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::{DefKind, Res};
27 use rustc::hir::def_id::{DefId, CRATE_DEF_INDEX, LOCAL_CRATE};
28 use rustc::hir::intravisit::{NestedVisitorMap, Visitor};
31 use rustc::lint::{LateContext, Level, Lint, LintContext};
35 layout::{self, IntegerExt},
39 use rustc_data_structures::sync::Lrc;
40 use rustc_errors::Applicability;
41 use syntax::ast::{self, LitKind};
43 use syntax::ext::hygiene::ExpnFormat;
44 use syntax::source_map::{Span, DUMMY_SP};
45 use syntax::symbol::{keywords, Symbol};
47 use crate::reexport::*;
49 /// Returns `true` if the two spans come from differing expansions (i.e., one is
50 /// from a macro and one isn't).
51 pub fn differing_macro_contexts(lhs: Span, rhs: Span) -> bool {
52 rhs.ctxt() != lhs.ctxt()
55 /// Returns `true` if the given `NodeId` is inside a constant context
60 /// if in_constant(cx, expr.id) {
64 pub fn in_constant(cx: &LateContext<'_, '_>, id: HirId) -> bool {
65 let parent_id = cx.tcx.hir().get_parent_item(id);
66 match cx.tcx.hir().get_by_hir_id(parent_id) {
68 node: ItemKind::Const(..),
71 | Node::TraitItem(&TraitItem {
72 node: TraitItemKind::Const(..),
75 | Node::ImplItem(&ImplItem {
76 node: ImplItemKind::Const(..),
81 node: ItemKind::Static(..),
85 node: ItemKind::Fn(_, header, ..),
87 }) => header.constness == Constness::Const,
92 /// Returns `true` if this `expn_info` was expanded by any macro or desugaring
93 pub fn in_macro_or_desugar(span: Span) -> bool {
94 span.ctxt().outer().expn_info().is_some()
97 /// Returns `true` if this `expn_info` was expanded by any macro.
98 pub fn in_macro(span: Span) -> bool {
99 if let Some(info) = span.ctxt().outer().expn_info() {
100 if let ExpnFormat::CompilerDesugaring(..) = info.format {
109 // If the snippet is empty, it's an attribute that was inserted during macro
110 // expansion and we want to ignore those, because they could come from external
111 // sources that the user has no control over.
112 // For some reason these attributes don't have any expansion info on them, so
113 // we have to check it this way until there is a better way.
114 pub fn is_present_in_source<'a, T: LintContext<'a>>(cx: &T, span: Span) -> bool {
115 if let Some(snippet) = snippet_opt(cx, span) {
116 if snippet.is_empty() {
123 /// Checks if type is struct, enum or union type with the given def path.
124 pub fn match_type(cx: &LateContext<'_, '_>, ty: Ty<'_>, path: &[&str]) -> bool {
126 ty::Adt(adt, _) => cx.match_def_path(adt.did, path),
131 /// Checks if the method call given in `expr` belongs to the given trait.
132 pub fn match_trait_method(cx: &LateContext<'_, '_>, expr: &Expr, path: &[&str]) -> bool {
133 let def_id = cx.tables.type_dependent_def_id(expr.hir_id).unwrap();
134 let trt_id = cx.tcx.trait_of_item(def_id);
135 if let Some(trt_id) = trt_id {
136 cx.match_def_path(trt_id, path)
142 /// Checks if an expression references a variable of the given name.
143 pub fn match_var(expr: &Expr, var: Name) -> bool {
144 if let ExprKind::Path(QPath::Resolved(None, ref path)) = expr.node {
145 if path.segments.len() == 1 && path.segments[0].ident.name == var {
152 pub fn last_path_segment(path: &QPath) -> &PathSegment {
154 QPath::Resolved(_, ref path) => path.segments.last().expect("A path must have at least one segment"),
155 QPath::TypeRelative(_, ref seg) => seg,
159 pub fn single_segment_path(path: &QPath) -> Option<&PathSegment> {
161 QPath::Resolved(_, ref path) if path.segments.len() == 1 => Some(&path.segments[0]),
162 QPath::Resolved(..) => None,
163 QPath::TypeRelative(_, ref seg) => Some(seg),
167 /// Matches a `QPath` against a slice of segment string literals.
