11 pub mod internal_lints;
17 pub use self::attrs::*;
18 pub use self::diagnostics::*;
19 pub use self::hir_utils::{SpanlessEq, SpanlessHash};
24 use if_chain::if_chain;
27 use rustc::hir::def::{DefKind, Res};
28 use rustc::hir::def_id::{DefId, CRATE_DEF_INDEX, LOCAL_CRATE};
29 use rustc::hir::intravisit::{NestedVisitorMap, Visitor};
32 use rustc::lint::{LateContext, Level, Lint, LintContext};
36 layout::{self, IntegerExt},
40 use rustc_data_structures::sync::Lrc;
41 use rustc_errors::Applicability;
42 use syntax::ast::{self, LitKind};
44 use syntax::ext::hygiene::ExpnFormat;
45 use syntax::source_map::{Span, DUMMY_SP};
46 use syntax::symbol::{keywords, 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 or desugaring
94 pub fn in_macro_or_desugar(span: Span) -> bool {
95 span.ctxt().outer().expn_info().is_some()
98 /// Returns `true` if this `expn_info` was expanded by any macro.
99 pub fn in_macro(span: Span) -> bool {
100 if let Some(info) = span.ctxt().outer().expn_info() {
101 if let ExpnFormat::CompilerDesugaring(..) = info.format {
110 // If the snippet is empty, it's an attribute that was inserted during macro
111 // expansion and we want to ignore those, because they could come from external
112 // sources that the user has no control over.
113 // For some reason these attributes don't have any expansion info on them, so
114 // we have to check it this way until there is a better way.
115 pub fn is_present_in_source<'a, T: LintContext<'a>>(cx: &T, span: Span) -> bool {
116 if let Some(snippet) = snippet_opt(cx, span) {
117 if snippet.is_empty() {
124 /// Checks if type is struct, enum or union type with the given def path.
125 pub fn match_type(cx: &LateContext<'_, '_>, ty: Ty<'_>, path: &[Symbol]) -> bool {
127 ty::Adt(adt, _) => match_def_path(cx, adt.did, path),
132 /// Checks if the method call given in `expr` belongs to the given trait.
133 pub fn match_trait_method(cx: &LateContext<'_, '_>, expr: &Expr, path: &[Symbol]) -> bool {
134 let def_id = cx.tables.type_dependent_def_id(expr.hir_id).unwrap();
135 let trt_id = cx.tcx.trait_of_item(def_id);
136 if let Some(trt_id) = trt_id {
137 match_def_path(cx, trt_id, path)
143 /// Checks if an expression references a variable of the given name.
144 pub fn match_var(expr: &Expr, var: Name) -> bool {
145 if let ExprKind::Path(QPath::Resolved(None, ref path)) = expr.node {
146 if path.segments.len() == 1 && path.segments[0].ident.name == var {
153 pub fn last_path_segment(path: &QPath) -> &PathSegment {
155 QPath::Resolved(_, ref path) => path.segments.last().expect("A path must have at least one segment"),
156 QPath::TypeRelative(_, ref seg) => seg,
160 pub fn single_segment_path(path: &QPath) -> Option<&PathSegment> {
162 QPath::Resolved(_, ref path) if path.segments.len() == 1 => Some(&path.segments[0]),
163 QPath::Resolved(..) => None,
164 QPath::TypeRelative(_, ref seg) => Some(seg),
168 /// Matches a `QPath` against a slice of segment string literals.
170 /// There is also `match_path` if you are dealing with a `rustc::hir::Path` instead of a
171 /// `rustc::hir::QPath`.
175 /// match_qpath(path, &["std", "rt", "begin_unwind"])
177 pub fn match_qpath(path: &QPath, segments: &[Symbol]) -> bool {
179 QPath::Resolved(_, ref path) => match_path(path, segments),
180 QPath::TypeRelative(ref ty, ref segment) => match ty.node {
181 TyKind::Path(ref inner_path) => {
183 && match_qpath(inner_path, &segments[..(segments.len() - 1)])
184 && segment.ident.name == segments[segments.len() - 1]
191 /// Matches a `Path` against a slice of segment string literals.
