1 use crate::reexport::*;
2 use if_chain::if_chain;
5 use rustc::hir::def::Def;
6 use rustc::hir::def_id::{DefId, CRATE_DEF_INDEX, LOCAL_CRATE};
7 use rustc::hir::intravisit::{NestedVisitorMap, Visitor};
10 use rustc::lint::{LateContext, Level, Lint, LintContext};
11 use rustc::session::Session;
15 layout::{self, IntegerExt},
19 use rustc_data_structures::sync::Lrc;
20 use rustc_errors::Applicability;
23 use std::str::FromStr;
24 use syntax::ast::{self, LitKind};
26 use syntax::source_map::{Span, DUMMY_SP};
28 use syntax::symbol::{keywords, Symbol};
39 pub mod internal_lints;
44 pub use self::diagnostics::*;
45 pub use self::hir_utils::{SpanlessEq, SpanlessHash};
49 /// Returns true if the two spans come from differing expansions (i.e. one is
50 /// from a macro and one
52 pub fn differing_macro_contexts(lhs: Span, rhs: Span) -> bool {
53 rhs.ctxt() != lhs.ctxt()
56 /// Returns `true` if the given `NodeId` is inside a constant context
61 /// if in_constant(cx, expr.id) {
65 pub fn in_constant(cx: &LateContext<'_, '_>, id: NodeId) -> bool {
66 let parent_id = cx.tcx.hir().get_parent(id);
67 match cx.tcx.hir().get(parent_id) {
69 node: ItemKind::Const(..),
72 | Node::TraitItem(&TraitItem {
73 node: TraitItemKind::Const(..),
76 | Node::ImplItem(&ImplItem {
77 node: ImplItemKind::Const(..),
82 node: ItemKind::Static(..),
86 node: ItemKind::Fn(_, header, ..),
88 }) => header.constness == Constness::Const,
93 /// Returns true if this `expn_info` was expanded by any macro.
94 pub fn in_macro(span: Span) -> bool {
95 span.ctxt().outer().expn_info().is_some()
98 /// Used to store the absolute path to a type.
100 /// See `match_def_path` for usage.
102 pub struct AbsolutePathBuffer {
103 pub names: Vec<symbol::LocalInternedString>,
106 impl ty::item_path::ItemPathBuffer for AbsolutePathBuffer {
107 fn root_mode(&self) -> &ty::item_path::RootMode {
108 const ABSOLUTE: &ty::item_path::RootMode = &ty::item_path::RootMode::Absolute;
112 fn push(&mut self, text: &str) {
113 self.names.push(symbol::Symbol::intern(text).as_str());
117 /// Check if a `DefId`'s path matches the given absolute type path usage.
121 /// match_def_path(cx.tcx, id, &["core", "option", "Option"])
124 /// See also the `paths` module.
125 pub fn match_def_path(tcx: TyCtxt<'_, '_, '_>, def_id: DefId, path: &[&str]) -> bool {
126 let mut apb = AbsolutePathBuffer { names: vec![] };
128 tcx.push_item_path(&mut apb, def_id, false);
130 apb.names.len() == path.len() && apb.names.into_iter().zip(path.iter()).all(|(a, &b)| *a == *b)
133 /// Get the absolute path of `def_id` as a vector of `&str`.
137 /// let def_path = get_def_path(tcx, def_id);
138 /// if let &["core", "option", "Option"] = &def_path[..] {
139 /// // The given `def_id` is that of an `Option` type
142 pub fn get_def_path(tcx: TyCtxt<'_, '_, '_>, def_id: DefId) -> Vec<&'static str> {
143 let mut apb = AbsolutePathBuffer { names: vec![] };
144 tcx.push_item_path(&mut apb, def_id, false);
147 .map(syntax_pos::symbol::LocalInternedString::get)
151 /// Check if type is struct, enum or union type with given def path.
152 pub fn match_type(cx: &LateContext<'_, '_>, ty: Ty<'_>, path: &[&str]) -> bool {
154 ty::Adt(adt, _) => match_def_path(cx.tcx, adt.did, path),
159 /// Check if the method call given in `expr` belongs to given trait.
