11 pub mod internal_lints;
16 pub use self::attrs::*;
17 pub use self::diagnostics::*;
18 pub use self::hir_utils::{SpanlessEq, SpanlessHash};
23 use if_chain::if_chain;
26 use rustc::hir::def::Def;
27 use rustc::hir::def_id::{DefId, CRATE_DEF_INDEX, LOCAL_CRATE};
28 use rustc::hir::intravisit::{NestedVisitorMap, Visitor};
31 use rustc::lint::{LateContext, Level, Lint, LintContext};
35 layout::{self, IntegerExt},
39 use rustc_data_structures::sync::Lrc;
40 use rustc_errors::Applicability;
41 use syntax::ast::{self, LitKind};
43 use syntax::source_map::{Span, DUMMY_SP};
44 use syntax::symbol::{keywords, Symbol};
46 use crate::reexport::*;
48 /// Returns `true` if the two spans come from differing expansions (i.e., one is
49 /// from a macro and one isn't).
50 pub fn differing_macro_contexts(lhs: Span, rhs: Span) -> bool {
51 rhs.ctxt() != lhs.ctxt()
54 /// Returns `true` if the given `NodeId` is inside a constant context
59 /// if in_constant(cx, expr.id) {
63 pub fn in_constant(cx: &LateContext<'_, '_>, id: HirId) -> bool {
64 let parent_id = cx.tcx.hir().get_parent_item(id);
65 match cx.tcx.hir().get_by_hir_id(parent_id) {
67 node: ItemKind::Const(..),
70 | Node::TraitItem(&TraitItem {
71 node: TraitItemKind::Const(..),
74 | Node::ImplItem(&ImplItem {
75 node: ImplItemKind::Const(..),
80 node: ItemKind::Static(..),
84 node: ItemKind::Fn(_, header, ..),
86 }) => header.constness == Constness::Const,
91 /// Returns `true` if this `expn_info` was expanded by any macro.
92 pub fn in_macro(span: Span) -> bool {
93 span.ctxt().outer().expn_info().is_some()
96 /// Checks if type is struct, enum or union type with the given def path.
97 pub fn match_type(cx: &LateContext<'_, '_>, ty: Ty<'_>, path: &[&str]) -> bool {
99 ty::Adt(adt, _) => cx.match_def_path(adt.did, path),
104 /// Checks if the method call given in `expr` belongs to the given trait.
105 pub fn match_trait_method(cx: &LateContext<'_, '_>, expr: &Expr, path: &[&str]) -> bool {
106 let def_id = cx.tables.type_dependent_def_id(expr.hir_id).unwrap();
107 let trt_id = cx.tcx.trait_of_item(def_id);
108 if let Some(trt_id) = trt_id {
109 cx.match_def_path(trt_id, path)
115 /// Checks if an expression references a variable of the given name.
116 pub fn match_var(expr: &Expr, var: Name) -> bool {
117 if let ExprKind::Path(QPath::Resolved(None, ref path)) = expr.node {
118 if path.segments.len() == 1 && path.segments[0].ident.name == var {
125 pub fn last_path_segment(path: &QPath) -> &PathSegment {
127 QPath::Resolved(_, ref path) => path.segments.last().expect("A path must have at least one segment"),
128 QPath::TypeRelative(_, ref seg) => seg,
132 pub fn single_segment_path(path: &QPath) -> Option<&PathSegment> {
134 QPath::Resolved(_, ref path) if path.segments.len() == 1 => Some(&path.segments[0]),
135 QPath::Resolved(..) => None,
136 QPath::TypeRelative(_, ref seg) => Some(seg),
140 /// Matches a `QPath` against a slice of segment string literals.
142 /// There is also `match_path` if you are dealing with a `rustc::hir::Path` instead of a
143 /// `rustc::hir::QPath`.
