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};
14 layout::{self, IntegerExt},
18 use rustc_data_structures::sync::Lrc;
19 use rustc_errors::Applicability;
22 use syntax::ast::{self, LitKind};
24 use syntax::source_map::{Span, DUMMY_SP};
26 use syntax::symbol::{keywords, Symbol};
38 pub mod internal_lints;
43 pub use self::attrs::*;
44 pub use self::diagnostics::*;
45 pub use self::hir_utils::{SpanlessEq, SpanlessHash};
47 /// Returns true if the two spans come from differing expansions (i.e. one is
48 /// from a macro and one
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 /// Used to store the absolute path to a type.
98 /// See `match_def_path` for usage.
100 pub struct AbsolutePathBuffer {
101 pub names: Vec<symbol::LocalInternedString>,
104 impl ty::item_path::ItemPathBuffer for AbsolutePathBuffer {
105 fn root_mode(&self) -> &ty::item_path::RootMode {
106 const ABSOLUTE: &ty::item_path::RootMode = &ty::item_path::RootMode::Absolute;
110 fn push(&mut self, text: &str) {
111 self.names.push(symbol::Symbol::intern(text).as_str());
115 /// Check if a `DefId`'s path matches the given absolute type path usage.
119 /// match_def_path(cx.tcx, id, &["core", "option", "Option"])
122 /// See also the `paths` module.
123 pub fn match_def_path(tcx: TyCtxt<'_, '_, '_>, def_id: DefId, path: &[&str]) -> bool {
124 let mut apb = AbsolutePathBuffer { names: vec![] };
126 tcx.push_item_path(&mut apb, def_id, false);
128 apb.names.len() == path.len() && apb.names.into_iter().zip(path.iter()).all(|(a, &b)| *a == *b)
131 /// Get the absolute path of `def_id` as a vector of `&str`.
135 /// let def_path = get_def_path(tcx, def_id);
136 /// if let &["core", "option", "Option"] = &def_path[..] {
137 /// // The given `def_id` is that of an `Option` type
140 pub fn get_def_path(tcx: TyCtxt<'_, '_, '_>, def_id: DefId) -> Vec<&'static str> {
141 let mut apb = AbsolutePathBuffer { names: vec![] };
142 tcx.push_item_path(&mut apb, def_id, false);
145 .map(syntax_pos::symbol::LocalInternedString::get)
149 /// Check if type is struct, enum or union type with given def path.
150 pub fn match_type(cx: &LateContext<'_, '_>, ty: Ty<'_>, path: &[&str]) -> bool {
152 ty::Adt(adt, _) => match_def_path(cx.tcx, adt.did, path),
157 /// Check if the method call given in `expr` belongs to given trait.
158 pub fn match_trait_method(cx: &LateContext<'_, '_>, expr: &Expr, path: &[&str]) -> bool {
159 let method_call = cx.tables.type_dependent_defs()[expr.hir_id];
160 let trt_id = cx.tcx.trait_of_item(method_call.def_id());
161 if let Some(trt_id) = trt_id {
162 match_def_path(cx.tcx, trt_id, path)
168 /// Check if an expression references a variable of the given name.
169 pub fn match_var(expr: &Expr, var: Name) -> bool {
170 if let ExprKind::Path(QPath::Resolved(None, ref path)) = expr.node {
171 if path.segments.len() == 1 && path.segments[0].ident.name == var {
178 pub fn last_path_segment(path: &QPath) -> &PathSegment {
180 QPath::Resolved(_, ref path) => path.segments.last().expect("A path must have at least one segment"),
181 QPath::TypeRelative(_, ref seg) => seg,
185 pub fn single_segment_path(path: &QPath) -> Option<&PathSegment> {
187 QPath::Resolved(_, ref path) if path.segments.len() == 1 => Some(&path.segments[0]),
188 QPath::Resolved(..) => None,
189 QPath::TypeRelative(_, ref seg) => Some(seg),
193 /// Match a `Path` against a slice of segment string literals.