169 /// There is also `match_path` if you are dealing with a `rustc::hir::Path` instead of a
170 /// `rustc::hir::QPath`.
174 /// match_qpath(path, &["std", "rt", "begin_unwind"])
176 pub fn match_qpath(path: &QPath, segments: &[&str]) -> bool {
178 QPath::Resolved(_, ref path) => match_path(path, segments),
179 QPath::TypeRelative(ref ty, ref segment) => match ty.node {
180 TyKind::Path(ref inner_path) => {
182 && match_qpath(inner_path, &segments[..(segments.len() - 1)])
183 && segment.ident.name == segments[segments.len() - 1]
190 /// Matches a `Path` against a slice of segment string literals.
192 /// There is also `match_qpath` if you are dealing with a `rustc::hir::QPath` instead of a
193 /// `rustc::hir::Path`.
198 /// if match_path(&trait_ref.path, &paths::HASH) {
199 /// // This is the `std::hash::Hash` trait.
202 /// if match_path(ty_path, &["rustc", "lint", "Lint"]) {
203 /// // This is a `rustc::lint::Lint`.
206 pub fn match_path(path: &Path, segments: &[&str]) -> bool {
210 .zip(segments.iter().rev())
211 .all(|(a, b)| a.ident.name == *b)
214 /// Matches a `Path` against a slice of segment string literals, e.g.
218 /// match_qpath(path, &["std", "rt", "begin_unwind"])
220 pub fn match_path_ast(path: &ast::Path, segments: &[&str]) -> bool {
224 .zip(segments.iter().rev())
225 .all(|(a, b)| a.ident.name == *b)
228 /// Gets the definition associated to a path.
229 pub fn path_to_res(cx: &LateContext<'_, '_>, path: &[&str]) -> Option<(def::Res)> {
230 let crates = cx.tcx.crates();
231 let krate = crates.iter().find(|&&krate| cx.tcx.crate_name(krate) == path[0]);
232 if let Some(krate) = krate {
235 index: CRATE_DEF_INDEX,
237 let mut items = cx.tcx.item_children(krate);
238 let mut path_it = path.iter().skip(1).peekable();
241 let segment = match path_it.next() {
242 Some(segment) => segment,
246 for item in mem::replace(&mut items, Lrc::new(vec![])).iter() {
247 if item.ident.name == *segment {
248 if path_it.peek().is_none() {
249 return Some(item.res);
252 items = cx.tcx.item_children(item.res.def_id());
262 /// Convenience function to get the `DefId` of a trait by path.
263 pub fn get_trait_def_id(cx: &LateContext<'_, '_>, path: &[&str]) -> Option<DefId> {
264 let res = match path_to_res(cx, path) {
270 def::Res::Def(DefKind::Trait, trait_id) => Some(trait_id),
275 /// Checks whether a type implements a trait.
276 /// See also `get_trait_def_id`.
277 pub fn implements_trait<'a, 'tcx>(
278 cx: &LateContext<'a, 'tcx>,
281 ty_params: &[Kind<'tcx>],
283 let ty = cx.tcx.erase_regions(&ty);
284 let obligation = cx.tcx.predicate_for_trait_def(
286 traits::ObligationCause::dummy(),
294 .enter(|infcx| infcx.predicate_must_hold_modulo_regions(&obligation))
297 /// Gets the `hir::TraitRef` of the trait the given method is implemented for.
299 /// Use this if you want to find the `TraitRef` of the `Add` trait in this example:
302 /// struct Point(isize, isize);
304 /// impl std::ops::Add for Point {
305 /// type Output = Self;
307 /// fn add(self, other: Self) -> Self {
312 pub fn trait_ref_of_method(cx: &LateContext<'_, '_>, hir_id: HirId) -> Option<TraitRef> {
313 // Get the implemented trait for the current function
314 let parent_impl = cx.tcx.hir().get_parent_item(hir_id);
316 if parent_impl != hir::CRATE_HIR_ID;
317 if let hir::Node::Item(item) = cx.tcx.hir().get_by_hir_id(parent_impl);
318 if let hir::ItemKind::Impl(_, _, _, _, trait_ref, _, _) = &item.node;
319 then { return trait_ref.clone(); }
324 /// Checks whether this type implements `Drop`.