147 /// match_qpath(path, &["std", "rt", "begin_unwind"])
149 pub fn match_qpath(path: &QPath, segments: &[&str]) -> bool {
151 QPath::Resolved(_, ref path) => match_path(path, segments),
152 QPath::TypeRelative(ref ty, ref segment) => match ty.node {
153 TyKind::Path(ref inner_path) => {
155 && match_qpath(inner_path, &segments[..(segments.len() - 1)])
156 && segment.ident.name == segments[segments.len() - 1]
163 /// Matches a `Path` against a slice of segment string literals.
165 /// There is also `match_qpath` if you are dealing with a `rustc::hir::QPath` instead of a
166 /// `rustc::hir::Path`.
171 /// if match_path(&trait_ref.path, &paths::HASH) {
172 /// // This is the `std::hash::Hash` trait.
175 /// if match_path(ty_path, &["rustc", "lint", "Lint"]) {
176 /// // This is a `rustc::lint::Lint`.
179 pub fn match_path(path: &Path, segments: &[&str]) -> bool {
183 .zip(segments.iter().rev())
184 .all(|(a, b)| a.ident.name == *b)
187 /// Matches a `Path` against a slice of segment string literals, e.g.
191 /// match_qpath(path, &["std", "rt", "begin_unwind"])
193 pub fn match_path_ast(path: &ast::Path, segments: &[&str]) -> bool {
197 .zip(segments.iter().rev())
198 .all(|(a, b)| a.ident.name == *b)
201 /// Gets the definition associated to a path.
202 pub fn path_to_def(cx: &LateContext<'_, '_>, path: &[&str]) -> Option<def::Def> {
203 let crates = cx.tcx.crates();
204 let krate = crates.iter().find(|&&krate| cx.tcx.crate_name(krate) == path[0]);
205 if let Some(krate) = krate {
208 index: CRATE_DEF_INDEX,
210 let mut items = cx.tcx.item_children(krate);
211 let mut path_it = path.iter().skip(1).peekable();
214 let segment = match path_it.next() {
215 Some(segment) => segment,
219 for item in mem::replace(&mut items, Lrc::new(vec![])).iter() {
220 if item.ident.name == *segment {
221 if path_it.peek().is_none() {
222 return Some(item.def);
225 items = cx.tcx.item_children(item.def.def_id());
235 /// Convenience function to get the `DefId` of a trait by path.
236 pub fn get_trait_def_id(cx: &LateContext<'_, '_>, path: &[&str]) -> Option<DefId> {
237 let def = match path_to_def(cx, path) {
243 def::Def::Trait(trait_id) => Some(trait_id),
248 /// Checks whether a type implements a trait.
249 /// See also `get_trait_def_id`.
250 pub fn implements_trait<'a, 'tcx>(
251 cx: &LateContext<'a, 'tcx>,
254 ty_params: &[Kind<'tcx>],
256 let ty = cx.tcx.erase_regions(&ty);
257 let obligation = cx.tcx.predicate_for_trait_def(
259 traits::ObligationCause::dummy(),
267 .enter(|infcx| infcx.predicate_must_hold_modulo_regions(&obligation))
270 /// Gets the `hir::TraitRef` of the trait the given method is implemented for.
272 /// Use this if you want to find the `TraitRef` of the `Add` trait in this example:
275 /// struct Point(isize, isize);
277 /// impl std::ops::Add for Point {
278 /// type Output = Self;
280 /// fn add(self, other: Self) -> Self {
285 pub fn trait_ref_of_method(cx: &LateContext<'_, '_>, hir_id: HirId) -> Option<TraitRef> {
286 // Get the implemented trait for the current function
287 let parent_impl = cx.tcx.hir().get_parent_item(hir_id);
289 if parent_impl != hir::CRATE_HIR_ID;
290 if let hir::Node::Item(item) = cx.tcx.hir().get_by_hir_id(parent_impl);
291 if let hir::ItemKind::Impl(_, _, _, _, trait_ref, _, _) = &item.node;
292 then { return trait_ref.clone(); }
297 /// Checks whether this type implements `Drop`.