160 pub fn match_trait_method(cx: &LateContext<'_, '_>, expr: &Expr, path: &[&str]) -> bool {
161 let method_call = cx.tables.type_dependent_defs()[expr.hir_id];
162 let trt_id = cx.tcx.trait_of_item(method_call.def_id());
163 if let Some(trt_id) = trt_id {
164 match_def_path(cx.tcx, trt_id, path)
170 /// Check if an expression references a variable of the given name.
171 pub fn match_var(expr: &Expr, var: Name) -> bool {
172 if let ExprKind::Path(QPath::Resolved(None, ref path)) = expr.node {
173 if path.segments.len() == 1 && path.segments[0].ident.name == var {
180 pub fn last_path_segment(path: &QPath) -> &PathSegment {
182 QPath::Resolved(_, ref path) => path.segments.last().expect("A path must have at least one segment"),
183 QPath::TypeRelative(_, ref seg) => seg,
187 pub fn single_segment_path(path: &QPath) -> Option<&PathSegment> {
189 QPath::Resolved(_, ref path) if path.segments.len() == 1 => Some(&path.segments[0]),
190 QPath::Resolved(..) => None,
191 QPath::TypeRelative(_, ref seg) => Some(seg),
195 /// Match a `Path` against a slice of segment string literals.
199 /// match_qpath(path, &["std", "rt", "begin_unwind"])
201 pub fn match_qpath(path: &QPath, segments: &[&str]) -> bool {
203 QPath::Resolved(_, ref path) => match_path(path, segments),
204 QPath::TypeRelative(ref ty, ref segment) => match ty.node {
205 TyKind::Path(ref inner_path) => {
207 && match_qpath(inner_path, &segments[..(segments.len() - 1)])
208 && segment.ident.name == segments[segments.len() - 1]
215 pub fn match_path(path: &Path, segments: &[&str]) -> bool {
219 .zip(segments.iter().rev())
220 .all(|(a, b)| a.ident.name == *b)
223 /// Match a `Path` against a slice of segment string literals, e.g.
227 /// match_qpath(path, &["std", "rt", "begin_unwind"])
229 pub fn match_path_ast(path: &ast::Path, segments: &[&str]) -> bool {
233 .zip(segments.iter().rev())
234 .all(|(a, b)| a.ident.name == *b)
237 /// Get the definition associated to a path.
238 pub fn path_to_def(cx: &LateContext<'_, '_>, path: &[&str]) -> Option<def::Def> {
239 let crates = cx.tcx.crates();
240 let krate = crates.iter().find(|&&krate| cx.tcx.crate_name(krate) == path[0]);
241 if let Some(krate) = krate {
244 index: CRATE_DEF_INDEX,
246 let mut items = cx.tcx.item_children(krate);
247 let mut path_it = path.iter().skip(1).peekable();
250 let segment = match path_it.next() {
251 Some(segment) => segment,
255 for item in mem::replace(&mut items, Lrc::new(vec![])).iter() {
256 if item.ident.name == *segment {
257 if path_it.peek().is_none() {
258 return Some(item.def);
261 items = cx.tcx.item_children(item.def.def_id());
271 /// Convenience function to get the `DefId` of a trait by path.
272 pub fn get_trait_def_id(cx: &LateContext<'_, '_>, path: &[&str]) -> Option<DefId> {
273 let def = match path_to_def(cx, path) {
279 def::Def::Trait(trait_id) => Some(trait_id),
284 /// Check whether a type implements a trait.
285 /// See also `get_trait_def_id`.
286 pub fn implements_trait<'a, 'tcx>(
287 cx: &LateContext<'a, 'tcx>,
290 ty_params: &[Kind<'tcx>],
292 let ty = cx.tcx.erase_regions(&ty);
293 let obligation = cx.tcx.predicate_for_trait_def(
295 traits::ObligationCause::dummy(),
303 .enter(|infcx| infcx.predicate_must_hold_modulo_regions(&obligation))
306 /// Check whether this type implements Drop.
307 pub fn has_drop<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
308 match ty.ty_adt_def() {
309 Some(def) => def.has_dtor(cx.tcx),
314 /// Resolve the definition of a node from its `HirId`.
