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::ExpnFormat;
47 use syntax::source_map::{Span, DUMMY_SP};
48 use syntax::symbol::{kw, Symbol};
50 use crate::reexport::*;
52 /// Returns `true` if the two spans come from differing expansions (i.e., one is
53 /// from a macro and one isn't).
54 pub fn differing_macro_contexts(lhs: Span, rhs: Span) -> bool {
55 rhs.ctxt() != lhs.ctxt()
58 /// Returns `true` if the given `NodeId` is inside a constant context
63 /// if in_constant(cx, expr.id) {
67 pub fn in_constant(cx: &LateContext<'_, '_>, id: HirId) -> bool {
68 let parent_id = cx.tcx.hir().get_parent_item(id);
69 match cx.tcx.hir().get(parent_id) {
71 node: ItemKind::Const(..),
74 | Node::TraitItem(&TraitItem {
75 node: TraitItemKind::Const(..),
78 | Node::ImplItem(&ImplItem {
79 node: ImplItemKind::Const(..),
84 node: ItemKind::Static(..),
88 node: ItemKind::Fn(_, header, ..),
90 }) => header.constness == Constness::Const,
95 /// Returns `true` if this `expn_info` was expanded by any macro or desugaring
96 pub fn in_macro_or_desugar(span: Span) -> bool {
97 span.ctxt().outer_expn_info().is_some()
100 /// Returns `true` if this `expn_info` was expanded by any macro.
101 pub fn in_macro(span: Span) -> bool {
102 if let Some(info) = span.ctxt().outer_expn_info() {
103 if let ExpnFormat::CompilerDesugaring(..) = info.format {
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 method call given in `expr` belongs to the given trait.
135 pub fn match_trait_method(cx: &LateContext<'_, '_>, expr: &Expr, path: &[&str]) -> bool {
136 let def_id = cx.tables.type_dependent_def_id(expr.hir_id).unwrap();
137 let trt_id = cx.tcx.trait_of_item(def_id);
138 if let Some(trt_id) = trt_id {
139 match_def_path(cx, trt_id, path)
145 /// Checks if an expression references a variable of the given name.
146 pub fn match_var(expr: &Expr, var: Name) -> bool {
147 if let ExprKind::Path(QPath::Resolved(None, ref path)) = expr.node {
148 if path.segments.len() == 1 && path.segments[0].ident.name == var {
155 pub fn last_path_segment(path: &QPath) -> &PathSegment {
157 QPath::Resolved(_, ref path) => path.segments.last().expect("A path must have at least one segment"),
158 QPath::TypeRelative(_, ref seg) => seg,
162 pub fn single_segment_path(path: &QPath) -> Option<&PathSegment> {
164 QPath::Resolved(_, ref path) if path.segments.len() == 1 => Some(&path.segments[0]),
165 QPath::Resolved(..) => None,
166 QPath::TypeRelative(_, ref seg) => Some(seg),
170 /// Matches a `QPath` against a slice of segment string literals.
172 /// There is also `match_path` if you are dealing with a `rustc::hir::Path` instead of a
173 /// `rustc::hir::QPath`.
177 /// match_qpath(path, &["std", "rt", "begin_unwind"])
179 pub fn match_qpath(path: &QPath, segments: &[&str]) -> bool {
181 QPath::Resolved(_, ref path) => match_path(path, segments),
182 QPath::TypeRelative(ref ty, ref segment) => match ty.node {
183 TyKind::Path(ref inner_path) => {
185 && match_qpath(inner_path, &segments[..(segments.len() - 1)])
186 && segment.ident.name.as_str() == segments[segments.len() - 1]
193 /// Matches a `Path` against a slice of segment string literals.
195 /// There is also `match_qpath` if you are dealing with a `rustc::hir::QPath` instead of a
196 /// `rustc::hir::Path`.
201 /// if match_path(&trait_ref.path, &paths::HASH) {
202 /// // This is the `std::hash::Hash` trait.
