14 pub mod internal_lints;
19 pub use self::attrs::*;
20 pub use self::diagnostics::*;
21 pub use self::hir_utils::{SpanlessEq, SpanlessHash};
26 use if_chain::if_chain;
29 use rustc::hir::def::{DefKind, Res};
30 use rustc::hir::def_id::{DefId, CRATE_DEF_INDEX, LOCAL_CRATE};
31 use rustc::hir::intravisit::{NestedVisitorMap, Visitor};
34 use rustc::lint::{LateContext, Level, Lint, LintContext};
38 layout::{self, IntegerExt},
42 use rustc_errors::Applicability;
43 use smallvec::SmallVec;
44 use syntax::ast::{self, LitKind};
46 use syntax::ext::hygiene::ExpnKind;
47 use syntax::source_map::{Span, DUMMY_SP};
48 use syntax::symbol::{kw, Symbol};
50 use crate::consts::{constant, Constant};
51 use crate::reexport::*;
53 /// Returns `true` if the two spans come from differing expansions (i.e., one is
54 /// from a macro and one isn't).
55 pub fn differing_macro_contexts(lhs: Span, rhs: Span) -> bool {
56 rhs.ctxt() != lhs.ctxt()
59 /// Returns `true` if the given `NodeId` is inside a constant context
64 /// if in_constant(cx, expr.id) {
68 pub fn in_constant(cx: &LateContext<'_, '_>, id: HirId) -> bool {
69 let parent_id = cx.tcx.hir().get_parent_item(id);
70 match cx.tcx.hir().get(parent_id) {
72 node: ItemKind::Const(..),
75 | Node::TraitItem(&TraitItem {
76 node: TraitItemKind::Const(..),
79 | Node::ImplItem(&ImplItem {
80 node: ImplItemKind::Const(..),
85 node: ItemKind::Static(..),
89 node: ItemKind::Fn(_, header, ..),
91 }) => header.constness == Constness::Const,
92 Node::ImplItem(&ImplItem {
93 node: ImplItemKind::Method(ref sig, _),
95 }) => sig.header.constness == Constness::Const,
100 /// Returns `true` if this `span` was expanded by any macro.
101 pub fn in_macro(span: Span) -> bool {
102 if span.from_expansion() {
103 if let ExpnKind::Desugaring(..) = span.ctxt().outer_expn_data().kind {
112 // If the snippet is empty, it's an attribute that was inserted during macro
113 // expansion and we want to ignore those, because they could come from external
114 // sources that the user has no control over.
115 // For some reason these attributes don't have any expansion info on them, so
116 // we have to check it this way until there is a better way.
117 pub fn is_present_in_source<T: LintContext>(cx: &T, span: Span) -> bool {
118 if let Some(snippet) = snippet_opt(cx, span) {
119 if snippet.is_empty() {
126 /// Checks if type is struct, enum or union type with the given def path.
127 pub fn match_type(cx: &LateContext<'_, '_>, ty: Ty<'_>, path: &[&str]) -> bool {
129 ty::Adt(adt, _) => match_def_path(cx, adt.did, path),
134 /// Checks if the type is equal to a diagnostic item
135 pub fn is_type_diagnostic_item(cx: &LateContext<'_, '_>, ty: Ty<'_>, diag_item: Symbol) -> bool {
137 ty::Adt(adt, _) => cx.tcx.is_diagnostic_item(diag_item, adt.did),
142 /// Checks if the method call given in `expr` belongs to the given trait.
143 pub fn match_trait_method(cx: &LateContext<'_, '_>, expr: &Expr, path: &[&str]) -> bool {
144 let def_id = cx.tables.type_dependent_def_id(expr.hir_id).unwrap();
145 let trt_id = cx.tcx.trait_of_item(def_id);
146 if let Some(trt_id) = trt_id {
147 match_def_path(cx, trt_id, path)
153 /// Checks if an expression references a variable of the given name.
154 pub fn match_var(expr: &Expr, var: Name) -> bool {
155 if let ExprKind::Path(QPath::Resolved(None, ref path)) = expr.node {
156 if path.segments.len() == 1 && path.segments[0].ident.name == var {
163 pub fn last_path_segment(path: &QPath) -> &PathSegment {
165 QPath::Resolved(_, ref path) => path.segments.last().expect("A path must have at least one segment"),
166 QPath::TypeRelative(_, ref seg) => seg,
170 pub fn single_segment_path(path: &QPath) -> Option<&PathSegment> {
172 QPath::Resolved(_, ref path) if path.segments.len() == 1 => Some(&path.segments[0]),
173 QPath::Resolved(..) => None,
174 QPath::TypeRelative(_, ref seg) => Some(seg),
178 /// Matches a `QPath` against a slice of segment string literals.