298 pub fn has_drop<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
299 match ty.ty_adt_def() {
300 Some(def) => def.has_dtor(cx.tcx),
305 /// Resolves the definition of a node from its `HirId`.
306 pub fn resolve_node(cx: &LateContext<'_, '_>, qpath: &QPath, id: HirId) -> def::Def {
307 cx.tables.qpath_def(qpath, id)
310 /// Returns the method names and argument list of nested method call expressions that make up
312 pub fn method_calls<'a>(expr: &'a Expr, max_depth: usize) -> (Vec<Symbol>, Vec<&'a [Expr]>) {
313 let mut method_names = Vec::with_capacity(max_depth);
314 let mut arg_lists = Vec::with_capacity(max_depth);
316 let mut current = expr;
317 for _ in 0..max_depth {
318 if let ExprKind::MethodCall(path, _, args) = ¤t.node {
319 if args.iter().any(|e| in_macro(e.span)) {
322 method_names.push(path.ident.name);
323 arg_lists.push(&**args);
330 (method_names, arg_lists)
333 /// Matches an `Expr` against a chain of methods, and return the matched `Expr`s.
335 /// For example, if `expr` represents the `.baz()` in `foo.bar().baz()`,
336 /// `matched_method_chain(expr, &["bar", "baz"])` will return a `Vec`
337 /// containing the `Expr`s for
338 /// `.bar()` and `.baz()`
339 pub fn method_chain_args<'a>(expr: &'a Expr, methods: &[&str]) -> Option<Vec<&'a [Expr]>> {
340 let mut current = expr;
341 let mut matched = Vec::with_capacity(methods.len());
342 for method_name in methods.iter().rev() {
343 // method chains are stored last -> first
344 if let ExprKind::MethodCall(ref path, _, ref args) = current.node {
345 if path.ident.name == *method_name {
346 if args.iter().any(|e| in_macro(e.span)) {
349 matched.push(&**args); // build up `matched` backwards
350 current = &args[0] // go to parent expression
358 // Reverse `matched` so that it is in the same order as `methods`.
363 /// Returns `true` if the provided `def_id` is an entrypoint to a program.
364 pub fn is_entrypoint_fn(cx: &LateContext<'_, '_>, def_id: DefId) -> bool {
365 if let Some((entry_fn_def_id, _)) = cx.tcx.entry_fn(LOCAL_CRATE) {
366 return def_id == entry_fn_def_id;
371 /// Gets the name of the item the expression is in, if available.
372 pub fn get_item_name(cx: &LateContext<'_, '_>, expr: &Expr) -> Option<Name> {
373 let parent_id = cx.tcx.hir().get_parent_item(expr.hir_id);
374 match cx.tcx.hir().find_by_hir_id(parent_id) {
375 Some(Node::Item(&Item { ref ident, .. })) => Some(ident.name),
376 Some(Node::TraitItem(&TraitItem { ident, .. })) | Some(Node::ImplItem(&ImplItem { ident, .. })) => {
383 /// Gets the name of a `Pat`, if any.
384 pub fn get_pat_name(pat: &Pat) -> Option<Name> {
386 PatKind::Binding(.., ref spname, _) => Some(spname.name),
387 PatKind::Path(ref qpath) => single_segment_path(qpath).map(|ps| ps.ident.name),
388 PatKind::Box(ref p) | PatKind::Ref(ref p, _) => get_pat_name(&*p),
393 struct ContainsName {
398 impl<'tcx> Visitor<'tcx> for ContainsName {
399 fn visit_name(&mut self, _: Span, name: Name) {
400 if self.name == name {
404 fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
405 NestedVisitorMap::None
409 /// Checks if an `Expr` contains a certain name.
410 pub fn contains_name(name: Name, expr: &Expr) -> bool {
411 let mut cn = ContainsName { name, result: false };
416 /// Converts a span to a code snippet if available, otherwise use default.
418 /// This is useful if you want to provide suggestions for your lint or more generally, if you want
419 /// to convert a given `Span` to a `str`.
423 /// snippet(cx, expr.span, "..")