325 pub fn has_drop<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
326 match ty.ty_adt_def() {
327 Some(def) => def.has_dtor(cx.tcx),
332 /// Resolves the definition of a node from its `HirId`.
333 pub fn resolve_node(cx: &LateContext<'_, '_>, qpath: &QPath, id: HirId) -> Res {
334 cx.tables.qpath_res(qpath, id)
337 /// Returns the method names and argument list of nested method call expressions that make up
339 pub fn method_calls<'a>(expr: &'a Expr, max_depth: usize) -> (Vec<Symbol>, Vec<&'a [Expr]>) {
340 let mut method_names = Vec::with_capacity(max_depth);
341 let mut arg_lists = Vec::with_capacity(max_depth);
343 let mut current = expr;
344 for _ in 0..max_depth {
345 if let ExprKind::MethodCall(path, _, args) = ¤t.node {
346 if args.iter().any(|e| in_macro_or_desugar(e.span)) {
349 method_names.push(path.ident.name);
350 arg_lists.push(&**args);
357 (method_names, arg_lists)
360 /// Matches an `Expr` against a chain of methods, and return the matched `Expr`s.
362 /// For example, if `expr` represents the `.baz()` in `foo.bar().baz()`,
363 /// `matched_method_chain(expr, &["bar", "baz"])` will return a `Vec`
364 /// containing the `Expr`s for
365 /// `.bar()` and `.baz()`
366 pub fn method_chain_args<'a>(expr: &'a Expr, methods: &[&str]) -> Option<Vec<&'a [Expr]>> {
367 let mut current = expr;
368 let mut matched = Vec::with_capacity(methods.len());
369 for method_name in methods.iter().rev() {
370 // method chains are stored last -> first
371 if let ExprKind::MethodCall(ref path, _, ref args) = current.node {
372 if path.ident.name == *method_name {
373 if args.iter().any(|e| in_macro_or_desugar(e.span)) {
376 matched.push(&**args); // build up `matched` backwards
377 current = &args[0] // go to parent expression
385 // Reverse `matched` so that it is in the same order as `methods`.
390 /// Returns `true` if the provided `def_id` is an entrypoint to a program.
391 pub fn is_entrypoint_fn(cx: &LateContext<'_, '_>, def_id: DefId) -> bool {
392 if let Some((entry_fn_def_id, _)) = cx.tcx.entry_fn(LOCAL_CRATE) {
393 return def_id == entry_fn_def_id;
398 /// Gets the name of the item the expression is in, if available.
399 pub fn get_item_name(cx: &LateContext<'_, '_>, expr: &Expr) -> Option<Name> {
400 let parent_id = cx.tcx.hir().get_parent_item(expr.hir_id);
401 match cx.tcx.hir().find_by_hir_id(parent_id) {
402 Some(Node::Item(&Item { ref ident, .. })) => Some(ident.name),
403 Some(Node::TraitItem(&TraitItem { ident, .. })) | Some(Node::ImplItem(&ImplItem { ident, .. })) => {
410 /// Gets the name of a `Pat`, if any.
411 pub fn get_pat_name(pat: &Pat) -> Option<Name> {
413 PatKind::Binding(.., ref spname, _) => Some(spname.name),
414 PatKind::Path(ref qpath) => single_segment_path(qpath).map(|ps| ps.ident.name),
415 PatKind::Box(ref p) | PatKind::Ref(ref p, _) => get_pat_name(&*p),
420 struct ContainsName {
425 impl<'tcx> Visitor<'tcx> for ContainsName {
426 fn visit_name(&mut self, _: Span, name: Name) {
427 if self.name == name {
431 fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
432 NestedVisitorMap::None
436 /// Checks if an `Expr` contains a certain name.
437 pub fn contains_name(name: Name, expr: &Expr) -> bool {
438 let mut cn = ContainsName { name, result: false };
443 /// Converts a span to a code snippet if available, otherwise use default.
