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: HirId) -> bool {
66 let parent_id = cx.tcx.hir().get_parent_item(id);
67 match cx.tcx.hir().get_by_hir_id(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_item(expr.hir_id);
382 match cx.tcx.hir().find_by_hir_id(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 hir_id = e.hir_id;
575 let parent_id = map.get_parent_node_by_hir_id(hir_id);
576 if hir_id == parent_id {
579 map.find_by_hir_id(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: HirId) -> Option<&'tcx Block> {
589 let map = &cx.tcx.hir();
590 let node_id = map.hir_to_node_id(node);
591 let enclosing_node = map
592 .get_enclosing_scope(node_id)
593 .and_then(|enclosing_id| map.find(enclosing_id));
594 if let Some(node) = enclosing_node {
596 Node::Block(block) => Some(block),
598 node: ItemKind::Fn(_, _, _, eid),
601 | Node::ImplItem(&ImplItem {
602 node: ImplItemKind::Method(_, eid),
604 }) => match cx.tcx.hir().body(eid).value.node {
605 ExprKind::Block(ref block, _) => Some(block),
615 /// Return the base type for HIR references and pointers.
616 pub fn walk_ptrs_hir_ty(ty: &hir::Ty) -> &hir::Ty {
618 TyKind::Ptr(ref mut_ty) | TyKind::Rptr(_, ref mut_ty) => walk_ptrs_hir_ty(&mut_ty.ty),
623 /// Return the base type for references and raw pointers.
624 pub fn walk_ptrs_ty(ty: Ty<'_>) -> Ty<'_> {
626 ty::Ref(_, ty, _) => walk_ptrs_ty(ty),
631 /// Return the base type for references and raw pointers, and count reference
633 pub fn walk_ptrs_ty_depth(ty: Ty<'_>) -> (Ty<'_>, usize) {
634 fn inner(ty: Ty<'_>, depth: usize) -> (Ty<'_>, usize) {
636 ty::Ref(_, ty, _) => inner(ty, depth + 1),
643 /// Check whether the given expression is a constant literal of the given value.
644 pub fn is_integer_literal(expr: &Expr, value: u128) -> bool {
645 // FIXME: use constant folding
646 if let ExprKind::Lit(ref spanned) = expr.node {
647 if let LitKind::Int(v, _) = spanned.node {
654 /// Returns `true` if the given `Expr` has been coerced before.
656 /// Examples of coercions can be found in the Nomicon at
657 /// <https://doc.rust-lang.org/nomicon/coercions.html>.
659 /// See `rustc::ty::adjustment::Adjustment` and `rustc_typeck::check::coercion` for more
660 /// information on adjustments and coercions.
661 pub fn is_adjusted(cx: &LateContext<'_, '_>, e: &Expr) -> bool {
662 cx.tables.adjustments().get(e.hir_id).is_some()
665 pub struct LimitStack {
669 impl Drop for LimitStack {
671 assert_eq!(self.stack.len(), 1);
676 pub fn new(limit: u64) -> Self {
677 Self { stack: vec![limit] }
679 pub fn limit(&self) -> u64 {
680 *self.stack.last().expect("there should always be a value in the stack")
682 pub fn push_attrs(&mut self, sess: &Session, attrs: &[ast::Attribute], name: &'static str) {
683 let stack = &mut self.stack;
684 parse_attrs(sess, attrs, name, |val| stack.push(val));
686 pub fn pop_attrs(&mut self, sess: &Session, attrs: &[ast::Attribute], name: &'static str) {
687 let stack = &mut self.stack;
688 parse_attrs(sess, attrs, name, |val| assert_eq!(stack.pop(), Some(val)));
692 pub fn get_attr<'a>(attrs: &'a [ast::Attribute], name: &'static str) -> impl Iterator<Item = &'a ast::Attribute> {
693 attrs.iter().filter(move |attr| {
694 attr.path.segments.len() == 2
695 && attr.path.segments[0].ident.to_string() == "clippy"
696 && attr.path.segments[1].ident.to_string() == name
700 fn parse_attrs<F: FnMut(u64)>(sess: &Session, attrs: &[ast::Attribute], name: &'static str, mut f: F) {
701 for attr in get_attr(attrs, name) {
702 if let Some(ref value) = attr.value_str() {
703 if let Ok(value) = FromStr::from_str(&value.as_str()) {
706 sess.span_err(attr.span, "not a number");
709 sess.span_err(attr.span, "bad clippy attribute");
714 /// Return the pre-expansion span if is this comes from an expansion of the
716 /// See also `is_direct_expn_of`.