425 pub fn snippet<'a, 'b, T: LintContext<'b>>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
426 snippet_opt(cx, span).map_or_else(|| Cow::Borrowed(default), From::from)
429 /// Same as `snippet`, but it adapts the applicability level by following rules:
431 /// - Applicability level `Unspecified` will never be changed.
432 /// - If the span is inside a macro, change the applicability level to `MaybeIncorrect`.
433 /// - If the default value is used and the applicability level is `MachineApplicable`, change it to
434 /// `HasPlaceholders`
435 pub fn snippet_with_applicability<'a, 'b, T: LintContext<'b>>(
439 applicability: &mut Applicability,
441 if *applicability != Applicability::Unspecified && in_macro(span) {
442 *applicability = Applicability::MaybeIncorrect;
444 snippet_opt(cx, span).map_or_else(
446 if *applicability == Applicability::MachineApplicable {
447 *applicability = Applicability::HasPlaceholders;
449 Cow::Borrowed(default)
455 /// Same as `snippet`, but should only be used when it's clear that the input span is
456 /// not a macro argument.
457 pub fn snippet_with_macro_callsite<'a, 'b, T: LintContext<'b>>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
458 snippet(cx, span.source_callsite(), default)
461 /// Converts a span to a code snippet. Returns `None` if not available.
462 pub fn snippet_opt<'a, T: LintContext<'a>>(cx: &T, span: Span) -> Option<String> {
463 cx.sess().source_map().span_to_snippet(span).ok()
466 /// Converts a span (from a block) to a code snippet if available, otherwise use
468 /// This trims the code of indentation, except for the first line. Use it for
469 /// blocks or block-like
470 /// things which need to be printed as such.
474 /// snippet_block(cx, expr.span, "..")
476 pub fn snippet_block<'a, 'b, T: LintContext<'b>>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
477 let snip = snippet(cx, span, default);
478 trim_multiline(snip, true)
481 /// Same as `snippet_block`, but adapts the applicability level by the rules of
482 /// `snippet_with_applicabiliy`.
483 pub fn snippet_block_with_applicability<'a, 'b, T: LintContext<'b>>(
487 applicability: &mut Applicability,
489 let snip = snippet_with_applicability(cx, span, default, applicability);
490 trim_multiline(snip, true)
493 /// Returns a new Span that covers the full last line of the given Span
494 pub fn last_line_of_span<'a, T: LintContext<'a>>(cx: &T, span: Span) -> Span {
495 let source_map_and_line = cx.sess().source_map().lookup_line(span.lo()).unwrap();
496 let line_no = source_map_and_line.line;
497 let line_start = &source_map_and_line.sf.lines[line_no];
498 Span::new(*line_start, span.hi(), span.ctxt())
501 /// Like `snippet_block`, but add braces if the expr is not an `ExprKind::Block`.
502 /// Also takes an `Option<String>` which can be put inside the braces.
503 pub fn expr_block<'a, 'b, T: LintContext<'b>>(
506 option: Option<String>,
509 let code = snippet_block(cx, expr.span, default);
510 let string = option.unwrap_or_default();
511 if in_macro(expr.span) {
512 Cow::Owned(format!("{{ {} }}", snippet_with_macro_callsite(cx, expr.span, default)))
513 } else if let ExprKind::Block(_, _) = expr.node {
514 Cow::Owned(format!("{}{}", code, string))
515 } else if string.is_empty() {
516 Cow::Owned(format!("{{ {} }}", code))
518 Cow::Owned(format!("{{\n{};\n{}\n}}", code, string))
522 /// Trim indentation from a multiline string with possibility of ignoring the
524 pub fn trim_multiline(s: Cow<'_, str>, ignore_first: bool) -> Cow<'_, str> {
525 let s_space = trim_multiline_inner(s, ignore_first, ' ');
526 let s_tab = trim_multiline_inner(s_space, ignore_first, '\t');
527 trim_multiline_inner(s_tab, ignore_first, ' ')
530 fn trim_multiline_inner(s: Cow<'_, str>, ignore_first: bool, ch: char) -> Cow<'_, str> {
533 .skip(ignore_first as usize)
538 // ignore empty lines
539 Some(l.char_indices().find(|&(_, x)| x != ch).unwrap_or((l.len(), ch)).0)
549 if (ignore_first && i == 0) || l.is_empty() {
563 /// Gets the parent expression, if any –- this is useful to constrain a lint.
