4 #[allow(clippy::module_name_repetitions)]
13 pub mod eager_or_lazy;
17 #[cfg(feature = "internal-lints")]
18 pub mod internal_lints;
19 pub mod numeric_literal;
22 pub mod qualify_min_const_fn;
27 pub use self::attrs::*;
28 pub use self::diagnostics::*;
29 pub use self::hir_utils::{both, eq_expr_value, over, SpanlessEq, SpanlessHash};
32 use std::collections::hash_map::Entry;
33 use std::hash::BuildHasherDefault;
36 use if_chain::if_chain;
37 use rustc_ast::ast::{self, Attribute, LitKind};
38 use rustc_attr as attr;
39 use rustc_data_structures::fx::FxHashMap;
40 use rustc_errors::Applicability;
42 use rustc_hir::def::{DefKind, Res};
43 use rustc_hir::def_id::{DefId, CRATE_DEF_INDEX, LOCAL_CRATE};
44 use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor};
47 def, Arm, Block, Body, Constness, Crate, Expr, ExprKind, FnDecl, HirId, ImplItem, ImplItemKind, Item, ItemKind,
48 MatchSource, Param, Pat, PatKind, Path, PathSegment, QPath, TraitItem, TraitItemKind, TraitRef, TyKind, Unsafety,
50 use rustc_infer::infer::TyCtxtInferExt;
51 use rustc_lint::{LateContext, Level, Lint, LintContext};
52 use rustc_middle::hir::map::Map;
53 use rustc_middle::ty::subst::{GenericArg, GenericArgKind};
54 use rustc_middle::ty::{self, layout::IntegerExt, Ty, TyCtxt, TypeFoldable};
55 use rustc_semver::RustcVersion;
56 use rustc_session::Session;
57 use rustc_span::hygiene::{ExpnKind, MacroKind};
58 use rustc_span::source_map::original_sp;
60 use rustc_span::symbol::{kw, Symbol};
61 use rustc_span::{BytePos, Pos, Span, DUMMY_SP};
62 use rustc_target::abi::Integer;
63 use rustc_trait_selection::traits::query::normalize::AtExt;
64 use smallvec::SmallVec;
66 use crate::consts::{constant, Constant};
68 pub fn parse_msrv(msrv: &str, sess: Option<&Session>, span: Option<Span>) -> Option<RustcVersion> {
69 if let Ok(version) = RustcVersion::parse(msrv) {
71 } else if let Some(sess) = sess {
72 if let Some(span) = span {
73 sess.span_err(span, &format!("`{}` is not a valid Rust version", msrv));
79 pub fn meets_msrv(msrv: Option<&RustcVersion>, lint_msrv: &RustcVersion) -> bool {
80 msrv.map_or(true, |msrv| msrv.meets(*lint_msrv))
83 macro_rules! extract_msrv_attr {
85 extract_msrv_attr!(@LateContext, ());
88 extract_msrv_attr!(@EarlyContext);
90 (@$context:ident$(, $call:tt)?) => {
91 fn enter_lint_attrs(&mut self, cx: &rustc_lint::$context<'tcx>, attrs: &'tcx [rustc_ast::ast::Attribute]) {
92 use $crate::utils::get_unique_inner_attr;
93 match get_unique_inner_attr(cx.sess$($call)?, attrs, "msrv") {
95 if let Some(msrv) = msrv_attr.value_str() {
96 self.msrv = $crate::utils::parse_msrv(
98 Some(cx.sess$($call)?),
102 cx.sess$($call)?.span_err(msrv_attr.span, "bad clippy attribute");
111 /// Returns `true` if the two spans come from differing expansions (i.e., one is
112 /// from a macro and one isn't).
114 pub fn differing_macro_contexts(lhs: Span, rhs: Span) -> bool {
115 rhs.ctxt() != lhs.ctxt()
118 /// Returns `true` if the given `NodeId` is inside a constant context
123 /// if in_constant(cx, expr.hir_id) {
127 pub fn in_constant(cx: &LateContext<'_>, id: HirId) -> bool {
128 let parent_id = cx.tcx.hir().get_parent_item(id);
129 match cx.tcx.hir().get(parent_id) {
131 kind: ItemKind::Const(..) | ItemKind::Static(..),
134 | Node::TraitItem(&TraitItem {
135 kind: TraitItemKind::Const(..),
138 | Node::ImplItem(&ImplItem {
139 kind: ImplItemKind::Const(..),
142 | Node::AnonConst(_) => true,
144 kind: ItemKind::Fn(ref sig, ..),
147 | Node::ImplItem(&ImplItem {
148 kind: ImplItemKind::Fn(ref sig, _),
150 }) => sig.header.constness == Constness::Const,
155 /// Returns `true` if this `span` was expanded by any macro.
157 pub fn in_macro(span: Span) -> bool {
158 if span.from_expansion() {
159 !matches!(span.ctxt().outer_expn_data().kind, ExpnKind::Desugaring(..))
165 // If the snippet is empty, it's an attribute that was inserted during macro
166 // expansion and we want to ignore those, because they could come from external
167 // sources that the user has no control over.
168 // For some reason these attributes don't have any expansion info on them, so
169 // we have to check it this way until there is a better way.
170 pub fn is_present_in_source<T: LintContext>(cx: &T, span: Span) -> bool {
171 if let Some(snippet) = snippet_opt(cx, span) {
172 if snippet.is_empty() {
179 /// Checks if given pattern is a wildcard (`_`)
180 pub fn is_wild<'tcx>(pat: &impl std::ops::Deref<Target = Pat<'tcx>>) -> bool {
181 matches!(pat.kind, PatKind::Wild)
184 /// Checks if type is struct, enum or union type with the given def path.
186 /// If the type is a diagnostic item, use `is_type_diagnostic_item` instead.
187 /// If you change the signature, remember to update the internal lint `MatchTypeOnDiagItem`
188 pub fn match_type(cx: &LateContext<'_>, ty: Ty<'_>, path: &[&str]) -> bool {
190 ty::Adt(adt, _) => match_def_path(cx, adt.did, path),
195 /// Checks if the type is equal to a diagnostic item
197 /// If you change the signature, remember to update the internal lint `MatchTypeOnDiagItem`
198 pub fn is_type_diagnostic_item(cx: &LateContext<'_>, ty: Ty<'_>, diag_item: Symbol) -> bool {
200 ty::Adt(adt, _) => cx.tcx.is_diagnostic_item(diag_item, adt.did),
205 /// Checks if the type is equal to a lang item
206 pub fn is_type_lang_item(cx: &LateContext<'_>, ty: Ty<'_>, lang_item: hir::LangItem) -> bool {
208 ty::Adt(adt, _) => cx.tcx.lang_items().require(lang_item).unwrap() == adt.did,
213 /// Checks if the method call given in `expr` belongs to the given trait.
214 pub fn match_trait_method(cx: &LateContext<'_>, expr: &Expr<'_>, path: &[&str]) -> bool {
215 let def_id = cx.typeck_results().type_dependent_def_id(expr.hir_id).unwrap();
216 let trt_id = cx.tcx.trait_of_item(def_id);
217 trt_id.map_or(false, |trt_id| match_def_path(cx, trt_id, path))
220 /// Checks if an expression references a variable of the given name.