193 /// There is also `match_qpath` if you are dealing with a `rustc::hir::QPath` instead of a
194 /// `rustc::hir::Path`.
199 /// if match_path(&trait_ref.path, &*paths::HASH) {
200 /// // This is the `std::hash::Hash` trait.
203 /// if match_path(ty_path, &["rustc", "lint", "Lint"]) {
204 /// // This is a `rustc::lint::Lint`.
207 pub fn match_path(path: &Path, segments: &[Symbol]) -> bool {
211 .zip(segments.iter().rev())
212 .all(|(a, b)| a.ident.name == *b)
215 /// Matches a `Path` against a slice of segment string literals, e.g.
219 /// match_qpath(path, &["std", "rt", "begin_unwind"])
221 pub fn match_path_ast(path: &ast::Path, segments: &[Symbol]) -> bool {
225 .zip(segments.iter().rev())
226 .all(|(a, b)| a.ident.name == *b)
229 /// Gets the definition associated to a path.
230 pub fn path_to_res(cx: &LateContext<'_, '_>, path: &[Symbol]) -> Option<(def::Res)> {
231 let crates = cx.tcx.crates();
232 let krate = crates.iter().find(|&&krate| cx.tcx.crate_name(krate) == path[0]);
233 if let Some(krate) = krate {
236 index: CRATE_DEF_INDEX,
238 let mut items = cx.tcx.item_children(krate);
239 let mut path_it = path.iter().skip(1).peekable();
242 let segment = match path_it.next() {
243 Some(segment) => segment,
247 for item in mem::replace(&mut items, Lrc::new(vec![])).iter() {
248 if item.ident.name == *segment {
249 if path_it.peek().is_none() {
250 return Some(item.res);
253 items = cx.tcx.item_children(item.res.def_id());
263 /// Convenience function to get the `DefId` of a trait by path.
264 pub fn get_trait_def_id(cx: &LateContext<'_, '_>, path: &[Symbol]) -> Option<DefId> {
265 let res = match path_to_res(cx, path) {
271 def::Res::Def(DefKind::Trait, trait_id) => Some(trait_id),
276 /// Checks whether a type implements a trait.
277 /// See also `get_trait_def_id`.
278 pub fn implements_trait<'a, 'tcx>(
279 cx: &LateContext<'a, 'tcx>,
282 ty_params: &[Kind<'tcx>],
284 let ty = cx.tcx.erase_regions(&ty);
285 let obligation = cx.tcx.predicate_for_trait_def(
287 traits::ObligationCause::dummy(),
295 .enter(|infcx| infcx.predicate_must_hold_modulo_regions(&obligation))
298 /// Gets the `hir::TraitRef` of the trait the given method is implemented for.
300 /// Use this if you want to find the `TraitRef` of the `Add` trait in this example:
303 /// struct Point(isize, isize);
305 /// impl std::ops::Add for Point {
306 /// type Output = Self;
308 /// fn add(self, other: Self) -> Self {
313 pub fn trait_ref_of_method(cx: &LateContext<'_, '_>, hir_id: HirId) -> Option<TraitRef> {
314 // Get the implemented trait for the current function
315 let parent_impl = cx.tcx.hir().get_parent_item(hir_id);
317 if parent_impl != hir::CRATE_HIR_ID;
318 if let hir::Node::Item(item) = cx.tcx.hir().get_by_hir_id(parent_impl);
319 if let hir::ItemKind::Impl(_, _, _, _, trait_ref, _, _) = &item.node;
320 then { return trait_ref.clone(); }
325 /// Checks whether this type implements `Drop`.
326 pub fn has_drop<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
327 match ty.ty_adt_def() {
328 Some(def) => def.has_dtor(cx.tcx),
333 /// Resolves the definition of a node from its `HirId`.