564 pub fn get_parent_expr<'c>(cx: &'c LateContext<'_, '_>, e: &Expr) -> Option<&'c Expr> {
565 let map = &cx.tcx.hir();
566 let hir_id = e.hir_id;
567 let parent_id = map.get_parent_node_by_hir_id(hir_id);
568 if hir_id == parent_id {
571 map.find_by_hir_id(parent_id).and_then(|node| {
572 if let Node::Expr(parent) = node {
580 pub fn get_enclosing_block<'a, 'tcx: 'a>(cx: &LateContext<'a, 'tcx>, node: HirId) -> Option<&'tcx Block> {
581 let map = &cx.tcx.hir();
582 let node_id = map.hir_to_node_id(node);
583 let enclosing_node = map
584 .get_enclosing_scope(node_id)
585 .and_then(|enclosing_id| map.find(enclosing_id));
586 if let Some(node) = enclosing_node {
588 Node::Block(block) => Some(block),
590 node: ItemKind::Fn(_, _, _, eid),
593 | Node::ImplItem(&ImplItem {
594 node: ImplItemKind::Method(_, eid),
596 }) => match cx.tcx.hir().body(eid).value.node {
597 ExprKind::Block(ref block, _) => Some(block),
607 /// Returns the base type for HIR references and pointers.
608 pub fn walk_ptrs_hir_ty(ty: &hir::Ty) -> &hir::Ty {
610 TyKind::Ptr(ref mut_ty) | TyKind::Rptr(_, ref mut_ty) => walk_ptrs_hir_ty(&mut_ty.ty),
615 /// Returns the base type for references and raw pointers.
616 pub fn walk_ptrs_ty(ty: Ty<'_>) -> Ty<'_> {
618 ty::Ref(_, ty, _) => walk_ptrs_ty(ty),
623 /// Returns the base type for references and raw pointers, and count reference
625 pub fn walk_ptrs_ty_depth(ty: Ty<'_>) -> (Ty<'_>, usize) {
626 fn inner(ty: Ty<'_>, depth: usize) -> (Ty<'_>, usize) {
628 ty::Ref(_, ty, _) => inner(ty, depth + 1),
635 /// Checks whether the given expression is a constant literal of the given value.
636 pub fn is_integer_literal(expr: &Expr, value: u128) -> bool {
637 // FIXME: use constant folding
638 if let ExprKind::Lit(ref spanned) = expr.node {
639 if let LitKind::Int(v, _) = spanned.node {
646 /// Returns `true` if the given `Expr` has been coerced before.
648 /// Examples of coercions can be found in the Nomicon at
649 /// <https://doc.rust-lang.org/nomicon/coercions.html>.
651 /// See `rustc::ty::adjustment::Adjustment` and `rustc_typeck::check::coercion` for more
652 /// information on adjustments and coercions.
653 pub fn is_adjusted(cx: &LateContext<'_, '_>, e: &Expr) -> bool {
654 cx.tables.adjustments().get(e.hir_id).is_some()
657 /// Returns the pre-expansion span if is this comes from an expansion of the
659 /// See also `is_direct_expn_of`.
660 pub fn is_expn_of(mut span: Span, name: &str) -> Option<Span> {
662 let span_name_span = span
666 .map(|ei| (ei.format.name(), ei.call_site));
668 match span_name_span {
669 Some((mac_name, new_span)) if mac_name == name => return Some(new_span),
671 Some((_, new_span)) => span = new_span,
676 /// Returns the pre-expansion span if the span directly comes from an expansion
677 /// of the macro `name`.