445 /// This is useful if you want to provide suggestions for your lint or more generally, if you want
446 /// to convert a given `Span` to a `str`.
450 /// snippet(cx, expr.span, "..")
452 pub fn snippet<'a, 'b, T: LintContext<'b>>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
453 snippet_opt(cx, span).map_or_else(|| Cow::Borrowed(default), From::from)
456 /// Same as `snippet`, but it adapts the applicability level by following rules:
458 /// - Applicability level `Unspecified` will never be changed.
459 /// - If the span is inside a macro, change the applicability level to `MaybeIncorrect`.
460 /// - If the default value is used and the applicability level is `MachineApplicable`, change it to
461 /// `HasPlaceholders`
462 pub fn snippet_with_applicability<'a, 'b, T: LintContext<'b>>(
466 applicability: &mut Applicability,
468 if *applicability != Applicability::Unspecified && in_macro_or_desugar(span) {
469 *applicability = Applicability::MaybeIncorrect;
471 snippet_opt(cx, span).map_or_else(
473 if *applicability == Applicability::MachineApplicable {
474 *applicability = Applicability::HasPlaceholders;
476 Cow::Borrowed(default)
482 /// Same as `snippet`, but should only be used when it's clear that the input span is
483 /// not a macro argument.
484 pub fn snippet_with_macro_callsite<'a, 'b, T: LintContext<'b>>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
485 snippet(cx, span.source_callsite(), default)
488 /// Converts a span to a code snippet. Returns `None` if not available.
489 pub fn snippet_opt<'a, T: LintContext<'a>>(cx: &T, span: Span) -> Option<String> {
490 cx.sess().source_map().span_to_snippet(span).ok()
493 /// Converts a span (from a block) to a code snippet if available, otherwise use
495 /// This trims the code of indentation, except for the first line. Use it for
496 /// blocks or block-like
497 /// things which need to be printed as such.
501 /// snippet_block(cx, expr.span, "..")
503 pub fn snippet_block<'a, 'b, T: LintContext<'b>>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
504 let snip = snippet(cx, span, default);
505 trim_multiline(snip, true)
508 /// Same as `snippet_block`, but adapts the applicability level by the rules of
509 /// `snippet_with_applicabiliy`.
510 pub fn snippet_block_with_applicability<'a, 'b, T: LintContext<'b>>(
514 applicability: &mut Applicability,
516 let snip = snippet_with_applicability(cx, span, default, applicability);
517 trim_multiline(snip, true)
520 /// Returns a new Span that covers the full last line of the given Span
521 pub fn last_line_of_span<'a, T: LintContext<'a>>(cx: &T, span: Span) -> Span {
522 let source_map_and_line = cx.sess().source_map().lookup_line(span.lo()).unwrap();
523 let line_no = source_map_and_line.line;
524 let line_start = &source_map_and_line.sf.lines[line_no];
525 Span::new(*line_start, span.hi(), span.ctxt())
528 /// Like `snippet_block`, but add braces if the expr is not an `ExprKind::Block`.
529 /// Also takes an `Option<String>` which can be put inside the braces.
530 pub fn expr_block<'a, 'b, T: LintContext<'b>>(
533 option: Option<String>,
536 let code = snippet_block(cx, expr.span, default);
537 let string = option.unwrap_or_default();
538 if in_macro_or_desugar(expr.span) {
539 Cow::Owned(format!("{{ {} }}", snippet_with_macro_callsite(cx, expr.span, default)))
540 } else if let ExprKind::Block(_, _) = expr.node {
541 Cow::Owned(format!("{}{}", code, string))
542 } else if string.is_empty() {
543 Cow::Owned(format!("{{ {} }}", code))
545 Cow::Owned(format!("{{\n{};\n{}\n}}", code, string))
549 /// Trim indentation from a multiline string with possibility of ignoring the
551 pub fn trim_multiline(s: Cow<'_, str>, ignore_first: bool) -> Cow<'_, str> {
552 let s_space = trim_multiline_inner(s, ignore_first, ' ');
553 let s_tab = trim_multiline_inner(s_space, ignore_first, '\t');
554 trim_multiline_inner(s_tab, ignore_first, ' ')
557 fn trim_multiline_inner(s: Cow<'_, str>, ignore_first: bool, ch: char) -> Cow<'_, str> {
560 .skip(ignore_first as usize)
565 // ignore empty lines
566 Some(l.char_indices().find(|&(_, x)| x != ch).unwrap_or((l.len(), ch)).0)
576 if (ignore_first && i == 0) || l.is_empty() {
590 /// Gets the parent expression, if any –- this is useful to constrain a lint.
