1 // Copyright 2014-2018 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution.
4 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
5 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
6 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
7 // option. This file may not be copied, modified, or distributed
8 // except according to those terms.
10 use crate::reexport::*;
11 use if_chain::if_chain;
14 use rustc::hir::def::Def;
15 use rustc::hir::def_id::{DefId, CRATE_DEF_INDEX};
16 use rustc::hir::intravisit::{NestedVisitorMap, Visitor};
19 use rustc::lint::{LateContext, Level, Lint, LintContext};
20 use rustc::session::Session;
24 layout::{self, IntegerExt},
28 use rustc_errors::{Applicability, CodeSuggestion, Substitution, SubstitutionPart};
33 use std::str::FromStr;
34 use syntax::ast::{self, LitKind};
36 use syntax::errors::DiagnosticBuilder;
37 use syntax::source_map::{Span, DUMMY_SP};
39 use syntax::symbol::{keywords, Symbol};
49 pub mod internal_lints;
54 pub use self::hir_utils::{SpanlessEq, SpanlessHash};
58 /// Returns true if the two spans come from differing expansions (i.e. one is
59 /// from a macro and one
61 pub fn differing_macro_contexts(lhs: Span, rhs: Span) -> bool {
62 rhs.ctxt() != lhs.ctxt()
65 pub fn in_constant(cx: &LateContext<'_, '_>, id: NodeId) -> bool {
66 let parent_id = cx.tcx.hir().get_parent(id);
67 match cx.tcx.hir().body_owner_kind(parent_id) {
68 hir::BodyOwnerKind::Fn => false,
69 hir::BodyOwnerKind::Const | hir::BodyOwnerKind::Static(..) => true,
73 /// Returns true if this `expn_info` was expanded by any macro.
74 pub fn in_macro(span: Span) -> bool {
75 span.ctxt().outer().expn_info().is_some()
78 /// Used to store the absolute path to a type.
80 /// See `match_def_path` for usage.
82 pub struct AbsolutePathBuffer {
83 pub names: Vec<symbol::LocalInternedString>,
86 impl ty::item_path::ItemPathBuffer for AbsolutePathBuffer {
87 fn root_mode(&self) -> &ty::item_path::RootMode {
88 const ABSOLUTE: &ty::item_path::RootMode = &ty::item_path::RootMode::Absolute;
92 fn push(&mut self, text: &str) {
93 self.names.push(symbol::Symbol::intern(text).as_str());
97 /// Check if a `DefId`'s path matches the given absolute type path usage.
101 /// match_def_path(cx.tcx, id, &["core", "option", "Option"])
104 /// See also the `paths` module.
105 pub fn match_def_path(tcx: TyCtxt<'_, '_, '_>, def_id: DefId, path: &[&str]) -> bool {
106 let mut apb = AbsolutePathBuffer { names: vec![] };
108 tcx.push_item_path(&mut apb, def_id, false);
110 apb.names.len() == path.len() && apb.names.into_iter().zip(path.iter()).all(|(a, &b)| *a == *b)
113 /// Check if type is struct, enum or union type with given def path.
114 pub fn match_type(cx: &LateContext<'_, '_>, ty: Ty<'_>, path: &[&str]) -> bool {
116 ty::Adt(adt, _) => match_def_path(cx.tcx, adt.did, path),
121 /// Check if the method call given in `expr` belongs to given trait.
122 pub fn match_trait_method(cx: &LateContext<'_, '_>, expr: &Expr, path: &[&str]) -> bool {
123 let method_call = cx.tables.type_dependent_defs()[expr.hir_id];
124 let trt_id = cx.tcx.trait_of_item(method_call.def_id());
125 if let Some(trt_id) = trt_id {
126 match_def_path(cx.tcx, trt_id, path)
132 /// Check if an expression references a variable of the given name.
133 pub fn match_var(expr: &Expr, var: Name) -> bool {
134 if let ExprKind::Path(QPath::Resolved(None, ref path)) = expr.node {
135 if path.segments.len() == 1 && path.segments[0].ident.name == var {
142 pub fn last_path_segment(path: &QPath) -> &PathSegment {
144 QPath::Resolved(_, ref path) => path.segments.last().expect("A path must have at least one segment"),
145 QPath::TypeRelative(_, ref seg) => seg,
149 pub fn single_segment_path(path: &QPath) -> Option<&PathSegment> {
151 QPath::Resolved(_, ref path) if path.segments.len() == 1 => Some(&path.segments[0]),
152 QPath::Resolved(..) => None,
153 QPath::TypeRelative(_, ref seg) => Some(seg),
157 /// Match a `Path` against a slice of segment string literals.
