -> first
474 if let ExprKind::MethodCall(ref path, _, ref args) = current.node {
475 if path.ident.name == *method_name {
476 if args.iter().any(|e| in_macro(e.span)) {
479 matched.push(&**args); // build up `matched` backwards
480 current = &args[0] // go to parent expression
488 // Reverse `matched` so that it is in the same order as `methods`.
493 /// Returns `true` if the provided `def_id` is an entrypoint to a program.
494 pub fn is_entrypoint_fn(cx: &LateContext<'_, '_>, def_id: DefId) -> bool {
495 if let Some((entry_fn_def_id, _)) = cx.tcx.entry_fn(LOCAL_CRATE) {
496 return def_id == entry_fn_def_id;
501 /// Gets the name of the item the expression is in, if available.
502 pub fn get_item_name(cx: &LateContext<'_, '_>, expr: &Expr) -> Option<Name> {
503 let parent_id = cx.tcx.hir().get_parent_item(expr.hir_id);
504 match cx.tcx.hir().find_by_hir_id(parent_id) {
505 Some(Node::Item(&Item { ref ident, .. })) => Some(ident.name),
506 Some(Node::TraitItem(&TraitItem { ident, .. })) | Some(Node::ImplItem(&ImplItem { ident, .. })) => {
513 /// Gets the name of a `Pat`, if any.
514 pub fn get_pat_name(pat: &Pat) -> Option<Name> {
516 PatKind::Binding(.., ref spname, _) => Some(spname.name),
517 PatKind::Path(ref qpath) => single_segment_path(qpath).map(|ps| ps.ident.name),
518 PatKind::Box(ref p) | PatKind::Ref(ref p, _) => get_pat_name(&*p),
523 struct ContainsName {
528 impl<'tcx> Visitor<'tcx> for ContainsName {
529 fn visit_name(&mut self, _: Span, name: Name) {
530 if self.name == name {
534 fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
535 NestedVisitorMap::None
539 /// Checks if an `Expr` contains a certain name.
540 pub fn contains_name(name: Name, expr: &Expr) -> bool {
541 let mut cn = ContainsName { name, result: false };
546 /// Converts a span to a code snippet if available, otherwise use default.
548 /// This is useful if you want to provide suggestions for your lint or more generally, if you want
549 /// to convert a given `Span` to a `str`.
553 /// snippet(cx, expr.span, "..")
555 pub fn snippet<'a, 'b, T: LintContext<'b>>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
556 snippet_opt(cx, span).map_or_else(|| Cow::Borrowed(default), From::from)
559 /// Same as `snippet`, but it adapts the applicability level by following rules:
561 /// - Applicability level `Unspecified` will never be changed.
562 /// - If the span is inside a macro, change the applicability level to `MaybeIncorrect`.
563 /// - If the default value is used and the applicability level is `MachineApplicable`, change it to
564 /// `HasPlaceholders`
565 pub fn snippet_with_applicability<'a, 'b, T: LintContext<'b>>(
569 applicability: &mut Applicability,
571 if *applicability != Applicability::Unspecified && in_macro(span) {
572 *applicability = Applicability::MaybeIncorrect;
574 snippet_opt(cx, span).map_or_else(
576 if *applicability == Applicability::MachineApplicable {
577 *applicability = Applicability::HasPlaceholders;
579 Cow::Borrowed(default)
585 /// Same as `snippet`, but should only be used when it's clear that the input span is
586 /// not a macro argument.
587 pub fn snippet_with_macro_callsite<'a, 'b, T: LintContext<'b>>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
588 snippet(cx, span.source_callsite(), default)
591 /// Converts a span to a code snippet. Returns `None` if not available.
592 pub fn snippet_opt<'a, T: LintContext<'a>>(cx: &T, span: Span) -> Option<String> {
593 cx.sess().source_map().span_to_snippet(span).ok()
596 /// Converts a span (from a block) to a code snippet if available, otherwise use
598 /// This trims the code of indentation, except for the first line. Use it for
599 /// blocks or block-like
600 /// things which need to be printed as such.
604 /// snippet_block(cx, expr.span, "..")
606 pub fn snippet_block<'a, 'b, T: LintContext<'b>>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
607 let snip = snippet(cx, span, default);
608 trim_multiline(snip, true)
611 /// Same as `snippet_block`, but adapts the applicability level by the rules of
612 /// `snippet_with_applicabiliy`.