180 /// There is also `match_path` if you are dealing with a `rustc::hir::Path` instead of a
181 /// `rustc::hir::QPath`.
185 /// match_qpath(path, &["std", "rt", "begin_unwind"])
187 pub fn match_qpath(path: &QPath, segments: &[&str]) -> bool {
189 QPath::Resolved(_, ref path) => match_path(path, segments),
190 QPath::TypeRelative(ref ty, ref segment) => match ty.node {
191 TyKind::Path(ref inner_path) => {
193 && match_qpath(inner_path, &segments[..(segments.len() - 1)])
194 && segment.ident.name.as_str() == segments[segments.len() - 1]
201 /// Matches a `Path` against a slice of segment string literals.
203 /// There is also `match_qpath` if you are dealing with a `rustc::hir::QPath` instead of a
204 /// `rustc::hir::Path`.
209 /// if match_path(&trait_ref.path, &paths::HASH) {
210 /// // This is the `std::hash::Hash` trait.
213 /// if match_path(ty_path, &["rustc", "lint", "Lint"]) {
214 /// // This is a `rustc::lint::Lint`.
217 pub fn match_path(path: &Path, segments: &[&str]) -> bool {
221 .zip(segments.iter().rev())
222 .all(|(a, b)| a.ident.name.as_str() == *b)
225 /// Matches a `Path` against a slice of segment string literals, e.g.
229 /// match_qpath(path, &["std", "rt", "begin_unwind"])
231 pub fn match_path_ast(path: &ast::Path, segments: &[&str]) -> bool {
235 .zip(segments.iter().rev())
236 .all(|(a, b)| a.ident.name.as_str() == *b)
239 /// Gets the definition associated to a path.
240 pub fn path_to_res(cx: &LateContext<'_, '_>, path: &[&str]) -> Option<(def::Res)> {
241 let crates = cx.tcx.crates();
244 .find(|&&krate| cx.tcx.crate_name(krate).as_str() == path[0]);
245 if let Some(krate) = krate {
248 index: CRATE_DEF_INDEX,
250 let mut items = cx.tcx.item_children(krate);
251 let mut path_it = path.iter().skip(1).peekable();
254 let segment = match path_it.next() {
255 Some(segment) => segment,
259 let result = SmallVec::<[_; 8]>::new();
260 for item in mem::replace(&mut items, cx.tcx.arena.alloc_slice(&result)).iter() {
261 if item.ident.name.as_str() == *segment {
262 if path_it.peek().is_none() {
263 return Some(item.res);
266 items = cx.tcx.item_children(item.res.def_id());
276 pub fn qpath_res(cx: &LateContext<'_, '_>, qpath: &hir::QPath, id: hir::HirId) -> Res {
278 hir::QPath::Resolved(_, path) => path.res,
279 hir::QPath::TypeRelative(..) => {
280 if cx.tcx.has_typeck_tables(id.owner_def_id()) {
281 cx.tcx.typeck_tables_of(id.owner_def_id()).qpath_res(qpath, id)
289 /// Convenience function to get the `DefId` of a trait by path.
290 /// It could be a trait or trait alias.
291 pub fn get_trait_def_id(cx: &LateContext<'_, '_>, path: &[&str]) -> Option<DefId> {
292 let res = match path_to_res(cx, path) {
298 Res::Def(DefKind::Trait, trait_id) | Res::Def(DefKind::TraitAlias, trait_id) => Some(trait_id),
299 Res::Err => unreachable!("this trait resolution is impossible: {:?}", &path),
304 /// Checks whether a type implements a trait.
305 /// See also `get_trait_def_id`.
306 pub fn implements_trait<'a, 'tcx>(
307 cx: &LateContext<'a, 'tcx>,
310 ty_params: &[Kind<'tcx>],
312 let ty = cx.tcx.erase_regions(&ty);
313 let obligation = cx.tcx.predicate_for_trait_def(
315 traits::ObligationCause::dummy(),
323 .enter(|infcx| infcx.predicate_must_hold_modulo_regions(&obligation))
326 /// Gets the `hir::TraitRef` of the trait the given method is implemented for.
