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::{DefPathData, 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)?;
182 // Skip `::{{constructor}}` on tuple/unit structs.
183 if let DefPathData::Ctor = disambiguated_data.data {
187 path.push(disambiguated_data.data.as_interned_str().as_str());
191 fn path_generic_args(
193 print_prefix: impl FnOnce(Self) -> Result<Self::Path, Self::Error>,
194 _args: &[Kind<'tcx>],
195 ) -> Result<Self::Path, Self::Error> {
200 /// Checks if a `DefId`'s path matches the given absolute type path usage.
204 /// match_def_path(cx.tcx, id, &["core", "option", "Option"])
207 /// See also the `paths` module.
208 pub fn match_def_path<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId, path: &[&str]) -> bool {
209 let names = get_def_path(tcx, def_id);
211 names.len() == path.len() && names.into_iter().zip(path.iter()).all(|(a, &b)| *a == *b)
214 /// Gets the absolute path of `def_id` as a vector of `&str`.
218 /// let def_path = get_def_path(tcx, def_id);
219 /// if let &["core", "option", "Option"] = &def_path[..] {
220 /// // The given `def_id` is that of an `Option` type
223 pub fn get_def_path<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Vec<LocalInternedString> {
224 AbsolutePathPrinter { tcx }.print_def_path(def_id, &[]).unwrap()
227 /// Checks if type is struct, enum or union type with the given def path.
228 pub fn match_type(cx: &LateContext<'_, '_>, ty: Ty<'_>, path: &[&str]) -> bool {
230 ty::Adt(adt, _) => match_def_path(cx.tcx, adt.did, path),
235 /// Checks if the method call given in `expr` belongs to the given trait.
236 pub fn match_trait_method(cx: &LateContext<'_, '_>, expr: &Expr, path: &[&str]) -> bool {
237 let def_id = cx.tables.type_dependent_def_id(expr.hir_id).unwrap();
238 let trt_id = cx.tcx.trait_of_item(def_id);
239 if let Some(trt_id) = trt_id {
240 match_def_path(cx.tcx, trt_id, path)
246 /// Checks if an expression references a variable of the given name.
247 pub fn match_var(expr: &Expr, var: Name) -> bool {
248 if let ExprKind::Path(QPath::Resolved(None, ref path)) = expr.node {
249 if path.segments.len() == 1 && path.segments[0].ident.name == var {
256 pub fn last_path_segment(path: &QPath) -> &PathSegment {
258 QPath::Resolved(_, ref path) => path.segments.last().expect("A path must have at least one segment"),
259 QPath::TypeRelative(_, ref seg) => seg,
263 pub fn single_segment_path(path: &QPath) -> Option<&PathSegment> {
265 QPath::Resolved(_, ref path) if path.segments.len() == 1 => Some(&path.segments[0]),
266 QPath::Resolved(..) => None,
267 QPath::TypeRelative(_, ref seg) => Some(seg),
271 /// Matches a `QPath` against a slice of segment string literals.
273 /// There is also `match_path` if you are dealing with a `rustc::hir::Path` instead of a
274 /// `rustc::hir::QPath`.
278 /// match_qpath(path, &["std", "rt", "begin_unwind"])
280 pub fn match_qpath(path: &QPath, segments: &[&str]) -> bool {
282 QPath::Resolved(_, ref path) => match_path(path, segments),
283 QPath::TypeRelative(ref ty, ref segment) => match ty.node {
284 TyKind::Path(ref inner_path) => {
286 && match_qpath(inner_path, &segments[..(segments.len() - 1)])
287 && segment.ident.name == segments[segments.len() - 1]
294 /// Matches a `Path` against a slice of segment string literals.
296 /// There is also `match_qpath` if you are dealing with a `rustc::hir::QPath` instead of a
297 /// `rustc::hir::Path`.
302 /// if match_path(&trait_ref.path, &paths::HASH) {
303 /// // This is the `std::hash::Hash` trait.