334 pub fn resolve_node(cx: &LateContext<'_, '_>, qpath: &QPath, id: HirId) -> Res {
335 cx.tables.qpath_res(qpath, id)
338 /// Returns the method names and argument list of nested method call expressions that make up
340 pub fn method_calls<'a>(expr: &'a Expr, max_depth: usize) -> (Vec<Symbol>, Vec<&'a [Expr]>) {
341 let mut method_names = Vec::with_capacity(max_depth);
342 let mut arg_lists = Vec::with_capacity(max_depth);
344 let mut current = expr;
345 for _ in 0..max_depth {
346 if let ExprKind::MethodCall(path, _, args) = ¤t.node {
347 if args.iter().any(|e| in_macro_or_desugar(e.span)) {
350 method_names.push(path.ident.name);
351 arg_lists.push(&**args);
358 (method_names, arg_lists)
361 /// Matches an `Expr` against a chain of methods, and return the matched `Expr`s.
363 /// For example, if `expr` represents the `.baz()` in `foo.bar().baz()`,
364 /// `matched_method_chain(expr, &["bar", "baz"])` will return a `Vec`
365 /// containing the `Expr`s for
366 /// `.bar()` and `.baz()`
367 pub fn method_chain_args<'a>(expr: &'a Expr, methods: &[Symbol]) -> Option<Vec<&'a [Expr]>> {
368 let mut current = expr;
369 let mut matched = Vec::with_capacity(methods.len());
370 for method_name in methods.iter().rev() {
371 // method chains are stored last -> first
372 if let ExprKind::MethodCall(ref path, _, ref args) = current.node {
373 if path.ident.name == *method_name {
374 if args.iter().any(|e| in_macro_or_desugar(e.span)) {
377 matched.push(&**args); // build up `matched` backwards
378 current = &args[0] // go to parent expression
386 // Reverse `matched` so that it is in the same order as `methods`.
391 /// Returns `true` if the provided `def_id` is an entrypoint to a program.
392 pub fn is_entrypoint_fn(cx: &LateContext<'_, '_>, def_id: DefId) -> bool {
393 if let Some((entry_fn_def_id, _)) = cx.tcx.entry_fn(LOCAL_CRATE) {
394 return def_id == entry_fn_def_id;
399 /// Gets the name of the item the expression is in, if available.
400 pub fn get_item_name(cx: &LateContext<'_, '_>, expr: &Expr) -> Option<Name> {
401 let parent_id = cx.tcx.hir().get_parent_item(expr.hir_id);
402 match cx.tcx.hir().find_by_hir_id(parent_id) {
403 Some(Node::Item(&Item { ref ident, .. })) => Some(ident.name),
404 Some(Node::TraitItem(&TraitItem { ident, .. })) | Some(Node::ImplItem(&ImplItem { ident, .. })) => {
411 /// Gets the name of a `Pat`, if any.
412 pub fn get_pat_name(pat: &Pat) -> Option<Name> {
414 PatKind::Binding(.., ref spname, _) => Some(spname.name),
415 PatKind::Path(ref qpath) => single_segment_path(qpath).map(|ps| ps.ident.name),
416 PatKind::Box(ref p) | PatKind::Ref(ref p, _) => get_pat_name(&*p),
421 struct ContainsName {
426 impl<'tcx> Visitor<'tcx> for ContainsName {
427 fn visit_name(&mut self, _: Span, name: Name) {
428 if self.name == name {
432 fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
433 NestedVisitorMap::None
437 /// Checks if an `Expr` contains a certain name.
438 pub fn contains_name(name: Name, expr: &Expr) -> bool {
439 let mut cn = ContainsName { name, result: false };
444 /// Converts a span to a code snippet if available, otherwise use default.
446 /// This is useful if you want to provide suggestions for your lint or more generally, if you want
447 /// to convert a given `Span` to a `str`.
451 /// snippet(cx, expr.span, "..")
453 pub fn snippet<'a, 'b, T: LintContext<'b>>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
454 snippet_opt(cx, span).map_or_else(|| Cow::Borrowed(default), From::from)
457 /// Same as `snippet`, but it adapts the applicability level by following rules:
459 /// - Applicability level `Unspecified` will never be changed.
460 /// - If the span is inside a macro, change the applicability level to `MaybeIncorrect`.
