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 /// Check whether this type implements Drop.
305 pub fn has_drop<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
306 match ty.ty_adt_def() {
307 Some(def) => def.has_dtor(cx.tcx),
312 /// Resolve the definition of a node from its `HirId`.
313 pub fn resolve_node(cx: &LateContext<'_, '_>, qpath: &QPath, id: HirId) -> def::Def {
314 cx.tables.qpath_def(qpath, id)
317 /// Return the method names and argument list of nested method call expressions that make up
319 pub fn method_calls<'a>(expr: &'a Expr, max_depth: usize) -> (Vec<Symbol>, Vec<&'a [Expr]>) {
320 let mut method_names = Vec::with_capacity(max_depth);
321 let mut arg_lists = Vec::with_capacity(max_depth);
323 let mut current = expr;
324 for _ in 0..max_depth {
325 if let ExprKind::MethodCall(path, _, args) = ¤t.node {
326 if args.iter().any(|e| in_macro(e.span)) {
329 method_names.push(path.ident.name);
330 arg_lists.push(&**args);
337 (method_names, arg_lists)
340 /// Match an `Expr` against a chain of methods, and return the matched `Expr`s.
342 /// For example, if `expr` represents the `.baz()` in `foo.bar().baz()`,
343 /// `matched_method_chain(expr, &["bar", "baz"])` will return a `Vec`
344 /// containing the `Expr`s for
345 /// `.bar()` and `.baz()`
346 pub fn method_chain_args<'a>(expr: &'a Expr, methods: &[&str]) -> Option<Vec<&'a [Expr]>> {
347 let mut current = expr;
348 let mut matched = Vec::with_capacity(methods.len());
349 for method_name in methods.iter().rev() {
350 // method chains are stored last -> first
351 if let ExprKind::MethodCall(ref path, _, ref args) = current.node {
352 if path.ident.name == *method_name {
353 if args.iter().any(|e| in_macro(e.span)) {
356 matched.push(&**args); // build up `matched` backwards
357 current = &args[0] // go to parent expression
365 matched.reverse(); // reverse `matched`, so that it is in the same order as `methods`
369 /// Returns true if the provided `def_id` is an entrypoint to a program
370 pub fn is_entrypoint_fn(cx: &LateContext<'_, '_>, def_id: DefId) -> bool {
371 if let Some((entry_fn_def_id, _)) = cx.tcx.entry_fn(LOCAL_CRATE) {
372 return def_id == entry_fn_def_id;
377 /// Get the name of the item the expression is in, if available.
378 pub fn get_item_name(cx: &LateContext<'_, '_>, expr: &Expr) -> Option<Name> {
379 let parent_id = cx.tcx.hir().get_parent_item(expr.hir_id);
380 match cx.tcx.hir().find_by_hir_id(parent_id) {
381 Some(Node::Item(&Item { ref ident, .. })) => Some(ident.name),
382 Some(Node::TraitItem(&TraitItem { ident, .. })) | Some(Node::ImplItem(&ImplItem { ident, .. })) => {
389 /// Get the name of a `Pat`, if any
390 pub fn get_pat_name(pat: &Pat) -> Option<Name> {
392 PatKind::Binding(.., ref spname, _) => Some(spname.name),
393 PatKind::Path(ref qpath) => single_segment_path(qpath).map(|ps| ps.ident.name),
394 PatKind::Box(ref p) | PatKind::Ref(ref p, _) => get_pat_name(&*p),
399 struct ContainsName {
404 impl<'tcx> Visitor<'tcx> for ContainsName {
405 fn visit_name(&mut self, _: Span, name: Name) {
406 if self.name == name {
410 fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
411 NestedVisitorMap::None
415 /// check if an `Expr` contains a certain name
416 pub fn contains_name(name: Name, expr: &Expr) -> bool {
417 let mut cn = ContainsName { name, result: false };
422 /// Convert a span to a code snippet if available, otherwise use default.
424 /// This is useful if you want to provide suggestions for your lint or more generally, if you want
425 /// to convert a given `Span` to a `str`.
