11 pub mod internal_lints;
16 pub use self::attrs::*;
17 pub use self::diagnostics::*;
18 pub use self::hir_utils::{SpanlessEq, SpanlessHash};
23 use if_chain::if_chain;
26 use rustc::hir::def::Def;
27 use rustc::hir::def_id::{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::source_map::{Span, DUMMY_SP};
44 use syntax::symbol::{keywords, Symbol};
46 use crate::reexport::*;
48 /// Returns `true` if the two spans come from differing expansions (i.e., one is
49 /// from a macro and one isn't).
50 pub fn differing_macro_contexts(lhs: Span, rhs: Span) -> bool {
51 rhs.ctxt() != lhs.ctxt()
54 /// Returns `true` if the given `NodeId` is inside a constant context
59 /// if in_constant(cx, expr.id) {
63 pub fn in_constant(cx: &LateContext<'_, '_>, id: HirId) -> bool {
64 let parent_id = cx.tcx.hir().get_parent_item(id);
65 match cx.tcx.hir().get_by_hir_id(parent_id) {
67 node: ItemKind::Const(..),
70 | Node::TraitItem(&TraitItem {
71 node: TraitItemKind::Const(..),
74 | Node::ImplItem(&ImplItem {
75 node: ImplItemKind::Const(..),
80 node: ItemKind::Static(..),
84 node: ItemKind::Fn(_, header, ..),
86 }) => header.constness == Constness::Const,
91 /// Returns `true` if this `expn_info` was expanded by any macro.
92 pub fn in_macro(span: Span) -> bool {
93 span.ctxt().outer().expn_info().is_some()
96 // If the snippet is empty, it's an attribute that was inserted during macro
97 // expansion and we want to ignore those, because they could come from external
98 // sources that the user has no control over.
99 // For some reason these attributes don't have any expansion info on them, so
100 // we have to check it this way until there is a better way.
101 pub fn is_present_in_source<'a, T: LintContext<'a>>(cx: &T, span: Span) -> bool {
102 if let Some(snippet) = snippet_opt(cx, span) {
103 if snippet.is_empty() {
110 /// Checks if type is struct, enum or union type with the given def path.
111 pub fn match_type(cx: &LateContext<'_, '_>, ty: Ty<'_>, path: &[&str]) -> bool {
113 ty::Adt(adt, _) => cx.match_def_path(adt.did, path),
118 /// Checks if the method call given in `expr` belongs to the given trait.
119 pub fn match_trait_method(cx: &LateContext<'_, '_>, expr: &Expr, path: &[&str]) -> bool {
120 let def_id = cx.tables.type_dependent_def_id(expr.hir_id).unwrap();
121 let trt_id = cx.tcx.trait_of_item(def_id);
122 if let Some(trt_id) = trt_id {
123 cx.match_def_path(trt_id, path)
129 /// Checks if an expression references a variable of the given name.
130 pub fn match_var(expr: &Expr, var: Name) -> bool {
131 if let ExprKind::Path(QPath::Resolved(None, ref path)) = expr.node {
132 if path.segments.len() == 1 && path.segments[0].ident.name == var {
139 pub fn last_path_segment(path: &QPath) -> &PathSegment {
141 QPath::Resolved(_, ref path) => path.segments.last().expect("A path must have at least one segment"),
142 QPath::TypeRelative(_, ref seg) => seg,
146 pub fn single_segment_path(path: &QPath) -> Option<&PathSegment> {
148 QPath::Resolved(_, ref path) if path.segments.len() == 1 => Some(&path.segments[0]),
149 QPath::Resolved(..) => None,
150 QPath::TypeRelative(_, ref seg) => Some(seg),
154 /// Matches a `QPath` against a slice of segment string literals.
156 /// There is also `match_path` if you are dealing with a `rustc::hir::Path` instead of a
157 /// `rustc::hir::QPath`.