591 pub fn get_parent_expr<'c>(cx: &'c LateContext<'_, '_>, e: &Expr) -> Option<&'c Expr> {
592 let map = &cx.tcx.hir();
593 let hir_id = e.hir_id;
594 let parent_id = map.get_parent_node_by_hir_id(hir_id);
595 if hir_id == parent_id {
598 map.find_by_hir_id(parent_id).and_then(|node| {
599 if let Node::Expr(parent) = node {
607 pub fn get_enclosing_block<'a, 'tcx: 'a>(cx: &LateContext<'a, 'tcx>, hir_id: HirId) -> Option<&'tcx Block> {
608 let map = &cx.tcx.hir();
609 let enclosing_node = map
610 .get_enclosing_scope(hir_id)
611 .and_then(|enclosing_id| map.find_by_hir_id(enclosing_id));
612 if let Some(node) = enclosing_node {
614 Node::Block(block) => Some(block),
616 node: ItemKind::Fn(_, _, _, eid),
619 | Node::ImplItem(&ImplItem {
620 node: ImplItemKind::Method(_, eid),
622 }) => match cx.tcx.hir().body(eid).value.node {
623 ExprKind::Block(ref block, _) => Some(block),
633 /// Returns the base type for HIR references and pointers.
634 pub fn walk_ptrs_hir_ty(ty: &hir::Ty) -> &hir::Ty {
636 TyKind::Ptr(ref mut_ty) | TyKind::Rptr(_, ref mut_ty) => walk_ptrs_hir_ty(&mut_ty.ty),
641 /// Returns the base type for references and raw pointers.
642 pub fn walk_ptrs_ty(ty: Ty<'_>) -> Ty<'_> {
644 ty::Ref(_, ty, _) => walk_ptrs_ty(ty),
649 /// Returns the base type for references and raw pointers, and count reference
651 pub fn walk_ptrs_ty_depth(ty: Ty<'_>) -> (Ty<'_>, usize) {
652 fn inner(ty: Ty<'_>, depth: usize) -> (Ty<'_>, usize) {
654 ty::Ref(_, ty, _) => inner(ty, depth + 1),
661 /// Checks whether the given expression is a constant literal of the given value.
662 pub fn is_integer_literal(expr: &Expr, value: u128) -> bool {
663 // FIXME: use constant folding
664 if let ExprKind::Lit(ref spanned) = expr.node {
665 if let LitKind::Int(v, _) = spanned.node {
672 /// Returns `true` if the given `Expr` has been coerced before.
674 /// Examples of coercions can be found in the Nomicon at
675 /// <https://doc.rust-lang.org/nomicon/coercions.html>.
677 /// See `rustc::ty::adjustment::Adjustment` and `rustc_typeck::check::coercion` for more
678 /// information on adjustments and coercions.
679 pub fn is_adjusted(cx: &LateContext<'_, '_>, e: &Expr) -> bool {
680 cx.tables.adjustments().get(e.hir_id).is_some()
683 /// Returns the pre-expansion span if is this comes from an expansion of the
685 /// See also `is_direct_expn_of`.
686 pub fn is_expn_of(mut span: Span, name: &str) -> Option<Span> {
688 let span_name_span = span
692 .map(|ei| (ei.format.name(), ei.call_site));
694 match span_name_span {
695 Some((mac_name, new_span)) if mac_name == name => return Some(new_span),
697 Some((_, new_span)) => span = new_span,
702 /// Returns the pre-expansion span if the span directly comes from an expansion
703 /// of the macro `name`.
704 /// The difference with `is_expn_of` is that in
708 /// `42` is considered expanded from `foo!` and `bar!` by `is_expn_of` but only
710 /// `is_direct_expn_of`.