678 /// The difference with `is_expn_of` is that in
682 /// `42` is considered expanded from `foo!` and `bar!` by `is_expn_of` but only
684 /// `is_direct_expn_of`.
685 pub fn is_direct_expn_of(span: Span, name: &str) -> Option<Span> {
686 let span_name_span = span
690 .map(|ei| (ei.format.name(), ei.call_site));
692 match span_name_span {
693 Some((mac_name, new_span)) if mac_name == name => Some(new_span),
698 /// Convenience function to get the return type of a function.
699 pub fn return_ty<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, fn_item: hir::HirId) -> Ty<'tcx> {
700 let fn_def_id = cx.tcx.hir().local_def_id_from_hir_id(fn_item);
701 let ret_ty = cx.tcx.fn_sig(fn_def_id).output();
702 cx.tcx.erase_late_bound_regions(&ret_ty)
705 /// Checks if two types are the same.
707 /// This discards any lifetime annotations, too.
709 // FIXME: this works correctly for lifetimes bounds (`for <'a> Foo<'a>` ==
710 // `for <'b> Foo<'b>`, but not for type parameters).
711 pub fn same_tys<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, a: Ty<'tcx>, b: Ty<'tcx>) -> bool {
712 let a = cx.tcx.erase_late_bound_regions(&Binder::bind(a));
713 let b = cx.tcx.erase_late_bound_regions(&Binder::bind(b));
716 .enter(|infcx| infcx.can_eq(cx.param_env, a, b).is_ok())
719 /// Returns `true` if the given type is an `unsafe` function.
720 pub fn type_is_unsafe_function<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
722 ty::FnDef(..) | ty::FnPtr(_) => ty.fn_sig(cx.tcx).unsafety() == Unsafety::Unsafe,
727 pub fn is_copy<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
728 ty.is_copy_modulo_regions(cx.tcx.global_tcx(), cx.param_env, DUMMY_SP)
731 /// Returns `true` if a pattern is refutable.
732 pub fn is_refutable(cx: &LateContext<'_, '_>, pat: &Pat) -> bool {
733 fn is_enum_variant(cx: &LateContext<'_, '_>, qpath: &QPath, id: HirId) -> bool {
735 cx.tables.qpath_def(qpath, id),
736 def::Def::Variant(..) | def::Def::Ctor(_, def::CtorOf::Variant, _)
740 fn are_refutable<'a, I: Iterator<Item = &'a Pat>>(cx: &LateContext<'_, '_>, mut i: I) -> bool {
741 i.any(|pat| is_refutable(cx, pat))
745 PatKind::Binding(..) | PatKind::Wild => false,
746 PatKind::Box(ref pat) | PatKind::Ref(ref pat, _) => is_refutable(cx, pat),
747 PatKind::Lit(..) | PatKind::Range(..) => true,
748 PatKind::Path(ref qpath) => is_enum_variant(cx, qpath, pat.hir_id),
749 PatKind::Tuple(ref pats, _) => are_refutable(cx, pats.iter().map(|pat| &**pat)),
750 PatKind::Struct(ref qpath, ref fields, _) => {
751 if is_enum_variant(cx, qpath, pat.hir_id) {
754 are_refutable(cx, fields.iter().map(|field| &*field.node.pat))
757 PatKind::TupleStruct(ref qpath, ref pats, _) => {
758 if is_enum_variant(cx, qpath, pat.hir_id) {
761 are_refutable(cx, pats.iter().map(|pat| &**pat))
764 PatKind::Slice(ref head, ref middle, ref tail) => {
765 are_refutable(cx, head.iter().chain(middle).chain(tail.iter()).map(|pat| &**pat))
770 /// Checks for the `#[automatically_derived]` attribute all `#[derive]`d
771 /// implementations have.
772 pub fn is_automatically_derived(attrs: &[ast::Attribute]) -> bool {
773 attr::contains_name(attrs, "automatically_derived")
776 /// Remove blocks around an expression.
