1 use crate::utils::internal_lints::metadata_collector::is_deprecated_lint;
2 use clippy_utils::consts::{constant_simple, Constant};
3 use clippy_utils::diagnostics::{span_lint, span_lint_and_help, span_lint_and_sugg, span_lint_and_then};
4 use clippy_utils::macros::root_macro_call_first_node;
5 use clippy_utils::source::snippet;
6 use clippy_utils::ty::match_type;
8 def_path_res, higher, is_else_clause, is_expn_of, is_expr_path_def_path, is_lint_allowed, match_def_path,
9 method_calls, paths, peel_blocks_with_stmt, SpanlessEq,
11 use if_chain::if_chain;
13 use rustc_ast::ast::{Crate, ItemKind, LitKind, ModKind, NodeId};
14 use rustc_ast::visit::FnKind;
15 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
16 use rustc_errors::Applicability;
18 use rustc_hir::def::{DefKind, Res};
19 use rustc_hir::def_id::DefId;
20 use rustc_hir::hir_id::CRATE_HIR_ID;
21 use rustc_hir::intravisit::Visitor;
23 BinOpKind, Block, Closure, Expr, ExprKind, HirId, Item, Local, MutTy, Mutability, Node, Path, Stmt, StmtKind, Ty,
26 use rustc_lint::{EarlyContext, EarlyLintPass, LateContext, LateLintPass, LintContext};
27 use rustc_middle::hir::nested_filter;
28 use rustc_middle::mir::interpret::ConstValue;
29 use rustc_middle::ty::{self, fast_reject::SimplifiedTypeGen, subst::GenericArgKind, FloatTy};
30 use rustc_semver::RustcVersion;
31 use rustc_session::{declare_lint_pass, declare_tool_lint, impl_lint_pass};
32 use rustc_span::source_map::Spanned;
33 use rustc_span::symbol::Symbol;
34 use rustc_span::{sym, BytePos, Span};
35 use rustc_hir_analysis::hir_ty_to_ty;
37 use std::borrow::{Borrow, Cow};
39 #[cfg(feature = "internal")]
40 pub mod metadata_collector;
42 declare_clippy_lint! {
44 /// Checks for various things we like to keep tidy in clippy.
46 /// ### Why is this bad?
47 /// We like to pretend we're an example of tidy code.
50 /// Wrong ordering of the util::paths constants.
51 pub CLIPPY_LINTS_INTERNAL,
53 "various things that will negatively affect your clippy experience"
56 declare_clippy_lint! {
58 /// Ensures every lint is associated to a `LintPass`.
60 /// ### Why is this bad?
61 /// The compiler only knows lints via a `LintPass`. Without
62 /// putting a lint to a `LintPass::get_lints()`'s return, the compiler will not
63 /// know the name of the lint.
65 /// ### Known problems
66 /// Only checks for lints associated using the
67 /// `declare_lint_pass!`, `impl_lint_pass!`, and `lint_array!` macros.
71 /// declare_lint! { pub LINT_1, ... }
72 /// declare_lint! { pub LINT_2, ... }
73 /// declare_lint! { pub FORGOTTEN_LINT, ... }
75 /// declare_lint_pass!(Pass => [LINT_1, LINT_2]);
76 /// // missing FORGOTTEN_LINT
78 pub LINT_WITHOUT_LINT_PASS,
80 "declaring a lint without associating it in a LintPass"
83 declare_clippy_lint! {
85 /// Checks for calls to `cx.span_lint*` and suggests to use the `utils::*`
86 /// variant of the function.
88 /// ### Why is this bad?
89 /// The `utils::*` variants also add a link to the Clippy documentation to the
90 /// warning/error messages.
94 /// cx.span_lint(LINT_NAME, "message");
99 /// utils::span_lint(cx, LINT_NAME, "message");
101 pub COMPILER_LINT_FUNCTIONS,
103 "usage of the lint functions of the compiler instead of the utils::* variant"
106 declare_clippy_lint! {
108 /// Checks for calls to `cx.outer().expn_data()` and suggests to use
109 /// the `cx.outer_expn_data()`
111 /// ### Why is this bad?
112 /// `cx.outer_expn_data()` is faster and more concise.