221 pub fn match_var(expr: &Expr<'_>, var: Symbol) -> bool {
222 if let ExprKind::Path(QPath::Resolved(None, ref path)) = expr.kind {
223 if let [p] = path.segments {
224 return p.ident.name == var;
230 pub fn last_path_segment<'tcx>(path: &QPath<'tcx>) -> &'tcx PathSegment<'tcx> {
232 QPath::Resolved(_, ref path) => path.segments.last().expect("A path must have at least one segment"),
233 QPath::TypeRelative(_, ref seg) => seg,
234 QPath::LangItem(..) => panic!("last_path_segment: lang item has no path segments"),
238 pub fn single_segment_path<'tcx>(path: &QPath<'tcx>) -> Option<&'tcx PathSegment<'tcx>> {
240 QPath::Resolved(_, ref path) => path.segments.get(0),
241 QPath::TypeRelative(_, ref seg) => Some(seg),
242 QPath::LangItem(..) => None,
246 /// Matches a `QPath` against a slice of segment string literals.
248 /// There is also `match_path` if you are dealing with a `rustc_hir::Path` instead of a
249 /// `rustc_hir::QPath`.
253 /// match_qpath(path, &["std", "rt", "begin_unwind"])
255 pub fn match_qpath(path: &QPath<'_>, segments: &[&str]) -> bool {
257 QPath::Resolved(_, ref path) => match_path(path, segments),
258 QPath::TypeRelative(ref ty, ref segment) => match ty.kind {
259 TyKind::Path(ref inner_path) => {
260 if let [prefix @ .., end] = segments {
261 if match_qpath(inner_path, prefix) {
262 return segment.ident.name.as_str() == *end;
269 QPath::LangItem(..) => false,
273 /// Matches a `Path` against a slice of segment string literals.
275 /// There is also `match_qpath` if you are dealing with a `rustc_hir::QPath` instead of a
276 /// `rustc_hir::Path`.
281 /// if match_path(&trait_ref.path, &paths::HASH) {
282 /// // This is the `std::hash::Hash` trait.
285 /// if match_path(ty_path, &["rustc", "lint", "Lint"]) {
286 /// // This is a `rustc_middle::lint::Lint`.
289 pub fn match_path(path: &Path<'_>, segments: &[&str]) -> bool {
293 .zip(segments.iter().rev())
294 .all(|(a, b)| a.ident.name.as_str() == *b)
297 /// Matches a `Path` against a slice of segment string literals, e.g.
301 /// match_path_ast(path, &["std", "rt", "begin_unwind"])
303 pub fn match_path_ast(path: &ast::Path, segments: &[&str]) -> bool {
307 .zip(segments.iter().rev())
308 .all(|(a, b)| a.ident.name.as_str() == *b)
311 /// Gets the definition associated to a path.
312 pub fn path_to_res(cx: &LateContext<'_>, path: &[&str]) -> Option<def::Res> {
313 let crates = cx.tcx.crates();
316 .find(|&&krate| cx.tcx.crate_name(krate).as_str() == path[0]);
317 if let Some(krate) = krate {
320 index: CRATE_DEF_INDEX,
322 let mut current_item = None;
323 let mut items = cx.tcx.item_children(krate);
324 let mut path_it = path.iter().skip(1).peekable();
327 let segment = match path_it.next() {
328 Some(segment) => segment,
332 // `get_def_path` seems to generate these empty segments for extern blocks.
333 // We can just ignore them.
334 if segment.is_empty() {
338 let result = SmallVec::<[_; 8]>::new();
339 for item in mem::replace(&mut items, cx.tcx.arena.alloc_slice(&result)).iter() {
340 if item.ident.name.as_str() == *segment {
341 if path_it.peek().is_none() {
342 return Some(item.res);
345 current_item = Some(item);
346 items = cx.tcx.item_children(item.res.def_id());
351 // The segment isn't a child_item.
352 // Try to find it under an inherent impl.
354 if path_it.peek().is_none();
355 if let Some(current_item) = current_item;
356 let item_def_id = current_item.res.def_id();
357 if cx.tcx.def_kind(item_def_id) == DefKind::Struct;
359 // Bad `find_map` suggestion. See #4193.
360 #[allow(clippy::find_map)]
361 return cx.tcx.inherent_impls(item_def_id).iter()
362 .flat_map(|&impl_def_id| cx.tcx.item_children(impl_def_id))
363 .find(|item| item.ident.name.as_str() == *segment)
364 .map(|item| item.res);
373 /// Convenience function to get the `DefId` of a trait by path.
374 /// It could be a trait or trait alias.
375 pub fn get_trait_def_id(cx: &LateContext<'_>, path: &[&str]) -> Option<DefId> {
376 let res = match path_to_res(cx, path) {
382 Res::Def(DefKind::Trait | DefKind::TraitAlias, trait_id) => Some(trait_id),
383 Res::Err => unreachable!("this trait resolution is impossible: {:?}", &path),
388 /// Checks whether a type implements a trait.
389 /// See also `get_trait_def_id`.
390 pub fn implements_trait<'tcx>(
391 cx: &LateContext<'tcx>,
394 ty_params: &[GenericArg<'tcx>],
396 // Do not check on infer_types to avoid panic in evaluate_obligation.
397 if ty.has_infer_types() {
400 let ty = cx.tcx.erase_regions(ty);
401 if ty.has_escaping_bound_vars() {
404 let ty_params = cx.tcx.mk_substs(ty_params.iter());
405 cx.tcx.type_implements_trait((trait_id, ty, ty_params, cx.param_env))
408 /// Gets the `hir::TraitRef` of the trait the given method is implemented for.
410 /// Use this if you want to find the `TraitRef` of the `Add` trait in this example:
413 /// struct Point(isize, isize);
415 /// impl std::ops::Add for Point {
416 /// type Output = Self;
418 /// fn add(self, other: Self) -> Self {
423 pub fn trait_ref_of_method<'tcx>(cx: &LateContext<'tcx>, hir_id: HirId) -> Option<&'tcx TraitRef<'tcx>> {
424 // Get the implemented trait for the current function
425 let parent_impl = cx.tcx.hir().get_parent_item(hir_id);
427 if parent_impl != hir::CRATE_HIR_ID;
428 if let hir::Node::Item(item) = cx.tcx.hir().get(parent_impl);
429 if let hir::ItemKind::Impl(impl_) = &item.kind;
430 then { return impl_.of_trait.as_ref(); }
435 /// Checks whether this type implements `Drop`.
436 pub fn has_drop<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
437 match ty.ty_adt_def() {
438 Some(def) => def.has_dtor(cx.tcx),
443 /// Returns the method names and argument list of nested method call expressions that make up
444 /// `expr`. method/span lists are sorted with the most recent call first.