613 pub fn snippet_block_with_applicability<'a, 'b, T: LintContext<'b>>(
617 applicability: &mut Applicability,
619 let snip = snippet_with_applicability(cx, span, default, applicability);
620 trim_multiline(snip, true)
623 /// Returns a new Span that covers the full last line of the given Span
624 pub fn last_line_of_span<'a, T: LintContext<'a>>(cx: &T, span: Span) -> Span {
625 let source_map_and_line = cx.sess().source_map().lookup_line(span.lo()).unwrap();
626 let line_no = source_map_and_line.line;
627 let line_start = &source_map_and_line.sf.lines[line_no];
628 Span::new(*line_start, span.hi(), span.ctxt())
631 /// Like `snippet_block`, but add braces if the expr is not an `ExprKind::Block`.
632 /// Also takes an `Option<String>` which can be put inside the braces.
633 pub fn expr_block<'a, 'b, T: LintContext<'b>>(
636 option: Option<String>,
639 let code = snippet_block(cx, expr.span, default);
640 let string = option.unwrap_or_default();
641 if in_macro(expr.span) {
642 Cow::Owned(format!("{{ {} }}", snippet_with_macro_callsite(cx, expr.span, default)))
643 } else if let ExprKind::Block(_, _) = expr.node {
644 Cow::Owned(format!("{}{}", code, string))
645 } else if string.is_empty() {
646 Cow::Owned(format!("{{ {} }}", code))
648 Cow::Owned(format!("{{\n{};\n{}\n}}", code, string))
652 /// Trim indentation from a multiline string with possibility of ignoring the
654 pub fn trim_multiline(s: Cow<'_, str>, ignore_first: bool) -> Cow<'_, str> {
655 let s_space = trim_multiline_inner(s, ignore_first, ' ');
656 let s_tab = trim_multiline_inner(s_space, ignore_first, '\t');
657 trim_multiline_inner(s_tab, ignore_first, ' ')
660 fn trim_multiline_inner(s: Cow<'_, str>, ignore_first: bool, ch: char) -> Cow<'_, str> {
663 .skip(ignore_first as usize)
668 // ignore empty lines
669 Some(l.char_indices().find(|&(_, x)| x != ch).unwrap_or((l.len(), ch)).0)
679 if (ignore_first && i == 0) || l.is_empty() {
693 /// Gets the parent expression, if any –- this is useful to constrain a lint.
694 pub fn get_parent_expr<'c>(cx: &'c LateContext<'_, '_>, e: &Expr) -> Option<&'c Expr> {
695 let map = &cx.tcx.hir();
696 let hir_id = e.hir_id;
697 let parent_id = map.get_parent_node_by_hir_id(hir_id);
698 if hir_id == parent_id {
701 map.find_by_hir_id(parent_id).and_then(|node| {
702 if let Node::Expr(parent) = node {
710 pub fn get_enclosing_block<'a, 'tcx: 'a>(cx: &LateContext<'a, 'tcx>, node: HirId) -> Option<&'tcx Block> {
711 let map = &cx.tcx.hir();
712 let node_id = map.hir_to_node_id(node);
713 let enclosing_node = map
714 .get_enclosing_scope(node_id)
715 .and_then(|enclosing_id| map.find(enclosing_id));
716 if let Some(node) = enclosing_node {
718 Node::Block(block) => Some(block),
720 node: ItemKind::Fn(_, _, _, eid),
723 | Node::ImplItem(&ImplItem {
724 node: ImplItemKind::Method(_, eid),
726 }) => match cx.tcx.hir().body(eid).value.node {
727 ExprKind::Block(ref block, _) => Some(block),
737 /// Returns the base type for HIR references and pointers.
738 pub fn walk_ptrs_hir_ty(ty: &hir::Ty) -> &hir::Ty {
740 TyKind::Ptr(ref mut_ty) | TyKind::Rptr(_, ref mut_ty) => walk_ptrs_hir_ty(&mut_ty.ty),
745 /// Returns the base type for references and raw pointers.
746 pub fn walk_ptrs_ty(ty: Ty<'_>) -> Ty<'_> {
748 ty::Ref(_, ty, _) => walk_ptrs_ty(ty),
753 /// Returns the base type for references and raw pointers, and count reference
755 pub fn walk_ptrs_ty_depth(ty: Ty<'_>) -> (Ty<'_>, usize) {
756 fn inner(ty: Ty<'_>, depth: usize) -> (Ty<'_>, usize) {
758 ty::Ref(_, ty, _) => inner(ty, depth + 1),
765 /// Checks whether the given expression is a constant literal of the given value.