306 /// if match_path(ty_path, &["rustc", "lint", "Lint"]) {
307 /// // This is a `rustc::lint::Lint`.
310 pub fn match_path(path: &Path, segments: &[&str]) -> bool {
314 .zip(segments.iter().rev())
315 .all(|(a, b)| a.ident.name == *b)
318 /// Matches a `Path` against a slice of segment string literals, e.g.
322 /// match_qpath(path, &["std", "rt", "begin_unwind"])
324 pub fn match_path_ast(path: &ast::Path, segments: &[&str]) -> bool {
328 .zip(segments.iter().rev())
329 .all(|(a, b)| a.ident.name == *b)
332 /// Gets the definition associated to a path.
333 pub fn path_to_def(cx: &LateContext<'_, '_>, path: &[&str]) -> Option<def::Def> {
334 let crates = cx.tcx.crates();
335 let krate = crates.iter().find(|&&krate| cx.tcx.crate_name(krate) == path[0]);
336 if let Some(krate) = krate {
339 index: CRATE_DEF_INDEX,
341 let mut items = cx.tcx.item_children(krate);
342 let mut path_it = path.iter().skip(1).peekable();
345 let segment = match path_it.next() {
346 Some(segment) => segment,
350 for item in mem::replace(&mut items, Lrc::new(vec![])).iter() {
351 if item.ident.name == *segment {
352 if path_it.peek().is_none() {
353 return Some(item.def);
356 items = cx.tcx.item_children(item.def.def_id());
366 /// Convenience function to get the `DefId` of a trait by path.
367 pub fn get_trait_def_id(cx: &LateContext<'_, '_>, path: &[&str]) -> Option<DefId> {
368 let def = match path_to_def(cx, path) {
374 def::Def::Trait(trait_id) => Some(trait_id),
379 /// Checks whether a type implements a trait.
380 /// See also `get_trait_def_id`.
381 pub fn implements_trait<'a, 'tcx>(
382 cx: &LateContext<'a, 'tcx>,
385 ty_params: &[Kind<'tcx>],
387 let ty = cx.tcx.erase_regions(&ty);
388 let obligation = cx.tcx.predicate_for_trait_def(
390 traits::ObligationCause::dummy(),
398 .enter(|infcx| infcx.predicate_must_hold_modulo_regions(&obligation))
401 /// Gets the `hir::TraitRef` of the trait the given method is implemented for.
403 /// Use this if you want to find the `TraitRef` of the `Add` trait in this example:
406 /// struct Point(isize, isize);
408 /// impl std::ops::Add for Point {
409 /// type Output = Self;
411 /// fn add(self, other: Self) -> Self {
416 pub fn trait_ref_of_method(cx: &LateContext<'_, '_>, hir_id: HirId) -> Option<TraitRef> {
417 // Get the implemented trait for the current function
418 let parent_impl = cx.tcx.hir().get_parent_item(hir_id);
420 if parent_impl != hir::CRATE_HIR_ID;
421 if let hir::Node::Item(item) = cx.tcx.hir().get_by_hir_id(parent_impl);
422 if let hir::ItemKind::Impl(_, _, _, _, trait_ref, _, _) = &item.node;
423 then { return trait_ref.clone(); }
428 /// Checks whether this type implements `Drop`.
429 pub fn has_drop<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
430 match ty.ty_adt_def() {
431 Some(def) => def.has_dtor(cx.tcx),
436 /// Resolves the definition of a node from its `HirId`.