315 pub fn resolve_node(cx: &LateContext<'_, '_>, qpath: &QPath, id: HirId) -> def::Def {
316 cx.tables.qpath_def(qpath, id)
319 /// Return the method names and argument list of nested method call expressions that make up
321 pub fn method_calls<'a>(expr: &'a Expr, max_depth: usize) -> (Vec<Symbol>, Vec<&'a [Expr]>) {
322 let mut method_names = Vec::with_capacity(max_depth);
323 let mut arg_lists = Vec::with_capacity(max_depth);
325 let mut current = expr;
326 for _ in 0..max_depth {
327 if let ExprKind::MethodCall(path, _, args) = ¤t.node {
328 if args.iter().any(|e| in_macro(e.span)) {
331 method_names.push(path.ident.name);
332 arg_lists.push(&**args);
339 (method_names, arg_lists)
342 /// Match an `Expr` against a chain of methods, and return the matched `Expr`s.
344 /// For example, if `expr` represents the `.baz()` in `foo.bar().baz()`,
345 /// `matched_method_chain(expr, &["bar", "baz"])` will return a `Vec`
346 /// containing the `Expr`s for
347 /// `.bar()` and `.baz()`
348 pub fn method_chain_args<'a>(expr: &'a Expr, methods: &[&str]) -> Option<Vec<&'a [Expr]>> {
349 let mut current = expr;
350 let mut matched = Vec::with_capacity(methods.len());
351 for method_name in methods.iter().rev() {
352 // method chains are stored last -> first
353 if let ExprKind::MethodCall(ref path, _, ref args) = current.node {
354 if path.ident.name == *method_name {
355 if args.iter().any(|e| in_macro(e.span)) {
358 matched.push(&**args); // build up `matched` backwards
359 current = &args[0] // go to parent expression
367 matched.reverse(); // reverse `matched`, so that it is in the same order as `methods`
371 /// Returns true if the provided `def_id` is an entrypoint to a program
372 pub fn is_entrypoint_fn(cx: &LateContext<'_, '_>, def_id: DefId) -> bool {
373 if let Some((entry_fn_def_id, _)) = cx.tcx.entry_fn(LOCAL_CRATE) {
374 return def_id == entry_fn_def_id;
379 /// Get the name of the item the expression is in, if available.
380 pub fn get_item_name(cx: &LateContext<'_, '_>, expr: &Expr) -> Option<Name> {
381 let parent_id = cx.tcx.hir().get_parent(expr.id);
382 match cx.tcx.hir().find(parent_id) {
383 Some(Node::Item(&Item { ref ident, .. })) => Some(ident.name),
384 Some(Node::TraitItem(&TraitItem { ident, .. })) | Some(Node::ImplItem(&ImplItem { ident, .. })) => {
391 /// Get the name of a `Pat`, if any
392 pub fn get_pat_name(pat: &Pat) -> Option<Name> {
394 PatKind::Binding(.., ref spname, _) => Some(spname.name),
395 PatKind::Path(ref qpath) => single_segment_path(qpath).map(|ps| ps.ident.name),
396 PatKind::Box(ref p) | PatKind::Ref(ref p, _) => get_pat_name(&*p),
401 struct ContainsName {
406 impl<'tcx> Visitor<'tcx> for ContainsName {
407 fn visit_name(&mut self, _: Span, name: Name) {
408 if self.name == name {
412 fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
413 NestedVisitorMap::None
417 /// check if an `Expr` contains a certain name
418 pub fn contains_name(name: Name, expr: &Expr) -> bool {
419 let mut cn = ContainsName { name, result: false };
424 /// Convert a span to a code snippet if available, otherwise use default.
426 /// This is useful if you want to provide suggestions for your lint or more generally, if you want
427 /// to convert a given `Span` to a `str`.
431 /// snippet(cx, expr.span, "..")
433 pub fn snippet<'a, 'b, T: LintContext<'b>>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
434 snippet_opt(cx, span).map_or_else(|| Cow::Borrowed(default), From::from)
437 /// Same as `snippet`, but it adapts the applicability level by following rules:
439 /// - Applicability level `Unspecified` will never be changed.
440 /// - If the span is inside a macro, change the applicability level to `MaybeIncorrect`.