461 /// - If the default value is used and the applicability level is `MachineApplicable`, change it to
462 /// `HasPlaceholders`
463 pub fn snippet_with_applicability<'a, 'b, T: LintContext<'b>>(
467 applicability: &mut Applicability,
469 if *applicability != Applicability::Unspecified && in_macro_or_desugar(span) {
470 *applicability = Applicability::MaybeIncorrect;
472 snippet_opt(cx, span).map_or_else(
474 if *applicability == Applicability::MachineApplicable {
475 *applicability = Applicability::HasPlaceholders;
477 Cow::Borrowed(default)
483 /// Same as `snippet`, but should only be used when it's clear that the input span is
484 /// not a macro argument.
485 pub fn snippet_with_macro_callsite<'a, 'b, T: LintContext<'b>>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
486 snippet(cx, span.source_callsite(), default)
489 /// Converts a span to a code snippet. Returns `None` if not available.
490 pub fn snippet_opt<'a, T: LintContext<'a>>(cx: &T, span: Span) -> Option<String> {
491 cx.sess().source_map().span_to_snippet(span).ok()
494 /// Converts a span (from a block) to a code snippet if available, otherwise use
496 /// This trims the code of indentation, except for the first line. Use it for
497 /// blocks or block-like
498 /// things which need to be printed as such.
502 /// snippet_block(cx, expr.span, "..")
504 pub fn snippet_block<'a, 'b, T: LintContext<'b>>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
505 let snip = snippet(cx, span, default);
506 trim_multiline(snip, true)
509 /// Same as `snippet_block`, but adapts the applicability level by the rules of
510 /// `snippet_with_applicabiliy`.
511 pub fn snippet_block_with_applicability<'a, 'b, T: LintContext<'b>>(
515 applicability: &mut Applicability,
517 let snip = snippet_with_applicability(cx, span, default, applicability);
518 trim_multiline(snip, true)
521 /// Returns a new Span that covers the full last line of the given Span
522 pub fn last_line_of_span<'a, T: LintContext<'a>>(cx: &T, span: Span) -> Span {
523 let source_map_and_line = cx.sess().source_map().lookup_line(span.lo()).unwrap();
524 let line_no = source_map_and_line.line;
525 let line_start = &source_map_and_line.sf.lines[line_no];
526 Span::new(*line_start, span.hi(), span.ctxt())
529 /// Like `snippet_block`, but add braces if the expr is not an `ExprKind::Block`.
530 /// Also takes an `Option<String>` which can be put inside the braces.
531 pub fn expr_block<'a, 'b, T: LintContext<'b>>(
534 option: Option<String>,
537 let code = snippet_block(cx, expr.span, default);
538 let string = option.unwrap_or_default();
539 if in_macro_or_desugar(expr.span) {
540 Cow::Owned(format!("{{ {} }}", snippet_with_macro_callsite(cx, expr.span, default)))
541 } else if let ExprKind::Block(_, _) = expr.node {
542 Cow::Owned(format!("{}{}", code, string))
543 } else if string.is_empty() {
544 Cow::Owned(format!("{{ {} }}", code))
546 Cow::Owned(format!("{{\n{};\n{}\n}}", code, string))
550 /// Trim indentation from a multiline string with possibility of ignoring the
552 pub fn trim_multiline(s: Cow<'_, str>, ignore_first: bool) -> Cow<'_, str> {
553 let s_space = trim_multiline_inner(s, ignore_first, ' ');
554 let s_tab = trim_multiline_inner(s_space, ignore_first, '\t');
555 trim_multiline_inner(s_tab, ignore_first, ' ')
558 fn trim_multiline_inner(s: Cow<'_, str>, ignore_first: bool, ch: char) -> Cow<'_, str> {
561 .skip(ignore_first as usize)
566 // ignore empty lines
567 Some(l.char_indices().find(|&(_, x)| x != ch).unwrap_or((l.len(), ch)).0)
577 if (ignore_first && i == 0) || l.is_empty() {
591 /// Gets the parent expression, if any –- this is useful to constrain a lint.