437 pub fn resolve_node(cx: &LateContext<'_, '_>, qpath: &QPath, id: HirId) -> def::Def {
438 cx.tables.qpath_def(qpath, id)
441 /// Returns the method names and argument list of nested method call expressions that make up
443 pub fn method_calls<'a>(expr: &'a Expr, max_depth: usize) -> (Vec<Symbol>, Vec<&'a [Expr]>) {
444 let mut method_names = Vec::with_capacity(max_depth);
445 let mut arg_lists = Vec::with_capacity(max_depth);
447 let mut current = expr;
448 for _ in 0..max_depth {
449 if let ExprKind::MethodCall(path, _, args) = ¤t.node {
450 if args.iter().any(|e| in_macro(e.span)) {
453 method_names.push(path.ident.name);
454 arg_lists.push(&**args);
461 (method_names, arg_lists)
464 /// Matches an `Expr` against a chain of methods, and return the matched `Expr`s.
466 /// For example, if `expr` represents the `.baz()` in `foo.bar().baz()`,
467 /// `matched_method_chain(expr, &["bar", "baz"])` will return a `Vec`
468 /// containing the `Expr`s for
469 /// `.bar()` and `.baz()`
470 pub fn method_chain_args<'a>(expr: &'a Expr, methods: &[&str]) -> Option<Vec<&'a [Expr]>> {
471 let mut current = expr;
472 let mut matched = Vec::with_capacity(methods.len());
473 for method_name in methods.iter().rev() {
474 // method chains are stored last -> first
475 if let ExprKind::MethodCall(ref path, _, ref args) = current.node {
476 if path.ident.name == *method_name {
477 if args.iter().any(|e| in_macro(e.span)) {
480 matched.push(&**args); // build up `matched` backwards
481 current = &args[0] // go to parent expression
489 // Reverse `matched` so that it is in the same order as `methods`.
494 /// Returns `true` if the provided `def_id` is an entrypoint to a program.
495 pub fn is_entrypoint_fn(cx: &LateContext<'_, '_>, def_id: DefId) -> bool {
496 if let Some((entry_fn_def_id, _)) = cx.tcx.entry_fn(LOCAL_CRATE) {
497 return def_id == entry_fn_def_id;
502 /// Gets the name of the item the expression is in, if available.
503 pub fn get_item_name(cx: &LateContext<'_, '_>, expr: &Expr) -> Option<Name> {
504 let parent_id = cx.tcx.hir().get_parent_item(expr.hir_id);
505 match cx.tcx.hir().find_by_hir_id(parent_id) {
506 Some(Node::Item(&Item { ref ident, .. })) => Some(ident.name),
507 Some(Node::TraitItem(&TraitItem { ident, .. })) | Some(Node::ImplItem(&ImplItem { ident, .. })) => {
514 /// Gets the name of a `Pat`, if any.
515 pub fn get_pat_name(pat: &Pat) -> Option<Name> {
517 PatKind::Binding(.., ref spname, _) => Some(spname.name),
518 PatKind::Path(ref qpath) => single_segment_path(qpath).map(|ps| ps.ident.name),
519 PatKind::Box(ref p) | PatKind::Ref(ref p, _) => get_pat_name(&*p),
524 struct ContainsName {
529 impl<'tcx> Visitor<'tcx> for ContainsName {
530 fn visit_name(&mut self, _: Span, name: Name) {
531 if self.name == name {
535 fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
536 NestedVisitorMap::None
540 /// Checks if an `Expr` contains a certain name.
541 pub fn contains_name(name: Name, expr: &Expr) -> bool {
542 let mut cn = ContainsName { name, result: false };
547 /// Converts a span to a code snippet if available, otherwise use default.
549 /// This is useful if you want to provide suggestions for your lint or more generally, if you want
550 /// to convert a given `Span` to a `str`.
554 /// snippet(cx, expr.span, "..")
556 pub fn snippet<'a, 'b, T: LintContext<'b>>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
557 snippet_opt(cx, span).map_or_else(|| Cow::Borrowed(default), From::from)
560 /// Same as `snippet`, but it adapts the applicability level by following rules:
562 /// - Applicability level `Unspecified` will never be changed.
563 /// - If the span is inside a macro, change the applicability level to `MaybeIncorrect`.