441 /// - If the default value is used and the applicability level is `MachineApplicable`, change it to
442 /// `HasPlaceholders`
443 pub fn snippet_with_applicability<'a, 'b, T: LintContext<'b>>(
447 applicability: &mut Applicability,
449 if *applicability != Applicability::Unspecified && in_macro(span) {
450 *applicability = Applicability::MaybeIncorrect;
452 snippet_opt(cx, span).map_or_else(
454 if *applicability == Applicability::MachineApplicable {
455 *applicability = Applicability::HasPlaceholders;
457 Cow::Borrowed(default)
463 /// Same as `snippet`, but should only be used when it's clear that the input span is
464 /// not a macro argument.
465 pub fn snippet_with_macro_callsite<'a, 'b, T: LintContext<'b>>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
466 snippet(cx, span.source_callsite(), default)
469 /// Convert a span to a code snippet. Returns `None` if not available.
470 pub fn snippet_opt<'a, T: LintContext<'a>>(cx: &T, span: Span) -> Option<String> {
471 cx.sess().source_map().span_to_snippet(span).ok()
474 /// Convert a span (from a block) to a code snippet if available, otherwise use
476 /// This trims the code of indentation, except for the first line. Use it for
477 /// blocks or block-like
478 /// things which need to be printed as such.
482 /// snippet_block(cx, expr.span, "..")
484 pub fn snippet_block<'a, 'b, T: LintContext<'b>>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
485 let snip = snippet(cx, span, default);
486 trim_multiline(snip, true)
489 /// Same as `snippet_block`, but adapts the applicability level by the rules of
490 /// `snippet_with_applicabiliy`.
491 pub fn snippet_block_with_applicability<'a, 'b, T: LintContext<'b>>(
495 applicability: &mut Applicability,
497 let snip = snippet_with_applicability(cx, span, default, applicability);
498 trim_multiline(snip, true)
501 /// Returns a new Span that covers the full last line of the given Span
502 pub fn last_line_of_span<'a, T: LintContext<'a>>(cx: &T, span: Span) -> Span {
503 let source_map_and_line = cx.sess().source_map().lookup_line(span.lo()).unwrap();
504 let line_no = source_map_and_line.line;
505 let line_start = &source_map_and_line.sf.lines[line_no];
506 Span::new(*line_start, span.hi(), span.ctxt())
509 /// Like `snippet_block`, but add braces if the expr is not an `ExprKind::Block`.
510 /// Also takes an `Option<String>` which can be put inside the braces.
511 pub fn expr_block<'a, 'b, T: LintContext<'b>>(
514 option: Option<String>,
517 let code = snippet_block(cx, expr.span, default);
518 let string = option.unwrap_or_default();
519 if in_macro(expr.span) {
520 Cow::Owned(format!("{{ {} }}", snippet_with_macro_callsite(cx, expr.span, default)))
521 } else if let ExprKind::Block(_, _) = expr.node {
522 Cow::Owned(format!("{}{}", code, string))
523 } else if string.is_empty() {
524 Cow::Owned(format!("{{ {} }}", code))
526 Cow::Owned(format!("{{\n{};\n{}\n}}", code, string))
530 /// Trim indentation from a multiline string with possibility of ignoring the
532 pub fn trim_multiline(s: Cow<'_, str>, ignore_first: bool) -> Cow<'_, str> {
533 let s_space = trim_multiline_inner(s, ignore_first, ' ');
534 let s_tab = trim_multiline_inner(s_space, ignore_first, '\t');
535 trim_multiline_inner(s_tab, ignore_first, ' ')
538 fn trim_multiline_inner(s: Cow<'_, str>, ignore_first: bool, ch: char) -> Cow<'_, str> {
541 .skip(ignore_first as usize)
546 // ignore empty lines
547 Some(l.char_indices().find(|&(_, x)| x != ch).unwrap_or((l.len(), ch)).0)
557 if (ignore_first && i == 0) || l.is_empty() {
571 /// Get a parent expressions if any – this is useful to constrain a lint.