429 /// snippet(cx, expr.span, "..")
431 pub fn snippet<'a, 'b, T: LintContext<'b>>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
432 snippet_opt(cx, span).map_or_else(|| Cow::Borrowed(default), From::from)
435 /// Same as `snippet`, but it adapts the applicability level by following rules:
437 /// - Applicability level `Unspecified` will never be changed.
438 /// - If the span is inside a macro, change the applicability level to `MaybeIncorrect`.
439 /// - If the default value is used and the applicability level is `MachineApplicable`, change it to
440 /// `HasPlaceholders`
441 pub fn snippet_with_applicability<'a, 'b, T: LintContext<'b>>(
445 applicability: &mut Applicability,
447 if *applicability != Applicability::Unspecified && in_macro(span) {
448 *applicability = Applicability::MaybeIncorrect;
450 snippet_opt(cx, span).map_or_else(
452 if *applicability == Applicability::MachineApplicable {
453 *applicability = Applicability::HasPlaceholders;
455 Cow::Borrowed(default)
461 /// Same as `snippet`, but should only be used when it's clear that the input span is
462 /// not a macro argument.
463 pub fn snippet_with_macro_callsite<'a, 'b, T: LintContext<'b>>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
464 snippet(cx, span.source_callsite(), default)
467 /// Convert a span to a code snippet. Returns `None` if not available.
468 pub fn snippet_opt<'a, T: LintContext<'a>>(cx: &T, span: Span) -> Option<String> {
469 cx.sess().source_map().span_to_snippet(span).ok()
472 /// Convert a span (from a block) to a code snippet if available, otherwise use
474 /// This trims the code of indentation, except for the first line. Use it for
475 /// blocks or block-like
476 /// things which need to be printed as such.
480 /// snippet_block(cx, expr.span, "..")
482 pub fn snippet_block<'a, 'b, T: LintContext<'b>>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
483 let snip = snippet(cx, span, default);
484 trim_multiline(snip, true)
487 /// Same as `snippet_block`, but adapts the applicability level by the rules of
488 /// `snippet_with_applicabiliy`.
489 pub fn snippet_block_with_applicability<'a, 'b, T: LintContext<'b>>(
493 applicability: &mut Applicability,
495 let snip = snippet_with_applicability(cx, span, default, applicability);
496 trim_multiline(snip, true)
499 /// Returns a new Span that covers the full last line of the given Span
500 pub fn last_line_of_span<'a, T: LintContext<'a>>(cx: &T, span: Span) -> Span {
501 let source_map_and_line = cx.sess().source_map().lookup_line(span.lo()).unwrap();
502 let line_no = source_map_and_line.line;
503 let line_start = &source_map_and_line.sf.lines[line_no];
504 Span::new(*line_start, span.hi(), span.ctxt())
507 /// Like `snippet_block`, but add braces if the expr is not an `ExprKind::Block`.
508 /// Also takes an `Option<String>` which can be put inside the braces.
509 pub fn expr_block<'a, 'b, T: LintContext<'b>>(
512 option: Option<String>,
515 let code = snippet_block(cx, expr.span, default);
516 let string = option.unwrap_or_default();
517 if in_macro(expr.span) {
518 Cow::Owned(format!("{{ {} }}", snippet_with_macro_callsite(cx, expr.span, default)))
519 } else if let ExprKind::Block(_, _) = expr.node {
520 Cow::Owned(format!("{}{}", code, string))
521 } else if string.is_empty() {
522 Cow::Owned(format!("{{ {} }}", code))
524 Cow::Owned(format!("{{\n{};\n{}\n}}", code, string))
528 /// Trim indentation from a multiline string with possibility of ignoring the
530 pub fn trim_multiline(s: Cow<'_, str>, ignore_first: bool) -> Cow<'_, str> {
531 let s_space = trim_multiline_inner(s, ignore_first, ' ');
532 let s_tab = trim_multiline_inner(s_space, ignore_first, '\t');
533 trim_multiline_inner(s_tab, ignore_first, ' ')
536 fn trim_multiline_inner(s: Cow<'_, str>, ignore_first: bool, ch: char) -> Cow<'_, str> {
539 .skip(ignore_first as usize)
544 // ignore empty lines
545 Some(l.char_indices().find(|&(_, x)| x != ch).unwrap_or((l.len(), ch)).0)
555 if (ignore_first && i == 0) || l.is_empty() {
569 /// Get a parent expressions if any – this is useful to constrain a lint.