161 /// match_qpath(path, &["std", "rt", "begin_unwind"])
163 pub fn match_qpath(path: &QPath, segments: &[&str]) -> bool {
165 QPath::Resolved(_, ref path) => match_path(path, segments),
166 QPath::TypeRelative(ref ty, ref segment) => match ty.node {
167 TyKind::Path(ref inner_path) => {
169 && match_qpath(inner_path, &segments[..(segments.len() - 1)])
170 && segment.ident.name == segments[segments.len() - 1]
177 /// Matches a `Path` against a slice of segment string literals.
179 /// There is also `match_qpath` if you are dealing with a `rustc::hir::QPath` instead of a
180 /// `rustc::hir::Path`.
185 /// if match_path(&trait_ref.path, &paths::HASH) {
186 /// // This is the `std::hash::Hash` trait.
189 /// if match_path(ty_path, &["rustc", "lint", "Lint"]) {
190 /// // This is a `rustc::lint::Lint`.
193 pub fn match_path(path: &Path, segments: &[&str]) -> bool {
197 .zip(segments.iter().rev())
198 .all(|(a, b)| a.ident.name == *b)
201 /// Matches a `Path` against a slice of segment string literals, e.g.
205 /// match_qpath(path, &["std", "rt", "begin_unwind"])
207 pub fn match_path_ast(path: &ast::Path, segments: &[&str]) -> bool {
211 .zip(segments.iter().rev())
212 .all(|(a, b)| a.ident.name == *b)
215 /// Gets the definition associated to a path.
216 pub fn path_to_def(cx: &LateContext<'_, '_>, path: &[&str]) -> Option<def::Def> {
217 let crates = cx.tcx.crates();
218 let krate = crates.iter().find(|&&krate| cx.tcx.crate_name(krate) == path[0]);
219 if let Some(krate) = krate {
222 index: CRATE_DEF_INDEX,
224 let mut items = cx.tcx.item_children(krate);
225 let mut path_it = path.iter().skip(1).peekable();
228 let segment = match path_it.next() {
229 Some(segment) => segment,
233 for item in mem::replace(&mut items, Lrc::new(vec![])).iter() {
234 if item.ident.name == *segment {
235 if path_it.peek().is_none() {
236 return Some(item.def);
239 items = cx.tcx.item_children(item.def.def_id());
249 /// Convenience function to get the `DefId` of a trait by path.
250 pub fn get_trait_def_id(cx: &LateContext<'_, '_>, path: &[&str]) -> Option<DefId> {
251 let def = match path_to_def(cx, path) {
257 def::Def::Trait(trait_id) => Some(trait_id),
262 /// Checks whether a type implements a trait.
263 /// See also `get_trait_def_id`.
264 pub fn implements_trait<'a, 'tcx>(
265 cx: &LateContext<'a, 'tcx>,
268 ty_params: &[Kind<'tcx>],
270 let ty = cx.tcx.erase_regions(&ty);
271 let obligation = cx.tcx.predicate_for_trait_def(
273 traits::ObligationCause::dummy(),
281 .enter(|infcx| infcx.predicate_must_hold_modulo_regions(&obligation))
284 /// Gets the `hir::TraitRef` of the trait the given method is implemented for.
286 /// Use this if you want to find the `TraitRef` of the `Add` trait in this example:
289 /// struct Point(isize, isize);
291 /// impl std::ops::Add for Point {
292 /// type Output = Self;
294 /// fn add(self, other: Self) -> Self {
299 pub fn trait_ref_of_method(cx: &LateContext<'_, '_>, hir_id: HirId) -> Option<TraitRef> {
300 // Get the implemented trait for the current function
301 let parent_impl = cx.tcx.hir().get_parent_item(hir_id);
303 if parent_impl != hir::CRATE_HIR_ID;
304 if let hir::Node::Item(item) = cx.tcx.hir().get_by_hir_id(parent_impl);
305 if let hir::ItemKind::Impl(_, _, _, _, trait_ref, _, _) = &item.node;
306 then { return trait_ref.clone(); }
311 /// Checks whether this type implements `Drop`.
312 pub fn has_drop<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
313 match ty.ty_adt_def() {
314 Some(def) => def.has_dtor(cx.tcx),
319 /// Resolves the definition of a node from its `HirId`.