205 /// if match_path(ty_path, &["rustc", "lint", "Lint"]) {
206 /// // This is a `rustc::lint::Lint`.
209 pub fn match_path(path: &Path, segments: &[&str]) -> bool {
213 .zip(segments.iter().rev())
214 .all(|(a, b)| a.ident.name.as_str() == *b)
217 /// Matches a `Path` against a slice of segment string literals, e.g.
221 /// match_qpath(path, &["std", "rt", "begin_unwind"])
223 pub fn match_path_ast(path: &ast::Path, segments: &[&str]) -> bool {
227 .zip(segments.iter().rev())
228 .all(|(a, b)| a.ident.name.as_str() == *b)
231 /// Gets the definition associated to a path.
232 pub fn path_to_res(cx: &LateContext<'_, '_>, path: &[&str]) -> Option<(def::Res)> {
233 let crates = cx.tcx.crates();
236 .find(|&&krate| cx.tcx.crate_name(krate).as_str() == path[0]);
237 if let Some(krate) = krate {
240 index: CRATE_DEF_INDEX,
242 let mut items = cx.tcx.item_children(krate);
243 let mut path_it = path.iter().skip(1).peekable();
246 let segment = match path_it.next() {
247 Some(segment) => segment,
251 let result = SmallVec::<[_; 8]>::new();
252 for item in mem::replace(&mut items, cx.tcx.arena.alloc_slice(&result)).iter() {
253 if item.ident.name.as_str() == *segment {
254 if path_it.peek().is_none() {
255 return Some(item.res);
258 items = cx.tcx.item_children(item.res.def_id());
268 /// Convenience function to get the `DefId` of a trait by path.
269 pub fn get_trait_def_id(cx: &LateContext<'_, '_>, path: &[&str]) -> Option<DefId> {
270 let res = match path_to_res(cx, path) {
276 def::Res::Def(DefKind::Trait, trait_id) => Some(trait_id),
281 /// Checks whether a type implements a trait.
282 /// See also `get_trait_def_id`.
283 pub fn implements_trait<'a, 'tcx>(
284 cx: &LateContext<'a, 'tcx>,
287 ty_params: &[Kind<'tcx>],
289 let ty = cx.tcx.erase_regions(&ty);
290 let obligation = cx.tcx.predicate_for_trait_def(
292 traits::ObligationCause::dummy(),
300 .enter(|infcx| infcx.predicate_must_hold_modulo_regions(&obligation))
303 /// Gets the `hir::TraitRef` of the trait the given method is implemented for.
305 /// Use this if you want to find the `TraitRef` of the `Add` trait in this example:
308 /// struct Point(isize, isize);
310 /// impl std::ops::Add for Point {
311 /// type Output = Self;
313 /// fn add(self, other: Self) -> Self {
318 pub fn trait_ref_of_method<'tcx>(cx: &LateContext<'_, 'tcx>, hir_id: HirId) -> Option<&'tcx TraitRef> {
319 // Get the implemented trait for the current function
320 let parent_impl = cx.tcx.hir().get_parent_item(hir_id);
322 if parent_impl != hir::CRATE_HIR_ID;
323 if let hir::Node::Item(item) = cx.tcx.hir().get(parent_impl);
324 if let hir::ItemKind::Impl(_, _, _, _, trait_ref, _, _) = &item.node;
325 then { return trait_ref.as_ref(); }
330 /// Checks whether this type implements `Drop`.
331 pub fn has_drop<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
332 match ty.ty_adt_def() {
333 Some(def) => def.has_dtor(cx.tcx),
338 /// Resolves the definition of a node from its `HirId`.