778 /// Ie. `x`, `{ x }` and `{{{{ x }}}}` all give `x`. `{ x; y }` and `{}` return
780 pub fn remove_blocks(expr: &Expr) -> &Expr {
781 if let ExprKind::Block(ref block, _) = expr.node {
782 if block.stmts.is_empty() {
783 if let Some(ref expr) = block.expr {
796 pub fn is_self(slf: &Arg) -> bool {
797 if let PatKind::Binding(.., name, _) = slf.pat.node {
798 name.name == keywords::SelfLower.name()
804 pub fn is_self_ty(slf: &hir::Ty) -> bool {
806 if let TyKind::Path(ref qp) = slf.node;
807 if let QPath::Resolved(None, ref path) = *qp;
808 if let Def::SelfTy(..) = path.def;
816 pub fn iter_input_pats<'tcx>(decl: &FnDecl, body: &'tcx Body) -> impl Iterator<Item = &'tcx Arg> {
817 (0..decl.inputs.len()).map(move |i| &body.arguments[i])
820 /// Checks if a given expression is a match expression expanded from the `?`
821 /// operator or the `try` macro.
822 pub fn is_try(expr: &Expr) -> Option<&Expr> {
823 fn is_ok(arm: &Arm) -> bool {
825 if let PatKind::TupleStruct(ref path, ref pat, None) = arm.pats[0].node;
826 if match_qpath(path, &paths::RESULT_OK[1..]);
827 if let PatKind::Binding(_, hir_id, _, None) = pat[0].node;
828 if let ExprKind::Path(QPath::Resolved(None, ref path)) = arm.body.node;
829 if let Def::Local(lid) = path.def;
838 fn is_err(arm: &Arm) -> bool {
839 if let PatKind::TupleStruct(ref path, _, _) = arm.pats[0].node {
840 match_qpath(path, &paths::RESULT_ERR[1..])
846 if let ExprKind::Match(_, ref arms, ref source) = expr.node {
847 // desugared from a `?` operator
848 if let MatchSource::TryDesugar = *source {
854 if arms[0].pats.len() == 1 && arms[0].guard.is_none();
855 if arms[1].pats.len() == 1 && arms[1].guard.is_none();
856 if (is_ok(&arms[0]) && is_err(&arms[1])) ||
857 (is_ok(&arms[1]) && is_err(&arms[0]));
867 /// Returns `true` if the lint is allowed in the current context
869 /// Useful for skipping long running code when it's unnecessary
870 pub fn is_allowed(cx: &LateContext<'_, '_>, lint: &'static Lint, id: HirId) -> bool {
871 cx.tcx.lint_level_at_node(lint, id).0 == Level::Allow
874 pub fn get_arg_name(pat: &Pat) -> Option<ast::Name> {
876 PatKind::Binding(.., ident, None) => Some(ident.name),
877 PatKind::Ref(ref subpat, _) => get_arg_name(subpat),
882 pub fn int_bits(tcx: TyCtxt<'_, '_, '_>, ity: ast::IntTy) -> u64 {
883 layout::Integer::from_attr(&tcx, attr::IntType::SignedInt(ity))
888 #[allow(clippy::cast_possible_wrap)]
889 /// Turn a constant int byte representation into an i128
890 pub fn sext(tcx: TyCtxt<'_, '_, '_>, u: u128, ity: ast::IntTy) -> i128 {
891 let amt = 128 - int_bits(tcx, ity);
892 ((u as i128) << amt) >> amt
895 #[allow(clippy::cast_sign_loss)]
896 /// clip unused bytes
897 pub fn unsext(tcx: TyCtxt<'_, '_, '_>, u: i128, ity: ast::IntTy) -> u128 {
898 let amt = 128 - int_bits(tcx, ity);
899 ((u as u128) << amt) >> amt
902 /// clip unused bytes
903 pub fn clip(tcx: TyCtxt<'_, '_, '_>, u: u128, ity: ast::UintTy) -> u128 {
904 let bits = layout::Integer::from_attr(&tcx, attr::IntType::UnsignedInt(ity))
907 let amt = 128 - bits;
911 /// Removes block comments from the given `Vec` of lines.