197 /// match_qpath(path, &["std", "rt", "begin_unwind"])
199 pub fn match_qpath(path: &QPath, segments: &[&str]) -> bool {
201 QPath::Resolved(_, ref path) => match_path(path, segments),
202 QPath::TypeRelative(ref ty, ref segment) => match ty.node {
203 TyKind::Path(ref inner_path) => {
205 && match_qpath(inner_path, &segments[..(segments.len() - 1)])
206 && segment.ident.name == segments[segments.len() - 1]
213 pub fn match_path(path: &Path, segments: &[&str]) -> bool {
217 .zip(segments.iter().rev())
218 .all(|(a, b)| a.ident.name == *b)
221 /// Match a `Path` against a slice of segment string literals, e.g.
225 /// match_qpath(path, &["std", "rt", "begin_unwind"])
227 pub fn match_path_ast(path: &ast::Path, segments: &[&str]) -> bool {
231 .zip(segments.iter().rev())
232 .all(|(a, b)| a.ident.name == *b)
235 /// Get the definition associated to a path.
236 pub fn path_to_def(cx: &LateContext<'_, '_>, path: &[&str]) -> Option<def::Def> {
237 let crates = cx.tcx.crates();
238 let krate = crates.iter().find(|&&krate| cx.tcx.crate_name(krate) == path[0]);
239 if let Some(krate) = krate {
242 index: CRATE_DEF_INDEX,
244 let mut items = cx.tcx.item_children(krate);
245 let mut path_it = path.iter().skip(1).peekable();
248 let segment = match path_it.next() {
249 Some(segment) => segment,
253 for item in mem::replace(&mut items, Lrc::new(vec![])).iter() {
254 if item.ident.name == *segment {
255 if path_it.peek().is_none() {
256 return Some(item.def);
259 items = cx.tcx.item_children(item.def.def_id());
269 /// Convenience function to get the `DefId` of a trait by path.
270 pub fn get_trait_def_id(cx: &LateContext<'_, '_>, path: &[&str]) -> Option<DefId> {
271 let def = match path_to_def(cx, path) {
277 def::Def::Trait(trait_id) => Some(trait_id),
282 /// Check whether a type implements a trait.
283 /// See also `get_trait_def_id`.
284 pub fn implements_trait<'a, 'tcx>(
285 cx: &LateContext<'a, 'tcx>,
288 ty_params: &[Kind<'tcx>],
290 let ty = cx.tcx.erase_regions(&ty);
291 let obligation = cx.tcx.predicate_for_trait_def(
293 traits::ObligationCause::dummy(),
301 .enter(|infcx| infcx.predicate_must_hold_modulo_regions(&obligation))
304 /// Get the `hir::TraitRef` of the trait the given method is implemented for
306 /// Use this if you want to find the `TraitRef` of the `Add` trait in this example:
309 /// struct Point(isize, isize);
311 /// impl std::ops::Add for Point {
312 /// type Output = Self;
314 /// fn add(self, other: Self) -> Self {
319 pub fn trait_ref_of_method(cx: &LateContext<'_, '_>, hir_id: HirId) -> Option<TraitRef> {
320 // Get the implemented trait for the current function
321 let parent_impl = cx.tcx.hir().get_parent_item(hir_id);
323 if parent_impl != hir::CRATE_HIR_ID;
324 if let hir::Node::Item(item) = cx.tcx.hir().get_by_hir_id(parent_impl);
325 if let hir::ItemKind::Impl(_, _, _, _, trait_ref, _, _) = &item.node;
326 then { return trait_ref.clone(); }
331 /// Check whether this type implements Drop.
332 pub fn has_drop<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
333 match ty.ty_adt_def() {
334 Some(def) => def.has_dtor(cx.tcx),
339 /// Resolve the definition of a node from its `HirId`.