564 /// - If the default value is used and the applicability level is `MachineApplicable`, change it to
565 /// `HasPlaceholders`
566 pub fn snippet_with_applicability<'a, 'b, T: LintContext<'b>>(
570 applicability: &mut Applicability,
572 if *applicability != Applicability::Unspecified && in_macro(span) {
573 *applicability = Applicability::MaybeIncorrect;
575 snippet_opt(cx, span).map_or_else(
577 if *applicability == Applicability::MachineApplicable {
578 *applicability = Applicability::HasPlaceholders;
580 Cow::Borrowed(default)
586 /// Same as `snippet`, but should only be used when it's clear that the input span is
587 /// not a macro argument.
588 pub fn snippet_with_macro_callsite<'a, 'b, T: LintContext<'b>>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
589 snippet(cx, span.source_callsite(), default)
592 /// Converts a span to a code snippet. Returns `None` if not available.
593 pub fn snippet_opt<'a, T: LintContext<'a>>(cx: &T, span: Span) -> Option<String> {
594 cx.sess().source_map().span_to_snippet(span).ok()
597 /// Converts a span (from a block) to a code snippet if available, otherwise use
599 /// This trims the code of indentation, except for the first line. Use it for
600 /// blocks or block-like
601 /// things which need to be printed as such.
605 /// snippet_block(cx, expr.span, "..")
607 pub fn snippet_block<'a, 'b, T: LintContext<'b>>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
608 let snip = snippet(cx, span, default);
609 trim_multiline(snip, true)
612 /// Same as `snippet_block`, but adapts the applicability level by the rules of
613 /// `snippet_with_applicabiliy`.
614 pub fn snippet_block_with_applicability<'a, 'b, T: LintContext<'b>>(
618 applicability: &mut Applicability,
620 let snip = snippet_with_applicability(cx, span, default, applicability);
621 trim_multiline(snip, true)
624 /// Returns a new Span that covers the full last line of the given Span
625 pub fn last_line_of_span<'a, T: LintContext<'a>>(cx: &T, span: Span) -> Span {
626 let source_map_and_line = cx.sess().source_map().lookup_line(span.lo()).unwrap();
627 let line_no = source_map_and_line.line;
628 let line_start = &source_map_and_line.sf.lines[line_no];
629 Span::new(*line_start, span.hi(), span.ctxt())
632 /// Like `snippet_block`, but add braces if the expr is not an `ExprKind::Block`.
633 /// Also takes an `Option<String>` which can be put inside the braces.
634 pub fn expr_block<'a, 'b, T: LintContext<'b>>(
637 option: Option<String>,
640 let code = snippet_block(cx, expr.span, default);
641 let string = option.unwrap_or_default();
642 if in_macro(expr.span) {
643 Cow::Owned(format!("{{ {} }}", snippet_with_macro_callsite(cx, expr.span, default)))
644 } else if let ExprKind::Block(_, _) = expr.node {
645 Cow::Owned(format!("{}{}", code, string))
646 } else if string.is_empty() {
647 Cow::Owned(format!("{{ {} }}", code))
649 Cow::Owned(format!("{{\n{};\n{}\n}}", code, string))
653 /// Trim indentation from a multiline string with possibility of ignoring the
655 pub fn trim_multiline(s: Cow<'_, str>, ignore_first: bool) -> Cow<'_, str> {
656 let s_space = trim_multiline_inner(s, ignore_first, ' ');
657 let s_tab = trim_multiline_inner(s_space, ignore_first, '\t');
658 trim_multiline_inner(s_tab, ignore_first, ' ')
661 fn trim_multiline_inner(s: Cow<'_, str>, ignore_first: bool, ch: char) -> Cow<'_, str> {
664 .skip(ignore_first as usize)
669 // ignore empty lines
670 Some(l.char_indices().find(|&(_, x)| x != ch).unwrap_or((l.len(), ch)).0)
680 if (ignore_first && i == 0) || l.is_empty() {
694 /// Gets the parent expression, if any –- this is useful to constrain a lint.