320 pub fn resolve_node(cx: &LateContext<'_, '_>, qpath: &QPath, id: HirId) -> def::Def {
321 cx.tables.qpath_def(qpath, id)
324 /// Returns the method names and argument list of nested method call expressions that make up
326 pub fn method_calls<'a>(expr: &'a Expr, max_depth: usize) -> (Vec<Symbol>, Vec<&'a [Expr]>) {
327 let mut method_names = Vec::with_capacity(max_depth);
328 let mut arg_lists = Vec::with_capacity(max_depth);
330 let mut current = expr;
331 for _ in 0..max_depth {
332 if let ExprKind::MethodCall(path, _, args) = ¤t.node {
333 if args.iter().any(|e| in_macro(e.span)) {
336 method_names.push(path.ident.name);
337 arg_lists.push(&**args);
344 (method_names, arg_lists)
347 /// Matches an `Expr` against a chain of methods, and return the matched `Expr`s.
349 /// For example, if `expr` represents the `.baz()` in `foo.bar().baz()`,
350 /// `matched_method_chain(expr, &["bar", "baz"])` will return a `Vec`
351 /// containing the `Expr`s for
352 /// `.bar()` and `.baz()`
353 pub fn method_chain_args<'a>(expr: &'a Expr, methods: &[&str]) -> Option<Vec<&'a [Expr]>> {
354 let mut current = expr;
355 let mut matched = Vec::with_capacity(methods.len());
356 for method_name in methods.iter().rev() {
357 // method chains are stored last -> first
358 if let ExprKind::MethodCall(ref path, _, ref args) = current.node {
359 if path.ident.name == *method_name {
360 if args.iter().any(|e| in_macro(e.span)) {
363 matched.push(&**args); // build up `matched` backwards
364 current = &args[0] // go to parent expression
372 // Reverse `matched` so that it is in the same order as `methods`.
377 /// Returns `true` if the provided `def_id` is an entrypoint to a program.
378 pub fn is_entrypoint_fn(cx: &LateContext<'_, '_>, def_id: DefId) -> bool {
379 if let Some((entry_fn_def_id, _)) = cx.tcx.entry_fn(LOCAL_CRATE) {
380 return def_id == entry_fn_def_id;
385 /// Gets the name of the item the expression is in, if available.
386 pub fn get_item_name(cx: &LateContext<'_, '_>, expr: &Expr) -> Option<Name> {
387 let parent_id = cx.tcx.hir().get_parent_item(expr.hir_id);
388 match cx.tcx.hir().find_by_hir_id(parent_id) {
389 Some(Node::Item(&Item { ref ident, .. })) => Some(ident.name),
390 Some(Node::TraitItem(&TraitItem { ident, .. })) | Some(Node::ImplItem(&ImplItem { ident, .. })) => {
397 /// Gets the name of a `Pat`, if any.
398 pub fn get_pat_name(pat: &Pat) -> Option<Name> {
400 PatKind::Binding(.., ref spname, _) => Some(spname.name),
401 PatKind::Path(ref qpath) => single_segment_path(qpath).map(|ps| ps.ident.name),
402 PatKind::Box(ref p) | PatKind::Ref(ref p, _) => get_pat_name(&*p),
407 struct ContainsName {
412 impl<'tcx> Visitor<'tcx> for ContainsName {
413 fn visit_name(&mut self, _: Span, name: Name) {
414 if self.name == name {
418 fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
419 NestedVisitorMap::None
423 /// Checks if an `Expr` contains a certain name.
424 pub fn contains_name(name: Name, expr: &Expr) -> bool {
425 let mut cn = ContainsName { name, result: false };
430 /// Converts a span to a code snippet if available, otherwise use default.
432 /// This is useful if you want to provide suggestions for your lint or more generally, if you want
433 /// to convert a given `Span` to a `str`.
437 /// snippet(cx, expr.span, "..")