339 pub fn resolve_node(cx: &LateContext<'_, '_>, qpath: &QPath, id: HirId) -> Res {
340 cx.tables.qpath_res(qpath, id)
343 /// Returns the method names and argument list of nested method call expressions that make up
345 pub fn method_calls(expr: &Expr, max_depth: usize) -> (Vec<Symbol>, Vec<&[Expr]>) {
346 let mut method_names = Vec::with_capacity(max_depth);
347 let mut arg_lists = Vec::with_capacity(max_depth);
349 let mut current = expr;
350 for _ in 0..max_depth {
351 if let ExprKind::MethodCall(path, _, args) = ¤t.node {
352 if args.iter().any(|e| in_macro_or_desugar(e.span)) {
355 method_names.push(path.ident.name);
356 arg_lists.push(&**args);
363 (method_names, arg_lists)
366 /// Matches an `Expr` against a chain of methods, and return the matched `Expr`s.
368 /// For example, if `expr` represents the `.baz()` in `foo.bar().baz()`,
369 /// `matched_method_chain(expr, &["bar", "baz"])` will return a `Vec`
370 /// containing the `Expr`s for
371 /// `.bar()` and `.baz()`
372 pub fn method_chain_args<'a>(expr: &'a Expr, methods: &[&str]) -> Option<Vec<&'a [Expr]>> {
373 let mut current = expr;
374 let mut matched = Vec::with_capacity(methods.len());
375 for method_name in methods.iter().rev() {
376 // method chains are stored last -> first
377 if let ExprKind::MethodCall(ref path, _, ref args) = current.node {
378 if path.ident.name.as_str() == *method_name {
379 if args.iter().any(|e| in_macro_or_desugar(e.span)) {
382 matched.push(&**args); // build up `matched` backwards
383 current = &args[0] // go to parent expression
391 // Reverse `matched` so that it is in the same order as `methods`.
396 /// Returns `true` if the provided `def_id` is an entrypoint to a program.
397 pub fn is_entrypoint_fn(cx: &LateContext<'_, '_>, def_id: DefId) -> bool {
398 if let Some((entry_fn_def_id, _)) = cx.tcx.entry_fn(LOCAL_CRATE) {
399 return def_id == entry_fn_def_id;
404 /// Gets the name of the item the expression is in, if available.
405 pub fn get_item_name(cx: &LateContext<'_, '_>, expr: &Expr) -> Option<Name> {
406 let parent_id = cx.tcx.hir().get_parent_item(expr.hir_id);
407 match cx.tcx.hir().find(parent_id) {
408 Some(Node::Item(&Item { ref ident, .. })) => Some(ident.name),
409 Some(Node::TraitItem(&TraitItem { ident, .. })) | Some(Node::ImplItem(&ImplItem { ident, .. })) => {
416 /// Gets the name of a `Pat`, if any.
417 pub fn get_pat_name(pat: &Pat) -> Option<Name> {
419 PatKind::Binding(.., ref spname, _) => Some(spname.name),
420 PatKind::Path(ref qpath) => single_segment_path(qpath).map(|ps| ps.ident.name),
421 PatKind::Box(ref p) | PatKind::Ref(ref p, _) => get_pat_name(&*p),
426 struct ContainsName {
431 impl<'tcx> Visitor<'tcx> for ContainsName {
432 fn visit_name(&mut self, _: Span, name: Name) {
433 if self.name == name {
437 fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
438 NestedVisitorMap::None
442 /// Checks if an `Expr` contains a certain name.
443 pub fn contains_name(name: Name, expr: &Expr) -> bool {
444 let mut cn = ContainsName { name, result: false };
449 /// Converts a span to a code snippet if available, otherwise use default.
451 /// This is useful if you want to provide suggestions for your lint or more generally, if you want
452 /// to convert a given `Span` to a `str`.
456 /// snippet(cx, expr.span, "..")
458 pub fn snippet<'a, T: LintContext>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
459 snippet_opt(cx, span).map_or_else(|| Cow::Borrowed(default), From::from)
462 /// Same as `snippet`, but it adapts the applicability level by following rules:
464 /// - Applicability level `Unspecified` will never be changed.
465 /// - If the span is inside a macro, change the applicability level to `MaybeIncorrect`.