695 pub fn get_parent_expr<'c>(cx: &'c LateContext<'_, '_>, e: &Expr) -> Option<&'c Expr> {
696 let map = &cx.tcx.hir();
697 let hir_id = e.hir_id;
698 let parent_id = map.get_parent_node_by_hir_id(hir_id);
699 if hir_id == parent_id {
702 map.find_by_hir_id(parent_id).and_then(|node| {
703 if let Node::Expr(parent) = node {
711 pub fn get_enclosing_block<'a, 'tcx: 'a>(cx: &LateContext<'a, 'tcx>, node: HirId) -> Option<&'tcx Block> {
712 let map = &cx.tcx.hir();
713 let node_id = map.hir_to_node_id(node);
714 let enclosing_node = map
715 .get_enclosing_scope(node_id)
716 .and_then(|enclosing_id| map.find(enclosing_id));
717 if let Some(node) = enclosing_node {
719 Node::Block(block) => Some(block),
721 node: ItemKind::Fn(_, _, _, eid),
724 | Node::ImplItem(&ImplItem {
725 node: ImplItemKind::Method(_, eid),
727 }) => match cx.tcx.hir().body(eid).value.node {
728 ExprKind::Block(ref block, _) => Some(block),
738 /// Returns the base type for HIR references and pointers.
739 pub fn walk_ptrs_hir_ty(ty: &hir::Ty) -> &hir::Ty {
741 TyKind::Ptr(ref mut_ty) | TyKind::Rptr(_, ref mut_ty) => walk_ptrs_hir_ty(&mut_ty.ty),
746 /// Returns the base type for references and raw pointers.
747 pub fn walk_ptrs_ty(ty: Ty<'_>) -> Ty<'_> {
749 ty::Ref(_, ty, _) => walk_ptrs_ty(ty),
754 /// Returns the base type for references and raw pointers, and count reference
756 pub fn walk_ptrs_ty_depth(ty: Ty<'_>) -> (Ty<'_>, usize) {
757 fn inner(ty: Ty<'_>, depth: usize) -> (Ty<'_>, usize) {
759 ty::Ref(_, ty, _) => inner(ty, depth + 1),
766 /// Checks whether the given expression is a constant literal of the given value.
767 pub fn is_integer_literal(expr: &Expr, value: u128) -> bool {
768 // FIXME: use constant folding
769 if let ExprKind::Lit(ref spanned) = expr.node {
770 if let LitKind::Int(v, _) = spanned.node {
777 /// Returns `true` if the given `Expr` has been coerced before.
779 /// Examples of coercions can be found in the Nomicon at
780 /// <https://doc.rust-lang.org/nomicon/coercions.html>.
782 /// See `rustc::ty::adjustment::Adjustment` and `rustc_typeck::check::coercion` for more
783 /// information on adjustments and coercions.
784 pub fn is_adjusted(cx: &LateContext<'_, '_>, e: &Expr) -> bool {
785 cx.tables.adjustments().get(e.hir_id).is_some()
788 /// Returns the pre-expansion span if is this comes from an expansion of the
790 /// See also `is_direct_expn_of`.
791 pub fn is_expn_of(mut span: Span, name: &str) -> Option<Span> {
793 let span_name_span = span
797 .map(|ei| (ei.format.name(), ei.call_site));
799 match span_name_span {
800 Some((mac_name, new_span)) if mac_name == name => return Some(new_span),
802 Some((_, new_span)) => span = new_span,
807 /// Returns the pre-expansion span if the span directly comes from an expansion
808 /// of the macro `name`.
809 /// The difference with `is_expn_of` is that in
813 /// `42` is considered expanded from `foo!` and `bar!` by `is_expn_of` but only
815 /// `is_direct_expn_of`.
816 pub fn is_direct_expn_of(span: Span, name: &str) -> Option<Span> {
817 let span_name_span = span
821 .map(|ei| (ei.format.name(), ei.call_site));
823 match span_name_span {
824 Some((mac_name, new_span)) if mac_name == name => Some(new_span),
829 /// Convenience function to get the return type of a function.
