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<&'static str> {
224 AbsolutePathPrinter { tcx }
225 .print_def_path(def_id, &[])
228 .map(LocalInternedString::get)
232 /// Checks if type is struct, enum or union type with the given def path.
233 pub fn match_type(cx: &LateContext<'_, '_>, ty: Ty<'_>, path: &[&str]) -> bool {
235 ty::Adt(adt, _) => match_def_path(cx.tcx, adt.did, path),
240 /// Checks if the method call given in `expr` belongs to the given trait.
241 pub fn match_trait_method(cx: &LateContext<'_, '_>, expr: &Expr, path: &[&str]) -> bool {
242 let method_call = cx.tables.type_dependent_defs()[expr.hir_id];
243 let trt_id = cx.tcx.trait_of_item(method_call.def_id());
244 if let Some(trt_id) = trt_id {
245 match_def_path(cx.tcx, trt_id, path)
251 /// Checks if an expression references a variable of the given name.
252 pub fn match_var(expr: &Expr, var: Name) -> bool {
253 if let ExprKind::Path(QPath::Resolved(None, ref path)) = expr.node {
254 if path.segments.len() == 1 && path.segments[0].ident.name == var {
261 pub fn last_path_segment(path: &QPath) -> &PathSegment {
263 QPath::Resolved(_, ref path) => path.segments.last().expect("A path must have at least one segment"),
264 QPath::TypeRelative(_, ref seg) => seg,
268 pub fn single_segment_path(path: &QPath) -> Option<&PathSegment> {
270 QPath::Resolved(_, ref path) if path.segments.len() == 1 => Some(&path.segments[0]),
271 QPath::Resolved(..) => None,
272 QPath::TypeRelative(_, ref seg) => Some(seg),
276 /// Matches a `QPath` against a slice of segment string literals.
278 /// There is also `match_path` if you are dealing with a `rustc::hir::Path` instead of a
279 /// `rustc::hir::QPath`.
283 /// match_qpath(path, &["std", "rt", "begin_unwind"])
285 pub fn match_qpath(path: &QPath, segments: &[&str]) -> bool {
287 QPath::Resolved(_, ref path) => match_path(path, segments),
288 QPath::TypeRelative(ref ty, ref segment) => match ty.node {
289 TyKind::Path(ref inner_path) => {
291 && match_qpath(inner_path, &segments[..(segments.len() - 1)])
292 && segment.ident.name == segments[segments.len() - 1]
299 /// Matches a `Path` against a slice of segment string literals.
301 /// There is also `match_qpath` if you are dealing with a `rustc::hir::QPath` instead of a
302 /// `rustc::hir::Path`.
307 /// if match_path(&trait_ref.path, &paths::HASH) {
308 /// // This is the `std::hash::Hash` trait.
311 /// if match_path(ty_path, &["rustc", "lint", "Lint"]) {
312 /// // This is a `rustc::lint::Lint`.
315 pub fn match_path(path: &Path, segments: &[&str]) -> bool {
319 .zip(segments.iter().rev())
320 .all(|(a, b)| a.ident.name == *b)
323 /// Matches a `Path` against a slice of segment string literals, e.g.
327 /// match_qpath(path, &["std", "rt", "begin_unwind"])
329 pub fn match_path_ast(path: &ast::Path, segments: &[&str]) -> bool {
333 .zip(segments.iter().rev())
334 .all(|(a, b)| a.ident.name == *b)
337 /// Gets the definition associated to a path.
338 pub fn path_to_def(cx: &LateContext<'_, '_>, path: &[&str]) -> Option<def::Def> {
339 let crates = cx.tcx.crates();
340 let krate = crates.iter().find(|&&krate| cx.tcx.crate_name(krate) == path[0]);
341 if let Some(krate) = krate {
344 index: CRATE_DEF_INDEX,
346 let mut items = cx.tcx.item_children(krate);
347 let mut path_it = path.iter().skip(1).peekable();
350 let segment = match path_it.next() {
351 Some(segment) => segment,
355 for item in mem::replace(&mut items, Lrc::new(vec![])).iter() {
356 if item.ident.name == *segment {
357 if path_it.peek().is_none() {
358 return Some(item.def);
361 items = cx.tcx.item_children(item.def.def_id());
371 /// Convenience function to get the `DefId` of a trait by path.