439 pub fn snippet<'a, 'b, T: LintContext<'b>>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
440 snippet_opt(cx, span).map_or_else(|| Cow::Borrowed(default), From::from)
443 /// Same as `snippet`, but it adapts the applicability level by following rules:
445 /// - Applicability level `Unspecified` will never be changed.
446 /// - If the span is inside a macro, change the applicability level to `MaybeIncorrect`.
447 /// - If the default value is used and the applicability level is `MachineApplicable`, change it to
448 /// `HasPlaceholders`
449 pub fn snippet_with_applicability<'a, 'b, T: LintContext<'b>>(
453 applicability: &mut Applicability,
455 if *applicability != Applicability::Unspecified && in_macro(span) {
456 *applicability = Applicability::MaybeIncorrect;
458 snippet_opt(cx, span).map_or_else(
460 if *applicability == Applicability::MachineApplicable {
461 *applicability = Applicability::HasPlaceholders;
463 Cow::Borrowed(default)
469 /// Same as `snippet`, but should only be used when it's clear that the input span is
470 /// not a macro argument.
471 pub fn snippet_with_macro_callsite<'a, 'b, T: LintContext<'b>>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
472 snippet(cx, span.source_callsite(), default)
475 /// Converts a span to a code snippet. Returns `None` if not available.
476 pub fn snippet_opt<'a, T: LintContext<'a>>(cx: &T, span: Span) -> Option<String> {
477 cx.sess().source_map().span_to_snippet(span).ok()
480 /// Converts a span (from a block) to a code snippet if available, otherwise use
482 /// This trims the code of indentation, except for the first line. Use it for
483 /// blocks or block-like
484 /// things which need to be printed as such.
488 /// snippet_block(cx, expr.span, "..")
490 pub fn snippet_block<'a, 'b, T: LintContext<'b>>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
491 let snip = snippet(cx, span, default);
492 trim_multiline(snip, true)
495 /// Same as `snippet_block`, but adapts the applicability level by the rules of
496 /// `snippet_with_applicabiliy`.
497 pub fn snippet_block_with_applicability<'a, 'b, T: LintContext<'b>>(
501 applicability: &mut Applicability,
503 let snip = snippet_with_applicability(cx, span, default, applicability);
504 trim_multiline(snip, true)
507 /// Returns a new Span that covers the full last line of the given Span
508 pub fn last_line_of_span<'a, T: LintContext<'a>>(cx: &T, span: Span) -> Span {
509 let source_map_and_line = cx.sess().source_map().lookup_line(span.lo()).unwrap();
510 let line_no = source_map_and_line.line;
511 let line_start = &source_map_and_line.sf.lines[line_no];
512 Span::new(*line_start, span.hi(), span.ctxt())
515 /// Like `snippet_block`, but add braces if the expr is not an `ExprKind::Block`.
516 /// Also takes an `Option<String>` which can be put inside the braces.
517 pub fn expr_block<'a, 'b, T: LintContext<'b>>(
520 option: Option<String>,
523 let code = snippet_block(cx, expr.span, default);
524 let string = option.unwrap_or_default();
525 if in_macro(expr.span) {
526 Cow::Owned(format!("{{ {} }}", snippet_with_macro_callsite(cx, expr.span, default)))
527 } else if let ExprKind::Block(_, _) = expr.node {
528 Cow::Owned(format!("{}{}", code, string))
529 } else if string.is_empty() {
530 Cow::Owned(format!("{{ {} }}", code))
532 Cow::Owned(format!("{{\n{};\n{}\n}}", code, string))
536 /// Trim indentation from a multiline string with possibility of ignoring the
538 pub fn trim_multiline(s: Cow<'_, str>, ignore_first: bool) -> Cow<'_, str> {
539 let s_space = trim_multiline_inner(s, ignore_first, ' ');
540 let s_tab = trim_multiline_inner(s_space, ignore_first, '\t');
541 trim_multiline_inner(s_tab, ignore_first, ' ')
544 fn trim_multiline_inner(s: Cow<'_, str>, ignore_first: bool, ch: char) -> Cow<'_, str> {
547 .skip(ignore_first as usize)
552 // ignore empty lines
553 Some(l.char_indices().find(|&(_, x)| x != ch).unwrap_or((l.len(), ch)).0)
563 if (ignore_first && i == 0) || l.is_empty() {
577 /// Gets the parent expression, if any –- this is useful to constrain a lint.