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 pub fn match_path(path: &Path, segments: &[&str]) -> bool {
181 .zip(segments.iter().rev())
182 .all(|(a, b)| a.ident.name == *b)
185 /// Match a `Path` against a slice of segment string literals, e.g.
189 /// match_qpath(path, &["std", "rt", "begin_unwind"])
191 pub fn match_path_ast(path: &ast::Path, segments: &[&str]) -> bool {
195 .zip(segments.iter().rev())
196 .all(|(a, b)| a.ident.name == *b)
199 /// Get the definition associated to a path.
200 pub fn path_to_def(cx: &LateContext<'_, '_>, path: &[&str]) -> Option<def::Def> {
201 let crates = cx.tcx.crates();
202 let krate = crates.iter().find(|&&krate| cx.tcx.crate_name(krate) == path[0]);
203 if let Some(krate) = krate {
206 index: CRATE_DEF_INDEX,
208 let mut items = cx.tcx.item_children(krate);
209 let mut path_it = path.iter().skip(1).peekable();
212 let segment = match path_it.next() {
213 Some(segment) => segment,
217 for item in mem::replace(&mut items, Rc::new(vec![])).iter() {
218 if item.ident.name == *segment {
219 if path_it.peek().is_none() {
220 return Some(item.def);
223 items = cx.tcx.item_children(item.def.def_id());
233 /// Convenience function to get the `DefId` of a trait by path.
234 pub fn get_trait_def_id(cx: &LateContext<'_, '_>, path: &[&str]) -> Option<DefId> {
235 let def = match path_to_def(cx, path) {
241 def::Def::Trait(trait_id) => Some(trait_id),
246 /// Check whether a type implements a trait.
247 /// See also `get_trait_def_id`.
248 pub fn implements_trait<'a, 'tcx>(
249 cx: &LateContext<'a, 'tcx>,
252 ty_params: &[Kind<'tcx>],
254 let ty = cx.tcx.erase_regions(&ty);
255 let obligation = cx.tcx.predicate_for_trait_def(
257 traits::ObligationCause::dummy(),
265 .enter(|infcx| infcx.predicate_must_hold(&obligation))
268 /// Check whether this type implements Drop.
269 pub fn has_drop<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
270 match ty.ty_adt_def() {
271 Some(def) => def.has_dtor(cx.tcx),
276 /// Resolve the definition of a node from its `HirId`.
277 pub fn resolve_node(cx: &LateContext<'_, '_>, qpath: &QPath, id: HirId) -> def::Def {
278 cx.tables.qpath_def(qpath, id)
281 /// Return the method names and argument list of nested method call expressions that make up
283 pub fn method_calls<'a>(expr: &'a Expr, max_depth: usize) -> (Vec<Symbol>, Vec<&'a [Expr]>) {
284 let mut method_names = Vec::with_capacity(max_depth);
285 let mut arg_lists = Vec::with_capacity(max_depth);
287 let mut current = expr;
288 for _ in 0..max_depth {
289 if let ExprKind::MethodCall(path, _, args) = ¤t.node {
290 if args.iter().any(|e| in_macro(e.span)) {
293 method_names.push(path.ident.name);
294 arg_lists.push(&**args);
301 (method_names, arg_lists)
304 /// Match an `Expr` against a chain of methods, and return the matched `Expr`s.
306 /// For example, if `expr` represents the `.baz()` in `foo.bar().baz()`,
307 /// `matched_method_chain(expr, &["bar", "baz"])` will return a `Vec`
308 /// containing the `Expr`s for
309 /// `.bar()` and `.baz()`
310 pub fn method_chain_args<'a>(expr: &'a Expr, methods: &[&str]) -> Option<Vec<&'a [Expr]>> {
311 let mut current = expr;
312 let mut matched = Vec::with_capacity(methods.len());
313 for method_name in methods.iter().rev() {
314 // method chains are stored last -> first
315 if let ExprKind::MethodCall(ref path, _, ref args) = current.node {
316 if path.ident.name == *method_name {
317 if args.iter().any(|e| in_macro(e.span)) {
320 matched.push(&**args); // build up `matched` backwards
321 current = &args[0] // go to parent expression
329 matched.reverse(); // reverse `matched`, so that it is in the same order as `methods`
333 /// Get the name of the item the expression is in, if available.