570 pub fn get_parent_expr<'c>(cx: &'c LateContext<'_, '_>, e: &Expr) -> Option<&'c Expr> {
571 let map = &cx.tcx.hir();
572 let hir_id = e.hir_id;
573 let parent_id = map.get_parent_node_by_hir_id(hir_id);
574 if hir_id == parent_id {
577 map.find_by_hir_id(parent_id).and_then(|node| {
578 if let Node::Expr(parent) = node {
586 pub fn get_enclosing_block<'a, 'tcx: 'a>(cx: &LateContext<'a, 'tcx>, node: HirId) -> Option<&'tcx Block> {
587 let map = &cx.tcx.hir();
588 let node_id = map.hir_to_node_id(node);
589 let enclosing_node = map
590 .get_enclosing_scope(node_id)
591 .and_then(|enclosing_id| map.find(enclosing_id));
592 if let Some(node) = enclosing_node {
594 Node::Block(block) => Some(block),
596 node: ItemKind::Fn(_, _, _, eid),
599 | Node::ImplItem(&ImplItem {
600 node: ImplItemKind::Method(_, eid),
602 }) => match cx.tcx.hir().body(eid).value.node {
603 ExprKind::Block(ref block, _) => Some(block),
613 /// Return the base type for HIR references and pointers.
614 pub fn walk_ptrs_hir_ty(ty: &hir::Ty) -> &hir::Ty {
616 TyKind::Ptr(ref mut_ty) | TyKind::Rptr(_, ref mut_ty) => walk_ptrs_hir_ty(&mut_ty.ty),
621 /// Return the base type for references and raw pointers.
622 pub fn walk_ptrs_ty(ty: Ty<'_>) -> Ty<'_> {
624 ty::Ref(_, ty, _) => walk_ptrs_ty(ty),
629 /// Return the base type for references and raw pointers, and count reference
631 pub fn walk_ptrs_ty_depth(ty: Ty<'_>) -> (Ty<'_>, usize) {
632 fn inner(ty: Ty<'_>, depth: usize) -> (Ty<'_>, usize) {
634 ty::Ref(_, ty, _) => inner(ty, depth + 1),
641 /// Check whether the given expression is a constant literal of the given value.
642 pub fn is_integer_literal(expr: &Expr, value: u128) -> bool {
643 // FIXME: use constant folding
644 if let ExprKind::Lit(ref spanned) = expr.node {
645 if let LitKind::Int(v, _) = spanned.node {
652 /// Returns `true` if the given `Expr` has been coerced before.
654 /// Examples of coercions can be found in the Nomicon at
655 /// <https://doc.rust-lang.org/nomicon/coercions.html>.
657 /// See `rustc::ty::adjustment::Adjustment` and `rustc_typeck::check::coercion` for more
658 /// information on adjustments and coercions.
659 pub fn is_adjusted(cx: &LateContext<'_, '_>, e: &Expr) -> bool {
660 cx.tables.adjustments().get(e.hir_id).is_some()
663 /// Return the pre-expansion span if is this comes from an expansion of the
665 /// See also `is_direct_expn_of`.
666 pub fn is_expn_of(mut span: Span, name: &str) -> Option<Span> {
668 let span_name_span = span
672 .map(|ei| (ei.format.name(), ei.call_site));
674 match span_name_span {
675 Some((mac_name, new_span)) if mac_name == name => return Some(new_span),
677 Some((_, new_span)) => span = new_span,
682 /// Return the pre-expansion span if is this directly comes from an expansion
683 /// of the macro `name`.