572 pub fn get_parent_expr<'c>(cx: &'c LateContext<'_, '_>, e: &Expr) -> Option<&'c Expr> {
573 let map = &cx.tcx.hir();
574 let node_id: NodeId = e.id;
575 let parent_id: NodeId = map.get_parent_node(node_id);
576 if node_id == parent_id {
579 map.find(parent_id).and_then(|node| {
580 if let Node::Expr(parent) = node {
588 pub fn get_enclosing_block<'a, 'tcx: 'a>(cx: &LateContext<'a, 'tcx>, node: NodeId) -> Option<&'tcx Block> {
589 let map = &cx.tcx.hir();
590 let enclosing_node = map
591 .get_enclosing_scope(node)
592 .and_then(|enclosing_id| map.find(enclosing_id));
593 if let Some(node) = enclosing_node {
595 Node::Block(block) => Some(block),
597 node: ItemKind::Fn(_, _, _, eid),
600 | Node::ImplItem(&ImplItem {
601 node: ImplItemKind::Method(_, eid),
603 }) => match cx.tcx.hir().body(eid).value.node {
604 ExprKind::Block(ref block, _) => Some(block),
614 /// Return the base type for HIR references and pointers.
615 pub fn walk_ptrs_hir_ty(ty: &hir::Ty) -> &hir::Ty {
617 TyKind::Ptr(ref mut_ty) | TyKind::Rptr(_, ref mut_ty) => walk_ptrs_hir_ty(&mut_ty.ty),
622 /// Return the base type for references and raw pointers.
623 pub fn walk_ptrs_ty(ty: Ty<'_>) -> Ty<'_> {
625 ty::Ref(_, ty, _) => walk_ptrs_ty(ty),
630 /// Return the base type for references and raw pointers, and count reference
632 pub fn walk_ptrs_ty_depth(ty: Ty<'_>) -> (Ty<'_>, usize) {
633 fn inner(ty: Ty<'_>, depth: usize) -> (Ty<'_>, usize) {
635 ty::Ref(_, ty, _) => inner(ty, depth + 1),
642 /// Check whether the given expression is a constant literal of the given value.
643 pub fn is_integer_literal(expr: &Expr, value: u128) -> bool {
644 // FIXME: use constant folding
645 if let ExprKind::Lit(ref spanned) = expr.node {
646 if let LitKind::Int(v, _) = spanned.node {
653 /// Returns `true` if the given `Expr` has been coerced before.
655 /// Examples of coercions can be found in the Nomicon at
656 /// <https://doc.rust-lang.org/nomicon/coercions.html>.
658 /// See `rustc::ty::adjustment::Adjustment` and `rustc_typeck::check::coercion` for more
659 /// information on adjustments and coercions.
660 pub fn is_adjusted(cx: &LateContext<'_, '_>, e: &Expr) -> bool {
661 cx.tables.adjustments().get(e.hir_id).is_some()
664 pub struct LimitStack {
668 impl Drop for LimitStack {
670 assert_eq!(self.stack.len(), 1);
675 pub fn new(limit: u64) -> Self {
676 Self { stack: vec![limit] }
678 pub fn limit(&self) -> u64 {
679 *self.stack.last().expect("there should always be a value in the stack")
681 pub fn push_attrs(&mut self, sess: &Session, attrs: &[ast::Attribute], name: &'static str) {
682 let stack = &mut self.stack;
683 parse_attrs(sess, attrs, name, |val| stack.push(val));
685 pub fn pop_attrs(&mut self, sess: &Session, attrs: &[ast::Attribute], name: &'static str) {
686 let stack = &mut self.stack;
687 parse_attrs(sess, attrs, name, |val| assert_eq!(stack.pop(), Some(val)));
691 pub fn get_attr<'a>(attrs: &'a [ast::Attribute], name: &'static str) -> impl Iterator<Item = &'a ast::Attribute> {
692 attrs.iter().filter(move |attr| {
693 attr.path.segments.len() == 2
694 && attr.path.segments[0].ident.to_string() == "clippy"
695 && attr.path.segments[1].ident.to_string() == name
699 fn parse_attrs<F: FnMut(u64)>(sess: &Session, attrs: &[ast::Attribute], name: &'static str, mut f: F) {
700 for attr in get_attr(attrs, name) {
701 if let Some(ref value) = attr.value_str() {
702 if let Ok(value) = FromStr::from_str(&value.as_str()) {
705 sess.span_err(attr.span, "not a number");
708 sess.span_err(attr.span, "bad clippy attribute");
713 /// Return the pre-expansion span if is this comes from an expansion of the
715 /// See also `is_direct_expn_of`.