766 pub fn is_integer_literal(expr: &Expr, value: u128) -> bool {
767 // FIXME: use constant folding
768 if let ExprKind::Lit(ref spanned) = expr.node {
769 if let LitKind::Int(v, _) = spanned.node {
776 /// Returns `true` if the given `Expr` has been coerced before.
778 /// Examples of coercions can be found in the Nomicon at
779 /// <https://doc.rust-lang.org/nomicon/coercions.html>.
781 /// See `rustc::ty::adjustment::Adjustment` and `rustc_typeck::check::coercion` for more
782 /// information on adjustments and coercions.
783 pub fn is_adjusted(cx: &LateContext<'_, '_>, e: &Expr) -> bool {
784 cx.tables.adjustments().get(e.hir_id).is_some()
787 /// Returns the pre-expansion span if is this comes from an expansion of the
789 /// See also `is_direct_expn_of`.
790 pub fn is_expn_of(mut span: Span, name: &str) -> Option<Span> {
792 let span_name_span = span
796 .map(|ei| (ei.format.name(), ei.call_site));
798 match span_name_span {
799 Some((mac_name, new_span)) if mac_name == name => return Some(new_span),
801 Some((_, new_span)) => span = new_span,
806 /// Returns the pre-expansion span if the span directly comes from an expansion
807 /// of the macro `name`.
808 /// The difference with `is_expn_of` is that in
812 /// `42` is considered expanded from `foo!` and `bar!` by `is_expn_of` but only
814 /// `is_direct_expn_of`.
815 pub fn is_direct_expn_of(span: Span, name: &str) -> Option<Span> {
816 let span_name_span = span
820 .map(|ei| (ei.format.name(), ei.call_site));
822 match span_name_span {
823 Some((mac_name, new_span)) if mac_name == name => Some(new_span),
828 /// Convenience function to get the return type of a function.
829 pub fn return_ty<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, fn_item: hir::HirId) -> Ty<'tcx> {
830 let fn_def_id = cx.tcx.hir().local_def_id_from_hir_id(fn_item);
831 let ret_ty = cx.tcx.fn_sig(fn_def_id).output();
832 cx.tcx.erase_late_bound_regions(&ret_ty)
835 /// Checks if two types are the same.
837 /// This discards any lifetime annotations, too.
839 // FIXME: this works correctly for lifetimes bounds (`for <'a> Foo<'a>` ==
840 // `for <'b> Foo<'b>`, but not for type parameters).
841 pub fn same_tys<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, a: Ty<'tcx>, b: Ty<'tcx>) -> bool {
842 let a = cx.tcx.erase_late_bound_regions(&Binder::bind(a));
843 let b = cx.tcx.erase_late_bound_regions(&Binder::bind(b));
846 .enter(|infcx| infcx.can_eq(cx.param_env, a, b).is_ok())
849 /// Returns `true` if the given type is an `unsafe` function.
850 pub fn type_is_unsafe_function<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
852 ty::FnDef(..) | ty::FnPtr(_) => ty.fn_sig(cx.tcx).unsafety() == Unsafety::Unsafe,
857 pub fn is_copy<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
858 ty.is_copy_modulo_regions(cx.tcx.global_tcx(), cx.param_env, DUMMY_SP)
861 /// Returns `true` if a pattern is refutable.
862 pub fn is_refutable(cx: &LateContext<'_, '_>, pat: &Pat) -> bool {
863 fn is_enum_variant(cx: &LateContext<'_, '_>, qpath: &QPath, id: HirId) -> bool {
865 cx.tables.qpath_def(qpath, id),
866 def::Def::Variant(..) | def::Def::VariantCtor(..)
870 fn are_refutable<'a, I: Iterator<Item = &'a Pat>>(cx: &LateContext<'_, '_>, mut i: I) -> bool {
871 i.any(|pat| is_refutable(cx, pat))
875 PatKind::Binding(..) | PatKind::Wild => false,
876 PatKind::Box(ref pat) | PatKind::Ref(ref pat, _) => is_refutable(cx, pat),
877 PatKind::Lit(..) | PatKind::Range(..) => true,
878 PatKind::Path(ref qpath) => is_enum_variant(cx, qpath, pat.hir_id),
879 PatKind::Tuple(ref pats, _) => are_refutable(cx, pats.iter().map(|pat| &**pat)),
880 PatKind::Struct(ref qpath, ref fields, _) => {
881 if is_enum_variant(cx, qpath, pat.hir_id) {
884 are_refutable(cx, fields.iter().map(|field| &*field.node.pat))
887 PatKind::TupleStruct(ref qpath, ref pats, _) => {
888 if is_enum_variant(cx, qpath, pat.hir_id) {
891 are_refutable(cx, pats.iter().map(|pat| &**pat))
894 PatKind::Slice(ref head, ref middle, ref tail) => {
895 are_refutable(cx, head.iter().chain(middle).chain(tail.iter()).map(|pat| &**pat))
900 /// Checks for the `#[automatically_derived]` attribute all `#[derive]`d
901 /// implementations have.