466 /// - If the default value is used and the applicability level is `MachineApplicable`, change it to
467 /// `HasPlaceholders`
468 pub fn snippet_with_applicability<'a, T: LintContext>(
472 applicability: &mut Applicability,
474 if *applicability != Applicability::Unspecified && in_macro_or_desugar(span) {
475 *applicability = Applicability::MaybeIncorrect;
477 snippet_opt(cx, span).map_or_else(
479 if *applicability == Applicability::MachineApplicable {
480 *applicability = Applicability::HasPlaceholders;
482 Cow::Borrowed(default)
488 /// Same as `snippet`, but should only be used when it's clear that the input span is
489 /// not a macro argument.
490 pub fn snippet_with_macro_callsite<'a, T: LintContext>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
491 snippet(cx, span.source_callsite(), default)
494 /// Converts a span to a code snippet. Returns `None` if not available.
495 pub fn snippet_opt<T: LintContext>(cx: &T, span: Span) -> Option<String> {
496 cx.sess().source_map().span_to_snippet(span).ok()
499 /// Converts a span (from a block) to a code snippet if available, otherwise use
501 /// This trims the code of indentation, except for the first line. Use it for
502 /// blocks or block-like
503 /// things which need to be printed as such.
507 /// snippet_block(cx, expr.span, "..")
509 pub fn snippet_block<'a, T: LintContext>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
510 let snip = snippet(cx, span, default);
511 trim_multiline(snip, true)
514 /// Same as `snippet_block`, but adapts the applicability level by the rules of
515 /// `snippet_with_applicabiliy`.
516 pub fn snippet_block_with_applicability<'a, T: LintContext>(
520 applicability: &mut Applicability,
522 let snip = snippet_with_applicability(cx, span, default, applicability);
523 trim_multiline(snip, true)
526 /// Returns a new Span that covers the full last line of the given Span
527 pub fn last_line_of_span<T: LintContext>(cx: &T, span: Span) -> Span {
528 let source_map_and_line = cx.sess().source_map().lookup_line(span.lo()).unwrap();
529 let line_no = source_map_and_line.line;
530 let line_start = &source_map_and_line.sf.lines[line_no];
531 Span::new(*line_start, span.hi(), span.ctxt())
534 /// Like `snippet_block`, but add braces if the expr is not an `ExprKind::Block`.
535 /// Also takes an `Option<String>` which can be put inside the braces.
536 pub fn expr_block<'a, T: LintContext>(cx: &T, expr: &Expr, option: Option<String>, default: &'a str) -> Cow<'a, str> {
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(hir_id);
596 if hir_id == parent_id {
599 map.find(parent_id).and_then(|node| {
600 if let Node::Expr(parent) = node {
608 pub fn get_enclosing_block<'a, 'tcx>(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(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: &str) -> Option<Span> {
689 let span_name_span = span.ctxt().outer_expn_info().map(|ei| (ei.format.name(), ei.call_site));
691 match span_name_span {
692 Some((mac_name, new_span)) if mac_name.as_str() == name => return Some(new_span),
694 Some((_, new_span)) => span = new_span,
699 /// Returns the pre-expansion span if the span directly comes from an expansion
700 /// of the macro `name`.
701 /// The difference with `is_expn_of` is that in
705 /// `42` is considered expanded from `foo!` and `bar!` by `is_expn_of` but only
707 /// `is_direct_expn_of`.
708 pub fn is_direct_expn_of(span: Span, name: &str) -> Option<Span> {
709 let span_name_span = span.ctxt().outer_expn_info().map(|ei| (ei.format.name(), ei.call_site));
711 match span_name_span {
712 Some((mac_name, new_span)) if mac_name.as_str() == name => Some(new_span),
717 /// Convenience function to get the return type of a function.
718 pub fn return_ty<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, fn_item: hir::HirId) -> Ty<'tcx> {
719 let fn_def_id = cx.tcx.hir().local_def_id_from_hir_id(fn_item);
720 let ret_ty = cx.tcx.fn_sig(fn_def_id).output();
721 cx.tcx.erase_late_bound_regions(&ret_ty)
724 /// Checks if two types are the same.