717 pub fn is_expn_of(mut span: Span, name: &str) -> Option<Span> {
719 let span_name_span = span
723 .map(|ei| (ei.format.name(), ei.call_site));
725 match span_name_span {
726 Some((mac_name, new_span)) if mac_name == name => return Some(new_span),
728 Some((_, new_span)) => span = new_span,
733 /// Return the pre-expansion span if is this directly comes from an expansion
734 /// of the macro `name`.
735 /// The difference with `is_expn_of` is that in
739 /// `42` is considered expanded from `foo!` and `bar!` by `is_expn_of` but only
741 /// `is_direct_expn_of`.
742 pub fn is_direct_expn_of(span: Span, name: &str) -> Option<Span> {
743 let span_name_span = span
747 .map(|ei| (ei.format.name(), ei.call_site));
749 match span_name_span {
750 Some((mac_name, new_span)) if mac_name == name => Some(new_span),
755 /// Convenience function to get the return type of a function
756 pub fn return_ty<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, fn_item: NodeId) -> Ty<'tcx> {
757 let fn_def_id = cx.tcx.hir().local_def_id(fn_item);
758 let ret_ty = cx.tcx.fn_sig(fn_def_id).output();
759 cx.tcx.erase_late_bound_regions(&ret_ty)
762 /// Check if two types are the same.
764 /// This discards any lifetime annotations, too.
765 // FIXME: this works correctly for lifetimes bounds (`for <'a> Foo<'a>` == `for
767 // not for type parameters.
768 pub fn same_tys<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, a: Ty<'tcx>, b: Ty<'tcx>) -> bool {
769 let a = cx.tcx.erase_late_bound_regions(&Binder::bind(a));
770 let b = cx.tcx.erase_late_bound_regions(&Binder::bind(b));
773 .enter(|infcx| infcx.can_eq(cx.param_env, a, b).is_ok())
776 /// Return whether the given type is an `unsafe` function.
777 pub fn type_is_unsafe_function<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
779 ty::FnDef(..) | ty::FnPtr(_) => ty.fn_sig(cx.tcx).unsafety() == Unsafety::Unsafe,
784 pub fn is_copy<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
785 ty.is_copy_modulo_regions(cx.tcx.global_tcx(), cx.param_env, DUMMY_SP)
788 /// Return whether a pattern is refutable.
789 pub fn is_refutable(cx: &LateContext<'_, '_>, pat: &Pat) -> bool {
790 fn is_enum_variant(cx: &LateContext<'_, '_>, qpath: &QPath, id: HirId) -> bool {
792 cx.tables.qpath_def(qpath, id),
793 def::Def::Variant(..) | def::Def::VariantCtor(..)
797 fn are_refutable<'a, I: Iterator<Item = &'a Pat>>(cx: &LateContext<'_, '_>, mut i: I) -> bool {
798 i.any(|pat| is_refutable(cx, pat))
802 PatKind::Binding(..) | PatKind::Wild => false,
803 PatKind::Box(ref pat) | PatKind::Ref(ref pat, _) => is_refutable(cx, pat),
804 PatKind::Lit(..) | PatKind::Range(..) => true,
805 PatKind::Path(ref qpath) => is_enum_variant(cx, qpath, pat.hir_id),
806 PatKind::Tuple(ref pats, _) => are_refutable(cx, pats.iter().map(|pat| &**pat)),
807 PatKind::Struct(ref qpath, ref fields, _) => {
808 if is_enum_variant(cx, qpath, pat.hir_id) {
811 are_refutable(cx, fields.iter().map(|field| &*field.node.pat))
814 PatKind::TupleStruct(ref qpath, ref pats, _) => {
815 if is_enum_variant(cx, qpath, pat.hir_id) {
818 are_refutable(cx, pats.iter().map(|pat| &**pat))
821 PatKind::Slice(ref head, ref middle, ref tail) => {
822 are_refutable(cx, head.iter().chain(middle).chain(tail.iter()).map(|pat| &**pat))
827 /// Checks for the `#[automatically_derived]` attribute all `#[derive]`d
828 /// implementations have.