578 pub fn get_parent_expr<'c>(cx: &'c LateContext<'_, '_>, e: &Expr) -> Option<&'c Expr> {
579 let map = &cx.tcx.hir();
580 let hir_id = e.hir_id;
581 let parent_id = map.get_parent_node_by_hir_id(hir_id);
582 if hir_id == parent_id {
585 map.find_by_hir_id(parent_id).and_then(|node| {
586 if let Node::Expr(parent) = node {
594 pub fn get_enclosing_block<'a, 'tcx: 'a>(cx: &LateContext<'a, 'tcx>, hir_id: HirId) -> Option<&'tcx Block> {
595 let map = &cx.tcx.hir();
596 let enclosing_node = map
597 .get_enclosing_scope(hir_id)
598 .and_then(|enclosing_id| map.find_by_hir_id(enclosing_id));
599 if let Some(node) = enclosing_node {
601 Node::Block(block) => Some(block),
603 node: ItemKind::Fn(_, _, _, eid),
606 | Node::ImplItem(&ImplItem {
607 node: ImplItemKind::Method(_, eid),
609 }) => match cx.tcx.hir().body(eid).value.node {
610 ExprKind::Block(ref block, _) => Some(block),
620 /// Returns the base type for HIR references and pointers.
621 pub fn walk_ptrs_hir_ty(ty: &hir::Ty) -> &hir::Ty {
623 TyKind::Ptr(ref mut_ty) | TyKind::Rptr(_, ref mut_ty) => walk_ptrs_hir_ty(&mut_ty.ty),
628 /// Returns the base type for references and raw pointers.
629 pub fn walk_ptrs_ty(ty: Ty<'_>) -> Ty<'_> {
631 ty::Ref(_, ty, _) => walk_ptrs_ty(ty),
636 /// Returns the base type for references and raw pointers, and count reference
638 pub fn walk_ptrs_ty_depth(ty: Ty<'_>) -> (Ty<'_>, usize) {
639 fn inner(ty: Ty<'_>, depth: usize) -> (Ty<'_>, usize) {
641 ty::Ref(_, ty, _) => inner(ty, depth + 1),
648 /// Checks whether the given expression is a constant literal of the given value.
649 pub fn is_integer_literal(expr: &Expr, value: u128) -> bool {
650 // FIXME: use constant folding
651 if let ExprKind::Lit(ref spanned) = expr.node {
652 if let LitKind::Int(v, _) = spanned.node {
659 /// Returns `true` if the given `Expr` has been coerced before.
661 /// Examples of coercions can be found in the Nomicon at
662 /// <https://doc.rust-lang.org/nomicon/coercions.html>.
664 /// See `rustc::ty::adjustment::Adjustment` and `rustc_typeck::check::coercion` for more
665 /// information on adjustments and coercions.
666 pub fn is_adjusted(cx: &LateContext<'_, '_>, e: &Expr) -> bool {
667 cx.tables.adjustments().get(e.hir_id).is_some()
670 /// Returns the pre-expansion span if is this comes from an expansion of the
672 /// See also `is_direct_expn_of`.
673 pub fn is_expn_of(mut span: Span, name: &str) -> Option<Span> {
675 let span_name_span = span
679 .map(|ei| (ei.format.name(), ei.call_site));
681 match span_name_span {
682 Some((mac_name, new_span)) if mac_name == name => return Some(new_span),
684 Some((_, new_span)) => span = new_span,
689 /// Returns the pre-expansion span if the span directly comes from an expansion
690 /// of the macro `name`.
691 /// The difference with `is_expn_of` is that in
695 /// `42` is considered expanded from `foo!` and `bar!` by `is_expn_of` but only
697 /// `is_direct_expn_of`.