334 pub fn get_item_name(cx: &LateContext<'_, '_>, expr: &Expr) -> Option<Name> {
335 let parent_id = cx.tcx.hir().get_parent(expr.id);
336 match cx.tcx.hir().find(parent_id) {
337 Some(Node::Item(&Item { ref ident, .. })) => Some(ident.name),
338 Some(Node::TraitItem(&TraitItem { ident, .. })) | Some(Node::ImplItem(&ImplItem { ident, .. })) => {
345 /// Get the name of a `Pat`, if any
346 pub fn get_pat_name(pat: &Pat) -> Option<Name> {
348 PatKind::Binding(_, _, ref spname, _) => Some(spname.name),
349 PatKind::Path(ref qpath) => single_segment_path(qpath).map(|ps| ps.ident.name),
350 PatKind::Box(ref p) | PatKind::Ref(ref p, _) => get_pat_name(&*p),
355 struct ContainsName {
360 impl<'tcx> Visitor<'tcx> for ContainsName {
361 fn visit_name(&mut self, _: Span, name: Name) {
362 if self.name == name {
366 fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
367 NestedVisitorMap::None
371 /// check if an `Expr` contains a certain name
372 pub fn contains_name(name: Name, expr: &Expr) -> bool {
373 let mut cn = ContainsName { name, result: false };
378 /// Convert a span to a code snippet if available, otherwise use default.
382 /// snippet(cx, expr.span, "..")
384 pub fn snippet<'a, 'b, T: LintContext<'b>>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
385 snippet_opt(cx, span).map_or_else(|| Cow::Borrowed(default), From::from)
388 /// Same as `snippet`, but it adapts the applicability level by following rules:
390 /// - Applicability level `Unspecified` will never be changed.
391 /// - If the span is inside a macro, change the applicability level to `MaybeIncorrect`.
392 /// - If the default value is used and the applicability level is `MachineApplicable`, change it to
393 /// `HasPlaceholders`
394 pub fn snippet_with_applicability<'a, 'b, T: LintContext<'b>>(
398 applicability: &mut Applicability,
400 if *applicability != Applicability::Unspecified && in_macro(span) {
401 *applicability = Applicability::MaybeIncorrect;
403 snippet_opt(cx, span).map_or_else(
405 if *applicability == Applicability::MachineApplicable {
406 *applicability = Applicability::HasPlaceholders;
408 Cow::Borrowed(default)
414 /// Same as `snippet`, but should only be used when it's clear that the input span is
415 /// not a macro argument.
416 pub fn snippet_with_macro_callsite<'a, 'b, T: LintContext<'b>>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
417 snippet(cx, span.source_callsite(), default)
420 /// Convert a span to a code snippet. Returns `None` if not available.
421 pub fn snippet_opt<'a, T: LintContext<'a>>(cx: &T, span: Span) -> Option<String> {
422 cx.sess().source_map().span_to_snippet(span).ok()
425 /// Convert a span (from a block) to a code snippet if available, otherwise use
427 /// This trims the code of indentation, except for the first line. Use it for
428 /// blocks or block-like
429 /// things which need to be printed as such.
433 /// snippet(cx, expr.span, "..")
435 pub fn snippet_block<'a, 'b, T: LintContext<'b>>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
436 let snip = snippet(cx, span, default);
437 trim_multiline(snip, true)
440 /// Same as `snippet_block`, but adapts the applicability level by the rules of
441 /// `snippet_with_applicabiliy`.
442 pub fn snippet_block_with_applicability<'a, 'b, T: LintContext<'b>>(
446 applicability: &mut Applicability,
448 let snip = snippet_with_applicability(cx, span, default, applicability);
449 trim_multiline(snip, true)
452 /// Returns a new Span that covers the full last line of the given Span
453 pub fn last_line_of_span<'a, T: LintContext<'a>>(cx: &T, span: Span) -> Span {
454 let source_map_and_line = cx.sess().source_map().lookup_line(span.lo()).unwrap();
455 let line_no = source_map_and_line.line;
456 let line_start = &source_map_and_line.sf.lines[line_no];
457 Span::new(*line_start, span.hi(), span.ctxt())
460 /// Like `snippet_block`, but add braces if the expr is not an `ExprKind::Block`.