116 /// expr.span.ctxt().outer().expn_data()
121 /// expr.span.ctxt().outer_expn_data()
123 pub OUTER_EXPN_EXPN_DATA,
125 "using `cx.outer_expn().expn_data()` instead of `cx.outer_expn_data()`"
128 declare_clippy_lint! {
130 /// Not an actual lint. This lint is only meant for testing our customized internal compiler
131 /// error message by calling `panic`.
133 /// ### Why is this bad?
134 /// ICE in large quantities can damage your teeth
142 "this message should not appear anywhere as we ICE before and don't emit the lint"
145 declare_clippy_lint! {
147 /// Checks for cases of an auto-generated lint without an updated description,
148 /// i.e. `default lint description`.
150 /// ### Why is this bad?
151 /// Indicates that the lint is not finished.
155 /// declare_lint! { pub COOL_LINT, nursery, "default lint description" }
160 /// declare_lint! { pub COOL_LINT, nursery, "a great new lint" }
164 "found 'default lint description' in a lint declaration"
167 declare_clippy_lint! {
169 /// Lints `span_lint_and_then` function calls, where the
170 /// closure argument has only one statement and that statement is a method
171 /// call to `span_suggestion`, `span_help`, `span_note` (using the same
172 /// span), `help` or `note`.
174 /// These usages of `span_lint_and_then` should be replaced with one of the
175 /// wrapper functions `span_lint_and_sugg`, span_lint_and_help`, or
176 /// `span_lint_and_note`.
178 /// ### Why is this bad?
179 /// Using the wrapper `span_lint_and_*` functions, is more
180 /// convenient, readable and less error prone.
184 /// span_lint_and_then(cx, TEST_LINT, expr.span, lint_msg, |diag| {
185 /// diag.span_suggestion(
188 /// sugg.to_string(),
189 /// Applicability::MachineApplicable,
192 /// span_lint_and_then(cx, TEST_LINT, expr.span, lint_msg, |diag| {
193 /// diag.span_help(expr.span, help_msg);
195 /// span_lint_and_then(cx, TEST_LINT, expr.span, lint_msg, |diag| {
196 /// diag.help(help_msg);
198 /// span_lint_and_then(cx, TEST_LINT, expr.span, lint_msg, |diag| {
199 /// diag.span_note(expr.span, note_msg);
201 /// span_lint_and_then(cx, TEST_LINT, expr.span, lint_msg, |diag| {
202 /// diag.note(note_msg);
208 /// span_lint_and_sugg(
214 /// sugg.to_string(),
215 /// Applicability::MachineApplicable,
217 /// span_lint_and_help(cx, TEST_LINT, expr.span, lint_msg, Some(expr.span), help_msg);
218 /// span_lint_and_help(cx, TEST_LINT, expr.span, lint_msg, None, help_msg);
219 /// span_lint_and_note(cx, TEST_LINT, expr.span, lint_msg, Some(expr.span), note_msg);
220 /// span_lint_and_note(cx, TEST_LINT, expr.span, lint_msg, None, note_msg);
222 pub COLLAPSIBLE_SPAN_LINT_CALLS,
224 "found collapsible `span_lint_and_then` calls"
227 declare_clippy_lint! {
229 /// Checks for calls to `utils::match_type()` on a type diagnostic item
230 /// and suggests to use `utils::is_type_diagnostic_item()` instead.
232 /// ### Why is this bad?
233 /// `utils::is_type_diagnostic_item()` does not require hardcoded paths.
237 /// utils::match_type(cx, ty, &paths::VEC)
242 /// utils::is_type_diagnostic_item(cx, ty, sym::Vec)
244 pub MATCH_TYPE_ON_DIAGNOSTIC_ITEM,
246 "using `utils::match_type()` instead of `utils::is_type_diagnostic_item()`"
249 declare_clippy_lint! {
251 /// Checks the paths module for invalid paths.
253 /// ### Why is this bad?
254 /// It indicates a bug in the code.
263 declare_clippy_lint! {
265 /// Checks for interning symbols that have already been pre-interned and defined as constants.
267 /// ### Why is this bad?
268 /// It's faster and easier to use the symbol constant.