698 pub fn is_direct_expn_of(span: Span, name: &str) -> Option<Span> {
699 let span_name_span = span
703 .map(|ei| (ei.format.name(), ei.call_site));
705 match span_name_span {
706 Some((mac_name, new_span)) if mac_name == name => Some(new_span),
711 /// Convenience function to get the return type of a function.
712 pub fn return_ty<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, fn_item: hir::HirId) -> Ty<'tcx> {
713 let fn_def_id = cx.tcx.hir().local_def_id_from_hir_id(fn_item);
714 let ret_ty = cx.tcx.fn_sig(fn_def_id).output();
715 cx.tcx.erase_late_bound_regions(&ret_ty)
718 /// Checks if two types are the same.
720 /// This discards any lifetime annotations, too.
722 // FIXME: this works correctly for lifetimes bounds (`for <'a> Foo<'a>` ==
723 // `for <'b> Foo<'b>`, but not for type parameters).
724 pub fn same_tys<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, a: Ty<'tcx>, b: Ty<'tcx>) -> bool {
725 let a = cx.tcx.erase_late_bound_regions(&Binder::bind(a));
726 let b = cx.tcx.erase_late_bound_regions(&Binder::bind(b));
729 .enter(|infcx| infcx.can_eq(cx.param_env, a, b).is_ok())
732 /// Returns `true` if the given type is an `unsafe` function.
733 pub fn type_is_unsafe_function<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
735 ty::FnDef(..) | ty::FnPtr(_) => ty.fn_sig(cx.tcx).unsafety() == Unsafety::Unsafe,
740 pub fn is_copy<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
741 ty.is_copy_modulo_regions(cx.tcx.global_tcx(), cx.param_env, DUMMY_SP)
744 /// Checks if an expression is constructing a tuple-like enum variant or struct
745 pub fn is_ctor_function(cx: &LateContext<'_, '_>, expr: &Expr) -> bool {
746 if let ExprKind::Call(ref fun, _) = expr.node {
747 if let ExprKind::Path(ref qp) = fun.node {
749 cx.tables.qpath_def(qp, fun.hir_id),
750 def::Def::Variant(..) | def::Def::Ctor(..)
757 /// Returns `true` if a pattern is refutable.
758 pub fn is_refutable(cx: &LateContext<'_, '_>, pat: &Pat) -> bool {
759 fn is_enum_variant(cx: &LateContext<'_, '_>, qpath: &QPath, id: HirId) -> bool {
761 cx.tables.qpath_def(qpath, id),
762 def::Def::Variant(..) | def::Def::Ctor(_, def::CtorOf::Variant, _)
766 fn are_refutable<'a, I: Iterator<Item = &'a Pat>>(cx: &LateContext<'_, '_>, mut i: I) -> bool {
767 i.any(|pat| is_refutable(cx, pat))
771 PatKind::Binding(..) | PatKind::Wild => false,
772 PatKind::Box(ref pat) | PatKind::Ref(ref pat, _) => is_refutable(cx, pat),
773 PatKind::Lit(..) | PatKind::Range(..) => true,
774 PatKind::Path(ref qpath) => is_enum_variant(cx, qpath, pat.hir_id),
775 PatKind::Tuple(ref pats, _) => are_refutable(cx, pats.iter().map(|pat| &**pat)),
776 PatKind::Struct(ref qpath, ref fields, _) => {
777 if is_enum_variant(cx, qpath, pat.hir_id) {
780 are_refutable(cx, fields.iter().map(|field| &*field.node.pat))
783 PatKind::TupleStruct(ref qpath, ref pats, _) => {
784 if is_enum_variant(cx, qpath, pat.hir_id) {
787 are_refutable(cx, pats.iter().map(|pat| &**pat))
790 PatKind::Slice(ref head, ref middle, ref tail) => {
791 are_refutable(cx, head.iter().chain(middle).chain(tail.iter()).map(|pat| &**pat))
796 /// Checks for the `#[automatically_derived]` attribute all `#[derive]`d
797 /// implementations have.