445 pub fn method_calls<'tcx>(
446 expr: &'tcx Expr<'tcx>,
448 ) -> (Vec<Symbol>, Vec<&'tcx [Expr<'tcx>]>, Vec<Span>) {
449 let mut method_names = Vec::with_capacity(max_depth);
450 let mut arg_lists = Vec::with_capacity(max_depth);
451 let mut spans = Vec::with_capacity(max_depth);
453 let mut current = expr;
454 for _ in 0..max_depth {
455 if let ExprKind::MethodCall(path, span, args, _) = ¤t.kind {
456 if args.iter().any(|e| e.span.from_expansion()) {
459 method_names.push(path.ident.name);
460 arg_lists.push(&**args);
468 (method_names, arg_lists, spans)
471 /// Matches an `Expr` against a chain of methods, and return the matched `Expr`s.
473 /// For example, if `expr` represents the `.baz()` in `foo.bar().baz()`,
474 /// `method_chain_args(expr, &["bar", "baz"])` will return a `Vec`
475 /// containing the `Expr`s for
476 /// `.bar()` and `.baz()`
477 pub fn method_chain_args<'a>(expr: &'a Expr<'_>, methods: &[&str]) -> Option<Vec<&'a [Expr<'a>]>> {
478 let mut current = expr;
479 let mut matched = Vec::with_capacity(methods.len());
480 for method_name in methods.iter().rev() {
481 // method chains are stored last -> first
482 if let ExprKind::MethodCall(ref path, _, ref args, _) = current.kind {
483 if path.ident.name.as_str() == *method_name {
484 if args.iter().any(|e| e.span.from_expansion()) {
487 matched.push(&**args); // build up `matched` backwards
488 current = &args[0] // go to parent expression
496 // Reverse `matched` so that it is in the same order as `methods`.
501 /// Returns `true` if the provided `def_id` is an entrypoint to a program.
502 pub fn is_entrypoint_fn(cx: &LateContext<'_>, def_id: DefId) -> bool {
504 .entry_fn(LOCAL_CRATE)
505 .map_or(false, |(entry_fn_def_id, _)| def_id == entry_fn_def_id.to_def_id())
508 /// Returns `true` if the expression is in the program's `#[panic_handler]`.
509 pub fn is_in_panic_handler(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
510 let parent = cx.tcx.hir().get_parent_item(e.hir_id);
511 let def_id = cx.tcx.hir().local_def_id(parent).to_def_id();
512 Some(def_id) == cx.tcx.lang_items().panic_impl()
515 /// Gets the name of the item the expression is in, if available.
516 pub fn get_item_name(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<Symbol> {
517 let parent_id = cx.tcx.hir().get_parent_item(expr.hir_id);
518 match cx.tcx.hir().find(parent_id) {
520 Node::Item(Item { ident, .. })
521 | Node::TraitItem(TraitItem { ident, .. })
522 | Node::ImplItem(ImplItem { ident, .. }),
523 ) => Some(ident.name),
528 /// Gets the name of a `Pat`, if any.
529 pub fn get_pat_name(pat: &Pat<'_>) -> Option<Symbol> {
531 PatKind::Binding(.., ref spname, _) => Some(spname.name),
532 PatKind::Path(ref qpath) => single_segment_path(qpath).map(|ps| ps.ident.name),
533 PatKind::Box(ref p) | PatKind::Ref(ref p, _) => get_pat_name(&*p),
538 struct ContainsName {
543 impl<'tcx> Visitor<'tcx> for ContainsName {
544 type Map = Map<'tcx>;
546 fn visit_name(&mut self, _: Span, name: Symbol) {
547 if self.name == name {
551 fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
552 NestedVisitorMap::None
556 /// Checks if an `Expr` contains a certain name.
557 pub fn contains_name(name: Symbol, expr: &Expr<'_>) -> bool {
558 let mut cn = ContainsName { name, result: false };
563 /// Returns `true` if `expr` contains a return expression
564 pub fn contains_return(expr: &hir::Expr<'_>) -> bool {
565 struct RetCallFinder {
569 impl<'tcx> hir::intravisit::Visitor<'tcx> for RetCallFinder {
570 type Map = Map<'tcx>;
572 fn visit_expr(&mut self, expr: &'tcx hir::Expr<'_>) {
576 if let hir::ExprKind::Ret(..) = &expr.kind {
579 hir::intravisit::walk_expr(self, expr);
583 fn nested_visit_map(&mut self) -> hir::intravisit::NestedVisitorMap<Self::Map> {
584 hir::intravisit::NestedVisitorMap::None
588 let mut visitor = RetCallFinder { found: false };
589 visitor.visit_expr(expr);
593 struct FindMacroCalls<'a, 'b> {
594 names: &'a [&'b str],
598 impl<'a, 'b, 'tcx> Visitor<'tcx> for FindMacroCalls<'a, 'b> {
599 type Map = Map<'tcx>;
601 fn visit_expr(&mut self, expr: &'tcx Expr<'_>) {
602 if self.names.iter().any(|fun| is_expn_of(expr.span, fun).is_some()) {
603 self.result.push(expr.span);
605 // and check sub-expressions
606 intravisit::walk_expr(self, expr);
609 fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
610 NestedVisitorMap::None
614 /// Finds calls of the specified macros in a function body.
615 pub fn find_macro_calls(names: &[&str], body: &Body<'_>) -> Vec<Span> {
616 let mut fmc = FindMacroCalls {
620 fmc.visit_expr(&body.value);
624 /// Converts a span to a code snippet if available, otherwise use default.
626 /// This is useful if you want to provide suggestions for your lint or more generally, if you want
627 /// to convert a given `Span` to a `str`.
631 /// snippet(cx, expr.span, "..")
633 pub fn snippet<'a, T: LintContext>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
634 snippet_opt(cx, span).map_or_else(|| Cow::Borrowed(default), From::from)
637 /// Same as `snippet`, but it adapts the applicability level by following rules:
639 /// - Applicability level `Unspecified` will never be changed.
640 /// - If the span is inside a macro, change the applicability level to `MaybeIncorrect`.
641 /// - If the default value is used and the applicability level is `MachineApplicable`, change it to
642 /// `HasPlaceholders`
643 pub fn snippet_with_applicability<'a, T: LintContext>(
647 applicability: &mut Applicability,
649 if *applicability != Applicability::Unspecified && span.from_expansion() {
650 *applicability = Applicability::MaybeIncorrect;
652 snippet_opt(cx, span).map_or_else(
654 if *applicability == Applicability::MachineApplicable {
655 *applicability = Applicability::HasPlaceholders;
657 Cow::Borrowed(default)
663 /// Same as `snippet`, but should only be used when it's clear that the input span is
664 /// not a macro argument.
665 pub fn snippet_with_macro_callsite<'a, T: LintContext>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
666 snippet(cx, span.source_callsite(), default)
669 /// Converts a span to a code snippet. Returns `None` if not available.
670 pub fn snippet_opt<T: LintContext>(cx: &T, span: Span) -> Option<String> {
671 cx.sess().source_map().span_to_snippet(span).ok()
674 /// Converts a span (from a block) to a code snippet if available, otherwise use default.
676 /// This trims the code of indentation, except for the first line. Use it for blocks or block-like
677 /// things which need to be printed as such.
679 /// The `indent_relative_to` arg can be used, to provide a span, where the indentation of the
680 /// resulting snippet of the given span.