328 /// Use this if you want to find the `TraitRef` of the `Add` trait in this example:
331 /// struct Point(isize, isize);
333 /// impl std::ops::Add for Point {
334 /// type Output = Self;
336 /// fn add(self, other: Self) -> Self {
341 pub fn trait_ref_of_method<'tcx>(cx: &LateContext<'_, 'tcx>, hir_id: HirId) -> Option<&'tcx TraitRef> {
342 // Get the implemented trait for the current function
343 let parent_impl = cx.tcx.hir().get_parent_item(hir_id);
345 if parent_impl != hir::CRATE_HIR_ID;
346 if let hir::Node::Item(item) = cx.tcx.hir().get(parent_impl);
347 if let hir::ItemKind::Impl(_, _, _, _, trait_ref, _, _) = &item.node;
348 then { return trait_ref.as_ref(); }
353 /// Checks whether this type implements `Drop`.
354 pub fn has_drop<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
355 match ty.ty_adt_def() {
356 Some(def) => def.has_dtor(cx.tcx),
361 /// Resolves the definition of a node from its `HirId`.
362 pub fn resolve_node(cx: &LateContext<'_, '_>, qpath: &QPath, id: HirId) -> Res {
363 cx.tables.qpath_res(qpath, id)
366 /// Returns the method names and argument list of nested method call expressions that make up
367 /// `expr`. method/span lists are sorted with the most recent call first.
368 pub fn method_calls(expr: &Expr, max_depth: usize) -> (Vec<Symbol>, Vec<&[Expr]>, Vec<Span>) {
369 let mut method_names = Vec::with_capacity(max_depth);
370 let mut arg_lists = Vec::with_capacity(max_depth);
371 let mut spans = Vec::with_capacity(max_depth);
373 let mut current = expr;
374 for _ in 0..max_depth {
375 if let ExprKind::MethodCall(path, span, args) = ¤t.node {
376 if args.iter().any(|e| e.span.from_expansion()) {
379 method_names.push(path.ident.name);
380 arg_lists.push(&**args);
388 (method_names, arg_lists, spans)
391 /// Matches an `Expr` against a chain of methods, and return the matched `Expr`s.
393 /// For example, if `expr` represents the `.baz()` in `foo.bar().baz()`,
394 /// `matched_method_chain(expr, &["bar", "baz"])` will return a `Vec`
395 /// containing the `Expr`s for
396 /// `.bar()` and `.baz()`
397 pub fn method_chain_args<'a>(expr: &'a Expr, methods: &[&str]) -> Option<Vec<&'a [Expr]>> {
398 let mut current = expr;
399 let mut matched = Vec::with_capacity(methods.len());
400 for method_name in methods.iter().rev() {
401 // method chains are stored last -> first
402 if let ExprKind::MethodCall(ref path, _, ref args) = current.node {
403 if path.ident.name.as_str() == *method_name {
404 if args.iter().any(|e| e.span.from_expansion()) {
407 matched.push(&**args); // build up `matched` backwards
408 current = &args[0] // go to parent expression
416 // Reverse `matched` so that it is in the same order as `methods`.
421 /// Returns `true` if the provided `def_id` is an entrypoint to a program.
422 pub fn is_entrypoint_fn(cx: &LateContext<'_, '_>, def_id: DefId) -> bool {
424 .entry_fn(LOCAL_CRATE)
425 .map_or(false, |(entry_fn_def_id, _)| def_id == entry_fn_def_id)
428 /// Gets the name of the item the expression is in, if available.
429 pub fn get_item_name(cx: &LateContext<'_, '_>, expr: &Expr) -> Option<Name> {
430 let parent_id = cx.tcx.hir().get_parent_item(expr.hir_id);
431 match cx.tcx.hir().find(parent_id) {
432 Some(Node::Item(&Item { ref ident, .. })) => Some(ident.name),
433 Some(Node::TraitItem(&TraitItem { ident, .. })) | Some(Node::ImplItem(&ImplItem { ident, .. })) => {
440 /// Gets the name of a `Pat`, if any.