461 /// Also takes an `Option<String>` which can be put inside the braces.
462 pub fn expr_block<'a, 'b, T: LintContext<'b>>(
465 option: Option<String>,
468 let code = snippet_block(cx, expr.span, default);
469 let string = option.unwrap_or_default();
470 if in_macro(expr.span) {
471 Cow::Owned(format!("{{ {} }}", snippet_with_macro_callsite(cx, expr.span, default)))
472 } else if let ExprKind::Block(_, _) = expr.node {
473 Cow::Owned(format!("{}{}", code, string))
474 } else if string.is_empty() {
475 Cow::Owned(format!("{{ {} }}", code))
477 Cow::Owned(format!("{{\n{};\n{}\n}}", code, string))
481 /// Trim indentation from a multiline string with possibility of ignoring the
483 pub fn trim_multiline(s: Cow<'_, str>, ignore_first: bool) -> Cow<'_, str> {
484 let s_space = trim_multiline_inner(s, ignore_first, ' ');
485 let s_tab = trim_multiline_inner(s_space, ignore_first, '\t');
486 trim_multiline_inner(s_tab, ignore_first, ' ')
489 fn trim_multiline_inner(s: Cow<'_, str>, ignore_first: bool, ch: char) -> Cow<'_, str> {
492 .skip(ignore_first as usize)
497 // ignore empty lines
498 Some(l.char_indices().find(|&(_, x)| x != ch).unwrap_or((l.len(), ch)).0)
508 if (ignore_first && i == 0) || l.is_empty() {
522 /// Get a parent expressions if any – this is useful to constrain a lint.
523 pub fn get_parent_expr<'c>(cx: &'c LateContext<'_, '_>, e: &Expr) -> Option<&'c Expr> {
524 let map = &cx.tcx.hir();
525 let node_id: NodeId = e.id;
526 let parent_id: NodeId = map.get_parent_node(node_id);
527 if node_id == parent_id {
530 map.find(parent_id).and_then(|node| {
531 if let Node::Expr(parent) = node {
539 pub fn get_enclosing_block<'a, 'tcx: 'a>(cx: &LateContext<'a, 'tcx>, node: NodeId) -> Option<&'tcx Block> {
540 let map = &cx.tcx.hir();
541 let enclosing_node = map
542 .get_enclosing_scope(node)
543 .and_then(|enclosing_id| map.find(enclosing_id));
544 if let Some(node) = enclosing_node {
546 Node::Block(block) => Some(block),
548 node: ItemKind::Fn(_, _, _, eid),
551 | Node::ImplItem(&ImplItem {
552 node: ImplItemKind::Method(_, eid),
554 }) => match cx.tcx.hir().body(eid).value.node {
555 ExprKind::Block(ref block, _) => Some(block),
565 pub struct DiagnosticWrapper<'a>(pub DiagnosticBuilder<'a>);
567 impl<'a> Drop for DiagnosticWrapper<'a> {
573 impl<'a> DiagnosticWrapper<'a> {
574 fn docs_link(&mut self, lint: &'static Lint) {
575 if env::var("CLIPPY_DISABLE_DOCS_LINKS").is_err() {
576 self.0.help(&format!(
577 "for further information visit https://rust-lang.github.io/rust-clippy/{}/index.html#{}",
578 &option_env!("RUST_RELEASE_NUM").map_or("master".to_string(), |n| {
579 // extract just major + minor version and ignore patch versions
580 format!("rust-{}", n.rsplitn(2, '.').nth(1).unwrap())
582 lint.name_lower().replacen("clippy::", "", 1)
588 pub fn span_lint<'a, T: LintContext<'a>>(cx: &T, lint: &'static Lint, sp: Span, msg: &str) {
589 DiagnosticWrapper(cx.struct_span_lint(lint, sp, msg)).docs_link(lint);
592 pub fn span_help_and_lint<'a, 'tcx: 'a, T: LintContext<'tcx>>(
599 let mut db = DiagnosticWrapper(cx.struct_span_lint(lint, span, msg));
604 pub fn span_note_and_lint<'a, 'tcx: 'a, T: LintContext<'tcx>>(
612 let mut db = DiagnosticWrapper(cx.struct_span_lint(lint, span, msg));
613 if note_span == span {
616 db.0.span_note(note_span, note);
621 pub fn span_lint_and_then<'a, 'tcx: 'a, T: LintContext<'tcx>, F>(
628 F: for<'b> FnOnce(&mut DiagnosticBuilder<'b>),
630 let mut db = DiagnosticWrapper(cx.struct_span_lint(lint, sp, msg));
635 pub fn span_lint_node(cx: &LateContext<'_, '_>, lint: &'static Lint, node: NodeId, sp: Span, msg: &str) {
636 DiagnosticWrapper(cx.tcx.struct_span_lint_node(lint, node, sp, msg)).docs_link(lint);
639 pub fn span_lint_node_and_then(
640 cx: &LateContext<'_, '_>,
645 f: impl FnOnce(&mut DiagnosticBuilder<'_>),
647 let mut db = DiagnosticWrapper(cx.tcx.struct_span_lint_node(lint, node, sp, msg));
652 /// Add a span lint with a suggestion on how to fix it.