685 /// snippet_block(cx, block.span, "..", None)
686 /// // where, `block` is the block of the if expr
690 /// // will return the snippet
697 /// snippet_block(cx, block.span, "..", Some(if_expr.span))
698 /// // where, `block` is the block of the if expr
702 /// // will return the snippet
705 /// } // aligned with `if`
707 /// Note that the first line of the snippet always has 0 indentation.
708 pub fn snippet_block<'a, T: LintContext>(
712 indent_relative_to: Option<Span>,
714 let snip = snippet(cx, span, default);
715 let indent = indent_relative_to.and_then(|s| indent_of(cx, s));
716 reindent_multiline(snip, true, indent)
719 /// Same as `snippet_block`, but adapts the applicability level by the rules of
720 /// `snippet_with_applicability`.
721 pub fn snippet_block_with_applicability<'a, T: LintContext>(
725 indent_relative_to: Option<Span>,
726 applicability: &mut Applicability,
728 let snip = snippet_with_applicability(cx, span, default, applicability);
729 let indent = indent_relative_to.and_then(|s| indent_of(cx, s));
730 reindent_multiline(snip, true, indent)
733 /// Returns a new Span that extends the original Span to the first non-whitespace char of the first
739 /// // will be converted to
743 pub fn first_line_of_span<T: LintContext>(cx: &T, span: Span) -> Span {
744 first_char_in_first_line(cx, span).map_or(span, |first_char_pos| span.with_lo(first_char_pos))
747 fn first_char_in_first_line<T: LintContext>(cx: &T, span: Span) -> Option<BytePos> {
748 let line_span = line_span(cx, span);
749 snippet_opt(cx, line_span).and_then(|snip| {
750 snip.find(|c: char| !c.is_whitespace())
751 .map(|pos| line_span.lo() + BytePos::from_usize(pos))
755 /// Returns the indentation of the line of a span
759 /// // ^^ -- will return 0
761 /// // ^^ -- will return 4
763 pub fn indent_of<T: LintContext>(cx: &T, span: Span) -> Option<usize> {
764 snippet_opt(cx, line_span(cx, span)).and_then(|snip| snip.find(|c: char| !c.is_whitespace()))
767 /// Returns the positon just before rarrow
770 /// fn into(self) -> () {}
772 /// // in case of unformatted code
773 /// fn into2(self)-> () {}
775 /// fn into3(self) -> () {}
778 pub fn position_before_rarrow(s: &str) -> Option<usize> {
779 s.rfind("->").map(|rpos| {
781 let chars: Vec<char> = s.chars().collect();
783 if let Some(c) = chars.get(rpos - 1) {
784 if c.is_whitespace() {
795 /// Extends the span to the beginning of the spans line, incl. whitespaces.
800 /// // will be converted to
802 /// // ^^^^^^^^^^^^^^
804 fn line_span<T: LintContext>(cx: &T, span: Span) -> Span {
805 let span = original_sp(span, DUMMY_SP);
806 let source_map_and_line = cx.sess().source_map().lookup_line(span.lo()).unwrap();
807 let line_no = source_map_and_line.line;
808 let line_start = source_map_and_line.sf.lines[line_no];
809 Span::new(line_start, span.hi(), span.ctxt())
812 /// Like `snippet_block`, but add braces if the expr is not an `ExprKind::Block`.
813 /// Also takes an `Option<String>` which can be put inside the braces.
814 pub fn expr_block<'a, T: LintContext>(
817 option: Option<String>,
819 indent_relative_to: Option<Span>,
821 let code = snippet_block(cx, expr.span, default, indent_relative_to);
822 let string = option.unwrap_or_default();
823 if expr.span.from_expansion() {
824 Cow::Owned(format!("{{ {} }}", snippet_with_macro_callsite(cx, expr.span, default)))
825 } else if let ExprKind::Block(_, _) = expr.kind {
826 Cow::Owned(format!("{}{}", code, string))
827 } else if string.is_empty() {
828 Cow::Owned(format!("{{ {} }}", code))
830 Cow::Owned(format!("{{\n{};\n{}\n}}", code, string))
834 /// Reindent a multiline string with possibility of ignoring the first line.
835 #[allow(clippy::needless_pass_by_value)]
836 pub fn reindent_multiline(s: Cow<'_, str>, ignore_first: bool, indent: Option<usize>) -> Cow<'_, str> {
837 let s_space = reindent_multiline_inner(&s, ignore_first, indent, ' ');
838 let s_tab = reindent_multiline_inner(&s_space, ignore_first, indent, '\t');
839 reindent_multiline_inner(&s_tab, ignore_first, indent, ' ').into()
842 fn reindent_multiline_inner(s: &str, ignore_first: bool, indent: Option<usize>, ch: char) -> String {
845 .skip(ignore_first as usize)
850 // ignore empty lines
851 Some(l.char_indices().find(|&(_, x)| x != ch).unwrap_or((l.len(), ch)).0)
856 let indent = indent.unwrap_or(0);
860 if (ignore_first && i == 0) || l.is_empty() {
862 } else if x > indent {
863 l.split_at(x - indent).1.to_owned()
865 " ".repeat(indent - x) + l
868 .collect::<Vec<String>>()
872 /// Gets the parent expression, if any –- this is useful to constrain a lint.
873 pub fn get_parent_expr<'tcx>(cx: &LateContext<'tcx>, e: &Expr<'_>) -> Option<&'tcx Expr<'tcx>> {
874 let map = &cx.tcx.hir();
875 let hir_id = e.hir_id;
876 let parent_id = map.get_parent_node(hir_id);
877 if hir_id == parent_id {
880 map.find(parent_id).and_then(|node| {
881 if let Node::Expr(parent) = node {
889 pub fn get_enclosing_block<'tcx>(cx: &LateContext<'tcx>, hir_id: HirId) -> Option<&'tcx Block<'tcx>> {
890 let map = &cx.tcx.hir();
891 let enclosing_node = map
892 .get_enclosing_scope(hir_id)
893 .and_then(|enclosing_id| map.find(enclosing_id));
894 enclosing_node.and_then(|node| match node {
895 Node::Block(block) => Some(block),
897 kind: ItemKind::Fn(_, _, eid),
900 | Node::ImplItem(&ImplItem {
901 kind: ImplItemKind::Fn(_, eid),
903 }) => match cx.tcx.hir().body(eid).value.kind {
904 ExprKind::Block(ref block, _) => Some(block),
911 /// Returns the base type for HIR references and pointers.
912 pub fn walk_ptrs_hir_ty<'tcx>(ty: &'tcx hir::Ty<'tcx>) -> &'tcx hir::Ty<'tcx> {
914 TyKind::Ptr(ref mut_ty) | TyKind::Rptr(_, ref mut_ty) => walk_ptrs_hir_ty(&mut_ty.ty),
919 /// Returns the base type for references and raw pointers, and count reference
921 pub fn walk_ptrs_ty_depth(ty: Ty<'_>) -> (Ty<'_>, usize) {
922 fn inner(ty: Ty<'_>, depth: usize) -> (Ty<'_>, usize) {
924 ty::Ref(_, ty, _) => inner(ty, depth + 1),
931 /// Checks whether the given expression is a constant integer of the given value.