441 pub fn get_pat_name(pat: &Pat) -> Option<Name> {
443 PatKind::Binding(.., ref spname, _) => Some(spname.name),
444 PatKind::Path(ref qpath) => single_segment_path(qpath).map(|ps| ps.ident.name),
445 PatKind::Box(ref p) | PatKind::Ref(ref p, _) => get_pat_name(&*p),
450 struct ContainsName {
455 impl<'tcx> Visitor<'tcx> for ContainsName {
456 fn visit_name(&mut self, _: Span, name: Name) {
457 if self.name == name {
461 fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
462 NestedVisitorMap::None
466 /// Checks if an `Expr` contains a certain name.
467 pub fn contains_name(name: Name, expr: &Expr) -> bool {
468 let mut cn = ContainsName { name, result: false };
473 /// Converts a span to a code snippet if available, otherwise use default.
475 /// This is useful if you want to provide suggestions for your lint or more generally, if you want
476 /// to convert a given `Span` to a `str`.
480 /// snippet(cx, expr.span, "..")
482 pub fn snippet<'a, T: LintContext>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
483 snippet_opt(cx, span).map_or_else(|| Cow::Borrowed(default), From::from)
486 /// Same as `snippet`, but it adapts the applicability level by following rules:
488 /// - Applicability level `Unspecified` will never be changed.
489 /// - If the span is inside a macro, change the applicability level to `MaybeIncorrect`.
490 /// - If the default value is used and the applicability level is `MachineApplicable`, change it to
491 /// `HasPlaceholders`
492 pub fn snippet_with_applicability<'a, T: LintContext>(
496 applicability: &mut Applicability,
498 if *applicability != Applicability::Unspecified && span.from_expansion() {
499 *applicability = Applicability::MaybeIncorrect;
501 snippet_opt(cx, span).map_or_else(
503 if *applicability == Applicability::MachineApplicable {
504 *applicability = Applicability::HasPlaceholders;
506 Cow::Borrowed(default)
512 /// Same as `snippet`, but should only be used when it's clear that the input span is
513 /// not a macro argument.
514 pub fn snippet_with_macro_callsite<'a, T: LintContext>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
515 snippet(cx, span.source_callsite(), default)
518 /// Converts a span to a code snippet. Returns `None` if not available.
519 pub fn snippet_opt<T: LintContext>(cx: &T, span: Span) -> Option<String> {
520 cx.sess().source_map().span_to_snippet(span).ok()
523 /// Converts a span (from a block) to a code snippet if available, otherwise use
525 /// This trims the code of indentation, except for the first line. Use it for
526 /// blocks or block-like
527 /// things which need to be printed as such.
531 /// snippet_block(cx, expr.span, "..")
533 pub fn snippet_block<'a, T: LintContext>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
534 let snip = snippet(cx, span, default);
535 trim_multiline(snip, true)
538 /// Same as `snippet_block`, but adapts the applicability level by the rules of
539 /// `snippet_with_applicabiliy`.
540 pub fn snippet_block_with_applicability<'a, T: LintContext>(
544 applicability: &mut Applicability,
546 let snip = snippet_with_applicability(cx, span, default, applicability);
547 trim_multiline(snip, true)
550 /// Returns a new Span that covers the full last line of the given Span
551 pub fn last_line_of_span<T: LintContext>(cx: &T, span: Span) -> Span {
552 let source_map_and_line = cx.sess().source_map().lookup_line(span.lo()).unwrap();
553 let line_no = source_map_and_line.line;
554 let line_start = &source_map_and_line.sf.lines[line_no];
555 Span::new(*line_start, span.hi(), span.ctxt())
558 /// Like `snippet_block`, but add braces if the expr is not an `ExprKind::Block`.
559 /// Also takes an `Option<String>` which can be put inside the braces.
560 pub fn expr_block<'a, T: LintContext>(cx: &T, expr: &Expr, option: Option<String>, default: &'a str) -> Cow<'a, str> {
561 let code = snippet_block(cx, expr.span, default);
562 let string = option.unwrap_or_default();
563 if expr.span.from_expansion() {
564 Cow::Owned(format!("{{ {} }}", snippet_with_macro_callsite(cx, expr.span, default)))
565 } else if let ExprKind::Block(_, _) = expr.node {
566 Cow::Owned(format!("{}{}", code, string))
567 } else if string.is_empty() {
568 Cow::Owned(format!("{{ {} }}", code))
570 Cow::Owned(format!("{{\n{};\n{}\n}}", code, string))
574 /// Trim indentation from a multiline string with possibility of ignoring the
576 pub fn trim_multiline(s: Cow<'_, str>, ignore_first: bool) -> Cow<'_, str> {
577 let s_space = trim_multiline_inner(s, ignore_first, ' ');
578 let s_tab = trim_multiline_inner(s_space, ignore_first, '\t');
579 trim_multiline_inner(s_tab, ignore_first, ' ')
582 fn trim_multiline_inner(s: Cow<'_, str>, ignore_first: bool, ch: char) -> Cow<'_, str> {
585 .skip(ignore_first as usize)
590 // ignore empty lines
591 Some(l.char_indices().find(|&(_, x)| x != ch).unwrap_or((l.len(), ch)).0)
601 if (ignore_first && i == 0) || l.is_empty() {
615 /// Gets the parent expression, if any –- this is useful to constrain a lint.