654 /// These suggestions can be parsed by rustfix to allow it to automatically fix your code.
655 /// In the example below, `help` is `"try"` and `sugg` is the suggested replacement `".any(|x| x >
659 /// error: This `.fold` can be more succinctly expressed as `.any`
660 /// --> $DIR/methods.rs:390:13
662 /// 390 | let _ = (0..3).fold(false, |acc, x| acc || x > 2);
663 /// | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `.any(|x| x > 2)`
665 /// = note: `-D fold-any` implied by `-D warnings`
667 pub fn span_lint_and_sugg<'a, 'tcx: 'a, T: LintContext<'tcx>>(
674 applicability: Applicability,
676 span_lint_and_then(cx, lint, sp, msg, |db| {
677 db.span_suggestion_with_applicability(sp, help, sugg, applicability);
681 /// Create a suggestion made from several `span → replacement`.
683 /// Note: in the JSON format (used by `compiletest_rs`), the help message will
685 /// replacement. In human-readable format though, it only appears once before
686 /// the whole suggestion.
687 pub fn multispan_sugg<I>(db: &mut DiagnosticBuilder<'_>, help_msg: String, sugg: I)
689 I: IntoIterator<Item = (Span, String)>,
691 let sugg = CodeSuggestion {
692 substitutions: vec![Substitution {
695 .map(|(span, snippet)| SubstitutionPart { snippet, span })
699 show_code_when_inline: true,
700 applicability: Applicability::Unspecified,
702 db.suggestions.push(sugg);
705 /// Return the base type for HIR references and pointers.
706 pub fn walk_ptrs_hir_ty(ty: &hir::Ty) -> &hir::Ty {
708 TyKind::Ptr(ref mut_ty) | TyKind::Rptr(_, ref mut_ty) => walk_ptrs_hir_ty(&mut_ty.ty),
713 /// Return the base type for references and raw pointers.
714 pub fn walk_ptrs_ty(ty: Ty<'_>) -> Ty<'_> {
716 ty::Ref(_, ty, _) => walk_ptrs_ty(ty),
721 /// Return the base type for references and raw pointers, and count reference
723 pub fn walk_ptrs_ty_depth(ty: Ty<'_>) -> (Ty<'_>, usize) {
724 fn inner(ty: Ty<'_>, depth: usize) -> (Ty<'_>, usize) {
726 ty::Ref(_, ty, _) => inner(ty, depth + 1),
733 /// Check whether the given expression is a constant literal of the given value.