932 /// unlike `is_integer_literal`, this version does const folding
933 pub fn is_integer_const(cx: &LateContext<'_>, e: &Expr<'_>, value: u128) -> bool {
934 if is_integer_literal(e, value) {
937 let map = cx.tcx.hir();
938 let parent_item = map.get_parent_item(e.hir_id);
939 if let Some((Constant::Int(v), _)) = map
940 .maybe_body_owned_by(parent_item)
941 .and_then(|body_id| constant(cx, cx.tcx.typeck_body(body_id), e))
949 /// Checks whether the given expression is a constant literal of the given value.
950 pub fn is_integer_literal(expr: &Expr<'_>, value: u128) -> bool {
951 // FIXME: use constant folding
952 if let ExprKind::Lit(ref spanned) = expr.kind {
953 if let LitKind::Int(v, _) = spanned.node {
960 /// Returns `true` if the given `Expr` has been coerced before.
962 /// Examples of coercions can be found in the Nomicon at
963 /// <https://doc.rust-lang.org/nomicon/coercions.html>.
965 /// See `rustc_middle::ty::adjustment::Adjustment` and `rustc_typeck::check::coercion` for more
966 /// information on adjustments and coercions.
967 pub fn is_adjusted(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
968 cx.typeck_results().adjustments().get(e.hir_id).is_some()
971 /// Returns the pre-expansion span if is this comes from an expansion of the
973 /// See also `is_direct_expn_of`.
975 pub fn is_expn_of(mut span: Span, name: &str) -> Option<Span> {
977 if span.from_expansion() {
978 let data = span.ctxt().outer_expn_data();
979 let new_span = data.call_site;
981 if let ExpnKind::Macro(MacroKind::Bang, mac_name) = data.kind {
982 if mac_name.as_str() == name {
983 return Some(new_span);
994 /// Returns the pre-expansion span if the span directly comes from an expansion
995 /// of the macro `name`.
996 /// The difference with `is_expn_of` is that in
1000 /// `42` is considered expanded from `foo!` and `bar!` by `is_expn_of` but only
1002 /// `is_direct_expn_of`.
1004 pub fn is_direct_expn_of(span: Span, name: &str) -> Option<Span> {
1005 if span.from_expansion() {
1006 let data = span.ctxt().outer_expn_data();
1007 let new_span = data.call_site;
1009 if let ExpnKind::Macro(MacroKind::Bang, mac_name) = data.kind {
1010 if mac_name.as_str() == name {
1011 return Some(new_span);
1019 /// Convenience function to get the return type of a function.
1020 pub fn return_ty<'tcx>(cx: &LateContext<'tcx>, fn_item: hir::HirId) -> Ty<'tcx> {
1021 let fn_def_id = cx.tcx.hir().local_def_id(fn_item);
1022 let ret_ty = cx.tcx.fn_sig(fn_def_id).output();
1023 cx.tcx.erase_late_bound_regions(ret_ty)
1026 /// Walks into `ty` and returns `true` if any inner type is the same as `other_ty`
1027 pub fn contains_ty(ty: Ty<'_>, other_ty: Ty<'_>) -> bool {
1028 ty.walk().any(|inner| match inner.unpack() {
1029 GenericArgKind::Type(inner_ty) => ty::TyS::same_type(other_ty, inner_ty),
1030 GenericArgKind::Lifetime(_) | GenericArgKind::Const(_) => false,
1034 /// Returns `true` if the given type is an `unsafe` function.
1035 pub fn type_is_unsafe_function<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
1037 ty::FnDef(..) | ty::FnPtr(_) => ty.fn_sig(cx.tcx).unsafety() == Unsafety::Unsafe,
1042 pub fn is_copy<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
1043 ty.is_copy_modulo_regions(cx.tcx.at(DUMMY_SP), cx.param_env)
1046 /// Checks if an expression is constructing a tuple-like enum variant or struct
1047 pub fn is_ctor_or_promotable_const_function(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
1048 if let ExprKind::Call(ref fun, _) = expr.kind {
1049 if let ExprKind::Path(ref qp) = fun.kind {
1050 let res = cx.qpath_res(qp, fun.hir_id);
1052 def::Res::Def(DefKind::Variant | DefKind::Ctor(..), ..) => true,
1053 def::Res::Def(_, def_id) => cx.tcx.is_promotable_const_fn(def_id),
1061 /// Returns `true` if a pattern is refutable.
1062 // TODO: should be implemented using rustc/mir_build/thir machinery
1063 pub fn is_refutable(cx: &LateContext<'_>, pat: &Pat<'_>) -> bool {
1064 fn is_enum_variant(cx: &LateContext<'_>, qpath: &QPath<'_>, id: HirId) -> bool {
1066 cx.qpath_res(qpath, id),
1067 def::Res::Def(DefKind::Variant, ..) | Res::Def(DefKind::Ctor(def::CtorOf::Variant, _), _)
1071 fn are_refutable<'a, I: Iterator<Item = &'a Pat<'a>>>(cx: &LateContext<'_>, mut i: I) -> bool {
1072 i.any(|pat| is_refutable(cx, pat))
1076 PatKind::Wild => false,
1077 PatKind::Binding(_, _, _, pat) => pat.map_or(false, |pat| is_refutable(cx, pat)),
1078 PatKind::Box(ref pat) | PatKind::Ref(ref pat, _) => is_refutable(cx, pat),
1079 PatKind::Lit(..) | PatKind::Range(..) => true,
1080 PatKind::Path(ref qpath) => is_enum_variant(cx, qpath, pat.hir_id),
1081 PatKind::Or(ref pats) => {
1082 // TODO: should be the honest check, that pats is exhaustive set
1083 are_refutable(cx, pats.iter().map(|pat| &**pat))
1085 PatKind::Tuple(ref pats, _) => are_refutable(cx, pats.iter().map(|pat| &**pat)),
1086 PatKind::Struct(ref qpath, ref fields, _) => {
1087 is_enum_variant(cx, qpath, pat.hir_id) || are_refutable(cx, fields.iter().map(|field| &*field.pat))
1089 PatKind::TupleStruct(ref qpath, ref pats, _) => {
1090 is_enum_variant(cx, qpath, pat.hir_id) || are_refutable(cx, pats.iter().map(|pat| &**pat))
1092 PatKind::Slice(ref head, ref middle, ref tail) => {
1093 match &cx.typeck_results().node_type(pat.hir_id).kind() {
1095 // [..] is the only irrefutable slice pattern.
1096 !head.is_empty() || middle.is_none() || !tail.is_empty()
1098 ty::Array(..) => are_refutable(cx, head.iter().chain(middle).chain(tail.iter()).map(|pat| &**pat)),
1108 /// Checks for the `#[automatically_derived]` attribute all `#[derive]`d
1109 /// implementations have.
1110 pub fn is_automatically_derived(attrs: &[ast::Attribute]) -> bool {
1111 attrs.iter().any(|attr| attr.has_name(sym::automatically_derived))
1114 /// Remove blocks around an expression.