829 pub fn is_automatically_derived(attrs: &[ast::Attribute]) -> bool {
830 attr::contains_name(attrs, "automatically_derived")
833 /// Remove blocks around an expression.
835 /// Ie. `x`, `{ x }` and `{{{{ x }}}}` all give `x`. `{ x; y }` and `{}` return
837 pub fn remove_blocks(expr: &Expr) -> &Expr {
838 if let ExprKind::Block(ref block, _) = expr.node {
839 if block.stmts.is_empty() {
840 if let Some(ref expr) = block.expr {
853 pub fn opt_def_id(def: Def) -> Option<DefId> {
857 pub fn is_self(slf: &Arg) -> bool {
858 if let PatKind::Binding(.., name, _) = slf.pat.node {
859 name.name == keywords::SelfLower.name()
865 pub fn is_self_ty(slf: &hir::Ty) -> bool {
867 if let TyKind::Path(ref qp) = slf.node;
868 if let QPath::Resolved(None, ref path) = *qp;
869 if let Def::SelfTy(..) = path.def;
877 pub fn iter_input_pats<'tcx>(decl: &FnDecl, body: &'tcx Body) -> impl Iterator<Item = &'tcx Arg> {
878 (0..decl.inputs.len()).map(move |i| &body.arguments[i])
881 /// Check if a given expression is a match expression
882 /// expanded from `?` operator or `try` macro.
883 pub fn is_try(expr: &Expr) -> Option<&Expr> {
884 fn is_ok(arm: &Arm) -> bool {
886 if let PatKind::TupleStruct(ref path, ref pat, None) = arm.pats[0].node;
887 if match_qpath(path, &paths::RESULT_OK[1..]);
888 if let PatKind::Binding(_, defid, _, _, None) = pat[0].node;
889 if let ExprKind::Path(QPath::Resolved(None, ref path)) = arm.body.node;
890 if let Def::Local(lid) = path.def;
899 fn is_err(arm: &Arm) -> bool {
900 if let PatKind::TupleStruct(ref path, _, _) = arm.pats[0].node {
901 match_qpath(path, &paths::RESULT_ERR[1..])
907 if let ExprKind::Match(_, ref arms, ref source) = expr.node {
908 // desugared from a `?` operator
909 if let MatchSource::TryDesugar = *source {
915 if arms[0].pats.len() == 1 && arms[0].guard.is_none();
916 if arms[1].pats.len() == 1 && arms[1].guard.is_none();
917 if (is_ok(&arms[0]) && is_err(&arms[1])) ||
918 (is_ok(&arms[1]) && is_err(&arms[0]));
928 /// Returns true if the lint is allowed in the current context
930 /// Useful for skipping long running code when it's unnecessary
931 pub fn is_allowed(cx: &LateContext<'_, '_>, lint: &'static Lint, id: HirId) -> bool {
932 let node_id = cx.tcx.hir().hir_to_node_id(id);
933 cx.tcx.lint_level_at_node(lint, node_id).0 == Level::Allow
936 pub fn get_arg_name(pat: &Pat) -> Option<ast::Name> {
938 PatKind::Binding(.., ident, None) => Some(ident.name),
939 PatKind::Ref(ref subpat, _) => get_arg_name(subpat),
944 pub fn int_bits(tcx: TyCtxt<'_, '_, '_>, ity: ast::IntTy) -> u64 {
945 layout::Integer::from_attr(&tcx, attr::IntType::SignedInt(ity))
950 #[allow(clippy::cast_possible_wrap)]
951 /// Turn a constant int byte representation into an i128
952 pub fn sext(tcx: TyCtxt<'_, '_, '_>, u: u128, ity: ast::IntTy) -> i128 {
953 let amt = 128 - int_bits(tcx, ity);
954 ((u as i128) << amt) >> amt
957 #[allow(clippy::cast_sign_loss)]
958 /// clip unused bytes
959 pub fn unsext(tcx: TyCtxt<'_, '_, '_>, u: i128, ity: ast::IntTy) -> u128 {
960 let amt = 128 - int_bits(tcx, ity);
961 ((u as u128) << amt) >> amt
964 /// clip unused bytes
965 pub fn clip(tcx: TyCtxt<'_, '_, '_>, u: u128, ity: ast::UintTy) -> u128 {
966 let bits = layout::Integer::from_attr(&tcx, attr::IntType::UnsignedInt(ity))
969 let amt = 128 - bits;