726 /// This discards any lifetime annotations, too.
728 // FIXME: this works correctly for lifetimes bounds (`for <'a> Foo<'a>` ==
729 // `for <'b> Foo<'b>`, but not for type parameters).
730 pub fn same_tys<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, a: Ty<'tcx>, b: Ty<'tcx>) -> bool {
731 let a = cx.tcx.erase_late_bound_regions(&Binder::bind(a));
732 let b = cx.tcx.erase_late_bound_regions(&Binder::bind(b));
735 .enter(|infcx| infcx.can_eq(cx.param_env, a, b).is_ok())
738 /// Returns `true` if the given type is an `unsafe` function.
739 pub fn type_is_unsafe_function<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
741 ty::FnDef(..) | ty::FnPtr(_) => ty.fn_sig(cx.tcx).unsafety() == Unsafety::Unsafe,
746 pub fn is_copy<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
747 ty.is_copy_modulo_regions(cx.tcx.global_tcx(), cx.param_env, DUMMY_SP)
750 /// Checks if an expression is constructing a tuple-like enum variant or struct
751 pub fn is_ctor_function(cx: &LateContext<'_, '_>, expr: &Expr) -> bool {
752 if let ExprKind::Call(ref fun, _) = expr.node {
753 if let ExprKind::Path(ref qp) = fun.node {
755 cx.tables.qpath_res(qp, fun.hir_id),
756 def::Res::Def(DefKind::Variant, ..) | Res::Def(DefKind::Ctor(..), _)
763 /// Returns `true` if a pattern is refutable.
764 pub fn is_refutable(cx: &LateContext<'_, '_>, pat: &Pat) -> bool {
765 fn is_enum_variant(cx: &LateContext<'_, '_>, qpath: &QPath, id: HirId) -> bool {
767 cx.tables.qpath_res(qpath, id),
768 def::Res::Def(DefKind::Variant, ..) | Res::Def(DefKind::Ctor(def::CtorOf::Variant, _), _)
772 fn are_refutable<'a, I: Iterator<Item = &'a Pat>>(cx: &LateContext<'_, '_>, mut i: I) -> bool {
773 i.any(|pat| is_refutable(cx, pat))
777 PatKind::Binding(..) | PatKind::Wild => false,
778 PatKind::Box(ref pat) | PatKind::Ref(ref pat, _) => is_refutable(cx, pat),
779 PatKind::Lit(..) | PatKind::Range(..) => true,
780 PatKind::Path(ref qpath) => is_enum_variant(cx, qpath, pat.hir_id),
781 PatKind::Tuple(ref pats, _) => are_refutable(cx, pats.iter().map(|pat| &**pat)),
782 PatKind::Struct(ref qpath, ref fields, _) => {
783 if is_enum_variant(cx, qpath, pat.hir_id) {
786 are_refutable(cx, fields.iter().map(|field| &*field.node.pat))
789 PatKind::TupleStruct(ref qpath, ref pats, _) => {
790 if is_enum_variant(cx, qpath, pat.hir_id) {
793 are_refutable(cx, pats.iter().map(|pat| &**pat))
796 PatKind::Slice(ref head, ref middle, ref tail) => {
797 are_refutable(cx, head.iter().chain(middle).chain(tail.iter()).map(|pat| &**pat))
802 /// Checks for the `#[automatically_derived]` attribute all `#[derive]`d
803 /// implementations have.
804 pub fn is_automatically_derived(attrs: &[ast::Attribute]) -> bool {
805 attr::contains_name(attrs, sym!(automatically_derived))
808 /// Remove blocks around an expression.