592 pub fn get_parent_expr<'c>(cx: &'c LateContext<'_, '_>, e: &Expr) -> Option<&'c Expr> {
593 let map = &cx.tcx.hir();
594 let hir_id = e.hir_id;
595 let parent_id = map.get_parent_node_by_hir_id(hir_id);
596 if hir_id == parent_id {
599 map.find_by_hir_id(parent_id).and_then(|node| {
600 if let Node::Expr(parent) = node {
608 pub fn get_enclosing_block<'a, 'tcx: 'a>(cx: &LateContext<'a, 'tcx>, hir_id: HirId) -> Option<&'tcx Block> {
609 let map = &cx.tcx.hir();
610 let enclosing_node = map
611 .get_enclosing_scope(hir_id)
612 .and_then(|enclosing_id| map.find_by_hir_id(enclosing_id));
613 if let Some(node) = enclosing_node {
615 Node::Block(block) => Some(block),
617 node: ItemKind::Fn(_, _, _, eid),
620 | Node::ImplItem(&ImplItem {
621 node: ImplItemKind::Method(_, eid),
623 }) => match cx.tcx.hir().body(eid).value.node {
624 ExprKind::Block(ref block, _) => Some(block),
634 /// Returns the base type for HIR references and pointers.
635 pub fn walk_ptrs_hir_ty(ty: &hir::Ty) -> &hir::Ty {
637 TyKind::Ptr(ref mut_ty) | TyKind::Rptr(_, ref mut_ty) => walk_ptrs_hir_ty(&mut_ty.ty),
642 /// Returns the base type for references and raw pointers.
643 pub fn walk_ptrs_ty(ty: Ty<'_>) -> Ty<'_> {
645 ty::Ref(_, ty, _) => walk_ptrs_ty(ty),
650 /// Returns the base type for references and raw pointers, and count reference
652 pub fn walk_ptrs_ty_depth(ty: Ty<'_>) -> (Ty<'_>, usize) {
653 fn inner(ty: Ty<'_>, depth: usize) -> (Ty<'_>, usize) {
655 ty::Ref(_, ty, _) => inner(ty, depth + 1),
662 /// Checks whether the given expression is a constant literal of the given value.
663 pub fn is_integer_literal(expr: &Expr, value: u128) -> bool {
664 // FIXME: use constant folding
665 if let ExprKind::Lit(ref spanned) = expr.node {
666 if let LitKind::Int(v, _) = spanned.node {
673 /// Returns `true` if the given `Expr` has been coerced before.
675 /// Examples of coercions can be found in the Nomicon at
676 /// <https://doc.rust-lang.org/nomicon/coercions.html>.
678 /// See `rustc::ty::adjustment::Adjustment` and `rustc_typeck::check::coercion` for more
679 /// information on adjustments and coercions.
680 pub fn is_adjusted(cx: &LateContext<'_, '_>, e: &Expr) -> bool {
681 cx.tables.adjustments().get(e.hir_id).is_some()
684 /// Returns the pre-expansion span if is this comes from an expansion of the
686 /// See also `is_direct_expn_of`.
687 pub fn is_expn_of(mut span: Span, name: Symbol) -> Option<Span> {
689 let span_name_span = span
693 .map(|ei| (ei.format.name(), ei.call_site));
695 match span_name_span {
696 Some((mac_name, new_span)) if mac_name == name => return Some(new_span),
698 Some((_, new_span)) => span = new_span,
703 /// Returns the pre-expansion span if the span directly comes from an expansion
704 /// of the macro `name`.
705 /// The difference with `is_expn_of` is that in
709 /// `42` is considered expanded from `foo!` and `bar!` by `is_expn_of` but only
711 /// `is_direct_expn_of`.
712 pub fn is_direct_expn_of(span: Span, name: Symbol) -> Option<Span> {
713 let span_name_span = span
717 .map(|ei| (ei.format.name(), ei.call_site));
719 match span_name_span {
720 Some((mac_name, new_span)) if mac_name == name => Some(new_span),
725 /// Convenience function to get the return type of a function.