711 pub fn is_direct_expn_of(span: Span, name: &str) -> Option<Span> {
712 let span_name_span = span
716 .map(|ei| (ei.format.name(), ei.call_site));
718 match span_name_span {
719 Some((mac_name, new_span)) if mac_name == name => Some(new_span),
724 /// Convenience function to get the return type of a function.
725 pub fn return_ty<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, fn_item: hir::HirId) -> Ty<'tcx> {
726 let fn_def_id = cx.tcx.hir().local_def_id_from_hir_id(fn_item);
727 let ret_ty = cx.tcx.fn_sig(fn_def_id).output();
728 cx.tcx.erase_late_bound_regions(&ret_ty)
731 /// Checks if two types are the same.
733 /// This discards any lifetime annotations, too.
735 // FIXME: this works correctly for lifetimes bounds (`for <'a> Foo<'a>` ==
736 // `for <'b> Foo<'b>`, but not for type parameters).
737 pub fn same_tys<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, a: Ty<'tcx>, b: Ty<'tcx>) -> bool {
738 let a = cx.tcx.erase_late_bound_regions(&Binder::bind(a));
739 let b = cx.tcx.erase_late_bound_regions(&Binder::bind(b));
742 .enter(|infcx| infcx.can_eq(cx.param_env, a, b).is_ok())
745 /// Returns `true` if the given type is an `unsafe` function.
746 pub fn type_is_unsafe_function<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
748 ty::FnDef(..) | ty::FnPtr(_) => ty.fn_sig(cx.tcx).unsafety() == Unsafety::Unsafe,
753 pub fn is_copy<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
754 ty.is_copy_modulo_regions(cx.tcx.global_tcx(), cx.param_env, DUMMY_SP)
757 /// Checks if an expression is constructing a tuple-like enum variant or struct
758 pub fn is_ctor_function(cx: &LateContext<'_, '_>, expr: &Expr) -> bool {
759 if let ExprKind::Call(ref fun, _) = expr.node {
760 if let ExprKind::Path(ref qp) = fun.node {
762 cx.tables.qpath_res(qp, fun.hir_id),
763 def::Res::Def(DefKind::Variant, ..) | Res::Def(DefKind::Ctor(..), _)
770 /// Returns `true` if a pattern is refutable.
771 pub fn is_refutable(cx: &LateContext<'_, '_>, pat: &Pat) -> bool {
772 fn is_enum_variant(cx: &LateContext<'_, '_>, qpath: &QPath, id: HirId) -> bool {
774 cx.tables.qpath_res(qpath, id),
775 def::Res::Def(DefKind::Variant, ..) | Res::Def(DefKind::Ctor(def::CtorOf::Variant, _), _)
779 fn are_refutable<'a, I: Iterator<Item = &'a Pat>>(cx: &LateContext<'_, '_>, mut i: I) -> bool {
780 i.any(|pat| is_refutable(cx, pat))
784 PatKind::Binding(..) | PatKind::Wild => false,
785 PatKind::Box(ref pat) | PatKind::Ref(ref pat, _) => is_refutable(cx, pat),
786 PatKind::Lit(..) | PatKind::Range(..) => true,
787 PatKind::Path(ref qpath) => is_enum_variant(cx, qpath, pat.hir_id),
788 PatKind::Tuple(ref pats, _) => are_refutable(cx, pats.iter().map(|pat| &**pat)),
789 PatKind::Struct(ref qpath, ref fields, _) => {
790 if is_enum_variant(cx, qpath, pat.hir_id) {
793 are_refutable(cx, fields.iter().map(|field| &*field.node.pat))
796 PatKind::TupleStruct(ref qpath, ref pats, _) => {
797 if is_enum_variant(cx, qpath, pat.hir_id) {
800 are_refutable(cx, pats.iter().map(|pat| &**pat))
803 PatKind::Slice(ref head, ref middle, ref tail) => {
804 are_refutable(cx, head.iter().chain(middle).chain(tail.iter()).map(|pat| &**pat))
809 /// Checks for the `#[automatically_derived]` attribute all `#[derive]`d
810 /// implementations have.