716 pub fn is_expn_of(mut span: Span, name: &str) -> Option<Span> {
718 let span_name_span = span
722 .map(|ei| (ei.format.name(), ei.call_site));
724 match span_name_span {
725 Some((mac_name, new_span)) if mac_name == name => return Some(new_span),
727 Some((_, new_span)) => span = new_span,
732 /// Return the pre-expansion span if is this directly comes from an expansion
733 /// of the macro `name`.
734 /// The difference with `is_expn_of` is that in
738 /// `42` is considered expanded from `foo!` and `bar!` by `is_expn_of` but only
740 /// `is_direct_expn_of`.
741 pub fn is_direct_expn_of(span: Span, name: &str) -> Option<Span> {
742 let span_name_span = span
746 .map(|ei| (ei.format.name(), ei.call_site));
748 match span_name_span {
749 Some((mac_name, new_span)) if mac_name == name => Some(new_span),
754 /// Convenience function to get the return type of a function
755 pub fn return_ty<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, fn_item: NodeId) -> Ty<'tcx> {
756 let fn_def_id = cx.tcx.hir().local_def_id(fn_item);
757 let ret_ty = cx.tcx.fn_sig(fn_def_id).output();
758 cx.tcx.erase_late_bound_regions(&ret_ty)
761 /// Check if two types are the same.
763 /// This discards any lifetime annotations, too.
764 // FIXME: this works correctly for lifetimes bounds (`for <'a> Foo<'a>` == `for
766 // not for type parameters.
767 pub fn same_tys<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, a: Ty<'tcx>, b: Ty<'tcx>) -> bool {
768 let a = cx.tcx.erase_late_bound_regions(&Binder::bind(a));
769 let b = cx.tcx.erase_late_bound_regions(&Binder::bind(b));
772 .enter(|infcx| infcx.can_eq(cx.param_env, a, b).is_ok())
775 /// Return whether the given type is an `unsafe` function.
776 pub fn type_is_unsafe_function<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
778 ty::FnDef(..) | ty::FnPtr(_) => ty.fn_sig(cx.tcx).unsafety() == Unsafety::Unsafe,
783 pub fn is_copy<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
784 ty.is_copy_modulo_regions(cx.tcx.global_tcx(), cx.param_env, DUMMY_SP)
787 /// Return whether a pattern is refutable.
788 pub fn is_refutable(cx: &LateContext<'_, '_>, pat: &Pat) -> bool {
789 fn is_enum_variant(cx: &LateContext<'_, '_>, qpath: &QPath, id: HirId) -> bool {
791 cx.tables.qpath_def(qpath, id),
792 def::Def::Variant(..) | def::Def::VariantCtor(..)
796 fn are_refutable<'a, I: Iterator<Item = &'a Pat>>(cx: &LateContext<'_, '_>, mut i: I) -> bool {
797 i.any(|pat| is_refutable(cx, pat))
801 PatKind::Binding(..) | PatKind::Wild => false,
802 PatKind::Box(ref pat) | PatKind::Ref(ref pat, _) => is_refutable(cx, pat),
803 PatKind::Lit(..) | PatKind::Range(..) => true,
804 PatKind::Path(ref qpath) => is_enum_variant(cx, qpath, pat.hir_id),
805 PatKind::Tuple(ref pats, _) => are_refutable(cx, pats.iter().map(|pat| &**pat)),
806 PatKind::Struct(ref qpath, ref fields, _) => {
807 if is_enum_variant(cx, qpath, pat.hir_id) {
810 are_refutable(cx, fields.iter().map(|field| &*field.node.pat))
813 PatKind::TupleStruct(ref qpath, ref pats, _) => {
814 if is_enum_variant(cx, qpath, pat.hir_id) {
817 are_refutable(cx, pats.iter().map(|pat| &**pat))
820 PatKind::Slice(ref head, ref middle, ref tail) => {
821 are_refutable(cx, head.iter().chain(middle).chain(tail.iter()).map(|pat| &**pat))
826 /// Checks for the `#[automatically_derived]` attribute all `#[derive]`d
827 /// implementations have.