272 /// let _ = sym!(f32);
277 /// let _ = sym::f32;
279 pub INTERNING_DEFINED_SYMBOL,
281 "interning a symbol that is pre-interned and defined as a constant"
284 declare_clippy_lint! {
286 /// Checks for unnecessary conversion from Symbol to a string.
288 /// ### Why is this bad?
289 /// It's faster use symbols directly instead of strings.
293 /// symbol.as_str() == "clippy";
298 /// symbol == sym::clippy;
300 pub UNNECESSARY_SYMBOL_STR,
302 "unnecessary conversion between Symbol and string"
305 declare_clippy_lint! {
306 /// Finds unidiomatic usage of `if_chain!`
309 "non-idiomatic `if_chain!` usage"
312 declare_clippy_lint! {
314 /// Checks for invalid `clippy::version` attributes.
316 /// Valid values are:
318 /// * any valid semantic version
319 pub INVALID_CLIPPY_VERSION_ATTRIBUTE,
321 "found an invalid `clippy::version` attribute"
324 declare_clippy_lint! {
326 /// Checks for declared clippy lints without the `clippy::version` attribute.
328 pub MISSING_CLIPPY_VERSION_ATTRIBUTE,
330 "found clippy lint without `clippy::version` attribute"
333 declare_clippy_lint! {
335 /// Check that the `extract_msrv_attr!` macro is used, when a lint has a MSRV.
337 pub MISSING_MSRV_ATTR_IMPL,
339 "checking if all necessary steps were taken when adding a MSRV to a lint"
342 declare_clippy_lint! {
344 /// Checks for cases of an auto-generated deprecated lint without an updated reason,
345 /// i.e. `"default deprecation note"`.
347 /// ### Why is this bad?
348 /// Indicates that the documentation is incomplete.
352 /// declare_deprecated_lint! {
353 /// /// ### What it does
354 /// /// Nothing. This lint has been deprecated.
356 /// /// ### Deprecation reason
358 /// #[clippy::version = "1.63.0"]
360 /// "default deprecation note"
366 /// declare_deprecated_lint! {
367 /// /// ### What it does
368 /// /// Nothing. This lint has been deprecated.
370 /// /// ### Deprecation reason
371 /// /// This lint has been replaced by `cooler_lint`
372 /// #[clippy::version = "1.63.0"]
374 /// "this lint has been replaced by `cooler_lint`"
377 pub DEFAULT_DEPRECATION_REASON,
379 "found 'default deprecation note' in a deprecated lint declaration"
382 declare_lint_pass!(ClippyLintsInternal => [CLIPPY_LINTS_INTERNAL]);
384 impl EarlyLintPass for ClippyLintsInternal {
385 fn check_crate(&mut self, cx: &EarlyContext<'_>, krate: &Crate) {
386 if let Some(utils) = krate.items.iter().find(|item| item.ident.name.as_str() == "utils") {
387 if let ItemKind::Mod(_, ModKind::Loaded(ref items, ..)) = utils.kind {
388 if let Some(paths) = items.iter().find(|item| item.ident.name.as_str() == "paths") {
389 if let ItemKind::Mod(_, ModKind::Loaded(ref items, ..)) = paths.kind {
390 let mut last_name: Option<&str> = None;
392 let name = item.ident.as_str();
393 if let Some(last_name) = last_name {
394 if *last_name > *name {
397 CLIPPY_LINTS_INTERNAL,
399 "this constant should be before the previous constant due to lexical \
404 last_name = Some(name);
413 #[derive(Clone, Debug, Default)]
414 pub struct LintWithoutLintPass {
415 declared_lints: FxHashMap<Symbol, Span>,
416 registered_lints: FxHashSet<Symbol>,
419 impl_lint_pass!(LintWithoutLintPass => [DEFAULT_LINT, LINT_WITHOUT_LINT_PASS, INVALID_CLIPPY_VERSION_ATTRIBUTE, MISSING_CLIPPY_VERSION_ATTRIBUTE, DEFAULT_DEPRECATION_REASON]);