340 pub fn resolve_node(cx: &LateContext<'_, '_>, qpath: &QPath, id: HirId) -> def::Def {
341 cx.tables.qpath_def(qpath, id)
344 /// Return the method names and argument list of nested method call expressions that make up
346 pub fn method_calls<'a>(expr: &'a Expr, max_depth: usize) -> (Vec<Symbol>, Vec<&'a [Expr]>) {
347 let mut method_names = Vec::with_capacity(max_depth);
348 let mut arg_lists = Vec::with_capacity(max_depth);
350 let mut current = expr;
351 for _ in 0..max_depth {
352 if let ExprKind::MethodCall(path, _, args) = ¤t.node {
353 if args.iter().any(|e| in_macro(e.span)) {
356 method_names.push(path.ident.name);
357 arg_lists.push(&**args);
364 (method_names, arg_lists)
367 /// Match an `Expr` against a chain of methods, and return the matched `Expr`s.
369 /// For example, if `expr` represents the `.baz()` in `foo.bar().baz()`,
370 /// `matched_method_chain(expr, &["bar", "baz"])` will return a `Vec`
371 /// containing the `Expr`s for
372 /// `.bar()` and `.baz()`
373 pub fn method_chain_args<'a>(expr: &'a Expr, methods: &[&str]) -> Option<Vec<&'a [Expr]>> {
374 let mut current = expr;
375 let mut matched = Vec::with_capacity(methods.len());
376 for method_name in methods.iter().rev() {
377 // method chains are stored last -> first
378 if let ExprKind::MethodCall(ref path, _, ref args) = current.node {
379 if path.ident.name == *method_name {
380 if args.iter().any(|e| in_macro(e.span)) {
383 matched.push(&**args); // build up `matched` backwards
384 current = &args[0] // go to parent expression
392 matched.reverse(); // reverse `matched`, so that it is in the same order as `methods`
396 /// Returns true if the provided `def_id` is an entrypoint to a program
397 pub fn is_entrypoint_fn(cx: &LateContext<'_, '_>, def_id: DefId) -> bool {
398 if let Some((entry_fn_def_id, _)) = cx.tcx.entry_fn(LOCAL_CRATE) {
399 return def_id == entry_fn_def_id;
404 /// Get the name of the item the expression is in, if available.
405 pub fn get_item_name(cx: &LateContext<'_, '_>, expr: &Expr) -> Option<Name> {
406 let parent_id = cx.tcx.hir().get_parent_item(expr.hir_id);
407 match cx.tcx.hir().find_by_hir_id(parent_id) {
408 Some(Node::Item(&Item { ref ident, .. })) => Some(ident.name),
409 Some(Node::TraitItem(&TraitItem { ident, .. })) | Some(Node::ImplItem(&ImplItem { ident, .. })) => {
416 /// Get the name of a `Pat`, if any
417 pub fn get_pat_name(pat: &Pat) -> Option<Name> {
419 PatKind::Binding(.., ref spname, _) => Some(spname.name),
420 PatKind::Path(ref qpath) => single_segment_path(qpath).map(|ps| ps.ident.name),
421 PatKind::Box(ref p) | PatKind::Ref(ref p, _) => get_pat_name(&*p),
426 struct ContainsName {
431 impl<'tcx> Visitor<'tcx> for ContainsName {
432 fn visit_name(&mut self, _: Span, name: Name) {
433 if self.name == name {
437 fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
438 NestedVisitorMap::None
442 /// check if an `Expr` contains a certain name
443 pub fn contains_name(name: Name, expr: &Expr) -> bool {
444 let mut cn = ContainsName { name, result: false };
449 /// Convert a span to a code snippet if available, otherwise use default.
451 /// This is useful if you want to provide suggestions for your lint or more generally, if you want
452 /// to convert a given `Span` to a `str`.
456 /// snippet(cx, expr.span, "..")
458 pub fn snippet<'a, 'b, T: LintContext<'b>>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
459 snippet_opt(cx, span).map_or_else(|| Cow::Borrowed(default), From::from)
462 /// Same as `snippet`, but it adapts the applicability level by following rules:
464 /// - Applicability level `Unspecified` will never be changed.