734 pub fn is_integer_literal(expr: &Expr, value: u128) -> bool {
735 // FIXME: use constant folding
736 if let ExprKind::Lit(ref spanned) = expr.node {
737 if let LitKind::Int(v, _) = spanned.node {
744 pub fn is_adjusted(cx: &LateContext<'_, '_>, e: &Expr) -> bool {
745 cx.tables.adjustments().get(e.hir_id).is_some()
748 pub struct LimitStack {
752 impl Drop for LimitStack {
754 assert_eq!(self.stack.len(), 1);
759 pub fn new(limit: u64) -> Self {
760 Self { stack: vec![limit] }
762 pub fn limit(&self) -> u64 {
763 *self.stack.last().expect("there should always be a value in the stack")
765 pub fn push_attrs(&mut self, sess: &Session, attrs: &[ast::Attribute], name: &'static str) {
766 let stack = &mut self.stack;
767 parse_attrs(sess, attrs, name, |val| stack.push(val));
769 pub fn pop_attrs(&mut self, sess: &Session, attrs: &[ast::Attribute], name: &'static str) {
770 let stack = &mut self.stack;
771 parse_attrs(sess, attrs, name, |val| assert_eq!(stack.pop(), Some(val)));
775 pub fn get_attr<'a>(attrs: &'a [ast::Attribute], name: &'static str) -> impl Iterator<Item = &'a ast::Attribute> {
776 attrs.iter().filter(move |attr| {
777 attr.path.segments.len() == 2
778 && attr.path.segments[0].ident.to_string() == "clippy"
779 && attr.path.segments[1].ident.to_string() == name
783 fn parse_attrs<F: FnMut(u64)>(sess: &Session, attrs: &[ast::Attribute], name: &'static str, mut f: F) {
784 for attr in get_attr(attrs, name) {
785 if let Some(ref value) = attr.value_str() {
786 if let Ok(value) = FromStr::from_str(&value.as_str()) {
789 sess.span_err(attr.span, "not a number");
792 sess.span_err(attr.span, "bad clippy attribute");
797 /// Return the pre-expansion span if is this comes from an expansion of the
799 /// See also `is_direct_expn_of`.
800 pub fn is_expn_of(mut span: Span, name: &str) -> Option<Span> {
802 let span_name_span = span
806 .map(|ei| (ei.format.name(), ei.call_site));
808 match span_name_span {
809 Some((mac_name, new_span)) if mac_name == name => return Some(new_span),
811 Some((_, new_span)) => span = new_span,
816 /// Return the pre-expansion span if is this directly comes from an expansion
817 /// of the macro `name`.
818 /// The difference with `is_expn_of` is that in
822 /// `42` is considered expanded from `foo!` and `bar!` by `is_expn_of` but only
824 /// `is_direct_expn_of`.
825 pub fn is_direct_expn_of(span: Span, name: &str) -> Option<Span> {
826 let span_name_span = span
830 .map(|ei| (ei.format.name(), ei.call_site));
832 match span_name_span {
833 Some((mac_name, new_span)) if mac_name == name => Some(new_span),
838 /// Convenience function to get the return type of a function
839 pub fn return_ty<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, fn_item: NodeId) -> Ty<'tcx> {
840 let fn_def_id = cx.tcx.hir().local_def_id(fn_item);
841 let ret_ty = cx.tcx.fn_sig(fn_def_id).output();
842 cx.tcx.erase_late_bound_regions(&ret_ty)
845 /// Check if two types are the same.
847 /// This discards any lifetime annotations, too.
848 // FIXME: this works correctly for lifetimes bounds (`for <'a> Foo<'a>` == `for
850 // not for type parameters.
851 pub fn same_tys<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, a: Ty<'tcx>, b: Ty<'tcx>) -> bool {
852 let a = cx.tcx.erase_late_bound_regions(&Binder::bind(a));
853 let b = cx.tcx.erase_late_bound_regions(&Binder::bind(b));
856 .enter(|infcx| infcx.can_eq(cx.param_env, a, b).is_ok())
859 /// Return whether the given type is an `unsafe` function.
860 pub fn type_is_unsafe_function<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
862 ty::FnDef(..) | ty::FnPtr(_) => ty.fn_sig(cx.tcx).unsafety() == Unsafety::Unsafe,
867 pub fn is_copy<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
868 !ty.moves_by_default(cx.tcx.global_tcx(), cx.param_env, DUMMY_SP)
871 /// Return whether a pattern is refutable.
872 pub fn is_refutable(cx: &LateContext<'_, '_>, pat: &Pat) -> bool {
873 fn is_enum_variant(cx: &LateContext<'_, '_>, qpath: &QPath, id: HirId) -> bool {
875 cx.tables.qpath_def(qpath, id),
876 def::Def::Variant(..) | def::Def::VariantCtor(..)