372 pub fn get_trait_def_id(cx: &LateContext<'_, '_>, path: &[&str]) -> Option<DefId> {
373 let def = match path_to_def(cx, path) {
379 def::Def::Trait(trait_id) => Some(trait_id),
384 /// Checks whether a type implements a trait.
385 /// See also `get_trait_def_id`.
386 pub fn implements_trait<'a, 'tcx>(
387 cx: &LateContext<'a, 'tcx>,
390 ty_params: &[Kind<'tcx>],
392 let ty = cx.tcx.erase_regions(&ty);
393 let obligation = cx.tcx.predicate_for_trait_def(
395 traits::ObligationCause::dummy(),
403 .enter(|infcx| infcx.predicate_must_hold_modulo_regions(&obligation))
406 /// Gets the `hir::TraitRef` of the trait the given method is implemented for.
408 /// Use this if you want to find the `TraitRef` of the `Add` trait in this example:
411 /// struct Point(isize, isize);
413 /// impl std::ops::Add for Point {
414 /// type Output = Self;
416 /// fn add(self, other: Self) -> Self {
421 pub fn trait_ref_of_method(cx: &LateContext<'_, '_>, hir_id: HirId) -> Option<TraitRef> {
422 // Get the implemented trait for the current function
423 let parent_impl = cx.tcx.hir().get_parent_item(hir_id);
425 if parent_impl != hir::CRATE_HIR_ID;
426 if let hir::Node::Item(item) = cx.tcx.hir().get_by_hir_id(parent_impl);
427 if let hir::ItemKind::Impl(_, _, _, _, trait_ref, _, _) = &item.node;
428 then { return trait_ref.clone(); }
433 /// Checks whether this type implements `Drop`.
434 pub fn has_drop<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
435 match ty.ty_adt_def() {
436 Some(def) => def.has_dtor(cx.tcx),
441 /// Resolves the definition of a node from its `HirId`.
442 pub fn resolve_node(cx: &LateContext<'_, '_>, qpath: &QPath, id: HirId) -> def::Def {
443 cx.tables.qpath_def(qpath, id)
446 /// Returns the method names and argument list of nested method call expressions that make up
448 pub fn method_calls<'a>(expr: &'a Expr, max_depth: usize) -> (Vec<Symbol>, Vec<&'a [Expr]>) {
449 let mut method_names = Vec::with_capacity(max_depth);
450 let mut arg_lists = Vec::with_capacity(max_depth);
452 let mut current = expr;
453 for _ in 0..max_depth {
454 if let ExprKind::MethodCall(path, _, args) = ¤t.node {
455 if args.iter().any(|e| in_macro(e.span)) {
458 method_names.push(path.ident.name);
459 arg_lists.push(&**args);
466 (method_names, arg_lists)
469 /// Matches an `Expr` against a chain of methods, and return the matched `Expr`s.
471 /// For example, if `expr` represents the `.baz()` in `foo.bar().baz()`,
472 /// `matched_method_chain(expr, &["bar", "baz"])` will return a `Vec`
473 /// containing the `Expr`s for
474 /// `.bar()` and `.baz()`
475 pub fn method_chain_args<'a>(expr: &'a Expr, methods: &[&str]) -> Option<Vec<&'a [Expr]>> {
476 let mut current = expr;
477 let mut matched = Vec::with_capacity(methods.len());
478 for method_name in methods.iter().rev() {
479 // method chains are stored last -> first
480 if let ExprKind::MethodCall(ref path, _, ref args) = current.node {
481 if path.ident.name == *method_name {
482 if args.iter().any(|e| in_macro(e.span)) {
485 matched.push(&**args); // build up `matched` backwards
486 current = &args[0] // go to parent expression
494 // Reverse `matched` so that it is in the same order as `methods`.
499 /// Returns `true` if the provided `def_id` is an entrypoint to a program.
500 pub fn is_entrypoint_fn(cx: &LateContext<'_, '_>, def_id: DefId) -> bool {
501 if let Some((entry_fn_def_id, _)) = cx.tcx.entry_fn(LOCAL_CRATE) {
502 return def_id == entry_fn_def_id;
507 /// Gets the name of the item the expression is in, if available.