465 /// - If the span is inside a macro, change the applicability level to `MaybeIncorrect`.
466 /// - If the default value is used and the applicability level is `MachineApplicable`, change it to
467 /// `HasPlaceholders`
468 pub fn snippet_with_applicability<'a, 'b, T: LintContext<'b>>(
472 applicability: &mut Applicability,
474 if *applicability != Applicability::Unspecified && in_macro(span) {
475 *applicability = Applicability::MaybeIncorrect;
477 snippet_opt(cx, span).map_or_else(
479 if *applicability == Applicability::MachineApplicable {
480 *applicability = Applicability::HasPlaceholders;
482 Cow::Borrowed(default)
488 /// Same as `snippet`, but should only be used when it's clear that the input span is
489 /// not a macro argument.
490 pub fn snippet_with_macro_callsite<'a, 'b, T: LintContext<'b>>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
491 snippet(cx, span.source_callsite(), default)
494 /// Convert a span to a code snippet. Returns `None` if not available.
495 pub fn snippet_opt<'a, T: LintContext<'a>>(cx: &T, span: Span) -> Option<String> {
496 cx.sess().source_map().span_to_snippet(span).ok()
499 /// Convert a span (from a block) to a code snippet if available, otherwise use
501 /// This trims the code of indentation, except for the first line. Use it for
502 /// blocks or block-like
503 /// things which need to be printed as such.
507 /// snippet_block(cx, expr.span, "..")
509 pub fn snippet_block<'a, 'b, T: LintContext<'b>>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
510 let snip = snippet(cx, span, default);
511 trim_multiline(snip, true)
514 /// Same as `snippet_block`, but adapts the applicability level by the rules of
515 /// `snippet_with_applicabiliy`.
516 pub fn snippet_block_with_applicability<'a, 'b, T: LintContext<'b>>(
520 applicability: &mut Applicability,
522 let snip = snippet_with_applicability(cx, span, default, applicability);
523 trim_multiline(snip, true)
526 /// Returns a new Span that covers the full last line of the given Span
527 pub fn last_line_of_span<'a, T: LintContext<'a>>(cx: &T, span: Span) -> Span {
528 let source_map_and_line = cx.sess().source_map().lookup_line(span.lo()).unwrap();
529 let line_no = source_map_and_line.line;
530 let line_start = &source_map_and_line.sf.lines[line_no];
531 Span::new(*line_start, span.hi(), span.ctxt())
534 /// Like `snippet_block`, but add braces if the expr is not an `ExprKind::Block`.
535 /// Also takes an `Option<String>` which can be put inside the braces.
536 pub fn expr_block<'a, 'b, T: LintContext<'b>>(
539 option: Option<String>,
542 let code = snippet_block(cx, expr.span, default);
543 let string = option.unwrap_or_default();
544 if in_macro(expr.span) {
545 Cow::Owned(format!("{{ {} }}", snippet_with_macro_callsite(cx, expr.span, default)))
546 } else if let ExprKind::Block(_, _) = expr.node {
547 Cow::Owned(format!("{}{}", code, string))
548 } else if string.is_empty() {
549 Cow::Owned(format!("{{ {} }}", code))
551 Cow::Owned(format!("{{\n{};\n{}\n}}", code, string))
555 /// Trim indentation from a multiline string with possibility of ignoring the
557 pub fn trim_multiline(s: Cow<'_, str>, ignore_first: bool) -> Cow<'_, str> {
558 let s_space = trim_multiline_inner(s, ignore_first, ' ');
559 let s_tab = trim_multiline_inner(s_space, ignore_first, '\t');
560 trim_multiline_inner(s_tab, ignore_first, ' ')
563 fn trim_multiline_inner(s: Cow<'_, str>, ignore_first: bool, ch: char) -> Cow<'_, str> {
566 .skip(ignore_first as usize)
571 // ignore empty lines
572 Some(l.char_indices().find(|&(_, x)| x != ch).unwrap_or((l.len(), ch)).0)
582 if (ignore_first && i == 0) || l.is_empty() {
596 /// Get a parent expressions if any – this is useful to constrain a lint.