684 /// The difference with `is_expn_of` is that in
688 /// `42` is considered expanded from `foo!` and `bar!` by `is_expn_of` but only
690 /// `is_direct_expn_of`.
691 pub fn is_direct_expn_of(span: Span, name: &str) -> Option<Span> {
692 let span_name_span = span
696 .map(|ei| (ei.format.name(), ei.call_site));
698 match span_name_span {
699 Some((mac_name, new_span)) if mac_name == name => Some(new_span),
704 /// Convenience function to get the return type of a function
705 pub fn return_ty<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, fn_item: NodeId) -> Ty<'tcx> {
706 let fn_def_id = cx.tcx.hir().local_def_id(fn_item);
707 let ret_ty = cx.tcx.fn_sig(fn_def_id).output();
708 cx.tcx.erase_late_bound_regions(&ret_ty)
711 /// Check if two types are the same.
713 /// This discards any lifetime annotations, too.
714 // FIXME: this works correctly for lifetimes bounds (`for <'a> Foo<'a>` == `for
716 // not for type parameters.
717 pub fn same_tys<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, a: Ty<'tcx>, b: Ty<'tcx>) -> bool {
718 let a = cx.tcx.erase_late_bound_regions(&Binder::bind(a));
719 let b = cx.tcx.erase_late_bound_regions(&Binder::bind(b));
722 .enter(|infcx| infcx.can_eq(cx.param_env, a, b).is_ok())
725 /// Return whether the given type is an `unsafe` function.
726 pub fn type_is_unsafe_function<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
728 ty::FnDef(..) | ty::FnPtr(_) => ty.fn_sig(cx.tcx).unsafety() == Unsafety::Unsafe,
733 pub fn is_copy<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ty: Ty<'tcx>) -> bool {
734 ty.is_copy_modulo_regions(cx.tcx.global_tcx(), cx.param_env, DUMMY_SP)
737 /// Return whether a pattern is refutable.
738 pub fn is_refutable(cx: &LateContext<'_, '_>, pat: &Pat) -> bool {
739 fn is_enum_variant(cx: &LateContext<'_, '_>, qpath: &QPath, id: HirId) -> bool {
741 cx.tables.qpath_def(qpath, id),
742 def::Def::Variant(..) | def::Def::VariantCtor(..)
746 fn are_refutable<'a, I: Iterator<Item = &'a Pat>>(cx: &LateContext<'_, '_>, mut i: I) -> bool {
747 i.any(|pat| is_refutable(cx, pat))
751 PatKind::Binding(..) | PatKind::Wild => false,
752 PatKind::Box(ref pat) | PatKind::Ref(ref pat, _) => is_refutable(cx, pat),
753 PatKind::Lit(..) | PatKind::Range(..) => true,
754 PatKind::Path(ref qpath) => is_enum_variant(cx, qpath, pat.hir_id),
755 PatKind::Tuple(ref pats, _) => are_refutable(cx, pats.iter().map(|pat| &**pat)),
756 PatKind::Struct(ref qpath, ref fields, _) => {
757 if is_enum_variant(cx, qpath, pat.hir_id) {
760 are_refutable(cx, fields.iter().map(|field| &*field.node.pat))
763 PatKind::TupleStruct(ref qpath, ref pats, _) => {
764 if is_enum_variant(cx, qpath, pat.hir_id) {
767 are_refutable(cx, pats.iter().map(|pat| &**pat))
770 PatKind::Slice(ref head, ref middle, ref tail) => {
771 are_refutable(cx, head.iter().chain(middle).chain(tail.iter()).map(|pat| &**pat))
776 /// Checks for the `#[automatically_derived]` attribute all `#[derive]`d
777 /// implementations have.
778 pub fn is_automatically_derived(attrs: &[ast::Attribute]) -> bool {
779 attr::contains_name(attrs, "automatically_derived")
782 /// Remove blocks around an expression.