1116 /// Ie. `x`, `{ x }` and `{{{{ x }}}}` all give `x`. `{ x; y }` and `{}` return
1118 pub fn remove_blocks<'tcx>(mut expr: &'tcx Expr<'tcx>) -> &'tcx Expr<'tcx> {
1119 while let ExprKind::Block(ref block, ..) = expr.kind {
1120 match (block.stmts.is_empty(), block.expr.as_ref()) {
1121 (true, Some(e)) => expr = e,
1128 pub fn is_self(slf: &Param<'_>) -> bool {
1129 if let PatKind::Binding(.., name, _) = slf.pat.kind {
1130 name.name == kw::SelfLower
1136 pub fn is_self_ty(slf: &hir::Ty<'_>) -> bool {
1138 if let TyKind::Path(ref qp) = slf.kind;
1139 if let QPath::Resolved(None, ref path) = *qp;
1140 if let Res::SelfTy(..) = path.res;
1148 pub fn iter_input_pats<'tcx>(decl: &FnDecl<'_>, body: &'tcx Body<'_>) -> impl Iterator<Item = &'tcx Param<'tcx>> {
1149 (0..decl.inputs.len()).map(move |i| &body.params[i])
1152 /// Checks if a given expression is a match expression expanded from the `?`
1153 /// operator or the `try` macro.
1154 pub fn is_try<'tcx>(expr: &'tcx Expr<'tcx>) -> Option<&'tcx Expr<'tcx>> {
1155 fn is_ok(arm: &Arm<'_>) -> bool {
1157 if let PatKind::TupleStruct(ref path, ref pat, None) = arm.pat.kind;
1158 if match_qpath(path, &paths::RESULT_OK[1..]);
1159 if let PatKind::Binding(_, hir_id, _, None) = pat[0].kind;
1160 if let ExprKind::Path(QPath::Resolved(None, ref path)) = arm.body.kind;
1161 if let Res::Local(lid) = path.res;
1170 fn is_err(arm: &Arm<'_>) -> bool {
1171 if let PatKind::TupleStruct(ref path, _, _) = arm.pat.kind {
1172 match_qpath(path, &paths::RESULT_ERR[1..])
1178 if let ExprKind::Match(_, ref arms, ref source) = expr.kind {
1179 // desugared from a `?` operator
1180 if let MatchSource::TryDesugar = *source {
1186 if arms[0].guard.is_none();
1187 if arms[1].guard.is_none();
1188 if (is_ok(&arms[0]) && is_err(&arms[1])) ||
1189 (is_ok(&arms[1]) && is_err(&arms[0]));
1199 /// Returns `true` if the lint is allowed in the current context
1201 /// Useful for skipping long running code when it's unnecessary
1202 pub fn is_allowed(cx: &LateContext<'_>, lint: &'static Lint, id: HirId) -> bool {
1203 cx.tcx.lint_level_at_node(lint, id).0 == Level::Allow
1206 pub fn get_arg_name(pat: &Pat<'_>) -> Option<Symbol> {
1208 PatKind::Binding(.., ident, None) => Some(ident.name),
1209 PatKind::Ref(ref subpat, _) => get_arg_name(subpat),
1214 pub fn int_bits(tcx: TyCtxt<'_>, ity: ast::IntTy) -> u64 {
1215 Integer::from_attr(&tcx, attr::IntType::SignedInt(ity)).size().bits()
1218 #[allow(clippy::cast_possible_wrap)]
1219 /// Turn a constant int byte representation into an i128
1220 pub fn sext(tcx: TyCtxt<'_>, u: u128, ity: ast::IntTy) -> i128 {
1221 let amt = 128 - int_bits(tcx, ity);
1222 ((u as i128) << amt) >> amt
1225 #[allow(clippy::cast_sign_loss)]
1226 /// clip unused bytes
1227 pub fn unsext(tcx: TyCtxt<'_>, u: i128, ity: ast::IntTy) -> u128 {
1228 let amt = 128 - int_bits(tcx, ity);
1229 ((u as u128) << amt) >> amt
1232 /// clip unused bytes
1233 pub fn clip(tcx: TyCtxt<'_>, u: u128, ity: ast::UintTy) -> u128 {
1234 let bits = Integer::from_attr(&tcx, attr::IntType::UnsignedInt(ity)).size().bits();
1235 let amt = 128 - bits;
1239 /// Removes block comments from the given `Vec` of lines.
1244 /// without_block_comments(vec!["/*", "foo", "*/"]);
1247 /// without_block_comments(vec!["bar", "/*", "foo", "*/"]);
1248 /// // => vec!["bar"]
1250 pub fn without_block_comments(lines: Vec<&str>) -> Vec<&str> {
1251 let mut without = vec![];
1253 let mut nest_level = 0;
1256 if line.contains("/*") {
1259 } else if line.contains("*/") {
1264 if nest_level == 0 {
1272 pub fn any_parent_is_automatically_derived(tcx: TyCtxt<'_>, node: HirId) -> bool {
1273 let map = &tcx.hir();
1274 let mut prev_enclosing_node = None;
1275 let mut enclosing_node = node;
1276 while Some(enclosing_node) != prev_enclosing_node {
1277 if is_automatically_derived(map.attrs(enclosing_node)) {
1280 prev_enclosing_node = Some(enclosing_node);
1281 enclosing_node = map.get_parent_item(enclosing_node);
1286 /// Returns true if ty has `iter` or `iter_mut` methods
1287 pub fn has_iter_method(cx: &LateContext<'_>, probably_ref_ty: Ty<'_>) -> Option<&'static str> {
1288 // FIXME: instead of this hard-coded list, we should check if `<adt>::iter`
1289 // exists and has the desired signature. Unfortunately FnCtxt is not exported
1290 // so we can't use its `lookup_method` method.
1291 let into_iter_collections: [&[&str]; 13] = [
1298 &paths::LINKED_LIST,
1299 &paths::BINARY_HEAP,
1307 let ty_to_check = match probably_ref_ty.kind() {
1308 ty::Ref(_, ty_to_check, _) => ty_to_check,
1309 _ => probably_ref_ty,
1312 let def_id = match ty_to_check.kind() {
1313 ty::Array(..) => return Some("array"),
1314 ty::Slice(..) => return Some("slice"),
1315 ty::Adt(adt, _) => adt.did,
1319 for path in &into_iter_collections {
1320 if match_def_path(cx, def_id, path) {
1321 return Some(*path.last().unwrap());
1327 /// Matches a function call with the given path and returns the arguments.
1332 /// if let Some(args) = match_function_call(cx, cmp_max_call, &paths::CMP_MAX);
1334 pub fn match_function_call<'tcx>(
1335 cx: &LateContext<'tcx>,
1336 expr: &'tcx Expr<'_>,
1338 ) -> Option<&'tcx [Expr<'tcx>]> {
1340 if let ExprKind::Call(ref fun, ref args) = expr.kind;
1341 if let ExprKind::Path(ref qpath) = fun.kind;
1342 if let Some(fun_def_id) = cx.qpath_res(qpath, fun.hir_id).opt_def_id();
1343 if match_def_path(cx, fun_def_id, path);
1351 /// Checks if `Ty` is normalizable. This function is useful
1352 /// to avoid crashes on `layout_of`.