828 pub fn is_automatically_derived(attrs: &[ast::Attribute]) -> bool {
829 attr::contains_name(attrs, "automatically_derived")
832 /// Remove blocks around an expression.
834 /// Ie. `x`, `{ x }` and `{{{{ x }}}}` all give `x`. `{ x; y }` and `{}` return
836 pub fn remove_blocks(expr: &Expr) -> &Expr {
837 if let ExprKind::Block(ref block, _) = expr.node {
838 if block.stmts.is_empty() {
839 if let Some(ref expr) = block.expr {
852 pub fn opt_def_id(def: Def) -> Option<DefId> {
856 pub fn is_self(slf: &Arg) -> bool {
857 if let PatKind::Binding(.., name, _) = slf.pat.node {
858 name.name == keywords::SelfLower.name()
864 pub fn is_self_ty(slf: &hir::Ty) -> bool {
866 if let TyKind::Path(ref qp) = slf.node;
867 if let QPath::Resolved(None, ref path) = *qp;
868 if let Def::SelfTy(..) = path.def;
876 pub fn iter_input_pats<'tcx>(decl: &FnDecl, body: &'tcx Body) -> impl Iterator<Item = &'tcx Arg> {
877 (0..decl.inputs.len()).map(move |i| &body.arguments[i])
880 /// Check if a given expression is a match expression
881 /// expanded from `?` operator or `try` macro.
882 pub fn is_try(expr: &Expr) -> Option<&Expr> {
883 fn is_ok(arm: &Arm) -> bool {
885 if let PatKind::TupleStruct(ref path, ref pat, None) = arm.pats[0].node;
886 if match_qpath(path, &paths::RESULT_OK[1..]);
887 if let PatKind::Binding(_, defid, _, _, None) = pat[0].node;
888 if let ExprKind::Path(QPath::Resolved(None, ref path)) = arm.body.node;
889 if let Def::Local(lid) = path.def;
898 fn is_err(arm: &Arm) -> bool {
899 if let PatKind::TupleStruct(ref path, _, _) = arm.pats[0].node {
900 match_qpath(path, &paths::RESULT_ERR[1..])
906 if let ExprKind::Match(_, ref arms, ref source) = expr.node {
907 // desugared from a `?` operator
908 if let MatchSource::TryDesugar = *source {
914 if arms[0].pats.len() == 1 && arms[0].guard.is_none();
915 if arms[1].pats.len() == 1 && arms[1].guard.is_none();
916 if (is_ok(&arms[0]) && is_err(&arms[1])) ||
917 (is_ok(&arms[1]) && is_err(&arms[0]));
927 /// Returns true if the lint is allowed in the current context
929 /// Useful for skipping long running code when it's unnecessary
930 pub fn is_allowed(cx: &LateContext<'_, '_>, lint: &'static Lint, id: NodeId) -> bool {
931 cx.tcx.lint_level_at_node(lint, id).0 == Level::Allow
934 pub fn get_arg_name(pat: &Pat) -> Option<ast::Name> {
936 PatKind::Binding(.., ident, None) => Some(ident.name),
937 PatKind::Ref(ref subpat, _) => get_arg_name(subpat),
942 pub fn int_bits(tcx: TyCtxt<'_, '_, '_>, ity: ast::IntTy) -> u64 {
943 layout::Integer::from_attr(&tcx, attr::IntType::SignedInt(ity))
948 #[allow(clippy::cast_possible_wrap)]
949 /// Turn a constant int byte representation into an i128
950 pub fn sext(tcx: TyCtxt<'_, '_, '_>, u: u128, ity: ast::IntTy) -> i128 {
951 let amt = 128 - int_bits(tcx, ity);
952 ((u as i128) << amt) >> amt
955 #[allow(clippy::cast_sign_loss)]
956 /// clip unused bytes
957 pub fn unsext(tcx: TyCtxt<'_, '_, '_>, u: i128, ity: ast::IntTy) -> u128 {
958 let amt = 128 - int_bits(tcx, ity);
959 ((u as u128) << amt) >> amt
962 /// clip unused bytes
963 pub fn clip(tcx: TyCtxt<'_, '_, '_>, u: u128, ity: ast::UintTy) -> u128 {
964 let bits = layout::Integer::from_attr(&tcx, attr::IntType::UnsignedInt(ity))
967 let amt = 128 - bits;