798 pub fn is_automatically_derived(attrs: &[ast::Attribute]) -> bool {
799 attr::contains_name(attrs, "automatically_derived")
802 /// Remove blocks around an expression.
804 /// Ie. `x`, `{ x }` and `{{{{ x }}}}` all give `x`. `{ x; y }` and `{}` return
806 pub fn remove_blocks(expr: &Expr) -> &Expr {
807 if let ExprKind::Block(ref block, _) = expr.node {
808 if block.stmts.is_empty() {
809 if let Some(ref expr) = block.expr {
822 pub fn is_self(slf: &Arg) -> bool {
823 if let PatKind::Binding(.., name, _) = slf.pat.node {
824 name.name == keywords::SelfLower.name()
830 pub fn is_self_ty(slf: &hir::Ty) -> bool {
832 if let TyKind::Path(ref qp) = slf.node;
833 if let QPath::Resolved(None, ref path) = *qp;
834 if let Def::SelfTy(..) = path.def;
842 pub fn iter_input_pats<'tcx>(decl: &FnDecl, body: &'tcx Body) -> impl Iterator<Item = &'tcx Arg> {
843 (0..decl.inputs.len()).map(move |i| &body.arguments[i])
846 /// Checks if a given expression is a match expression expanded from the `?`
847 /// operator or the `try` macro.
848 pub fn is_try(expr: &Expr) -> Option<&Expr> {
849 fn is_ok(arm: &Arm) -> bool {
851 if let PatKind::TupleStruct(ref path, ref pat, None) = arm.pats[0].node;
852 if match_qpath(path, &paths::RESULT_OK[1..]);
853 if let PatKind::Binding(_, hir_id, _, None) = pat[0].node;
854 if let ExprKind::Path(QPath::Resolved(None, ref path)) = arm.body.node;
855 if let Def::Local(lid) = path.def;
864 fn is_err(arm: &Arm) -> bool {
865 if let PatKind::TupleStruct(ref path, _, _) = arm.pats[0].node {
866 match_qpath(path, &paths::RESULT_ERR[1..])
872 if let ExprKind::Match(_, ref arms, ref source) = expr.node {
873 // desugared from a `?` operator
874 if let MatchSource::TryDesugar = *source {
880 if arms[0].pats.len() == 1 && arms[0].guard.is_none();
881 if arms[1].pats.len() == 1 && arms[1].guard.is_none();
882 if (is_ok(&arms[0]) && is_err(&arms[1])) ||
883 (is_ok(&arms[1]) && is_err(&arms[0]));
893 /// Returns `true` if the lint is allowed in the current context
895 /// Useful for skipping long running code when it's unnecessary
896 pub fn is_allowed(cx: &LateContext<'_, '_>, lint: &'static Lint, id: HirId) -> bool {
897 cx.tcx.lint_level_at_node(lint, id).0 == Level::Allow
900 pub fn get_arg_name(pat: &Pat) -> Option<ast::Name> {
902 PatKind::Binding(.., ident, None) => Some(ident.name),
903 PatKind::Ref(ref subpat, _) => get_arg_name(subpat),
908 pub fn int_bits(tcx: TyCtxt<'_, '_, '_>, ity: ast::IntTy) -> u64 {
909 layout::Integer::from_attr(&tcx, attr::IntType::SignedInt(ity))
914 #[allow(clippy::cast_possible_wrap)]
915 /// Turn a constant int byte representation into an i128
916 pub fn sext(tcx: TyCtxt<'_, '_, '_>, u: u128, ity: ast::IntTy) -> i128 {
917 let amt = 128 - int_bits(tcx, ity);
918 ((u as i128) << amt) >> amt
921 #[allow(clippy::cast_sign_loss)]
922 /// clip unused bytes
923 pub fn unsext(tcx: TyCtxt<'_, '_, '_>, u: i128, ity: ast::IntTy) -> u128 {
924 let amt = 128 - int_bits(tcx, ity);
925 ((u as u128) << amt) >> amt
928 /// clip unused bytes
929 pub fn clip(tcx: TyCtxt<'_, '_, '_>, u: u128, ity: ast::UintTy) -> u128 {
930 let bits = layout::Integer::from_attr(&tcx, attr::IntType::UnsignedInt(ity))
933 let amt = 128 - bits;
937 /// Removes block comments from the given `Vec` of lines.