1353 pub fn is_normalizable<'tcx>(cx: &LateContext<'tcx>, param_env: ty::ParamEnv<'tcx>, ty: Ty<'tcx>) -> bool {
1354 cx.tcx.infer_ctxt().enter(|infcx| {
1355 let cause = rustc_middle::traits::ObligationCause::dummy();
1356 infcx.at(&cause, param_env).normalize(ty).is_ok()
1360 pub fn match_def_path<'tcx>(cx: &LateContext<'tcx>, did: DefId, syms: &[&str]) -> bool {
1361 // We have to convert `syms` to `&[Symbol]` here because rustc's `match_def_path`
1362 // accepts only that. We should probably move to Symbols in Clippy as well.
1363 let syms = syms.iter().map(|p| Symbol::intern(p)).collect::<Vec<Symbol>>();
1364 cx.match_def_path(did, &syms)
1367 pub fn match_panic_call<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> Option<&'tcx [Expr<'tcx>]> {
1368 match_function_call(cx, expr, &paths::BEGIN_PANIC)
1369 .or_else(|| match_function_call(cx, expr, &paths::BEGIN_PANIC_FMT))
1370 .or_else(|| match_function_call(cx, expr, &paths::PANIC_ANY))
1371 .or_else(|| match_function_call(cx, expr, &paths::PANICKING_PANIC))
1372 .or_else(|| match_function_call(cx, expr, &paths::PANICKING_PANIC_FMT))
1373 .or_else(|| match_function_call(cx, expr, &paths::PANICKING_PANIC_STR))
1376 pub fn match_panic_def_id(cx: &LateContext<'_>, did: DefId) -> bool {
1377 match_def_path(cx, did, &paths::BEGIN_PANIC)
1378 || match_def_path(cx, did, &paths::BEGIN_PANIC_FMT)
1379 || match_def_path(cx, did, &paths::PANIC_ANY)
1380 || match_def_path(cx, did, &paths::PANICKING_PANIC)
1381 || match_def_path(cx, did, &paths::PANICKING_PANIC_FMT)
1382 || match_def_path(cx, did, &paths::PANICKING_PANIC_STR)
1385 /// Returns the list of condition expressions and the list of blocks in a
1386 /// sequence of `if/else`.
1387 /// E.g., this returns `([a, b], [c, d, e])` for the expression
1388 /// `if a { c } else if b { d } else { e }`.
1389 pub fn if_sequence<'tcx>(
1390 mut expr: &'tcx Expr<'tcx>,
1391 ) -> (SmallVec<[&'tcx Expr<'tcx>; 1]>, SmallVec<[&'tcx Block<'tcx>; 1]>) {
1392 let mut conds = SmallVec::new();
1393 let mut blocks: SmallVec<[&Block<'_>; 1]> = SmallVec::new();
1395 while let ExprKind::If(ref cond, ref then_expr, ref else_expr) = expr.kind {
1396 conds.push(&**cond);
1397 if let ExprKind::Block(ref block, _) = then_expr.kind {
1400 panic!("ExprKind::If node is not an ExprKind::Block");
1403 if let Some(ref else_expr) = *else_expr {
1410 // final `else {..}`
1411 if !blocks.is_empty() {
1412 if let ExprKind::Block(ref block, _) = expr.kind {
1413 blocks.push(&**block);
1420 pub fn parent_node_is_if_expr(expr: &Expr<'_>, cx: &LateContext<'_>) -> bool {
1421 let map = cx.tcx.hir();
1422 let parent_id = map.get_parent_node(expr.hir_id);
1423 let parent_node = map.get(parent_id);
1427 kind: ExprKind::If(_, _, _),
1433 // Finds the attribute with the given name, if any
1434 pub fn attr_by_name<'a>(attrs: &'a [Attribute], name: &'_ str) -> Option<&'a Attribute> {
1437 .find(|attr| attr.ident().map_or(false, |ident| ident.as_str() == name))
1440 // Finds the `#[must_use]` attribute, if any
1441 pub fn must_use_attr(attrs: &[Attribute]) -> Option<&Attribute> {
1442 attr_by_name(attrs, "must_use")
1445 // Returns whether the type has #[must_use] attribute
1446 pub fn is_must_use_ty<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
1448 ty::Adt(ref adt, _) => must_use_attr(&cx.tcx.get_attrs(adt.did)).is_some(),
1449 ty::Foreign(ref did) => must_use_attr(&cx.tcx.get_attrs(*did)).is_some(),
1451 | ty::Array(ref ty, _)
1452 | ty::RawPtr(ty::TypeAndMut { ref ty, .. })
1453 | ty::Ref(_, ref ty, _) => {
1454 // for the Array case we don't need to care for the len == 0 case
1455 // because we don't want to lint functions returning empty arrays
1456 is_must_use_ty(cx, *ty)
1458 ty::Tuple(ref substs) => substs.types().any(|ty| is_must_use_ty(cx, ty)),
1459 ty::Opaque(ref def_id, _) => {
1460 for (predicate, _) in cx.tcx.explicit_item_bounds(*def_id) {
1461 if let ty::PredicateKind::Trait(trait_predicate, _) = predicate.kind().skip_binder() {
1462 if must_use_attr(&cx.tcx.get_attrs(trait_predicate.trait_ref.def_id)).is_some() {
1469 ty::Dynamic(binder, _) => {
1470 for predicate in binder.iter() {
1471 if let ty::ExistentialPredicate::Trait(ref trait_ref) = predicate.skip_binder() {
1472 if must_use_attr(&cx.tcx.get_attrs(trait_ref.def_id)).is_some() {
1483 // check if expr is calling method or function with #[must_use] attribute
1484 pub fn is_must_use_func_call(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
1485 let did = match expr.kind {
1486 ExprKind::Call(ref path, _) => if_chain! {
1487 if let ExprKind::Path(ref qpath) = path.kind;
1488 if let def::Res::Def(_, did) = cx.qpath_res(qpath, path.hir_id);
1495 ExprKind::MethodCall(_, _, _, _) => cx.typeck_results().type_dependent_def_id(expr.hir_id),
1499 did.map_or(false, |did| must_use_attr(&cx.tcx.get_attrs(did)).is_some())
1502 pub fn is_no_std_crate(krate: &Crate<'_>) -> bool {
1503 krate.item.attrs.iter().any(|attr| {
1504 if let ast::AttrKind::Normal(ref attr, _) = attr.kind {
1505 attr.path == sym::no_std
1512 /// Check if parent of a hir node is a trait implementation block.
1513 /// For example, `f` in
1515 /// impl Trait for S {
1519 pub fn is_trait_impl_item(cx: &LateContext<'_>, hir_id: HirId) -> bool {
1520 if let Some(Node::Item(item)) = cx.tcx.hir().find(cx.tcx.hir().get_parent_node(hir_id)) {
1521 matches!(item.kind, ItemKind::Impl(hir::Impl { of_trait: Some(_), .. }))
1527 /// Check if it's even possible to satisfy the `where` clause for the item.