616 pub fn get_parent_expr<'c>(cx: &'c LateContext<'_, '_>, e: &Expr) -> Option<&'c Expr> {
617 let map = &cx.tcx.hir();
618 let hir_id = e.hir_id;
619 let parent_id = map.get_parent_node(hir_id);
620 if hir_id == parent_id {
623 map.find(parent_id).and_then(|node| {
624 if let Node::Expr(parent) = node {
632 pub fn get_enclosing_block<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, hir_id: HirId) -> Option<&'tcx Block> {
633 let map = &cx.tcx.hir();
634 let enclosing_node = map
635 .get_enclosing_scope(hir_id)
636 .and_then(|enclosing_id| map.find(enclosing_id));
637 if let Some(node) = enclosing_node {
639 Node::Block(block) => Some(block),
641 node: ItemKind::Fn(_, _, _, eid),
644 | Node::ImplItem(&ImplItem {
645 node: ImplItemKind::Method(_, eid),
647 }) => match cx.tcx.hir().body(eid).value.node {
648 ExprKind::Block(ref block, _) => Some(block),
658 /// Returns the base type for HIR references and pointers.
659 pub fn walk_ptrs_hir_ty(ty: &hir::Ty) -> &hir::Ty {
661 TyKind::Ptr(ref mut_ty) | TyKind::Rptr(_, ref mut_ty) => walk_ptrs_hir_ty(&mut_ty.ty),
666 /// Returns the base type for references and raw pointers.
667 pub fn walk_ptrs_ty(ty: Ty<'_>) -> Ty<'_> {
669 ty::Ref(_, ty, _) => walk_ptrs_ty(ty),
674 /// Returns the base type for references and raw pointers, and count reference
676 pub fn walk_ptrs_ty_depth(ty: Ty<'_>) -> (Ty<'_>, usize) {
677 fn inner(ty: Ty<'_>, depth: usize) -> (Ty<'_>, usize) {
679 ty::Ref(_, ty, _) => inner(ty, depth + 1),
686 /// Checks whether the given expression is a constant integer of the given value.
687 /// unlike `is_integer_literal`, this version does const folding
688 pub fn is_integer_const(cx: &LateContext<'_, '_>, e: &Expr, value: u128) -> bool {
689 if is_integer_literal(e, value) {
692 let map = cx.tcx.hir();
693 let parent_item = map.get_parent_item(e.hir_id);
694 if let Some((Constant::Int(v), _)) = map
695 .maybe_body_owned_by(parent_item)
696 .and_then(|body_id| constant(cx, cx.tcx.body_tables(body_id), e))
704 /// Checks whether the given expression is a constant literal of the given value.
705 pub fn is_integer_literal(expr: &Expr, value: u128) -> bool {
706 // FIXME: use constant folding
707 if let ExprKind::Lit(ref spanned) = expr.node {
708 if let LitKind::Int(v, _) = spanned.node {
715 /// Returns `true` if the given `Expr` has been coerced before.
717 /// Examples of coercions can be found in the Nomicon at
718 /// <https://doc.rust-lang.org/nomicon/coercions.html>.
720 /// See `rustc::ty::adjustment::Adjustment` and `rustc_typeck::check::coercion` for more
721 /// information on adjustments and coercions.
722 pub fn is_adjusted(cx: &LateContext<'_, '_>, e: &Expr) -> bool {
723 cx.tables.adjustments().get(e.hir_id).is_some()
726 /// Returns the pre-expansion span if is this comes from an expansion of the
728 /// See also `is_direct_expn_of`.