597 pub fn get_parent_expr<'c>(cx: &'c LateContext<'_, '_>, e: &Expr) -> Option<&'c Expr> {
598 let map = &cx.tcx.hir();
599 let hir_id = e.hir_id;
600 let parent_id = map.get_parent_node_by_hir_id(hir_id);
601 if hir_id == parent_id {
604 map.find_by_hir_id(parent_id).and_then(|node| {
605 if let Node::Expr(parent) = node {
613 pub fn get_enclosing_block<'a, 'tcx: 'a>(cx: &LateContext<'a, 'tcx>, node: HirId) -> Option<&'tcx Block> {
614 let map = &cx.tcx.hir();
615 let node_id = map.hir_to_node_id(node);
616 let enclosing_node = map
617 .get_enclosing_scope(node_id)
618 .and_then(|enclosing_id| map.find(enclosing_id));
619 if let Some(node) = enclosing_node {
621 Node::Block(block) => Some(block),
623 node: ItemKind::Fn(_, _, _, eid),
626 | Node::ImplItem(&ImplItem {
627 node: ImplItemKind::Method(_, eid),
629 }) => match cx.tcx.hir().body(eid).value.node {
630 ExprKind::Block(ref block, _) => Some(block),
640 /// Return the base type for HIR references and pointers.
641 pub fn walk_ptrs_hir_ty(ty: &hir::Ty) -> &hir::Ty {
643 TyKind::Ptr(ref mut_ty) | TyKind::Rptr(_, ref mut_ty) => walk_ptrs_hir_ty(&mut_ty.ty),
648 /// Return the base type for references and raw pointers.
649 pub fn walk_ptrs_ty(ty: Ty<'_>) -> Ty<'_> {
651 ty::Ref(_, ty, _) => walk_ptrs_ty(ty),
656 /// Return the base type for references and raw pointers, and count reference
658 pub fn walk_ptrs_ty_depth(ty: Ty<'_>) -> (Ty<'_>, usize) {
659 fn inner(ty: Ty<'_>, depth: usize) -> (Ty<'_>, usize) {
661 ty::Ref(_, ty, _) => inner(ty, depth + 1),
668 /// Check whether the given expression is a constant literal of the given value.
669 pub fn is_integer_literal(expr: &Expr, value: u128) -> bool {
670 // FIXME: use constant folding
671 if let ExprKind::Lit(ref spanned) = expr.node {
672 if let LitKind::Int(v, _) = spanned.node {
679 /// Returns `true` if the given `Expr` has been coerced before.
681 /// Examples of coercions can be found in the Nomicon at
682 /// <https://doc.rust-lang.org/nomicon/coercions.html>.
684 /// See `rustc::ty::adjustment::Adjustment` and `rustc_typeck::check::coercion` for more
685 /// information on adjustments and coercions.
686 pub fn is_adjusted(cx: &LateContext<'_, '_>, e: &Expr) -> bool {
687 cx.tables.adjustments().get(e.hir_id).is_some()
690 /// Return the pre-expansion span if is this comes from an expansion of the
692 /// See also `is_direct_expn_of`.
693 pub fn is_expn_of(mut span: Span, name: &str) -> Option<Span> {
695 let span_name_span = span
699 .map(|ei| (ei.format.name(), ei.call_site));
701 match span_name_span {
702 Some((mac_name, new_span)) if mac_name == name => return Some(new_span),
704 Some((_, new_span)) => span = new_span,
709 /// Return the pre-expansion span if is this directly comes from an expansion
710 /// of the macro `name`.
711 /// The difference with `is_expn_of` is that in
715 /// `42` is considered expanded from `foo!` and `bar!` by `is_expn_of` but only
717 /// `is_direct_expn_of`.