902 pub fn is_automatically_derived(attrs: &[ast::Attribute]) -> bool {
903 attr::contains_name(attrs, "automatically_derived")
906 /// Remove blocks around an expression.
908 /// Ie. `x`, `{ x }` and `{{{{ x }}}}` all give `x`. `{ x; y }` and `{}` return
910 pub fn remove_blocks(expr: &Expr) -> &Expr {
911 if let ExprKind::Block(ref block, _) = expr.node {
912 if block.stmts.is_empty() {
913 if let Some(ref expr) = block.expr {
926 pub fn is_self(slf: &Arg) -> bool {
927 if let PatKind::Binding(.., name, _) = slf.pat.node {
928 name.name == keywords::SelfLower.name()
934 pub fn is_self_ty(slf: &hir::Ty) -> bool {
936 if let TyKind::Path(ref qp) = slf.node;
937 if let QPath::Resolved(None, ref path) = *qp;
938 if let Def::SelfTy(..) = path.def;
946 pub fn iter_input_pats<'tcx>(decl: &FnDecl, body: &'tcx Body) -> impl Iterator<Item = &'tcx Arg> {
947 (0..decl.inputs.len()).map(move |i| &body.arguments[i])
950 /// Checks if a given expression is a match expression expanded from the `?`
951 /// operator or the `try` macro.
952 pub fn is_try<'a>(cx: &'_ LateContext<'_, '_>, expr: &'a Expr) -> Option<&'a Expr> {
953 fn is_ok(cx: &'_ LateContext<'_, '_>, arm: &Arm) -> bool {
955 if let PatKind::TupleStruct(ref path, ref pat, None) = arm.pats[0].node;
956 if match_qpath(path, &paths::RESULT_OK[1..]);
957 if let PatKind::Binding(_, hir_id, _, None) = pat[0].node;
958 if let ExprKind::Path(QPath::Resolved(None, ref path)) = arm.body.node;
959 if let Def::Local(lid) = path.def;
960 if cx.tcx.hir().node_to_hir_id(lid) == hir_id;
968 fn is_err(arm: &Arm) -> bool {
969 if let PatKind::TupleStruct(ref path, _, _) = arm.pats[0].node {
970 match_qpath(path, &paths::RESULT_ERR[1..])
976 if let ExprKind::Match(_, ref arms, ref source) = expr.node {
977 // desugared from a `?` operator
978 if let MatchSource::TryDesugar = *source {
984 if arms[0].pats.len() == 1 && arms[0].guard.is_none();
985 if arms[1].pats.len() == 1 && arms[1].guard.is_none();
986 if (is_ok(cx, &arms[0]) && is_err(&arms[1])) ||
987 (is_ok(cx, &arms[1]) && is_err(&arms[0]));
997 /// Returns `true` if the lint is allowed in the current context
999 /// Useful for skipping long running code when it's unnecessary
1000 pub fn is_allowed(cx: &LateContext<'_, '_>, lint: &'static Lint, id: HirId) -> bool {
1001 cx.tcx.lint_level_at_node(lint, id).0 == Level::Allow
1004 pub fn get_arg_name(pat: &Pat) -> Option<ast::Name> {
1006 PatKind::Binding(.., ident, None) => Some(ident.name),
1007 PatKind::Ref(ref subpat, _) => get_arg_name(subpat),
1012 pub fn int_bits(tcx: TyCtxt<'_, '_, '_>, ity: ast::IntTy) -> u64 {
1013 layout::Integer::from_attr(&tcx, attr::IntType::SignedInt(ity))
1018 #[allow(clippy::cast_possible_wrap)]
1019 /// Turn a constant int byte representation into an i128
1020 pub fn sext(tcx: TyCtxt<'_, '_, '_>, u: u128, ity: ast::IntTy) -> i128 {
1021 let amt = 128 - int_bits(tcx, ity);
1022 ((u as i128) << amt) >> amt
1025 #[allow(clippy::cast_sign_loss)]
1026 /// clip unused bytes
1027 pub fn unsext(tcx: TyCtxt<'_, '_, '_>, u: i128, ity: ast::IntTy) -> u128 {
1028 let amt = 128 - int_bits(tcx, ity);
1029 ((u as u128) << amt) >> amt
1032 /// clip unused bytes
1033 pub fn clip(tcx: TyCtxt<'_, '_, '_>, u: u128, ity: ast::UintTy) -> u128 {
1034 let bits = layout::Integer::from_attr(&tcx, attr::IntType::UnsignedInt(ity))
1037 let amt = 128 - bits;
1041 /// Removes block comments from the given `Vec` of lines.