1529 /// `trivial_bounds` feature allows functions with unsatisfiable bounds, for example:
1532 /// fn foo() where i32: Iterator {
1533 /// for _ in 2i32 {}
1536 pub fn fn_has_unsatisfiable_preds(cx: &LateContext<'_>, did: DefId) -> bool {
1537 use rustc_trait_selection::traits;
1543 .filter_map(|(p, _)| if p.is_global() { Some(*p) } else { None });
1544 traits::impossible_predicates(
1546 traits::elaborate_predicates(cx.tcx, predicates)
1547 .map(|o| o.predicate)
1548 .collect::<Vec<_>>(),
1552 /// Returns the `DefId` of the callee if the given expression is a function or method call.
1553 pub fn fn_def_id(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<DefId> {
1555 ExprKind::MethodCall(..) => cx.typeck_results().type_dependent_def_id(expr.hir_id),
1558 kind: ExprKind::Path(qpath),
1562 ) => cx.typeck_results().qpath_res(qpath, expr.hir_id).opt_def_id(),
1567 pub fn run_lints(cx: &LateContext<'_>, lints: &[&'static Lint], id: HirId) -> bool {
1568 lints.iter().any(|lint| {
1570 cx.tcx.lint_level_at_node(lint, id),
1571 (Level::Forbid | Level::Deny | Level::Warn, _)
1576 /// Returns true iff the given type is a primitive (a bool or char, any integer or floating-point
1577 /// number type, a str, or an array, slice, or tuple of those types).
1578 pub fn is_recursively_primitive_type(ty: Ty<'_>) -> bool {
1580 ty::Bool | ty::Char | ty::Int(_) | ty::Uint(_) | ty::Float(_) | ty::Str => true,
1581 ty::Ref(_, inner, _) if *inner.kind() == ty::Str => true,
1582 ty::Array(inner_type, _) | ty::Slice(inner_type) => is_recursively_primitive_type(inner_type),
1583 ty::Tuple(inner_types) => inner_types.types().all(is_recursively_primitive_type),
1588 /// Returns Option<String> where String is a textual representation of the type encapsulated in the
1589 /// slice iff the given expression is a slice of primitives (as defined in the
1590 /// `is_recursively_primitive_type` function) and None otherwise.
1591 pub fn is_slice_of_primitives(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<String> {
1592 let expr_type = cx.typeck_results().expr_ty_adjusted(expr);
1593 let expr_kind = expr_type.kind();
1594 let is_primitive = match expr_kind {
1595 ty::Slice(element_type) => is_recursively_primitive_type(element_type),
1596 ty::Ref(_, inner_ty, _) if matches!(inner_ty.kind(), &ty::Slice(_)) => {
1597 if let ty::Slice(element_type) = inner_ty.kind() {
1598 is_recursively_primitive_type(element_type)
1607 // if we have wrappers like Array, Slice or Tuple, print these
1608 // and get the type enclosed in the slice ref
1609 match expr_type.peel_refs().walk().nth(1).unwrap().expect_ty().kind() {
1610 ty::Slice(..) => return Some("slice".into()),
1611 ty::Array(..) => return Some("array".into()),
1612 ty::Tuple(..) => return Some("tuple".into()),
1614 // is_recursively_primitive_type() should have taken care
1615 // of the rest and we can rely on the type that is found
1616 let refs_peeled = expr_type.peel_refs();
1617 return Some(refs_peeled.walk().last().unwrap().to_string());
1624 /// returns list of all pairs (a, b) from `exprs` such that `eq(a, b)`
1625 /// `hash` must be comformed with `eq`
1626 pub fn search_same<T, Hash, Eq>(exprs: &[T], hash: Hash, eq: Eq) -> Vec<(&T, &T)>
1628 Hash: Fn(&T) -> u64,
1629 Eq: Fn(&T, &T) -> bool,
1631 if exprs.len() == 2 && eq(&exprs[0], &exprs[1]) {
1632 return vec![(&exprs[0], &exprs[1])];
1635 let mut match_expr_list: Vec<(&T, &T)> = Vec::new();
1637 let mut map: FxHashMap<_, Vec<&_>> =
1638 FxHashMap::with_capacity_and_hasher(exprs.len(), BuildHasherDefault::default());
1641 match map.entry(hash(expr)) {
1642 Entry::Occupied(mut o) => {
1645 match_expr_list.push((o, expr));
1648 o.get_mut().push(expr);
1650 Entry::Vacant(v) => {
1651 v.insert(vec![expr]);
1660 macro_rules! unwrap_cargo_metadata {
1661 ($cx: ident, $lint: ident, $deps: expr) => {{
1662 let mut command = cargo_metadata::MetadataCommand::new();
1667 match command.exec() {
1668 Ok(metadata) => metadata,
1670 span_lint($cx, $lint, DUMMY_SP, &format!("could not read cargo metadata: {}", err));
1677 pub fn is_hir_ty_cfg_dependant(cx: &LateContext<'_>, ty: &hir::Ty<'_>) -> bool {
1679 if let TyKind::Path(QPath::Resolved(_, path)) = ty.kind;
1680 if let Res::Def(_, def_id) = path.res;
1682 cx.tcx.has_attr(def_id, sym::cfg) || cx.tcx.has_attr(def_id, sym::cfg_attr)
1691 use super::{reindent_multiline, without_block_comments};
1694 fn test_reindent_multiline_single_line() {
1695 assert_eq!("", reindent_multiline("".into(), false, None));
1696 assert_eq!("...", reindent_multiline("...".into(), false, None));
1697 assert_eq!("...", reindent_multiline(" ...".into(), false, None));
1698 assert_eq!("...", reindent_multiline("\t...".into(), false, None));
1699 assert_eq!("...", reindent_multiline("\t\t...".into(), false, None));
1704 fn test_reindent_multiline_block() {
1710 }", reindent_multiline(" if x {
1714 }".into(), false, None));
1720 }", reindent_multiline(" if x {
1724 }".into(), false, None));
1729 fn test_reindent_multiline_empty_line() {
1736 }", reindent_multiline(" if x {
1741 }".into(), false, None));
1746 fn test_reindent_multiline_lines_deeper() {
1752 }", reindent_multiline("\
1757 }".into(), true, Some(8)));
1761 fn test_without_block_comments_lines_without_block_comments() {
1762 let result = without_block_comments(vec!["/*", "", "*/"]);
1763 println!("result: {:?}", result);
1764 assert!(result.is_empty());
1766 let result = without_block_comments(vec!["", "/*", "", "*/", "#[crate_type = \"lib\"]", "/*", "", "*/", ""]);
1767 assert_eq!(result, vec!["", "#[crate_type = \"lib\"]", ""]);
1769 let result = without_block_comments(vec!["/* rust", "", "*/"]);
1770 assert!(result.is_empty());
1772 let result = without_block_comments(vec!["/* one-line comment */"]);
1773 assert!(result.is_empty());
1775 let result = without_block_comments(vec!["/* nested", "/* multi-line", "comment", "*/", "test", "*/"]);
1776 assert!(result.is_empty());
1778 let result = without_block_comments(vec!["/* nested /* inline /* comment */ test */ */"]);
1779 assert!(result.is_empty());
1781 let result = without_block_comments(vec!["foo", "bar", "baz"]);
1782 assert_eq!(result, vec!["foo", "bar", "baz"]);