729 pub fn is_expn_of(mut span: Span, name: &str) -> Option<Span> {
731 if span.from_expansion() {
732 let data = span.ctxt().outer_expn_data();
733 let mac_name = data.kind.descr();
734 let new_span = data.call_site;
736 if mac_name.as_str() == name {
737 return Some(new_span);
747 /// Returns the pre-expansion span if the span directly comes from an expansion
748 /// of the macro `name`.
749 /// The difference with `is_expn_of` is that in
753 /// `42` is considered expanded from `foo!` and `bar!` by `is_expn_of` but only
755 /// `is_direct_expn_of`.
756 pub fn is_direct_expn_of(span: Span, name: &str) -> Option<Span> {
757 if span.from_expansion() {
758 let data = span.ctxt().outer_expn_data();
759 let mac_name = data.kind.descr();
760 let new_span = data.call_site;
762 if mac_name.as_str() == name {
772 /// Convenience function to get the return type of a function.
773 pub fn return_ty<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, fn_item: hir::HirId) -> Ty<'tcx> {
774 let fn_def_id = cx.tcx.hir().local_def_id(fn_item);
775 let ret_ty = cx.tcx.fn_sig(fn_def_id).output();
776 cx.tcx.erase_late_bound_regions(&ret_ty)
779 /// Checks if two types are the same.
781 /// This discards any lifetime annotations, too.
783 // FIXME: this works correctly for lifetimes bounds (`for <'a> Foo<'a>` ==
784 // `for <'b> Foo<'b>`, but not for type parameters).
785 pub fn same_tys<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, a: Ty<'tcx>, b: Ty<'tcx>) -> bool {
786 let a = cx.tcx.erase_late_bound_regions(&Binder::bind(a));
787 let b = cx.tcx.erase_late_bound_regions(&Binder::bind(b));
790 .enter(|infcx| infcx.can_eq(cx.param_env, a, b).is_ok())
793 /// Returns `true` if the given type is an `unsafe` function.
794 pub fn type_is_unsafe_function<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
796 ty::FnDef(..) | ty::FnPtr(_) => ty.fn_sig(cx.tcx).unsafety() == Unsafety::Unsafe,
801 pub fn is_copy<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
802 ty.is_copy_modulo_regions(cx.tcx.global_tcx(), cx.param_env, DUMMY_SP)
805 /// Checks if an expression is constructing a tuple-like enum variant or struct
806 pub fn is_ctor_function(cx: &LateContext<'_, '_>, expr: &Expr) -> bool {
807 if let ExprKind::Call(ref fun, _) = expr.node {
808 if let ExprKind::Path(ref qp) = fun.node {
810 cx.tables.qpath_res(qp, fun.hir_id),
811 def::Res::Def(DefKind::Variant, ..) | Res::Def(DefKind::Ctor(..), _)
818 /// Returns `true` if a pattern is refutable.
819 pub fn is_refutable(cx: &LateContext<'_, '_>, pat: &Pat) -> bool {
820 fn is_enum_variant(cx: &LateContext<'_, '_>, qpath: &QPath, id: HirId) -> bool {
822 cx.tables.qpath_res(qpath, id),
823 def::Res::Def(DefKind::Variant, ..) | Res::Def(DefKind::Ctor(def::CtorOf::Variant, _), _)
827 fn are_refutable<'a, I: Iterator<Item = &'a Pat>>(cx: &LateContext<'_, '_>, mut i: I) -> bool {
828 i.any(|pat| is_refutable(cx, pat))
832 PatKind::Binding(..) | PatKind::Wild => false,
833 PatKind::Box(ref pat) | PatKind::Ref(ref pat, _) => is_refutable(cx, pat),
834 PatKind::Lit(..) | PatKind::Range(..) => true,
835 PatKind::Path(ref qpath) => is_enum_variant(cx, qpath, pat.hir_id),
836 PatKind::Or(ref pats) | PatKind::Tuple(ref pats, _) => are_refutable(cx, pats.iter().map(|pat| &**pat)),
837 PatKind::Struct(ref qpath, ref fields, _) => {
838 if is_enum_variant(cx, qpath, pat.hir_id) {
841 are_refutable(cx, fields.iter().map(|field| &*field.pat))
844 PatKind::TupleStruct(ref qpath, ref pats, _) => {
845 if is_enum_variant(cx, qpath, pat.hir_id) {
848 are_refutable(cx, pats.iter().map(|pat| &**pat))
851 PatKind::Slice(ref head, ref middle, ref tail) => {
852 are_refutable(cx, head.iter().chain(middle).chain(tail.iter()).map(|pat| &**pat))
857 /// Checks for the `#[automatically_derived]` attribute all `#[derive]`d
858 /// implementations have.