880 fn are_refutable<'a, I: Iterator<Item = &'a Pat>>(cx: &LateContext<'_, '_>, mut i: I) -> bool {
881 i.any(|pat| is_refutable(cx, pat))
885 PatKind::Binding(..) | PatKind::Wild => false,
886 PatKind::Box(ref pat) | PatKind::Ref(ref pat, _) => is_refutable(cx, pat),
887 PatKind::Lit(..) | PatKind::Range(..) => true,
888 PatKind::Path(ref qpath) => is_enum_variant(cx, qpath, pat.hir_id),
889 PatKind::Tuple(ref pats, _) => are_refutable(cx, pats.iter().map(|pat| &**pat)),
890 PatKind::Struct(ref qpath, ref fields, _) => {
891 if is_enum_variant(cx, qpath, pat.hir_id) {
894 are_refutable(cx, fields.iter().map(|field| &*field.node.pat))
897 PatKind::TupleStruct(ref qpath, ref pats, _) => {
898 if is_enum_variant(cx, qpath, pat.hir_id) {
901 are_refutable(cx, pats.iter().map(|pat| &**pat))
904 PatKind::Slice(ref head, ref middle, ref tail) => {
905 are_refutable(cx, head.iter().chain(middle).chain(tail.iter()).map(|pat| &**pat))
910 /// Checks for the `#[automatically_derived]` attribute all `#[derive]`d
911 /// implementations have.
912 pub fn is_automatically_derived(attrs: &[ast::Attribute]) -> bool {
913 attr::contains_name(attrs, "automatically_derived")
916 /// Remove blocks around an expression.
918 /// Ie. `x`, `{ x }` and `{{{{ x }}}}` all give `x`. `{ x; y }` and `{}` return
920 pub fn remove_blocks(expr: &Expr) -> &Expr {
921 if let ExprKind::Block(ref block, _) = expr.node {
922 if block.stmts.is_empty() {
923 if let Some(ref expr) = block.expr {
936 pub fn opt_def_id(def: Def) -> Option<DefId> {
942 | Def::VariantCtor(id, ..)
945 | Def::AssociatedTy(id)
949 | Def::StructCtor(id, ..)
952 | Def::TraitAlias(id)
955 | Def::AssociatedConst(id)
957 | Def::Existential(id)
958 | Def::AssociatedExistential(id)
959 | Def::SelfCtor(id) => Some(id),
967 | Def::NonMacroAttr { .. }
972 pub fn is_self(slf: &Arg) -> bool {
973 if let PatKind::Binding(_, _, name, _) = slf.pat.node {
974 name.name == keywords::SelfLower.name()
980 pub fn is_self_ty(slf: &hir::Ty) -> bool {
982 if let TyKind::Path(ref qp) = slf.node;
983 if let QPath::Resolved(None, ref path) = *qp;
984 if let Def::SelfTy(..) = path.def;
992 pub fn iter_input_pats<'tcx>(decl: &FnDecl, body: &'tcx Body) -> impl Iterator<Item = &'tcx Arg> {
993 (0..decl.inputs.len()).map(move |i| &body.arguments[i])
996 /// Check if a given expression is a match expression
997 /// expanded from `?` operator or `try` macro.
998 pub fn is_try(expr: &Expr) -> Option<&Expr> {
999 fn is_ok(arm: &Arm) -> bool {
1001 if let PatKind::TupleStruct(ref path, ref pat, None) = arm.pats[0].node;
1002 if match_qpath(path, &paths::RESULT_OK[1..]);
1003 if let PatKind::Binding(_, defid, _, None) = pat[0].node;
1004 if let ExprKind::Path(QPath::Resolved(None, ref path)) = arm.body.node;
1005 if let Def::Local(lid) = path.def;
1014 fn is_err(arm: &Arm) -> bool {
1015 if let PatKind::TupleStruct(ref path, _, _) = arm.pats[0].node {
1016 match_qpath(path, &paths::RESULT_ERR[1..])