508 pub fn get_item_name(cx: &LateContext<'_, '_>, expr: &Expr) -> Option<Name> {
509 let parent_id = cx.tcx.hir().get_parent_item(expr.hir_id);
510 match cx.tcx.hir().find_by_hir_id(parent_id) {
511 Some(Node::Item(&Item { ref ident, .. })) => Some(ident.name),
512 Some(Node::TraitItem(&TraitItem { ident, .. })) | Some(Node::ImplItem(&ImplItem { ident, .. })) => {
519 /// Gets the name of a `Pat`, if any.
520 pub fn get_pat_name(pat: &Pat) -> Option<Name> {
522 PatKind::Binding(.., ref spname, _) => Some(spname.name),
523 PatKind::Path(ref qpath) => single_segment_path(qpath).map(|ps| ps.ident.name),
524 PatKind::Box(ref p) | PatKind::Ref(ref p, _) => get_pat_name(&*p),
529 struct ContainsName {
534 impl<'tcx> Visitor<'tcx> for ContainsName {
535 fn visit_name(&mut self, _: Span, name: Name) {
536 if self.name == name {
540 fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
541 NestedVisitorMap::None
545 /// Checks if an `Expr` contains a certain name.
546 pub fn contains_name(name: Name, expr: &Expr) -> bool {
547 let mut cn = ContainsName { name, result: false };
552 /// Converts a span to a code snippet if available, otherwise use default.
554 /// This is useful if you want to provide suggestions for your lint or more generally, if you want
555 /// to convert a given `Span` to a `str`.
559 /// snippet(cx, expr.span, "..")
561 pub fn snippet<'a, 'b, T: LintContext<'b>>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
562 snippet_opt(cx, span).map_or_else(|| Cow::Borrowed(default), From::from)
565 /// Same as `snippet`, but it adapts the applicability level by following rules:
567 /// - Applicability level `Unspecified` will never be changed.
568 /// - If the span is inside a macro, change the applicability level to `MaybeIncorrect`.
569 /// - If the default value is used and the applicability level is `MachineApplicable`, change it to
570 /// `HasPlaceholders`
571 pub fn snippet_with_applicability<'a, 'b, T: LintContext<'b>>(
575 applicability: &mut Applicability,
577 if *applicability != Applicability::Unspecified && in_macro(span) {
578 *applicability = Applicability::MaybeIncorrect;
580 snippet_opt(cx, span).map_or_else(
582 if *applicability == Applicability::MachineApplicable {
583 *applicability = Applicability::HasPlaceholders;
585 Cow::Borrowed(default)
591 /// Same as `snippet`, but should only be used when it's clear that the input span is
592 /// not a macro argument.
593 pub fn snippet_with_macro_callsite<'a, 'b, T: LintContext<'b>>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
594 snippet(cx, span.source_callsite(), default)
597 /// Converts a span to a code snippet. Returns `None` if not available.
598 pub fn snippet_opt<'a, T: LintContext<'a>>(cx: &T, span: Span) -> Option<String> {
599 cx.sess().source_map().span_to_snippet(span).ok()
602 /// Converts a span (from a block) to a code snippet if available, otherwise use
604 /// This trims the code of indentation, except for the first line. Use it for
605 /// blocks or block-like
606 /// things which need to be printed as such.
610 /// snippet_block(cx, expr.span, "..")
612 pub fn snippet_block<'a, 'b, T: LintContext<'b>>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
613 let snip = snippet(cx, span, default);
614 trim_multiline(snip, true)
617 /// Same as `snippet_block`, but adapts the applicability level by the rules of
618 /// `snippet_with_applicabiliy`.
619 pub fn snippet_block_with_applicability<'a, 'b, T: LintContext<'b>>(
623 applicability: &mut Applicability,
625 let snip = snippet_with_applicability(cx, span, default, applicability);
626 trim_multiline(snip, true)
629 /// Returns a new Span that covers the full last line of the given Span
630 pub fn last_line_of_span<'a, T: LintContext<'a>>(cx: &T, span: Span) -> Span {
631 let source_map_and_line = cx.sess().source_map().lookup_line(span.lo()).unwrap();
632 let line_no = source_map_and_line.line;
633 let line_start = &source_map_and_line.sf.lines[line_no];
634 Span::new(*line_start, span.hi(), span.ctxt())
637 /// Like `snippet_block`, but add braces if the expr is not an `ExprKind::Block`.
638 /// Also takes an `Option<String>` which can be put inside the braces.