718 pub fn is_direct_expn_of(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 => Some(new_span),
731 /// Convenience function to get the return type of a function
732 pub fn return_ty<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, fn_item: hir::HirId) -> Ty<'tcx> {
733 let fn_def_id = cx.tcx.hir().local_def_id_from_hir_id(fn_item);
734 let ret_ty = cx.tcx.fn_sig(fn_def_id).output();
735 cx.tcx.erase_late_bound_regions(&ret_ty)
738 /// Check if two types are the same.
740 /// This discards any lifetime annotations, too.
741 // FIXME: this works correctly for lifetimes bounds (`for <'a> Foo<'a>` == `for
743 // not for type parameters.
744 pub fn same_tys<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, a: Ty<'tcx>, b: Ty<'tcx>) -> bool {
745 let a = cx.tcx.erase_late_bound_regions(&Binder::bind(a));
746 let b = cx.tcx.erase_late_bound_regions(&Binder::bind(b));
749 .enter(|infcx| infcx.can_eq(cx.param_env, a, b).is_ok())
752 /// Return whether the given type is an `unsafe` function.
753 pub fn type_is_unsafe_function<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
755 ty::FnDef(..) | ty::FnPtr(_) => ty.fn_sig(cx.tcx).unsafety() == Unsafety::Unsafe,
760 pub fn is_copy<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
761 ty.is_copy_modulo_regions(cx.tcx.global_tcx(), cx.param_env, DUMMY_SP)
764 /// Return whether a pattern is refutable.
765 pub fn is_refutable(cx: &LateContext<'_, '_>, pat: &Pat) -> bool {
766 fn is_enum_variant(cx: &LateContext<'_, '_>, qpath: &QPath, id: HirId) -> bool {
768 cx.tables.qpath_def(qpath, id),
769 def::Def::Variant(..) | def::Def::VariantCtor(..)
773 fn are_refutable<'a, I: Iterator<Item = &'a Pat>>(cx: &LateContext<'_, '_>, mut i: I) -> bool {
774 i.any(|pat| is_refutable(cx, pat))
778 PatKind::Binding(..) | PatKind::Wild => false,
779 PatKind::Box(ref pat) | PatKind::Ref(ref pat, _) => is_refutable(cx, pat),
780 PatKind::Lit(..) | PatKind::Range(..) => true,
781 PatKind::Path(ref qpath) => is_enum_variant(cx, qpath, pat.hir_id),
782 PatKind::Tuple(ref pats, _) => are_refutable(cx, pats.iter().map(|pat| &**pat)),
783 PatKind::Struct(ref qpath, ref fields, _) => {
784 if is_enum_variant(cx, qpath, pat.hir_id) {
787 are_refutable(cx, fields.iter().map(|field| &*field.node.pat))
790 PatKind::TupleStruct(ref qpath, ref pats, _) => {
791 if is_enum_variant(cx, qpath, pat.hir_id) {
794 are_refutable(cx, pats.iter().map(|pat| &**pat))
797 PatKind::Slice(ref head, ref middle, ref tail) => {
798 are_refutable(cx, head.iter().chain(middle).chain(tail.iter()).map(|pat| &**pat))
803 /// Checks for the `#[automatically_derived]` attribute all `#[derive]`d
804 /// implementations have.
805 pub fn is_automatically_derived(attrs: &[ast::Attribute]) -> bool {
806 attr::contains_name(attrs, "automatically_derived")
809 /// Remove blocks around an expression.