811 pub fn is_automatically_derived(attrs: &[ast::Attribute]) -> bool {
812 attr::contains_name(attrs, "automatically_derived")
815 /// Remove blocks around an expression.
817 /// Ie. `x`, `{ x }` and `{{{{ x }}}}` all give `x`. `{ x; y }` and `{}` return
819 pub fn remove_blocks(expr: &Expr) -> &Expr {
820 if let ExprKind::Block(ref block, _) = expr.node {
821 if block.stmts.is_empty() {
822 if let Some(ref expr) = block.expr {
835 pub fn is_self(slf: &Arg) -> bool {
836 if let PatKind::Binding(.., name, _) = slf.pat.node {
837 name.name == keywords::SelfLower.name()
843 pub fn is_self_ty(slf: &hir::Ty) -> bool {
845 if let TyKind::Path(ref qp) = slf.node;
846 if let QPath::Resolved(None, ref path) = *qp;
847 if let Res::SelfTy(..) = path.res;
855 pub fn iter_input_pats<'tcx>(decl: &FnDecl, body: &'tcx Body) -> impl Iterator<Item = &'tcx Arg> {
856 (0..decl.inputs.len()).map(move |i| &body.arguments[i])
859 /// Checks if a given expression is a match expression expanded from the `?`
860 /// operator or the `try` macro.
861 pub fn is_try(expr: &Expr) -> Option<&Expr> {
862 fn is_ok(arm: &Arm) -> bool {
864 if let PatKind::TupleStruct(ref path, ref pat, None) = arm.pats[0].node;
865 if match_qpath(path, &paths::RESULT_OK[1..]);
866 if let PatKind::Binding(_, hir_id, _, None) = pat[0].node;
867 if let ExprKind::Path(QPath::Resolved(None, ref path)) = arm.body.node;
868 if let Res::Local(lid) = path.res;
877 fn is_err(arm: &Arm) -> bool {
878 if let PatKind::TupleStruct(ref path, _, _) = arm.pats[0].node {
879 match_qpath(path, &paths::RESULT_ERR[1..])
885 if let ExprKind::Match(_, ref arms, ref source) = expr.node {
886 // desugared from a `?` operator
887 if let MatchSource::TryDesugar = *source {
893 if arms[0].pats.len() == 1 && arms[0].guard.is_none();
894 if arms[1].pats.len() == 1 && arms[1].guard.is_none();
895 if (is_ok(&arms[0]) && is_err(&arms[1])) ||
896 (is_ok(&arms[1]) && is_err(&arms[0]));
906 /// Returns `true` if the lint is allowed in the current context
908 /// Useful for skipping long running code when it's unnecessary
909 pub fn is_allowed(cx: &LateContext<'_, '_>, lint: &'static Lint, id: HirId) -> bool {
910 cx.tcx.lint_level_at_node(lint, id).0 == Level::Allow
913 pub fn get_arg_name(pat: &Pat) -> Option<ast::Name> {
915 PatKind::Binding(.., ident, None) => Some(ident.name),
916 PatKind::Ref(ref subpat, _) => get_arg_name(subpat),
921 pub fn int_bits(tcx: TyCtxt<'_, '_, '_>, ity: ast::IntTy) -> u64 {
922 layout::Integer::from_attr(&tcx, attr::IntType::SignedInt(ity))
927 #[allow(clippy::cast_possible_wrap)]
928 /// Turn a constant int byte representation into an i128
929 pub fn sext(tcx: TyCtxt<'_, '_, '_>, u: u128, ity: ast::IntTy) -> i128 {
930 let amt = 128 - int_bits(tcx, ity);
931 ((u as i128) << amt) >> amt
934 #[allow(clippy::cast_sign_loss)]
935 /// clip unused bytes
936 pub fn unsext(tcx: TyCtxt<'_, '_, '_>, u: i128, ity: ast::IntTy) -> u128 {
937 let amt = 128 - int_bits(tcx, ity);
938 ((u as u128) << amt) >> amt
941 /// clip unused bytes
942 pub fn clip(tcx: TyCtxt<'_, '_, '_>, u: u128, ity: ast::UintTy) -> u128 {
943 let bits = layout::Integer::from_attr(&tcx, attr::IntType::UnsignedInt(ity))
946 let amt = 128 - bits;
950 /// Removes block comments from the given `Vec` of lines.