830 pub fn return_ty<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, fn_item: hir::HirId) -> Ty<'tcx> {
831 let fn_def_id = cx.tcx.hir().local_def_id_from_hir_id(fn_item);
832 let ret_ty = cx.tcx.fn_sig(fn_def_id).output();
833 cx.tcx.erase_late_bound_regions(&ret_ty)
836 /// Checks if two types are the same.
838 /// This discards any lifetime annotations, too.
840 // FIXME: this works correctly for lifetimes bounds (`for <'a> Foo<'a>` ==
841 // `for <'b> Foo<'b>`, but not for type parameters).
842 pub fn same_tys<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, a: Ty<'tcx>, b: Ty<'tcx>) -> bool {
843 let a = cx.tcx.erase_late_bound_regions(&Binder::bind(a));
844 let b = cx.tcx.erase_late_bound_regions(&Binder::bind(b));
847 .enter(|infcx| infcx.can_eq(cx.param_env, a, b).is_ok())
850 /// Returns `true` if the given type is an `unsafe` function.
851 pub fn type_is_unsafe_function<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
853 ty::FnDef(..) | ty::FnPtr(_) => ty.fn_sig(cx.tcx).unsafety() == Unsafety::Unsafe,
858 pub fn is_copy<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
859 ty.is_copy_modulo_regions(cx.tcx.global_tcx(), cx.param_env, DUMMY_SP)
862 /// Returns `true` if a pattern is refutable.
863 pub fn is_refutable(cx: &LateContext<'_, '_>, pat: &Pat) -> bool {
864 fn is_enum_variant(cx: &LateContext<'_, '_>, qpath: &QPath, id: HirId) -> bool {
866 cx.tables.qpath_def(qpath, id),
867 def::Def::Variant(..) | def::Def::Ctor(_, def::CtorOf::Variant, _)
871 fn are_refutable<'a, I: Iterator<Item = &'a Pat>>(cx: &LateContext<'_, '_>, mut i: I) -> bool {
872 i.any(|pat| is_refutable(cx, pat))
876 PatKind::Binding(..) | PatKind::Wild => false,
877 PatKind::Box(ref pat) | PatKind::Ref(ref pat, _) => is_refutable(cx, pat),
878 PatKind::Lit(..) | PatKind::Range(..) => true,
879 PatKind::Path(ref qpath) => is_enum_variant(cx, qpath, pat.hir_id),
880 PatKind::Tuple(ref pats, _) => are_refutable(cx, pats.iter().map(|pat| &**pat)),
881 PatKind::Struct(ref qpath, ref fields, _) => {
882 if is_enum_variant(cx, qpath, pat.hir_id) {
885 are_refutable(cx, fields.iter().map(|field| &*field.node.pat))
888 PatKind::TupleStruct(ref qpath, ref pats, _) => {
889 if is_enum_variant(cx, qpath, pat.hir_id) {
892 are_refutable(cx, pats.iter().map(|pat| &**pat))
895 PatKind::Slice(ref head, ref middle, ref tail) => {
896 are_refutable(cx, head.iter().chain(middle).chain(tail.iter()).map(|pat| &**pat))
901 /// Checks for the `#[automatically_derived]` attribute all `#[derive]`d
902 /// implementations have.
903 pub fn is_automatically_derived(attrs: &[ast::Attribute]) -> bool {
904 attr::contains_name(attrs, "automatically_derived")
907 /// Remove blocks around an expression.