811 /// Ie. `x`, `{ x }` and `{{{{ x }}}}` all give `x`. `{ x; y }` and `{}` return
813 pub fn remove_blocks(expr: &Expr) -> &Expr {
814 if let ExprKind::Block(ref block, _) = expr.node {
815 if block.stmts.is_empty() {
816 if let Some(ref expr) = block.expr {
829 pub fn opt_def_id(def: Def) -> Option<DefId> {
833 pub fn is_self(slf: &Arg) -> bool {
834 if let PatKind::Binding(.., name, _) = slf.pat.node {
835 name.name == keywords::SelfLower.name()
841 pub fn is_self_ty(slf: &hir::Ty) -> bool {
843 if let TyKind::Path(ref qp) = slf.node;
844 if let QPath::Resolved(None, ref path) = *qp;
845 if let Def::SelfTy(..) = path.def;
853 pub fn iter_input_pats<'tcx>(decl: &FnDecl, body: &'tcx Body) -> impl Iterator<Item = &'tcx Arg> {
854 (0..decl.inputs.len()).map(move |i| &body.arguments[i])
857 /// Check if a given expression is a match expression
858 /// expanded from `?` operator or `try` macro.
859 pub fn is_try<'a>(cx: &'_ LateContext<'_, '_>, expr: &'a Expr) -> Option<&'a Expr> {
860 fn is_ok(cx: &'_ LateContext<'_, '_>, arm: &Arm) -> bool {
862 if let PatKind::TupleStruct(ref path, ref pat, None) = arm.pats[0].node;
863 if match_qpath(path, &paths::RESULT_OK[1..]);
864 if let PatKind::Binding(_, hir_id, _, None) = pat[0].node;
865 if let ExprKind::Path(QPath::Resolved(None, ref path)) = arm.body.node;
866 if let Def::Local(lid) = path.def;
867 if cx.tcx.hir().node_to_hir_id(lid) == hir_id;
875 fn is_err(arm: &Arm) -> bool {
876 if let PatKind::TupleStruct(ref path, _, _) = arm.pats[0].node {
877 match_qpath(path, &paths::RESULT_ERR[1..])
883 if let ExprKind::Match(_, ref arms, ref source) = expr.node {
884 // desugared from a `?` operator
885 if let MatchSource::TryDesugar = *source {
891 if arms[0].pats.len() == 1 && arms[0].guard.is_none();
892 if arms[1].pats.len() == 1 && arms[1].guard.is_none();
893 if (is_ok(cx, &arms[0]) && is_err(&arms[1])) ||
894 (is_ok(cx, &arms[1]) && is_err(&arms[0]));
904 /// Returns true if the lint is allowed in the current context
906 /// Useful for skipping long running code when it's unnecessary
907 pub fn is_allowed(cx: &LateContext<'_, '_>, lint: &'static Lint, id: HirId) -> bool {
908 cx.tcx.lint_level_at_node(lint, id).0 == Level::Allow
911 pub fn get_arg_name(pat: &Pat) -> Option<ast::Name> {
913 PatKind::Binding(.., ident, None) => Some(ident.name),
914 PatKind::Ref(ref subpat, _) => get_arg_name(subpat),
919 pub fn int_bits(tcx: TyCtxt<'_, '_, '_>, ity: ast::IntTy) -> u64 {
920 layout::Integer::from_attr(&tcx, attr::IntType::SignedInt(ity))
925 #[allow(clippy::cast_possible_wrap)]
926 /// Turn a constant int byte representation into an i128
927 pub fn sext(tcx: TyCtxt<'_, '_, '_>, u: u128, ity: ast::IntTy) -> i128 {
928 let amt = 128 - int_bits(tcx, ity);
929 ((u as i128) << amt) >> amt
932 #[allow(clippy::cast_sign_loss)]
933 /// clip unused bytes
934 pub fn unsext(tcx: TyCtxt<'_, '_, '_>, u: i128, ity: ast::IntTy) -> u128 {
935 let amt = 128 - int_bits(tcx, ity);
936 ((u as u128) << amt) >> amt
939 /// clip unused bytes
940 pub fn clip(tcx: TyCtxt<'_, '_, '_>, u: u128, ity: ast::UintTy) -> u128 {
941 let bits = layout::Integer::from_attr(&tcx, attr::IntType::UnsignedInt(ity))
944 let amt = 128 - bits;
948 /// Remove block comments from the given Vec of lines