639 pub fn expr_block<'a, 'b, T: LintContext<'b>>(
642 option: Option<String>,
645 let code = snippet_block(cx, expr.span, default);
646 let string = option.unwrap_or_default();
647 if in_macro(expr.span) {
648 Cow::Owned(format!("{{ {} }}", snippet_with_macro_callsite(cx, expr.span, default)))
649 } else if let ExprKind::Block(_, _) = expr.node {
650 Cow::Owned(format!("{}{}", code, string))
651 } else if string.is_empty() {
652 Cow::Owned(format!("{{ {} }}", code))
654 Cow::Owned(format!("{{\n{};\n{}\n}}", code, string))
658 /// Trim indentation from a multiline string with possibility of ignoring the
660 pub fn trim_multiline(s: Cow<'_, str>, ignore_first: bool) -> Cow<'_, str> {
661 let s_space = trim_multiline_inner(s, ignore_first, ' ');
662 let s_tab = trim_multiline_inner(s_space, ignore_first, '\t');
663 trim_multiline_inner(s_tab, ignore_first, ' ')
666 fn trim_multiline_inner(s: Cow<'_, str>, ignore_first: bool, ch: char) -> Cow<'_, str> {
669 .skip(ignore_first as usize)
674 // ignore empty lines
675 Some(l.char_indices().find(|&(_, x)| x != ch).unwrap_or((l.len(), ch)).0)
685 if (ignore_first && i == 0) || l.is_empty() {
699 /// Gets the parent expression, if any –- this is useful to constrain a lint.
700 pub fn get_parent_expr<'c>(cx: &'c LateContext<'_, '_>, e: &Expr) -> Option<&'c Expr> {
701 let map = &cx.tcx.hir();
702 let hir_id = e.hir_id;
703 let parent_id = map.get_parent_node_by_hir_id(hir_id);
704 if hir_id == parent_id {
707 map.find_by_hir_id(parent_id).and_then(|node| {
708 if let Node::Expr(parent) = node {
716 pub fn get_enclosing_block<'a, 'tcx: 'a>(cx: &LateContext<'a, 'tcx>, node: HirId) -> Option<&'tcx Block> {
717 let map = &cx.tcx.hir();
718 let node_id = map.hir_to_node_id(node);
719 let enclosing_node = map
720 .get_enclosing_scope(node_id)
721 .and_then(|enclosing_id| map.find(enclosing_id));
722 if let Some(node) = enclosing_node {
724 Node::Block(block) => Some(block),
726 node: ItemKind::Fn(_, _, _, eid),
729 | Node::ImplItem(&ImplItem {
730 node: ImplItemKind::Method(_, eid),
732 }) => match cx.tcx.hir().body(eid).value.node {
733 ExprKind::Block(ref block, _) => Some(block),
743 /// Returns the base type for HIR references and pointers.
744 pub fn walk_ptrs_hir_ty(ty: &hir::Ty) -> &hir::Ty {
746 TyKind::Ptr(ref mut_ty) | TyKind::Rptr(_, ref mut_ty) => walk_ptrs_hir_ty(&mut_ty.ty),
751 /// Returns the base type for references and raw pointers.
752 pub fn walk_ptrs_ty(ty: Ty<'_>) -> Ty<'_> {
754 ty::Ref(_, ty, _) => walk_ptrs_ty(ty),
759 /// Returns the base type for references and raw pointers, and count reference
761 pub fn walk_ptrs_ty_depth(ty: Ty<'_>) -> (Ty<'_>, usize) {
762 fn inner(ty: Ty<'_>, depth: usize) -> (Ty<'_>, usize) {
764 ty::Ref(_, ty, _) => inner(ty, depth + 1),
771 /// Checks whether the given expression is a constant literal of the given value.
772 pub fn is_integer_literal(expr: &Expr, value: u128) -> bool {
773 // FIXME: use constant folding
774 if let ExprKind::Lit(ref spanned) = expr.node {
775 if let LitKind::Int(v, _) = spanned.node {
782 /// Returns `true` if the given `Expr` has been coerced before.
784 /// Examples of coercions can be found in the Nomicon at
785 /// <https://doc.rust-lang.org/nomicon/coercions.html>.
787 /// See `rustc::ty::adjustment::Adjustment` and `rustc_typeck::check::coercion` for more
788 /// information on adjustments and coercions.