726 pub fn return_ty<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, fn_item: hir::HirId) -> Ty<'tcx> {
727 let fn_def_id = cx.tcx.hir().local_def_id_from_hir_id(fn_item);
728 let ret_ty = cx.tcx.fn_sig(fn_def_id).output();
729 cx.tcx.erase_late_bound_regions(&ret_ty)
732 /// Checks if two types are the same.
734 /// This discards any lifetime annotations, too.
736 // FIXME: this works correctly for lifetimes bounds (`for <'a> Foo<'a>` ==
737 // `for <'b> Foo<'b>`, but not for type parameters).
738 pub fn same_tys<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, a: Ty<'tcx>, b: Ty<'tcx>) -> bool {
739 let a = cx.tcx.erase_late_bound_regions(&Binder::bind(a));
740 let b = cx.tcx.erase_late_bound_regions(&Binder::bind(b));
743 .enter(|infcx| infcx.can_eq(cx.param_env, a, b).is_ok())
746 /// Returns `true` if the given type is an `unsafe` function.
747 pub fn type_is_unsafe_function<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
749 ty::FnDef(..) | ty::FnPtr(_) => ty.fn_sig(cx.tcx).unsafety() == Unsafety::Unsafe,
754 pub fn is_copy<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
755 ty.is_copy_modulo_regions(cx.tcx.global_tcx(), cx.param_env, DUMMY_SP)
758 /// Checks if an expression is constructing a tuple-like enum variant or struct
759 pub fn is_ctor_function(cx: &LateContext<'_, '_>, expr: &Expr) -> bool {
760 if let ExprKind::Call(ref fun, _) = expr.node {
761 if let ExprKind::Path(ref qp) = fun.node {
763 cx.tables.qpath_res(qp, fun.hir_id),
764 def::Res::Def(DefKind::Variant, ..) | Res::Def(DefKind::Ctor(..), _)
771 /// Returns `true` if a pattern is refutable.
772 pub fn is_refutable(cx: &LateContext<'_, '_>, pat: &Pat) -> bool {
773 fn is_enum_variant(cx: &LateContext<'_, '_>, qpath: &QPath, id: HirId) -> bool {
775 cx.tables.qpath_res(qpath, id),
776 def::Res::Def(DefKind::Variant, ..) | Res::Def(DefKind::Ctor(def::CtorOf::Variant, _), _)
780 fn are_refutable<'a, I: Iterator<Item = &'a Pat>>(cx: &LateContext<'_, '_>, mut i: I) -> bool {
781 i.any(|pat| is_refutable(cx, pat))
785 PatKind::Binding(..) | PatKind::Wild => false,
786 PatKind::Box(ref pat) | PatKind::Ref(ref pat, _) => is_refutable(cx, pat),
787 PatKind::Lit(..) | PatKind::Range(..) => true,
788 PatKind::Path(ref qpath) => is_enum_variant(cx, qpath, pat.hir_id),
789 PatKind::Tuple(ref pats, _) => are_refutable(cx, pats.iter().map(|pat| &**pat)),
790 PatKind::Struct(ref qpath, ref fields, _) => {
791 if is_enum_variant(cx, qpath, pat.hir_id) {
794 are_refutable(cx, fields.iter().map(|field| &*field.node.pat))
797 PatKind::TupleStruct(ref qpath, ref pats, _) => {
798 if is_enum_variant(cx, qpath, pat.hir_id) {
801 are_refutable(cx, pats.iter().map(|pat| &**pat))
804 PatKind::Slice(ref head, ref middle, ref tail) => {
805 are_refutable(cx, head.iter().chain(middle).chain(tail.iter()).map(|pat| &**pat))
810 /// Checks for the `#[automatically_derived]` attribute all `#[derive]`d
811 /// implementations have.
812 pub fn is_automatically_derived(attrs: &[ast::Attribute]) -> bool {
813 attr::contains_name(attrs, *sym::automatically_derived)
816 /// Remove blocks around an expression.