953 /// without_block_comments(vec!["/*", "foo", "*/"]);
956 /// without_block_comments(vec!["bar", "/*", "foo", "*/"]);
957 /// // => vec!["bar"]
959 pub fn without_block_comments(lines: Vec<&str>) -> Vec<&str> {
960 let mut without = vec![];
962 let mut nest_level = 0;
965 if line.contains("/*") {
968 } else if line.contains("*/") {
981 pub fn any_parent_is_automatically_derived(tcx: TyCtxt<'_, '_, '_>, node: HirId) -> bool {
982 let map = &tcx.hir();
983 let mut prev_enclosing_node = None;
984 let mut enclosing_node = node;
985 while Some(enclosing_node) != prev_enclosing_node {
986 if is_automatically_derived(map.attrs_by_hir_id(enclosing_node)) {
989 prev_enclosing_node = Some(enclosing_node);
990 enclosing_node = map.get_parent_item(enclosing_node);
995 /// Returns true if ty has `iter` or `iter_mut` methods
996 pub fn has_iter_method(cx: &LateContext<'_, '_>, probably_ref_ty: ty::Ty<'_>) -> Option<&'static str> {
997 // FIXME: instead of this hard-coded list, we should check if `<adt>::iter`
998 // exists and has the desired signature. Unfortunately FnCtxt is not exported
999 // so we can't use its `lookup_method` method.
1000 static INTO_ITER_COLLECTIONS: [&[&str]; 13] = [
1007 &paths::LINKED_LIST,
1008 &paths::BINARY_HEAP,
1016 let ty_to_check = match probably_ref_ty.sty {
1017 ty::Ref(_, ty_to_check, _) => ty_to_check,
1018 _ => probably_ref_ty,
1021 let def_id = match ty_to_check.sty {
1022 ty::Array(..) => return Some("array"),
1023 ty::Slice(..) => return Some("slice"),
1024 ty::Adt(adt, _) => adt.did,
1028 for path in &INTO_ITER_COLLECTIONS {
1029 if match_def_path(cx.tcx, def_id, path) {
1030 return Some(path.last().unwrap());
1038 use super::{trim_multiline, without_block_comments};
1041 fn test_trim_multiline_single_line() {
1042 assert_eq!("", trim_multiline("".into(), false));
1043 assert_eq!("...", trim_multiline("...".into(), false));
1044 assert_eq!("...", trim_multiline(" ...".into(), false));
1045 assert_eq!("...", trim_multiline("\t...".into(), false));
1046 assert_eq!("...", trim_multiline("\t\t...".into(), false));
1051 fn test_trim_multiline_block() {
1057 }", trim_multiline(" if x {
1067 }", trim_multiline(" if x {
1076 fn test_trim_multiline_empty_line() {
1083 }", trim_multiline(" if x {
1092 fn test_without_block_comments_lines_without_block_comments() {
1093 let result = without_block_comments(vec!["/*", "", "*/"]);
1094 println!("result: {:?}", result);
1095 assert!(result.is_empty());
1097 let result = without_block_comments(vec!["", "/*", "", "*/", "#[crate_type = \"lib\"]", "/*", "", "*/", ""]);
1098 assert_eq!(result, vec!["", "#[crate_type = \"lib\"]", ""]);
1100 let result = without_block_comments(vec!["/* rust", "", "*/"]);
1101 assert!(result.is_empty());
1103 let result = without_block_comments(vec!["/* one-line comment */"]);
1104 assert!(result.is_empty());
1106 let result = without_block_comments(vec!["/* nested", "/* multi-line", "comment", "*/", "test", "*/"]);
1107 assert!(result.is_empty());
1109 let result = without_block_comments(vec!["/* nested /* inline /* comment */ test */ */"]);
1110 assert!(result.is_empty());
1112 let result = without_block_comments(vec!["foo", "bar", "baz"]);
1113 assert_eq!(result, vec!["foo", "bar", "baz"]);