955 /// without_block_comments(vec!["/*", "foo", "*/"]);
958 /// without_block_comments(vec!["bar", "/*", "foo", "*/"]);
959 /// // => vec!["bar"]
961 pub fn without_block_comments(lines: Vec<&str>) -> Vec<&str> {
962 let mut without = vec![];
964 let mut nest_level = 0;
967 if line.contains("/*") {
970 } else if line.contains("*/") {
983 pub fn any_parent_is_automatically_derived(tcx: TyCtxt<'_, '_, '_>, node: HirId) -> bool {
984 let map = &tcx.hir();
985 let mut prev_enclosing_node = None;
986 let mut enclosing_node = node;
987 while Some(enclosing_node) != prev_enclosing_node {
988 if is_automatically_derived(map.attrs_by_hir_id(enclosing_node)) {
991 prev_enclosing_node = Some(enclosing_node);
992 enclosing_node = map.get_parent_item(enclosing_node);
997 /// Returns true if ty has `iter` or `iter_mut` methods
998 pub fn has_iter_method(cx: &LateContext<'_, '_>, probably_ref_ty: Ty<'_>) -> Option<&'static str> {
999 // FIXME: instead of this hard-coded list, we should check if `<adt>::iter`
1000 // exists and has the desired signature. Unfortunately FnCtxt is not exported
1001 // so we can't use its `lookup_method` method.
1002 static INTO_ITER_COLLECTIONS: [&[&str]; 13] = [
1009 &paths::LINKED_LIST,
1010 &paths::BINARY_HEAP,
1018 let ty_to_check = match probably_ref_ty.sty {
1019 ty::Ref(_, ty_to_check, _) => ty_to_check,
1020 _ => probably_ref_ty,
1023 let def_id = match ty_to_check.sty {
1024 ty::Array(..) => return Some("array"),
1025 ty::Slice(..) => return Some("slice"),
1026 ty::Adt(adt, _) => adt.did,
1030 for path in &INTO_ITER_COLLECTIONS {
1031 if cx.match_def_path(def_id, path) {
1032 return Some(path.last().unwrap());
1040 use super::{trim_multiline, without_block_comments};
1043 fn test_trim_multiline_single_line() {
1044 assert_eq!("", trim_multiline("".into(), false));
1045 assert_eq!("...", trim_multiline("...".into(), false));
1046 assert_eq!("...", trim_multiline(" ...".into(), false));
1047 assert_eq!("...", trim_multiline("\t...".into(), false));
1048 assert_eq!("...", trim_multiline("\t\t...".into(), false));
1053 fn test_trim_multiline_block() {
1059 }", trim_multiline(" if x {
1069 }", trim_multiline(" if x {
1078 fn test_trim_multiline_empty_line() {
1085 }", trim_multiline(" if x {
1094 fn test_without_block_comments_lines_without_block_comments() {
1095 let result = without_block_comments(vec!["/*", "", "*/"]);
1096 println!("result: {:?}", result);
1097 assert!(result.is_empty());
1099 let result = without_block_comments(vec!["", "/*", "", "*/", "#[crate_type = \"lib\"]", "/*", "", "*/", ""]);
1100 assert_eq!(result, vec!["", "#[crate_type = \"lib\"]", ""]);
1102 let result = without_block_comments(vec!["/* rust", "", "*/"]);
1103 assert!(result.is_empty());
1105 let result = without_block_comments(vec!["/* one-line comment */"]);
1106 assert!(result.is_empty());
1108 let result = without_block_comments(vec!["/* nested", "/* multi-line", "comment", "*/", "test", "*/"]);
1109 assert!(result.is_empty());
1111 let result = without_block_comments(vec!["/* nested /* inline /* comment */ test */ */"]);
1112 assert!(result.is_empty());
1114 let result = without_block_comments(vec!["foo", "bar", "baz"]);
1115 assert_eq!(result, vec!["foo", "bar", "baz"]);