942 /// without_block_comments(vec!["/*", "foo", "*/"]);
945 /// without_block_comments(vec!["bar", "/*", "foo", "*/"]);
946 /// // => vec!["bar"]
948 pub fn without_block_comments(lines: Vec<&str>) -> Vec<&str> {
949 let mut without = vec![];
951 let mut nest_level = 0;
954 if line.contains("/*") {
957 } else if line.contains("*/") {
970 pub fn any_parent_is_automatically_derived(tcx: TyCtxt<'_, '_, '_>, node: HirId) -> bool {
971 let map = &tcx.hir();
972 let mut prev_enclosing_node = None;
973 let mut enclosing_node = node;
974 while Some(enclosing_node) != prev_enclosing_node {
975 if is_automatically_derived(map.attrs_by_hir_id(enclosing_node)) {
978 prev_enclosing_node = Some(enclosing_node);
979 enclosing_node = map.get_parent_item(enclosing_node);
984 /// Returns true if ty has `iter` or `iter_mut` methods
985 pub fn has_iter_method(cx: &LateContext<'_, '_>, probably_ref_ty: Ty<'_>) -> Option<&'static str> {
986 // FIXME: instead of this hard-coded list, we should check if `<adt>::iter`
987 // exists and has the desired signature. Unfortunately FnCtxt is not exported
988 // so we can't use its `lookup_method` method.
989 static INTO_ITER_COLLECTIONS: [&[&str]; 13] = [
1005 let ty_to_check = match probably_ref_ty.sty {
1006 ty::Ref(_, ty_to_check, _) => ty_to_check,
1007 _ => probably_ref_ty,
1010 let def_id = match ty_to_check.sty {
1011 ty::Array(..) => return Some("array"),
1012 ty::Slice(..) => return Some("slice"),
1013 ty::Adt(adt, _) => adt.did,
1017 for path in &INTO_ITER_COLLECTIONS {
1018 if cx.match_def_path(def_id, path) {
1019 return Some(path.last().unwrap());
1027 use super::{trim_multiline, without_block_comments};
1030 fn test_trim_multiline_single_line() {
1031 assert_eq!("", trim_multiline("".into(), false));
1032 assert_eq!("...", trim_multiline("...".into(), false));
1033 assert_eq!("...", trim_multiline(" ...".into(), false));
1034 assert_eq!("...", trim_multiline("\t...".into(), false));
1035 assert_eq!("...", trim_multiline("\t\t...".into(), false));
1040 fn test_trim_multiline_block() {
1046 }", trim_multiline(" if x {
1056 }", trim_multiline(" if x {
1065 fn test_trim_multiline_empty_line() {
1072 }", trim_multiline(" if x {
1081 fn test_without_block_comments_lines_without_block_comments() {
1082 let result = without_block_comments(vec!["/*", "", "*/"]);
1083 println!("result: {:?}", result);
1084 assert!(result.is_empty());
1086 let result = without_block_comments(vec!["", "/*", "", "*/", "#[crate_type = \"lib\"]", "/*", "", "*/", ""]);
1087 assert_eq!(result, vec!["", "#[crate_type = \"lib\"]", ""]);
1089 let result = without_block_comments(vec!["/* rust", "", "*/"]);
1090 assert!(result.is_empty());
1092 let result = without_block_comments(vec!["/* one-line comment */"]);
1093 assert!(result.is_empty());
1095 let result = without_block_comments(vec!["/* nested", "/* multi-line", "comment", "*/", "test", "*/"]);
1096 assert!(result.is_empty());
1098 let result = without_block_comments(vec!["/* nested /* inline /* comment */ test */ */"]);
1099 assert!(result.is_empty());
1101 let result = without_block_comments(vec!["foo", "bar", "baz"]);
1102 assert_eq!(result, vec!["foo", "bar", "baz"]);