859 pub fn is_automatically_derived(attrs: &[ast::Attribute]) -> bool {
860 attr::contains_name(attrs, sym!(automatically_derived))
863 /// Remove blocks around an expression.
865 /// Ie. `x`, `{ x }` and `{{{{ x }}}}` all give `x`. `{ x; y }` and `{}` return
867 pub fn remove_blocks(expr: &Expr) -> &Expr {
868 if let ExprKind::Block(ref block, _) = expr.node {
869 if block.stmts.is_empty() {
870 if let Some(ref expr) = block.expr {
883 pub fn is_self(slf: &Param) -> bool {
884 if let PatKind::Binding(.., name, _) = slf.pat.node {
885 name.name == kw::SelfLower
891 pub fn is_self_ty(slf: &hir::Ty) -> bool {
893 if let TyKind::Path(ref qp) = slf.node;
894 if let QPath::Resolved(None, ref path) = *qp;
895 if let Res::SelfTy(..) = path.res;
903 pub fn iter_input_pats<'tcx>(decl: &FnDecl, body: &'tcx Body) -> impl Iterator<Item = &'tcx Param> {
904 (0..decl.inputs.len()).map(move |i| &body.params[i])
907 /// Checks if a given expression is a match expression expanded from the `?`
908 /// operator or the `try` macro.
909 pub fn is_try(expr: &Expr) -> Option<&Expr> {
910 fn is_ok(arm: &Arm) -> bool {
912 if let PatKind::TupleStruct(ref path, ref pat, None) = arm.pats[0].node;
913 if match_qpath(path, &paths::RESULT_OK[1..]);
914 if let PatKind::Binding(_, hir_id, _, None) = pat[0].node;
915 if let ExprKind::Path(QPath::Resolved(None, ref path)) = arm.body.node;
916 if let Res::Local(lid) = path.res;
925 fn is_err(arm: &Arm) -> bool {
926 if let PatKind::TupleStruct(ref path, _, _) = arm.pats[0].node {
927 match_qpath(path, &paths::RESULT_ERR[1..])
933 if let ExprKind::Match(_, ref arms, ref source) = expr.node {
934 // desugared from a `?` operator
935 if let MatchSource::TryDesugar = *source {
941 if arms[0].pats.len() == 1 && arms[0].guard.is_none();
942 if arms[1].pats.len() == 1 && arms[1].guard.is_none();
943 if (is_ok(&arms[0]) && is_err(&arms[1])) ||
944 (is_ok(&arms[1]) && is_err(&arms[0]));
954 /// Returns `true` if the lint is allowed in the current context
956 /// Useful for skipping long running code when it's unnecessary
957 pub fn is_allowed(cx: &LateContext<'_, '_>, lint: &'static Lint, id: HirId) -> bool {
958 cx.tcx.lint_level_at_node(lint, id).0 == Level::Allow
961 pub fn get_arg_name(pat: &Pat) -> Option<ast::Name> {
963 PatKind::Binding(.., ident, None) => Some(ident.name),
964 PatKind::Ref(ref subpat, _) => get_arg_name(subpat),
969 pub fn int_bits(tcx: TyCtxt<'_>, ity: ast::IntTy) -> u64 {
970 layout::Integer::from_attr(&tcx, attr::IntType::SignedInt(ity))
975 #[allow(clippy::cast_possible_wrap)]
976 /// Turn a constant int byte representation into an i128
977 pub fn sext(tcx: TyCtxt<'_>, u: u128, ity: ast::IntTy) -> i128 {
978 let amt = 128 - int_bits(tcx, ity);
979 ((u as i128) << amt) >> amt
982 #[allow(clippy::cast_sign_loss)]
983 /// clip unused bytes
984 pub fn unsext(tcx: TyCtxt<'_>, u: i128, ity: ast::IntTy) -> u128 {
985 let amt = 128 - int_bits(tcx, ity);
986 ((u as u128) << amt) >> amt
989 /// clip unused bytes
990 pub fn clip(tcx: TyCtxt<'_>, u: u128, ity: ast::UintTy) -> u128 {
991 let bits = layout::Integer::from_attr(&tcx, attr::IntType::UnsignedInt(ity))
994 let amt = 128 - bits;
998 /// Removes block comments from the given `Vec` of lines.