810 /// Ie. `x`, `{ x }` and `{{{{ x }}}}` all give `x`. `{ x; y }` and `{}` return
812 pub fn remove_blocks(expr: &Expr) -> &Expr {
813 if let ExprKind::Block(ref block, _) = expr.node {
814 if block.stmts.is_empty() {
815 if let Some(ref expr) = block.expr {
828 pub fn is_self(slf: &Arg) -> bool {
829 if let PatKind::Binding(.., name, _) = slf.pat.node {
830 name.name == kw::SelfLower
836 pub fn is_self_ty(slf: &hir::Ty) -> bool {
838 if let TyKind::Path(ref qp) = slf.node;
839 if let QPath::Resolved(None, ref path) = *qp;
840 if let Res::SelfTy(..) = path.res;
848 pub fn iter_input_pats<'tcx>(decl: &FnDecl, body: &'tcx Body) -> impl Iterator<Item = &'tcx Arg> {
849 (0..decl.inputs.len()).map(move |i| &body.arguments[i])
852 /// Checks if a given expression is a match expression expanded from the `?`
853 /// operator or the `try` macro.
854 pub fn is_try(expr: &Expr) -> Option<&Expr> {
855 fn is_ok(arm: &Arm) -> bool {
857 if let PatKind::TupleStruct(ref path, ref pat, None) = arm.pats[0].node;
858 if match_qpath(path, &paths::RESULT_OK[1..]);
859 if let PatKind::Binding(_, hir_id, _, None) = pat[0].node;
860 if let ExprKind::Path(QPath::Resolved(None, ref path)) = arm.body.node;
861 if let Res::Local(lid) = path.res;
870 fn is_err(arm: &Arm) -> bool {
871 if let PatKind::TupleStruct(ref path, _, _) = arm.pats[0].node {
872 match_qpath(path, &paths::RESULT_ERR[1..])
878 if let ExprKind::Match(_, ref arms, ref source) = expr.node {
879 // desugared from a `?` operator
880 if let MatchSource::TryDesugar = *source {
886 if arms[0].pats.len() == 1 && arms[0].guard.is_none();
887 if arms[1].pats.len() == 1 && arms[1].guard.is_none();
888 if (is_ok(&arms[0]) && is_err(&arms[1])) ||
889 (is_ok(&arms[1]) && is_err(&arms[0]));
899 /// Returns `true` if the lint is allowed in the current context
901 /// Useful for skipping long running code when it's unnecessary
902 pub fn is_allowed(cx: &LateContext<'_, '_>, lint: &'static Lint, id: HirId) -> bool {
903 cx.tcx.lint_level_at_node(lint, id).0 == Level::Allow
906 pub fn get_arg_name(pat: &Pat) -> Option<ast::Name> {
908 PatKind::Binding(.., ident, None) => Some(ident.name),
909 PatKind::Ref(ref subpat, _) => get_arg_name(subpat),
914 pub fn int_bits(tcx: TyCtxt<'_>, ity: ast::IntTy) -> u64 {
915 layout::Integer::from_attr(&tcx, attr::IntType::SignedInt(ity))
920 #[allow(clippy::cast_possible_wrap)]
921 /// Turn a constant int byte representation into an i128
922 pub fn sext(tcx: TyCtxt<'_>, u: u128, ity: ast::IntTy) -> i128 {
923 let amt = 128 - int_bits(tcx, ity);
924 ((u as i128) << amt) >> amt
927 #[allow(clippy::cast_sign_loss)]
928 /// clip unused bytes
929 pub fn unsext(tcx: TyCtxt<'_>, u: i128, ity: ast::IntTy) -> u128 {
930 let amt = 128 - int_bits(tcx, ity);
931 ((u as u128) << amt) >> amt
934 /// clip unused bytes
935 pub fn clip(tcx: TyCtxt<'_>, u: u128, ity: ast::UintTy) -> u128 {
936 let bits = layout::Integer::from_attr(&tcx, attr::IntType::UnsignedInt(ity))
939 let amt = 128 - bits;
943 /// Removes block comments from the given `Vec` of lines.