784 /// Ie. `x`, `{ x }` and `{{{{ x }}}}` all give `x`. `{ x; y }` and `{}` return
786 pub fn remove_blocks(expr: &Expr) -> &Expr {
787 if let ExprKind::Block(ref block, _) = expr.node {
788 if block.stmts.is_empty() {
789 if let Some(ref expr) = block.expr {
802 pub fn opt_def_id(def: Def) -> Option<DefId> {
806 pub fn is_self(slf: &Arg) -> bool {
807 if let PatKind::Binding(.., name, _) = slf.pat.node {
808 name.name == keywords::SelfLower.name()
814 pub fn is_self_ty(slf: &hir::Ty) -> bool {
816 if let TyKind::Path(ref qp) = slf.node;
817 if let QPath::Resolved(None, ref path) = *qp;
818 if let Def::SelfTy(..) = path.def;
826 pub fn iter_input_pats<'tcx>(decl: &FnDecl, body: &'tcx Body) -> impl Iterator<Item = &'tcx Arg> {
827 (0..decl.inputs.len()).map(move |i| &body.arguments[i])
830 /// Check if a given expression is a match expression
831 /// expanded from `?` operator or `try` macro.
832 pub fn is_try(expr: &Expr) -> Option<&Expr> {
833 fn is_ok(arm: &Arm) -> bool {
835 if let PatKind::TupleStruct(ref path, ref pat, None) = arm.pats[0].node;
836 if match_qpath(path, &paths::RESULT_OK[1..]);
837 if let PatKind::Binding(_, defid, _, _, None) = pat[0].node;
838 if let ExprKind::Path(QPath::Resolved(None, ref path)) = arm.body.node;
839 if let Def::Local(lid) = path.def;
848 fn is_err(arm: &Arm) -> bool {
849 if let PatKind::TupleStruct(ref path, _, _) = arm.pats[0].node {
850 match_qpath(path, &paths::RESULT_ERR[1..])
856 if let ExprKind::Match(_, ref arms, ref source) = expr.node {
857 // desugared from a `?` operator
858 if let MatchSource::TryDesugar = *source {
864 if arms[0].pats.len() == 1 && arms[0].guard.is_none();
865 if arms[1].pats.len() == 1 && arms[1].guard.is_none();
866 if (is_ok(&arms[0]) && is_err(&arms[1])) ||
867 (is_ok(&arms[1]) && is_err(&arms[0]));
877 /// Returns true if the lint is allowed in the current context
879 /// Useful for skipping long running code when it's unnecessary
880 pub fn is_allowed(cx: &LateContext<'_, '_>, lint: &'static Lint, id: HirId) -> bool {
881 let node_id = cx.tcx.hir().hir_to_node_id(id);
882 cx.tcx.lint_level_at_node(lint, node_id).0 == Level::Allow
885 pub fn get_arg_name(pat: &Pat) -> Option<ast::Name> {
887 PatKind::Binding(.., ident, None) => Some(ident.name),
888 PatKind::Ref(ref subpat, _) => get_arg_name(subpat),
893 pub fn int_bits(tcx: TyCtxt<'_, '_, '_>, ity: ast::IntTy) -> u64 {
894 layout::Integer::from_attr(&tcx, attr::IntType::SignedInt(ity))
899 #[allow(clippy::cast_possible_wrap)]
900 /// Turn a constant int byte representation into an i128
901 pub fn sext(tcx: TyCtxt<'_, '_, '_>, u: u128, ity: ast::IntTy) -> i128 {
902 let amt = 128 - int_bits(tcx, ity);
903 ((u as i128) << amt) >> amt
906 #[allow(clippy::cast_sign_loss)]
907 /// clip unused bytes
908 pub fn unsext(tcx: TyCtxt<'_, '_, '_>, u: i128, ity: ast::IntTy) -> u128 {
909 let amt = 128 - int_bits(tcx, ity);
910 ((u as u128) << amt) >> amt
913 /// clip unused bytes
914 pub fn clip(tcx: TyCtxt<'_, '_, '_>, u: u128, ity: ast::UintTy) -> u128 {
915 let bits = layout::Integer::from_attr(&tcx, attr::IntType::UnsignedInt(ity))
918 let amt = 128 - bits;
922 /// Remove block comments from the given Vec of lines