1003 /// without_block_comments(vec!["/*", "foo", "*/"]);
1006 /// without_block_comments(vec!["bar", "/*", "foo", "*/"]);
1007 /// // => vec!["bar"]
1009 pub fn without_block_comments(lines: Vec<&str>) -> Vec<&str> {
1010 let mut without = vec![];
1012 let mut nest_level = 0;
1015 if line.contains("/*") {
1018 } else if line.contains("*/") {
1023 if nest_level == 0 {
1031 pub fn any_parent_is_automatically_derived(tcx: TyCtxt<'_>, node: HirId) -> bool {
1032 let map = &tcx.hir();
1033 let mut prev_enclosing_node = None;
1034 let mut enclosing_node = node;
1035 while Some(enclosing_node) != prev_enclosing_node {
1036 if is_automatically_derived(map.attrs(enclosing_node)) {
1039 prev_enclosing_node = Some(enclosing_node);
1040 enclosing_node = map.get_parent_item(enclosing_node);
1045 /// Returns true if ty has `iter` or `iter_mut` methods
1046 pub fn has_iter_method(cx: &LateContext<'_, '_>, probably_ref_ty: Ty<'_>) -> Option<&'static str> {
1047 // FIXME: instead of this hard-coded list, we should check if `<adt>::iter`
1048 // exists and has the desired signature. Unfortunately FnCtxt is not exported
1049 // so we can't use its `lookup_method` method.
1050 let into_iter_collections: [&[&str]; 13] = [
1057 &paths::LINKED_LIST,
1058 &paths::BINARY_HEAP,
1066 let ty_to_check = match probably_ref_ty.sty {
1067 ty::Ref(_, ty_to_check, _) => ty_to_check,
1068 _ => probably_ref_ty,
1071 let def_id = match ty_to_check.sty {
1072 ty::Array(..) => return Some("array"),
1073 ty::Slice(..) => return Some("slice"),
1074 ty::Adt(adt, _) => adt.did,
1078 for path in &into_iter_collections {
1079 if match_def_path(cx, def_id, path) {
1080 return Some(*path.last().unwrap());
1088 use super::{trim_multiline, without_block_comments};
1091 fn test_trim_multiline_single_line() {
1092 assert_eq!("", trim_multiline("".into(), false));
1093 assert_eq!("...", trim_multiline("...".into(), false));
1094 assert_eq!("...", trim_multiline(" ...".into(), false));
1095 assert_eq!("...", trim_multiline("\t...".into(), false));
1096 assert_eq!("...", trim_multiline("\t\t...".into(), false));
1101 fn test_trim_multiline_block() {
1107 }", trim_multiline(" if x {
1117 }", trim_multiline(" if x {
1126 fn test_trim_multiline_empty_line() {
1133 }", trim_multiline(" if x {
1142 fn test_without_block_comments_lines_without_block_comments() {
1143 let result = without_block_comments(vec!["/*", "", "*/"]);
1144 println!("result: {:?}", result);
1145 assert!(result.is_empty());
1147 let result = without_block_comments(vec!["", "/*", "", "*/", "#[crate_type = \"lib\"]", "/*", "", "*/", ""]);
1148 assert_eq!(result, vec!["", "#[crate_type = \"lib\"]", ""]);
1150 let result = without_block_comments(vec!["/* rust", "", "*/"]);
1151 assert!(result.is_empty());
1153 let result = without_block_comments(vec!["/* one-line comment */"]);
1154 assert!(result.is_empty());
1156 let result = without_block_comments(vec!["/* nested", "/* multi-line", "comment", "*/", "test", "*/"]);
1157 assert!(result.is_empty());
1159 let result = without_block_comments(vec!["/* nested /* inline /* comment */ test */ */"]);
1160 assert!(result.is_empty());
1162 let result = without_block_comments(vec!["foo", "bar", "baz"]);
1163 assert_eq!(result, vec!["foo", "bar", "baz"]);
1167 pub fn match_def_path<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, did: DefId, syms: &[&str]) -> bool {
1168 let path = cx.get_def_path(did);
1169 path.len() == syms.len() && path.into_iter().zip(syms.iter()).all(|(a, &b)| a.as_str() == b)