789 pub fn is_adjusted(cx: &LateContext<'_, '_>, e: &Expr) -> bool {
790 cx.tables.adjustments().get(e.hir_id).is_some()
793 /// Returns the pre-expansion span if is this comes from an expansion of the
795 /// See also `is_direct_expn_of`.
796 pub fn is_expn_of(mut span: Span, name: &str) -> Option<Span> {
798 let span_name_span = span
802 .map(|ei| (ei.format.name(), ei.call_site));
804 match span_name_span {
805 Some((mac_name, new_span)) if mac_name == name => return Some(new_span),
807 Some((_, new_span)) => span = new_span,
812 /// Returns the pre-expansion span if the span directly comes from an expansion
813 /// of the macro `name`.
814 /// The difference with `is_expn_of` is that in
818 /// `42` is considered expanded from `foo!` and `bar!` by `is_expn_of` but only
820 /// `is_direct_expn_of`.
821 pub fn is_direct_expn_of(span: Span, name: &str) -> Option<Span> {
822 let span_name_span = span
826 .map(|ei| (ei.format.name(), ei.call_site));
828 match span_name_span {
829 Some((mac_name, new_span)) if mac_name == name => Some(new_span),
834 /// Convenience function to get the return type of a function.
835 pub fn return_ty<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, fn_item: hir::HirId) -> Ty<'tcx> {
836 let fn_def_id = cx.tcx.hir().local_def_id_from_hir_id(fn_item);
837 let ret_ty = cx.tcx.fn_sig(fn_def_id).output();
838 cx.tcx.erase_late_bound_regions(&ret_ty)
841 /// Checks if two types are the same.
843 /// This discards any lifetime annotations, too.
845 // FIXME: this works correctly for lifetimes bounds (`for <'a> Foo<'a>` ==
846 // `for <'b> Foo<'b>`, but not for type parameters).
847 pub fn same_tys<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, a: Ty<'tcx>, b: Ty<'tcx>) -> bool {
848 let a = cx.tcx.erase_late_bound_regions(&Binder::bind(a));
849 let b = cx.tcx.erase_late_bound_regions(&Binder::bind(b));
852 .enter(|infcx| infcx.can_eq(cx.param_env, a, b).is_ok())
855 /// Returns `true` if the given type is an `unsafe` function.
856 pub fn type_is_unsafe_function<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
858 ty::FnDef(..) | ty::FnPtr(_) => ty.fn_sig(cx.tcx).unsafety() == Unsafety::Unsafe,
863 pub fn is_copy<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
864 ty.is_copy_modulo_regions(cx.tcx.global_tcx(), cx.param_env, DUMMY_SP)
867 /// Returns `true` if a pattern is refutable.
868 pub fn is_refutable(cx: &LateContext<'_, '_>, pat: &Pat) -> bool {
869 fn is_enum_variant(cx: &LateContext<'_, '_>, qpath: &QPath, id: HirId) -> bool {
871 cx.tables.qpath_def(qpath, id),
872 def::Def::Variant(..) | def::Def::Ctor(_, def::CtorOf::Variant, _)
876 fn are_refutable<'a, I: Iterator<Item = &'a Pat>>(cx: &LateContext<'_, '_>, mut i: I) -> bool {
877 i.any(|pat| is_refutable(cx, pat))
881 PatKind::Binding(..) | PatKind::Wild => false,
882 PatKind::Box(ref pat) | PatKind::Ref(ref pat, _) => is_refutable(cx, pat),
883 PatKind::Lit(..) | PatKind::Range(..) => true,
884 PatKind::Path(ref qpath) => is_enum_variant(cx, qpath, pat.hir_id),
885 PatKind::Tuple(ref pats, _) => are_refutable(cx, pats.iter().map(|pat| &**pat)),
886 PatKind::Struct(ref qpath, ref fields, _) => {
887 if is_enum_variant(cx, qpath, pat.hir_id) {
890 are_refutable(cx, fields.iter().map(|field| &*field.node.pat))
893 PatKind::TupleStruct(ref qpath, ref pats, _) => {
894 if is_enum_variant(cx, qpath, pat.hir_id) {
897 are_refutable(cx, pats.iter().map(|pat| &**pat))
900 PatKind::Slice(ref head, ref middle, ref tail) => {
901 are_refutable(cx, head.iter().chain(middle).chain(tail.iter()).map(|pat| &**pat))
906 /// Checks for the `#[automatically_derived]` attribute all `#[derive]`d
907 /// implementations have.