1022 if let ExprKind::Match(_, ref arms, ref source) = expr.node {
1023 // desugared from a `?` operator
1024 if let MatchSource::TryDesugar = *source {
1030 if arms[0].pats.len() == 1 && arms[0].guard.is_none();
1031 if arms[1].pats.len() == 1 && arms[1].guard.is_none();
1032 if (is_ok(&arms[0]) && is_err(&arms[1])) ||
1033 (is_ok(&arms[1]) && is_err(&arms[0]));
1043 /// Returns true if the lint is allowed in the current context
1045 /// Useful for skipping long running code when it's unnecessary
1046 pub fn is_allowed(cx: &LateContext<'_, '_>, lint: &'static Lint, id: NodeId) -> bool {
1047 cx.tcx.lint_level_at_node(lint, id).0 == Level::Allow
1050 pub fn get_arg_name(pat: &Pat) -> Option<ast::Name> {
1052 PatKind::Binding(_, _, ident, None) => Some(ident.name),
1053 PatKind::Ref(ref subpat, _) => get_arg_name(subpat),
1058 pub fn int_bits(tcx: TyCtxt<'_, '_, '_>, ity: ast::IntTy) -> u64 {
1059 layout::Integer::from_attr(&tcx, attr::IntType::SignedInt(ity))
1064 #[allow(clippy::cast_possible_wrap)]
1065 /// Turn a constant int byte representation into an i128
1066 pub fn sext(tcx: TyCtxt<'_, '_, '_>, u: u128, ity: ast::IntTy) -> i128 {
1067 let amt = 128 - int_bits(tcx, ity);
1068 ((u as i128) << amt) >> amt
1071 #[allow(clippy::cast_sign_loss)]
1072 /// clip unused bytes
1073 pub fn unsext(tcx: TyCtxt<'_, '_, '_>, u: i128, ity: ast::IntTy) -> u128 {
1074 let amt = 128 - int_bits(tcx, ity);
1075 ((u as u128) << amt) >> amt
1078 /// clip unused bytes
1079 pub fn clip(tcx: TyCtxt<'_, '_, '_>, u: u128, ity: ast::UintTy) -> u128 {
1080 let bits = layout::Integer::from_attr(&tcx, attr::IntType::UnsignedInt(ity))
1083 let amt = 128 - bits;
1087 /// Remove block comments from the given Vec of lines
1092 /// without_block_comments(vec!["/*", "foo", "*/"]);
1095 /// without_block_comments(vec!["bar", "/*", "foo", "*/"]);
1096 /// // => vec!["bar"]
1098 pub fn without_block_comments(lines: Vec<&str>) -> Vec<&str> {
1099 let mut without = vec![];
1101 let mut nest_level = 0;
1104 if line.contains("/*") {
1107 } else if line.contains("*/") {
1112 if nest_level == 0 {
1120 pub fn any_parent_is_automatically_derived(tcx: TyCtxt<'_, '_, '_>, node: NodeId) -> bool {
1121 let map = &tcx.hir();
1122 let mut prev_enclosing_node = None;
1123 let mut enclosing_node = node;
1124 while Some(enclosing_node) != prev_enclosing_node {
1125 if is_automatically_derived(map.attrs(enclosing_node)) {
1128 prev_enclosing_node = Some(enclosing_node);
1129 enclosing_node = map.get_parent(enclosing_node);
1136 use super::{trim_multiline, without_block_comments};
1139 fn test_trim_multiline_single_line() {
1140 assert_eq!("", trim_multiline("".into(), false));
1141 assert_eq!("...", trim_multiline("...".into(), false));
1142 assert_eq!("...", trim_multiline(" ...".into(), false));
1143 assert_eq!("...", trim_multiline("\t...".into(), false));
1144 assert_eq!("...", trim_multiline("\t\t...".into(), false));
1149 fn test_trim_multiline_block() {
1155 }", trim_multiline(" if x {
1165 }", trim_multiline(" if x {
1174 fn test_trim_multiline_empty_line() {
1181 }", trim_multiline(" if x {
1190 fn test_without_block_comments_lines_without_block_comments() {
1191 let result = without_block_comments(vec!["/*", "", "*/"]);
1192 println!("result: {:?}", result);
1193 assert!(result.is_empty());
1195 let result = without_block_comments(vec!["", "/*", "", "*/", "#[crate_type = \"lib\"]", "/*", "", "*/", ""]);
1196 assert_eq!(result, vec!["", "#[crate_type = \"lib\"]", ""]);
1198 let result = without_block_comments(vec!["/* rust", "", "*/"]);
1199 assert!(result.is_empty());
1201 let result = without_block_comments(vec!["/* one-line comment */"]);
1202 assert!(result.is_empty());
1204 let result = without_block_comments(vec!["/* nested", "/* multi-line", "comment", "*/", "test", "*/"]);
1205 assert!(result.is_empty());
1207 let result = without_block_comments(vec!["/* nested /* inline /* comment */ test */ */"]);
1208 assert!(result.is_empty());
1210 let result = without_block_comments(vec!["foo", "bar", "baz"]);
1211 assert_eq!(result, vec!["foo", "bar", "baz"]);