927 /// without_block_comments(vec!["/*", "foo", "*/"]);
930 /// without_block_comments(vec!["bar", "/*", "foo", "*/"]);
931 /// // => vec!["bar"]
933 pub fn without_block_comments(lines: Vec<&str>) -> Vec<&str> {
934 let mut without = vec![];
936 let mut nest_level = 0;
939 if line.contains("/*") {
942 } else if line.contains("*/") {
955 pub fn any_parent_is_automatically_derived(tcx: TyCtxt<'_, '_, '_>, node: HirId) -> bool {
956 let map = &tcx.hir();
957 let mut prev_enclosing_node = None;
958 let mut enclosing_node = node;
959 while Some(enclosing_node) != prev_enclosing_node {
960 if is_automatically_derived(map.attrs_by_hir_id(enclosing_node)) {
963 prev_enclosing_node = Some(enclosing_node);
964 enclosing_node = map.get_parent_item(enclosing_node);
969 /// Returns true if ty has `iter` or `iter_mut` methods
970 pub fn has_iter_method(cx: &LateContext<'_, '_>, probably_ref_ty: ty::Ty<'_>) -> Option<&'static str> {
971 // FIXME: instead of this hard-coded list, we should check if `<adt>::iter`
972 // exists and has the desired signature. Unfortunately FnCtxt is not exported
973 // so we can't use its `lookup_method` method.
974 static INTO_ITER_COLLECTIONS: [&[&str]; 13] = [
990 let ty_to_check = match probably_ref_ty.sty {
991 ty::Ref(_, ty_to_check, _) => ty_to_check,
992 _ => probably_ref_ty,
995 let def_id = match ty_to_check.sty {
996 ty::Array(..) => return Some("array"),
997 ty::Slice(..) => return Some("slice"),
998 ty::Adt(adt, _) => adt.did,
1002 for path in &INTO_ITER_COLLECTIONS {
1003 if match_def_path(cx.tcx, def_id, path) {
1004 return Some(path.last().unwrap());
1012 use super::{trim_multiline, without_block_comments};
1015 fn test_trim_multiline_single_line() {
1016 assert_eq!("", trim_multiline("".into(), false));
1017 assert_eq!("...", trim_multiline("...".into(), false));
1018 assert_eq!("...", trim_multiline(" ...".into(), false));
1019 assert_eq!("...", trim_multiline("\t...".into(), false));
1020 assert_eq!("...", trim_multiline("\t\t...".into(), false));
1025 fn test_trim_multiline_block() {
1031 }", trim_multiline(" if x {
1041 }", trim_multiline(" if x {
1050 fn test_trim_multiline_empty_line() {
1057 }", trim_multiline(" if x {
1066 fn test_without_block_comments_lines_without_block_comments() {
1067 let result = without_block_comments(vec!["/*", "", "*/"]);
1068 println!("result: {:?}", result);
1069 assert!(result.is_empty());
1071 let result = without_block_comments(vec!["", "/*", "", "*/", "#[crate_type = \"lib\"]", "/*", "", "*/", ""]);
1072 assert_eq!(result, vec!["", "#[crate_type = \"lib\"]", ""]);
1074 let result = without_block_comments(vec!["/* rust", "", "*/"]);
1075 assert!(result.is_empty());
1077 let result = without_block_comments(vec!["/* one-line comment */"]);
1078 assert!(result.is_empty());
1080 let result = without_block_comments(vec!["/* nested", "/* multi-line", "comment", "*/", "test", "*/"]);
1081 assert!(result.is_empty());
1083 let result = without_block_comments(vec!["/* nested /* inline /* comment */ test */ */"]);
1084 assert!(result.is_empty());
1086 let result = without_block_comments(vec!["foo", "bar", "baz"]);
1087 assert_eq!(result, vec!["foo", "bar", "baz"]);