973 /// Remove block comments from the given Vec of lines
978 /// without_block_comments(vec!["/*", "foo", "*/"]);
981 /// without_block_comments(vec!["bar", "/*", "foo", "*/"]);
982 /// // => vec!["bar"]
984 pub fn without_block_comments(lines: Vec<&str>) -> Vec<&str> {
985 let mut without = vec![];
987 let mut nest_level = 0;
990 if line.contains("/*") {
993 } else if line.contains("*/") {
1006 pub fn any_parent_is_automatically_derived(tcx: TyCtxt<'_, '_, '_>, node: HirId) -> bool {
1007 let map = &tcx.hir();
1008 let mut prev_enclosing_node = None;
1009 let mut enclosing_node = node;
1010 while Some(enclosing_node) != prev_enclosing_node {
1011 if is_automatically_derived(map.attrs_by_hir_id(enclosing_node)) {
1014 prev_enclosing_node = Some(enclosing_node);
1015 enclosing_node = map.get_parent_item(enclosing_node);
1020 /// Returns true if ty has `iter` or `iter_mut` methods
1021 pub fn has_iter_method(cx: &LateContext<'_, '_>, probably_ref_ty: ty::Ty<'_>) -> Option<&'static str> {
1022 // FIXME: instead of this hard-coded list, we should check if `<adt>::iter`
1023 // exists and has the desired signature. Unfortunately FnCtxt is not exported
1024 // so we can't use its `lookup_method` method.
1025 static INTO_ITER_COLLECTIONS: [&[&str]; 13] = [
1032 &paths::LINKED_LIST,
1033 &paths::BINARY_HEAP,
1041 let ty_to_check = match probably_ref_ty.sty {
1042 ty::Ref(_, ty_to_check, _) => ty_to_check,
1043 _ => probably_ref_ty,
1046 let def_id = match ty_to_check.sty {
1047 ty::Array(..) => return Some("array"),
1048 ty::Slice(..) => return Some("slice"),
1049 ty::Adt(adt, _) => adt.did,
1053 for path in &INTO_ITER_COLLECTIONS {
1054 if match_def_path(cx.tcx, def_id, path) {
1055 return Some(path.last().unwrap());
1063 use super::{trim_multiline, without_block_comments};
1066 fn test_trim_multiline_single_line() {
1067 assert_eq!("", trim_multiline("".into(), false));
1068 assert_eq!("...", trim_multiline("...".into(), false));
1069 assert_eq!("...", trim_multiline(" ...".into(), false));
1070 assert_eq!("...", trim_multiline("\t...".into(), false));
1071 assert_eq!("...", trim_multiline("\t\t...".into(), false));
1076 fn test_trim_multiline_block() {
1082 }", trim_multiline(" if x {
1092 }", trim_multiline(" if x {
1101 fn test_trim_multiline_empty_line() {
1108 }", trim_multiline(" if x {
1117 fn test_without_block_comments_lines_without_block_comments() {
1118 let result = without_block_comments(vec!["/*", "", "*/"]);
1119 println!("result: {:?}", result);
1120 assert!(result.is_empty());
1122 let result = without_block_comments(vec!["", "/*", "", "*/", "#[crate_type = \"lib\"]", "/*", "", "*/", ""]);
1123 assert_eq!(result, vec!["", "#[crate_type = \"lib\"]", ""]);
1125 let result = without_block_comments(vec!["/* rust", "", "*/"]);
1126 assert!(result.is_empty());
1128 let result = without_block_comments(vec!["/* one-line comment */"]);
1129 assert!(result.is_empty());
1131 let result = without_block_comments(vec!["/* nested", "/* multi-line", "comment", "*/", "test", "*/"]);
1132 assert!(result.is_empty());
1134 let result = without_block_comments(vec!["/* nested /* inline /* comment */ test */ */"]);
1135 assert!(result.is_empty());
1137 let result = without_block_comments(vec!["foo", "bar", "baz"]);
1138 assert_eq!(result, vec!["foo", "bar", "baz"]);