908 pub fn is_automatically_derived(attrs: &[ast::Attribute]) -> bool {
909 attr::contains_name(attrs, "automatically_derived")
912 /// Remove blocks around an expression.
914 /// Ie. `x`, `{ x }` and `{{{{ x }}}}` all give `x`. `{ x; y }` and `{}` return
916 pub fn remove_blocks(expr: &Expr) -> &Expr {
917 if let ExprKind::Block(ref block, _) = expr.node {
918 if block.stmts.is_empty() {
919 if let Some(ref expr) = block.expr {
932 pub fn is_self(slf: &Arg) -> bool {
933 if let PatKind::Binding(.., name, _) = slf.pat.node {
934 name.name == keywords::SelfLower.name()
940 pub fn is_self_ty(slf: &hir::Ty) -> bool {
942 if let TyKind::Path(ref qp) = slf.node;
943 if let QPath::Resolved(None, ref path) = *qp;
944 if let Def::SelfTy(..) = path.def;
952 pub fn iter_input_pats<'tcx>(decl: &FnDecl, body: &'tcx Body) -> impl Iterator<Item = &'tcx Arg> {
953 (0..decl.inputs.len()).map(move |i| &body.arguments[i])
956 /// Checks if a given expression is a match expression expanded from the `?`
957 /// operator or the `try` macro.
958 pub fn is_try<'a>(cx: &'_ LateContext<'_, '_>, expr: &'a Expr) -> Option<&'a Expr> {
959 fn is_ok(cx: &'_ LateContext<'_, '_>, arm: &Arm) -> bool {
961 if let PatKind::TupleStruct(ref path, ref pat, None) = arm.pats[0].node;
962 if match_qpath(path, &paths::RESULT_OK[1..]);
963 if let PatKind::Binding(_, hir_id, _, None) = pat[0].node;
964 if let ExprKind::Path(QPath::Resolved(None, ref path)) = arm.body.node;
965 if let Def::Local(lid) = path.def;
966 if cx.tcx.hir().node_to_hir_id(lid) == hir_id;
974 fn is_err(arm: &Arm) -> bool {
975 if let PatKind::TupleStruct(ref path, _, _) = arm.pats[0].node {
976 match_qpath(path, &paths::RESULT_ERR[1..])
982 if let ExprKind::Match(_, ref arms, ref source) = expr.node {
983 // desugared from a `?` operator
984 if let MatchSource::TryDesugar = *source {
990 if arms[0].pats.len() == 1 && arms[0].guard.is_none();
991 if arms[1].pats.len() == 1 && arms[1].guard.is_none();
992 if (is_ok(cx, &arms[0]) && is_err(&arms[1])) ||
993 (is_ok(cx, &arms[1]) && is_err(&arms[0]));
1003 /// Returns `true` if the lint is allowed in the current context
1005 /// Useful for skipping long running code when it's unnecessary
1006 pub fn is_allowed(cx: &LateContext<'_, '_>, lint: &'static Lint, id: HirId) -> bool {
1007 cx.tcx.lint_level_at_node(lint, id).0 == Level::Allow
1010 pub fn get_arg_name(pat: &Pat) -> Option<ast::Name> {
1012 PatKind::Binding(.., ident, None) => Some(ident.name),
1013 PatKind::Ref(ref subpat, _) => get_arg_name(subpat),
1018 pub fn int_bits(tcx: TyCtxt<'_, '_, '_>, ity: ast::IntTy) -> u64 {
1019 layout::Integer::from_attr(&tcx, attr::IntType::SignedInt(ity))
1024 #[allow(clippy::cast_possible_wrap)]
1025 /// Turn a constant int byte representation into an i128
1026 pub fn sext(tcx: TyCtxt<'_, '_, '_>, u: u128, ity: ast::IntTy) -> i128 {
1027 let amt = 128 - int_bits(tcx, ity);
1028 ((u as i128) << amt) >> amt
1031 #[allow(clippy::cast_sign_loss)]
1032 /// clip unused bytes
1033 pub fn unsext(tcx: TyCtxt<'_, '_, '_>, u: i128, ity: ast::IntTy) -> u128 {
1034 let amt = 128 - int_bits(tcx, ity);
1035 ((u as u128) << amt) >> amt
1038 /// clip unused bytes
1039 pub fn clip(tcx: TyCtxt<'_, '_, '_>, u: u128, ity: ast::UintTy) -> u128 {
1040 let bits = layout::Integer::from_attr(&tcx, attr::IntType::UnsignedInt(ity))
1043 let amt = 128 - bits;
1047 /// Removes block comments from the given `Vec` of lines.