909 /// Ie. `x`, `{ x }` and `{{{{ x }}}}` all give `x`. `{ x; y }` and `{}` return
911 pub fn remove_blocks(expr: &Expr) -> &Expr {
912 if let ExprKind::Block(ref block, _) = expr.node {
913 if block.stmts.is_empty() {
914 if let Some(ref expr) = block.expr {
927 pub fn is_self(slf: &Arg) -> bool {
928 if let PatKind::Binding(.., name, _) = slf.pat.node {
929 name.name == keywords::SelfLower.name()
935 pub fn is_self_ty(slf: &hir::Ty) -> bool {
937 if let TyKind::Path(ref qp) = slf.node;
938 if let QPath::Resolved(None, ref path) = *qp;
939 if let Def::SelfTy(..) = path.def;
947 pub fn iter_input_pats<'tcx>(decl: &FnDecl, body: &'tcx Body) -> impl Iterator<Item = &'tcx Arg> {
948 (0..decl.inputs.len()).map(move |i| &body.arguments[i])
951 /// Checks if a given expression is a match expression expanded from the `?`
952 /// operator or the `try` macro.
953 pub fn is_try(expr: &Expr) -> Option<&Expr> {
954 fn is_ok(arm: &Arm) -> bool {
956 if let PatKind::TupleStruct(ref path, ref pat, None) = arm.pats[0].node;
957 if match_qpath(path, &paths::RESULT_OK[1..]);
958 if let PatKind::Binding(_, hir_id, _, None) = pat[0].node;
959 if let ExprKind::Path(QPath::Resolved(None, ref path)) = arm.body.node;
960 if let Def::Local(lid) = path.def;
969 fn is_err(arm: &Arm) -> bool {
970 if let PatKind::TupleStruct(ref path, _, _) = arm.pats[0].node {
971 match_qpath(path, &paths::RESULT_ERR[1..])
977 if let ExprKind::Match(_, ref arms, ref source) = expr.node {
978 // desugared from a `?` operator
979 if let MatchSource::TryDesugar = *source {
985 if arms[0].pats.len() == 1 && arms[0].guard.is_none();
986 if arms[1].pats.len() == 1 && arms[1].guard.is_none();
987 if (is_ok(&arms[0]) && is_err(&arms[1])) ||
988 (is_ok(&arms[1]) && is_err(&arms[0]));
998 /// Returns `true` if the lint is allowed in the current context
1000 /// Useful for skipping long running code when it's unnecessary
1001 pub fn is_allowed(cx: &LateContext<'_, '_>, lint: &'static Lint, id: HirId) -> bool {
1002 cx.tcx.lint_level_at_node(lint, id).0 == Level::Allow
1005 pub fn get_arg_name(pat: &Pat) -> Option<ast::Name> {
1007 PatKind::Binding(.., ident, None) => Some(ident.name),
1008 PatKind::Ref(ref subpat, _) => get_arg_name(subpat),
1013 pub fn int_bits(tcx: TyCtxt<'_, '_, '_>, ity: ast::IntTy) -> u64 {
1014 layout::Integer::from_attr(&tcx, attr::IntType::SignedInt(ity))
1019 #[allow(clippy::cast_possible_wrap)]
1020 /// Turn a constant int byte representation into an i128
1021 pub fn sext(tcx: TyCtxt<'_, '_, '_>, u: u128, ity: ast::IntTy) -> i128 {
1022 let amt = 128 - int_bits(tcx, ity);
1023 ((u as i128) << amt) >> amt
1026 #[allow(clippy::cast_sign_loss)]
1027 /// clip unused bytes
1028 pub fn unsext(tcx: TyCtxt<'_, '_, '_>, u: i128, ity: ast::IntTy) -> u128 {
1029 let amt = 128 - int_bits(tcx, ity);
1030 ((u as u128) << amt) >> amt
1033 /// clip unused bytes
1034 pub fn clip(tcx: TyCtxt<'_, '_, '_>, u: u128, ity: ast::UintTy) -> u128 {
1035 let bits = layout::Integer::from_attr(&tcx, attr::IntType::UnsignedInt(ity))
1038 let amt = 128 - bits;
1042 /// Removes block comments from the given `Vec` of lines.