421 impl<'tcx> LateLintPass<'tcx> for LintWithoutLintPass {
422 fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx Item<'_>) {
423 if is_lint_allowed(cx, DEFAULT_LINT, item.hir_id())
424 || is_lint_allowed(cx, DEFAULT_DEPRECATION_REASON, item.hir_id())
429 if let hir::ItemKind::Static(ty, Mutability::Not, body_id) = item.kind {
430 let is_lint_ref_ty = is_lint_ref_type(cx, ty);
431 if is_deprecated_lint(cx, ty) || is_lint_ref_ty {
432 check_invalid_clippy_version_attribute(cx, item);
434 let expr = &cx.tcx.hir().body(body_id).value;
437 if let ExprKind::AddrOf(_, _, inner_exp) = expr.kind
438 && let ExprKind::Struct(_, struct_fields, _) = inner_exp.kind {
439 fields = struct_fields;
443 } else if let ExprKind::Struct(_, struct_fields, _) = expr.kind {
444 fields = struct_fields;
451 .find(|f| f.ident.as_str() == "desc")
452 .expect("lints must have a description field");
454 if let ExprKind::Lit(Spanned {
455 node: LitKind::Str(ref sym, _),
459 let sym_str = sym.as_str();
461 if sym_str == "default lint description" {
466 &format!("the lint `{}` has the default lint description", item.ident.name),
470 self.declared_lints.insert(item.ident.name, item.span);
471 } else if sym_str == "default deprecation note" {
474 DEFAULT_DEPRECATION_REASON,
476 &format!("the lint `{}` has the default deprecation reason", item.ident.name),
481 } else if let Some(macro_call) = root_macro_call_first_node(cx, item) {
483 cx.tcx.item_name(macro_call.def_id).as_str(),
484 "impl_lint_pass" | "declare_lint_pass"
488 if let hir::ItemKind::Impl(hir::Impl {
490 items: impl_item_refs,
494 let mut collector = LintCollector {
495 output: &mut self.registered_lints,
498 let body_id = cx.tcx.hir().body_owned_by(
499 cx.tcx.hir().local_def_id(
502 .find(|iiref| iiref.ident.as_str() == "get_lints")
503 .expect("LintPass needs to implement get_lints")
508 collector.visit_expr(cx.tcx.hir().body(body_id).value);
513 fn check_crate_post(&mut self, cx: &LateContext<'tcx>) {
514 if is_lint_allowed(cx, LINT_WITHOUT_LINT_PASS, CRATE_HIR_ID) {
518 for (lint_name, &lint_span) in &self.declared_lints {
519 // When using the `declare_tool_lint!` macro, the original `lint_span`'s
520 // file points to "<rustc macros>".
521 // `compiletest-rs` thinks that's an error in a different file and
522 // just ignores it. This causes the test in compile-fail/lint_pass
523 // not able to capture the error.
524 // Therefore, we need to climb the macro expansion tree and find the
525 // actual span that invoked `declare_tool_lint!`:
526 let lint_span = lint_span.ctxt().outer_expn_data().call_site;
528 if !self.registered_lints.contains(lint_name) {
531 LINT_WITHOUT_LINT_PASS,
533 &format!("the lint `{}` is not added to any `LintPass`", lint_name),
540 fn is_lint_ref_type<'tcx>(cx: &LateContext<'tcx>, ty: &Ty<'_>) -> bool {
545 mutbl: Mutability::Not,
549 if let TyKind::Path(ref path) = inner.kind {
550 if let Res::Def(DefKind::Struct, def_id) = cx.qpath_res(path, inner.hir_id) {
551 return match_def_path(cx, def_id, &paths::LINT);
559 fn check_invalid_clippy_version_attribute(cx: &LateContext<'_>, item: &'_ Item<'_>) {
560 if let Some(value) = extract_clippy_version_value(cx, item) {
561 // The `sym!` macro doesn't work as it only expects a single token.
562 // It's better to keep it this way and have a direct `Symbol::intern` call here.