818 /// Ie. `x`, `{ x }` and `{{{{ x }}}}` all give `x`. `{ x; y }` and `{}` return
820 pub fn remove_blocks(expr: &Expr) -> &Expr {
821 if let ExprKind::Block(ref block, _) = expr.node {
822 if block.stmts.is_empty() {
823 if let Some(ref expr) = block.expr {
836 pub fn is_self(slf: &Arg) -> bool {
837 if let PatKind::Binding(.., name, _) = slf.pat.node {
838 name.name == keywords::SelfLower.name()
844 pub fn is_self_ty(slf: &hir::Ty) -> bool {
846 if let TyKind::Path(ref qp) = slf.node;
847 if let QPath::Resolved(None, ref path) = *qp;
848 if let Res::SelfTy(..) = path.res;
856 pub fn iter_input_pats<'tcx>(decl: &FnDecl, body: &'tcx Body) -> impl Iterator<Item = &'tcx Arg> {
857 (0..decl.inputs.len()).map(move |i| &body.arguments[i])
860 /// Checks if a given expression is a match expression expanded from the `?`
861 /// operator or the `try` macro.
862 pub fn is_try(expr: &Expr) -> Option<&Expr> {
863 fn is_ok(arm: &Arm) -> bool {
865 if let PatKind::TupleStruct(ref path, ref pat, None) = arm.pats[0].node;
866 if match_qpath(path, &paths::RESULT_OK[1..]);
867 if let PatKind::Binding(_, hir_id, _, None) = pat[0].node;
868 if let ExprKind::Path(QPath::Resolved(None, ref path)) = arm.body.node;
869 if let Res::Local(lid) = path.res;
878 fn is_err(arm: &Arm) -> bool {
879 if let PatKind::TupleStruct(ref path, _, _) = arm.pats[0].node {
880 match_qpath(path, &paths::RESULT_ERR[1..])
886 if let ExprKind::Match(_, ref arms, ref source) = expr.node {
887 // desugared from a `?` operator
888 if let MatchSource::TryDesugar = *source {
894 if arms[0].pats.len() == 1 && arms[0].guard.is_none();
895 if arms[1].pats.len() == 1 && arms[1].guard.is_none();
896 if (is_ok(&arms[0]) && is_err(&arms[1])) ||
897 (is_ok(&arms[1]) && is_err(&arms[0]));
907 /// Returns `true` if the lint is allowed in the current context
909 /// Useful for skipping long running code when it's unnecessary
910 pub fn is_allowed(cx: &LateContext<'_, '_>, lint: &'static Lint, id: HirId) -> bool {
911 cx.tcx.lint_level_at_node(lint, id).0 == Level::Allow
914 pub fn get_arg_name(pat: &Pat) -> Option<ast::Name> {
916 PatKind::Binding(.., ident, None) => Some(ident.name),
917 PatKind::Ref(ref subpat, _) => get_arg_name(subpat),
922 pub fn int_bits(tcx: TyCtxt<'_, '_, '_>, ity: ast::IntTy) -> u64 {
923 layout::Integer::from_attr(&tcx, attr::IntType::SignedInt(ity))
928 #[allow(clippy::cast_possible_wrap)]
929 /// Turn a constant int byte representation into an i128
930 pub fn sext(tcx: TyCtxt<'_, '_, '_>, u: u128, ity: ast::IntTy) -> i128 {
931 let amt = 128 - int_bits(tcx, ity);
932 ((u as i128) << amt) >> amt
935 #[allow(clippy::cast_sign_loss)]
936 /// clip unused bytes
937 pub fn unsext(tcx: TyCtxt<'_, '_, '_>, u: i128, ity: ast::IntTy) -> u128 {
938 let amt = 128 - int_bits(tcx, ity);
939 ((u as u128) << amt) >> amt
942 /// clip unused bytes
943 pub fn clip(tcx: TyCtxt<'_, '_, '_>, u: u128, ity: ast::UintTy) -> u128 {
944 let bits = layout::Integer::from_attr(&tcx, attr::IntType::UnsignedInt(ity))
947 let amt = 128 - bits;
951 /// Removes block comments from the given `Vec` of lines.