916 /// without_block_comments(vec!["/*", "foo", "*/"]);
919 /// without_block_comments(vec!["bar", "/*", "foo", "*/"]);
920 /// // => vec!["bar"]
922 pub fn without_block_comments(lines: Vec<&str>) -> Vec<&str> {
923 let mut without = vec![];
925 let mut nest_level = 0;
928 if line.contains("/*") {
931 } else if line.contains("*/") {
944 pub fn any_parent_is_automatically_derived(tcx: TyCtxt<'_, '_, '_>, node: HirId) -> bool {
945 let map = &tcx.hir();
946 let mut prev_enclosing_node = None;
947 let mut enclosing_node = node;
948 while Some(enclosing_node) != prev_enclosing_node {
949 if is_automatically_derived(map.attrs_by_hir_id(enclosing_node)) {
952 prev_enclosing_node = Some(enclosing_node);
953 enclosing_node = map.get_parent_item(enclosing_node);
958 /// Returns true if ty has `iter` or `iter_mut` methods
959 pub fn has_iter_method(cx: &LateContext<'_, '_>, probably_ref_ty: Ty<'_>) -> Option<&'static str> {
960 // FIXME: instead of this hard-coded list, we should check if `<adt>::iter`
961 // exists and has the desired signature. Unfortunately FnCtxt is not exported
962 // so we can't use its `lookup_method` method.
963 static INTO_ITER_COLLECTIONS: [&[&str]; 13] = [
979 let ty_to_check = match probably_ref_ty.sty {
980 ty::Ref(_, ty_to_check, _) => ty_to_check,
981 _ => probably_ref_ty,
984 let def_id = match ty_to_check.sty {
985 ty::Array(..) => return Some("array"),
986 ty::Slice(..) => return Some("slice"),
987 ty::Adt(adt, _) => adt.did,
991 for path in &INTO_ITER_COLLECTIONS {
992 if cx.match_def_path(def_id, path) {
993 return Some(path.last().unwrap());
1001 use super::{trim_multiline, without_block_comments};
1004 fn test_trim_multiline_single_line() {
1005 assert_eq!("", trim_multiline("".into(), false));
1006 assert_eq!("...", trim_multiline("...".into(), false));
1007 assert_eq!("...", trim_multiline(" ...".into(), false));
1008 assert_eq!("...", trim_multiline("\t...".into(), false));
1009 assert_eq!("...", trim_multiline("\t\t...".into(), false));
1014 fn test_trim_multiline_block() {
1020 }", trim_multiline(" if x {
1030 }", trim_multiline(" if x {
1039 fn test_trim_multiline_empty_line() {
1046 }", trim_multiline(" if x {
1055 fn test_without_block_comments_lines_without_block_comments() {
1056 let result = without_block_comments(vec!["/*", "", "*/"]);
1057 println!("result: {:?}", result);
1058 assert!(result.is_empty());
1060 let result = without_block_comments(vec!["", "/*", "", "*/", "#[crate_type = \"lib\"]", "/*", "", "*/", ""]);
1061 assert_eq!(result, vec!["", "#[crate_type = \"lib\"]", ""]);
1063 let result = without_block_comments(vec!["/* rust", "", "*/"]);
1064 assert!(result.is_empty());
1066 let result = without_block_comments(vec!["/* one-line comment */"]);
1067 assert!(result.is_empty());
1069 let result = without_block_comments(vec!["/* nested", "/* multi-line", "comment", "*/", "test", "*/"]);
1070 assert!(result.is_empty());
1072 let result = without_block_comments(vec!["/* nested /* inline /* comment */ test */ */"]);
1073 assert!(result.is_empty());
1075 let result = without_block_comments(vec!["foo", "bar", "baz"]);
1076 assert_eq!(result, vec!["foo", "bar", "baz"]);