948 /// without_block_comments(vec!["/*", "foo", "*/"]);
951 /// without_block_comments(vec!["bar", "/*", "foo", "*/"]);
952 /// // => vec!["bar"]
954 pub fn without_block_comments(lines: Vec<&str>) -> Vec<&str> {
955 let mut without = vec![];
957 let mut nest_level = 0;
960 if line.contains("/*") {
963 } else if line.contains("*/") {
976 pub fn any_parent_is_automatically_derived(tcx: TyCtxt<'_>, node: HirId) -> bool {
977 let map = &tcx.hir();
978 let mut prev_enclosing_node = None;
979 let mut enclosing_node = node;
980 while Some(enclosing_node) != prev_enclosing_node {
981 if is_automatically_derived(map.attrs(enclosing_node)) {
984 prev_enclosing_node = Some(enclosing_node);
985 enclosing_node = map.get_parent_item(enclosing_node);
990 /// Returns true if ty has `iter` or `iter_mut` methods
991 pub fn has_iter_method(cx: &LateContext<'_, '_>, probably_ref_ty: Ty<'_>) -> Option<&'static str> {
992 // FIXME: instead of this hard-coded list, we should check if `<adt>::iter`
993 // exists and has the desired signature. Unfortunately FnCtxt is not exported
994 // so we can't use its `lookup_method` method.
995 let into_iter_collections: [&[&str]; 13] = [
1002 &paths::LINKED_LIST,
1003 &paths::BINARY_HEAP,
1011 let ty_to_check = match probably_ref_ty.sty {
1012 ty::Ref(_, ty_to_check, _) => ty_to_check,
1013 _ => probably_ref_ty,
1016 let def_id = match ty_to_check.sty {
1017 ty::Array(..) => return Some("array"),
1018 ty::Slice(..) => return Some("slice"),
1019 ty::Adt(adt, _) => adt.did,
1023 for path in &into_iter_collections {
1024 if match_def_path(cx, def_id, path) {
1025 return Some(*path.last().unwrap());
1033 use super::{trim_multiline, without_block_comments};
1036 fn test_trim_multiline_single_line() {
1037 assert_eq!("", trim_multiline("".into(), false));
1038 assert_eq!("...", trim_multiline("...".into(), false));
1039 assert_eq!("...", trim_multiline(" ...".into(), false));
1040 assert_eq!("...", trim_multiline("\t...".into(), false));
1041 assert_eq!("...", trim_multiline("\t\t...".into(), false));
1046 fn test_trim_multiline_block() {
1052 }", trim_multiline(" if x {
1062 }", trim_multiline(" if x {
1071 fn test_trim_multiline_empty_line() {
1078 }", trim_multiline(" if x {
1087 fn test_without_block_comments_lines_without_block_comments() {
1088 let result = without_block_comments(vec!["/*", "", "*/"]);
1089 println!("result: {:?}", result);
1090 assert!(result.is_empty());
1092 let result = without_block_comments(vec!["", "/*", "", "*/", "#[crate_type = \"lib\"]", "/*", "", "*/", ""]);
1093 assert_eq!(result, vec!["", "#[crate_type = \"lib\"]", ""]);
1095 let result = without_block_comments(vec!["/* rust", "", "*/"]);
1096 assert!(result.is_empty());
1098 let result = without_block_comments(vec!["/* one-line comment */"]);
1099 assert!(result.is_empty());
1101 let result = without_block_comments(vec!["/* nested", "/* multi-line", "comment", "*/", "test", "*/"]);
1102 assert!(result.is_empty());
1104 let result = without_block_comments(vec!["/* nested /* inline /* comment */ test */ */"]);
1105 assert!(result.is_empty());
1107 let result = without_block_comments(vec!["foo", "bar", "baz"]);
1108 assert_eq!(result, vec!["foo", "bar", "baz"]);
1112 pub fn match_def_path<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, did: DefId, syms: &[&str]) -> bool {
1113 // HACK: find a way to use symbols from clippy or just go fully to diagnostic items
1114 let syms: Vec<_> = syms.iter().map(|sym| Symbol::intern(sym)).collect();
1115 cx.match_def_path(did, &syms)