956 /// without_block_comments(vec!["/*", "foo", "*/"]);
959 /// without_block_comments(vec!["bar", "/*", "foo", "*/"]);
960 /// // => vec!["bar"]
962 pub fn without_block_comments(lines: Vec<&str>) -> Vec<&str> {
963 let mut without = vec![];
965 let mut nest_level = 0;
968 if line.contains("/*") {
971 } else if line.contains("*/") {
984 pub fn any_parent_is_automatically_derived(tcx: TyCtxt<'_, '_, '_>, node: HirId) -> bool {
985 let map = &tcx.hir();
986 let mut prev_enclosing_node = None;
987 let mut enclosing_node = node;
988 while Some(enclosing_node) != prev_enclosing_node {
989 if is_automatically_derived(map.attrs_by_hir_id(enclosing_node)) {
992 prev_enclosing_node = Some(enclosing_node);
993 enclosing_node = map.get_parent_item(enclosing_node);
998 /// Returns true if ty has `iter` or `iter_mut` methods
999 pub fn has_iter_method(cx: &LateContext<'_, '_>, probably_ref_ty: Ty<'_>) -> Option<Symbol> {
1000 // FIXME: instead of this hard-coded list, we should check if `<adt>::iter`
1001 // exists and has the desired signature. Unfortunately FnCtxt is not exported
1002 // so we can't use its `lookup_method` method.
1003 let into_iter_collections: [&[Symbol]; 13] = [
1010 &*paths::LINKED_LIST,
1011 &*paths::BINARY_HEAP,
1019 let ty_to_check = match probably_ref_ty.sty {
1020 ty::Ref(_, ty_to_check, _) => ty_to_check,
1021 _ => probably_ref_ty,
1024 let def_id = match ty_to_check.sty {
1025 ty::Array(..) => return Some(*sym::array),
1026 ty::Slice(..) => return Some(*sym::slice),
1027 ty::Adt(adt, _) => adt.did,
1031 for path in &into_iter_collections {
1032 if match_def_path(cx, def_id, path) {
1033 return Some(*path.last().unwrap());
1041 use super::{trim_multiline, without_block_comments};
1044 fn test_trim_multiline_single_line() {
1045 assert_eq!("", trim_multiline("".into(), false));
1046 assert_eq!("...", trim_multiline("...".into(), false));
1047 assert_eq!("...", trim_multiline(" ...".into(), false));
1048 assert_eq!("...", trim_multiline("\t...".into(), false));
1049 assert_eq!("...", trim_multiline("\t\t...".into(), false));
1054 fn test_trim_multiline_block() {
1060 }", trim_multiline(" if x {
1070 }", trim_multiline(" if x {
1079 fn test_trim_multiline_empty_line() {
1086 }", trim_multiline(" if x {
1095 fn test_without_block_comments_lines_without_block_comments() {
1096 let result = without_block_comments(vec!["/*", "", "*/"]);
1097 println!("result: {:?}", result);
1098 assert!(result.is_empty());
1100 let result = without_block_comments(vec!["", "/*", "", "*/", "#[crate_type = \"lib\"]", "/*", "", "*/", ""]);
1101 assert_eq!(result, vec!["", "#[crate_type = \"lib\"]", ""]);
1103 let result = without_block_comments(vec!["/* rust", "", "*/"]);
1104 assert!(result.is_empty());
1106 let result = without_block_comments(vec!["/* one-line comment */"]);
1107 assert!(result.is_empty());
1109 let result = without_block_comments(vec!["/* nested", "/* multi-line", "comment", "*/", "test", "*/"]);
1110 assert!(result.is_empty());
1112 let result = without_block_comments(vec!["/* nested /* inline /* comment */ test */ */"]);
1113 assert!(result.is_empty());
1115 let result = without_block_comments(vec!["foo", "bar", "baz"]);
1116 assert_eq!(result, vec!["foo", "bar", "baz"]);
1120 pub fn match_def_path<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, did: DefId, syms: &[Symbol]) -> bool {
1121 // HACK: fix upstream `match_def_path` to take symbols
1122 let syms: Vec<_> = syms.iter().map(|sym| sym.as_str()).collect();
1123 let syms: Vec<_> = syms.iter().map(|sym| &**sym).collect();
1124 cx.match_def_path(did, &syms)