1052 /// without_block_comments(vec!["/*", "foo", "*/"]);
1055 /// without_block_comments(vec!["bar", "/*", "foo", "*/"]);
1056 /// // => vec!["bar"]
1058 pub fn without_block_comments(lines: Vec<&str>) -> Vec<&str> {
1059 let mut without = vec![];
1061 let mut nest_level = 0;
1064 if line.contains("/*") {
1067 } else if line.contains("*/") {
1072 if nest_level == 0 {
1080 pub fn any_parent_is_automatically_derived(tcx: TyCtxt<'_, '_, '_>, node: HirId) -> bool {
1081 let map = &tcx.hir();
1082 let mut prev_enclosing_node = None;
1083 let mut enclosing_node = node;
1084 while Some(enclosing_node) != prev_enclosing_node {
1085 if is_automatically_derived(map.attrs_by_hir_id(enclosing_node)) {
1088 prev_enclosing_node = Some(enclosing_node);
1089 enclosing_node = map.get_parent_item(enclosing_node);
1094 /// Returns true if ty has `iter` or `iter_mut` methods
1095 pub fn has_iter_method(cx: &LateContext<'_, '_>, probably_ref_ty: Ty<'_>) -> Option<&'static str> {
1096 // FIXME: instead of this hard-coded list, we should check if `<adt>::iter`
1097 // exists and has the desired signature. Unfortunately FnCtxt is not exported
1098 // so we can't use its `lookup_method` method.
1099 static INTO_ITER_COLLECTIONS: [&[&str]; 13] = [
1106 &paths::LINKED_LIST,
1107 &paths::BINARY_HEAP,
1115 let ty_to_check = match probably_ref_ty.sty {
1116 ty::Ref(_, ty_to_check, _) => ty_to_check,
1117 _ => probably_ref_ty,
1120 let def_id = match ty_to_check.sty {
1121 ty::Array(..) => return Some("array"),
1122 ty::Slice(..) => return Some("slice"),
1123 ty::Adt(adt, _) => adt.did,
1127 for path in &INTO_ITER_COLLECTIONS {
1128 if match_def_path(cx.tcx, def_id, path) {
1129 return Some(path.last().unwrap());
1137 use super::{trim_multiline, without_block_comments};
1140 fn test_trim_multiline_single_line() {
1141 assert_eq!("", trim_multiline("".into(), false));
1142 assert_eq!("...", trim_multiline("...".into(), false));
1143 assert_eq!("...", trim_multiline(" ...".into(), false));
1144 assert_eq!("...", trim_multiline("\t...".into(), false));
1145 assert_eq!("...", trim_multiline("\t\t...".into(), false));
1150 fn test_trim_multiline_block() {
1156 }", trim_multiline(" if x {
1166 }", trim_multiline(" if x {
1175 fn test_trim_multiline_empty_line() {
1182 }", trim_multiline(" if x {
1191 fn test_without_block_comments_lines_without_block_comments() {
1192 let result = without_block_comments(vec!["/*", "", "*/"]);
1193 println!("result: {:?}", result);
1194 assert!(result.is_empty());
1196 let result = without_block_comments(vec!["", "/*", "", "*/", "#[crate_type = \"lib\"]", "/*", "", "*/", ""]);
1197 assert_eq!(result, vec!["", "#[crate_type = \"lib\"]", ""]);
1199 let result = without_block_comments(vec!["/* rust", "", "*/"]);
1200 assert!(result.is_empty());
1202 let result = without_block_comments(vec!["/* one-line comment */"]);
1203 assert!(result.is_empty());
1205 let result = without_block_comments(vec!["/* nested", "/* multi-line", "comment", "*/", "test", "*/"]);
1206 assert!(result.is_empty());
1208 let result = without_block_comments(vec!["/* nested /* inline /* comment */ test */ */"]);
1209 assert!(result.is_empty());
1211 let result = without_block_comments(vec!["foo", "bar", "baz"]);
1212 assert_eq!(result, vec!["foo", "bar", "baz"]);