1046 /// without_block_comments(vec!["/*", "foo", "*/"]);
1049 /// without_block_comments(vec!["bar", "/*", "foo", "*/"]);
1050 /// // => vec!["bar"]
1052 pub fn without_block_comments(lines: Vec<&str>) -> Vec<&str> {
1053 let mut without = vec![];
1055 let mut nest_level = 0;
1058 if line.contains("/*") {
1061 } else if line.contains("*/") {
1066 if nest_level == 0 {
1074 pub fn any_parent_is_automatically_derived(tcx: TyCtxt<'_, '_, '_>, node: HirId) -> bool {
1075 let map = &tcx.hir();
1076 let mut prev_enclosing_node = None;
1077 let mut enclosing_node = node;
1078 while Some(enclosing_node) != prev_enclosing_node {
1079 if is_automatically_derived(map.attrs_by_hir_id(enclosing_node)) {
1082 prev_enclosing_node = Some(enclosing_node);
1083 enclosing_node = map.get_parent_item(enclosing_node);
1088 /// Returns true if ty has `iter` or `iter_mut` methods
1089 pub fn has_iter_method(cx: &LateContext<'_, '_>, probably_ref_ty: Ty<'_>) -> Option<&'static str> {
1090 // FIXME: instead of this hard-coded list, we should check if `<adt>::iter`
1091 // exists and has the desired signature. Unfortunately FnCtxt is not exported
1092 // so we can't use its `lookup_method` method.
1093 static INTO_ITER_COLLECTIONS: [&[&str]; 13] = [
1100 &paths::LINKED_LIST,
1101 &paths::BINARY_HEAP,
1109 let ty_to_check = match probably_ref_ty.sty {
1110 ty::Ref(_, ty_to_check, _) => ty_to_check,
1111 _ => probably_ref_ty,
1114 let def_id = match ty_to_check.sty {
1115 ty::Array(..) => return Some("array"),
1116 ty::Slice(..) => return Some("slice"),
1117 ty::Adt(adt, _) => adt.did,
1121 for path in &INTO_ITER_COLLECTIONS {
1122 if match_def_path(cx.tcx, def_id, path) {
1123 return Some(path.last().unwrap());
1131 use super::{trim_multiline, without_block_comments};
1134 fn test_trim_multiline_single_line() {
1135 assert_eq!("", trim_multiline("".into(), false));
1136 assert_eq!("...", trim_multiline("...".into(), false));
1137 assert_eq!("...", trim_multiline(" ...".into(), false));
1138 assert_eq!("...", trim_multiline("\t...".into(), false));
1139 assert_eq!("...", trim_multiline("\t\t...".into(), false));
1144 fn test_trim_multiline_block() {
1150 }", trim_multiline(" if x {
1160 }", trim_multiline(" if x {
1169 fn test_trim_multiline_empty_line() {
1176 }", trim_multiline(" if x {
1185 fn test_without_block_comments_lines_without_block_comments() {
1186 let result = without_block_comments(vec!["/*", "", "*/"]);
1187 println!("result: {:?}", result);
1188 assert!(result.is_empty());
1190 let result = without_block_comments(vec!["", "/*", "", "*/", "#[crate_type = \"lib\"]", "/*", "", "*/", ""]);
1191 assert_eq!(result, vec!["", "#[crate_type = \"lib\"]", ""]);
1193 let result = without_block_comments(vec!["/* rust", "", "*/"]);
1194 assert!(result.is_empty());
1196 let result = without_block_comments(vec!["/* one-line comment */"]);
1197 assert!(result.is_empty());
1199 let result = without_block_comments(vec!["/* nested", "/* multi-line", "comment", "*/", "test", "*/"]);
1200 assert!(result.is_empty());
1202 let result = without_block_comments(vec!["/* nested /* inline /* comment */ test */ */"]);
1203 assert!(result.is_empty());
1205 let result = without_block_comments(vec!["foo", "bar", "baz"]);
1206 assert_eq!(result, vec!["foo", "bar", "baz"]);