971 /// Remove block comments from the given Vec of lines
976 /// without_block_comments(vec!["/*", "foo", "*/"]);
979 /// without_block_comments(vec!["bar", "/*", "foo", "*/"]);
980 /// // => vec!["bar"]
982 pub fn without_block_comments(lines: Vec<&str>) -> Vec<&str> {
983 let mut without = vec![];
985 let mut nest_level = 0;
988 if line.contains("/*") {
991 } else if line.contains("*/") {
1004 pub fn any_parent_is_automatically_derived(tcx: TyCtxt<'_, '_, '_>, node: NodeId) -> bool {
1005 let map = &tcx.hir();
1006 let mut prev_enclosing_node = None;
1007 let mut enclosing_node = node;
1008 while Some(enclosing_node) != prev_enclosing_node {
1009 if is_automatically_derived(map.attrs(enclosing_node)) {
1012 prev_enclosing_node = Some(enclosing_node);
1013 enclosing_node = map.get_parent(enclosing_node);
1018 /// Returns true if ty has `iter` or `iter_mut` methods
1019 pub fn has_iter_method(cx: &LateContext<'_, '_>, probably_ref_ty: ty::Ty<'_>) -> Option<&'static str> {
1020 // FIXME: instead of this hard-coded list, we should check if `<adt>::iter`
1021 // exists and has the desired signature. Unfortunately FnCtxt is not exported
1022 // so we can't use its `lookup_method` method.
1023 static INTO_ITER_COLLECTIONS: [&[&str]; 13] = [
1030 &paths::LINKED_LIST,
1031 &paths::BINARY_HEAP,
1039 let ty_to_check = match probably_ref_ty.sty {
1040 ty::Ref(_, ty_to_check, _) => ty_to_check,
1041 _ => probably_ref_ty,
1044 let def_id = match ty_to_check.sty {
1045 ty::Array(..) => return Some("array"),
1046 ty::Slice(..) => return Some("slice"),
1047 ty::Adt(adt, _) => adt.did,
1051 for path in &INTO_ITER_COLLECTIONS {
1052 if match_def_path(cx.tcx, def_id, path) {
1053 return Some(path.last().unwrap());
1061 use super::{trim_multiline, without_block_comments};
1064 fn test_trim_multiline_single_line() {
1065 assert_eq!("", trim_multiline("".into(), false));
1066 assert_eq!("...", trim_multiline("...".into(), false));
1067 assert_eq!("...", trim_multiline(" ...".into(), false));
1068 assert_eq!("...", trim_multiline("\t...".into(), false));
1069 assert_eq!("...", trim_multiline("\t\t...".into(), false));
1074 fn test_trim_multiline_block() {
1080 }", trim_multiline(" if x {
1090 }", trim_multiline(" if x {
1099 fn test_trim_multiline_empty_line() {
1106 }", trim_multiline(" if x {
1115 fn test_without_block_comments_lines_without_block_comments() {
1116 let result = without_block_comments(vec!["/*", "", "*/"]);
1117 println!("result: {:?}", result);
1118 assert!(result.is_empty());
1120 let result = without_block_comments(vec!["", "/*", "", "*/", "#[crate_type = \"lib\"]", "/*", "", "*/", ""]);
1121 assert_eq!(result, vec!["", "#[crate_type = \"lib\"]", ""]);
1123 let result = without_block_comments(vec!["/* rust", "", "*/"]);
1124 assert!(result.is_empty());
1126 let result = without_block_comments(vec!["/* one-line comment */"]);
1127 assert!(result.is_empty());
1129 let result = without_block_comments(vec!["/* nested", "/* multi-line", "comment", "*/", "test", "*/"]);
1130 assert!(result.is_empty());
1132 let result = without_block_comments(vec!["/* nested /* inline /* comment */ test */ */"]);
1133 assert!(result.is_empty());
1135 let result = without_block_comments(vec!["foo", "bar", "baz"]);
1136 assert_eq!(result, vec!["foo", "bar", "baz"]);