1047 /// without_block_comments(vec!["/*", "foo", "*/"]);
1050 /// without_block_comments(vec!["bar", "/*", "foo", "*/"]);
1051 /// // => vec!["bar"]
1053 pub fn without_block_comments(lines: Vec<&str>) -> Vec<&str> {
1054 let mut without = vec![];
1056 let mut nest_level = 0;
1059 if line.contains("/*") {
1062 } else if line.contains("*/") {
1067 if nest_level == 0 {
1075 pub fn any_parent_is_automatically_derived(tcx: TyCtxt<'_, '_, '_>, node: HirId) -> bool {
1076 let map = &tcx.hir();
1077 let mut prev_enclosing_node = None;
1078 let mut enclosing_node = node;
1079 while Some(enclosing_node) != prev_enclosing_node {
1080 if is_automatically_derived(map.attrs_by_hir_id(enclosing_node)) {
1083 prev_enclosing_node = Some(enclosing_node);
1084 enclosing_node = map.get_parent_item(enclosing_node);
1089 /// Returns true if ty has `iter` or `iter_mut` methods
1090 pub fn has_iter_method(cx: &LateContext<'_, '_>, probably_ref_ty: Ty<'_>) -> Option<&'static str> {
1091 // FIXME: instead of this hard-coded list, we should check if `<adt>::iter`
1092 // exists and has the desired signature. Unfortunately FnCtxt is not exported
1093 // so we can't use its `lookup_method` method.
1094 static INTO_ITER_COLLECTIONS: [&[&str]; 13] = [
1101 &paths::LINKED_LIST,
1102 &paths::BINARY_HEAP,
1110 let ty_to_check = match probably_ref_ty.sty {
1111 ty::Ref(_, ty_to_check, _) => ty_to_check,
1112 _ => probably_ref_ty,
1115 let def_id = match ty_to_check.sty {
1116 ty::Array(..) => return Some("array"),
1117 ty::Slice(..) => return Some("slice"),
1118 ty::Adt(adt, _) => adt.did,
1122 for path in &INTO_ITER_COLLECTIONS {
1123 if match_def_path(cx.tcx, def_id, path) {
1124 return Some(path.last().unwrap());
1132 use super::{trim_multiline, without_block_comments};
1135 fn test_trim_multiline_single_line() {
1136 assert_eq!("", trim_multiline("".into(), false));
1137 assert_eq!("...", trim_multiline("...".into(), false));
1138 assert_eq!("...", trim_multiline(" ...".into(), false));
1139 assert_eq!("...", trim_multiline("\t...".into(), false));
1140 assert_eq!("...", trim_multiline("\t\t...".into(), false));
1145 fn test_trim_multiline_block() {
1151 }", trim_multiline(" if x {
1161 }", trim_multiline(" if x {
1170 fn test_trim_multiline_empty_line() {
1177 }", trim_multiline(" if x {
1186 fn test_without_block_comments_lines_without_block_comments() {
1187 let result = without_block_comments(vec!["/*", "", "*/"]);
1188 println!("result: {:?}", result);
1189 assert!(result.is_empty());
1191 let result = without_block_comments(vec!["", "/*", "", "*/", "#[crate_type = \"lib\"]", "/*", "", "*/", ""]);
1192 assert_eq!(result, vec!["", "#[crate_type = \"lib\"]", ""]);
1194 let result = without_block_comments(vec!["/* rust", "", "*/"]);
1195 assert!(result.is_empty());
1197 let result = without_block_comments(vec!["/* one-line comment */"]);
1198 assert!(result.is_empty());
1200 let result = without_block_comments(vec!["/* nested", "/* multi-line", "comment", "*/", "test", "*/"]);
1201 assert!(result.is_empty());
1203 let result = without_block_comments(vec!["/* nested /* inline /* comment */ test */ */"]);
1204 assert!(result.is_empty());
1206 let result = without_block_comments(vec!["foo", "bar", "baz"]);
1207 assert_eq!(result, vec!["foo", "bar", "baz"]);