563 if value == Symbol::intern("pre 1.29.0") {
567 if RustcVersion::parse(value.as_str()).is_err() {
570 INVALID_CLIPPY_VERSION_ATTRIBUTE,
572 "this item has an invalid `clippy::version` attribute",
574 "please use a valid semantic version, see `doc/adding_lints.md`",
580 MISSING_CLIPPY_VERSION_ATTRIBUTE,
582 "this lint is missing the `clippy::version` attribute or version value",
584 "please use a `clippy::version` attribute, see `doc/adding_lints.md`",
589 /// This function extracts the version value of a `clippy::version` attribute if the given value has
591 fn extract_clippy_version_value(cx: &LateContext<'_>, item: &'_ Item<'_>) -> Option<Symbol> {
592 let attrs = cx.tcx.hir().attrs(item.hir_id());
593 attrs.iter().find_map(|attr| {
595 // Identify attribute
596 if let ast::AttrKind::Normal(ref attr_kind) = &attr.kind;
597 if let [tool_name, attr_name] = &attr_kind.item.path.segments[..];
598 if tool_name.ident.name == sym::clippy;
599 if attr_name.ident.name == sym::version;
600 if let Some(version) = attr.value_str();
610 struct LintCollector<'a, 'tcx> {
611 output: &'a mut FxHashSet<Symbol>,
612 cx: &'a LateContext<'tcx>,
615 impl<'a, 'tcx> Visitor<'tcx> for LintCollector<'a, 'tcx> {
616 type NestedFilter = nested_filter::All;
618 fn visit_path(&mut self, path: &'tcx Path<'_>, _: HirId) {
619 if path.segments.len() == 1 {
620 self.output.insert(path.segments[0].ident.name);
624 fn nested_visit_map(&mut self) -> Self::Map {
629 #[derive(Clone, Default)]
630 pub struct CompilerLintFunctions {
631 map: FxHashMap<&'static str, &'static str>,
634 impl CompilerLintFunctions {
636 pub fn new() -> Self {
637 let mut map = FxHashMap::default();
638 map.insert("span_lint", "utils::span_lint");
639 map.insert("struct_span_lint", "utils::span_lint");
640 map.insert("lint", "utils::span_lint");
641 map.insert("span_lint_note", "utils::span_lint_and_note");
642 map.insert("span_lint_help", "utils::span_lint_and_help");
647 impl_lint_pass!(CompilerLintFunctions => [COMPILER_LINT_FUNCTIONS]);
649 impl<'tcx> LateLintPass<'tcx> for CompilerLintFunctions {
650 fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
651 if is_lint_allowed(cx, COMPILER_LINT_FUNCTIONS, expr.hir_id) {
656 if let ExprKind::MethodCall(path, self_arg, _, _) = &expr.kind;
657 let fn_name = path.ident;
658 if let Some(sugg) = self.map.get(fn_name.as_str());
659 let ty = cx.typeck_results().expr_ty(self_arg).peel_refs();
660 if match_type(cx, ty, &paths::EARLY_CONTEXT)
661 || match_type(cx, ty, &paths::LATE_CONTEXT);
665 COMPILER_LINT_FUNCTIONS,
667 "usage of a compiler lint function",
669 &format!("please use the Clippy variant of this function: `{}`", sugg),
676 declare_lint_pass!(OuterExpnDataPass => [OUTER_EXPN_EXPN_DATA]);
678 impl<'tcx> LateLintPass<'tcx> for OuterExpnDataPass {
679 fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>) {
680 if is_lint_allowed(cx, OUTER_EXPN_EXPN_DATA, expr.hir_id) {
684 let (method_names, arg_lists, spans) = method_calls(expr, 2);
685 let method_names: Vec<&str> = method_names.iter().map(Symbol::as_str).collect();
687 if let ["expn_data", "outer_expn"] = method_names.as_slice();
688 let (self_arg, args)= arg_lists[1];
690 let self_ty = cx.typeck_results().expr_ty(self_arg).peel_refs();
691 if match_type(cx, self_ty, &paths::SYNTAX_CONTEXT);
695 OUTER_EXPN_EXPN_DATA,
696 spans[1].with_hi(expr.span.hi()),
697 "usage of `outer_expn().expn_data()`",
699 "outer_expn_data()".to_string(),
700 Applicability::MachineApplicable,
707 declare_lint_pass!(ProduceIce => [PRODUCE_ICE]);
709 impl EarlyLintPass for ProduceIce {
710 fn check_fn(&mut self, _: &EarlyContext<'_>, fn_kind: FnKind<'_>, _: Span, _: NodeId) {
711 assert!(!is_trigger_fn(fn_kind), "Would you like some help with that?");
715 fn is_trigger_fn(fn_kind: FnKind<'_>) -> bool {
717 FnKind::Fn(_, ident, ..) => ident.name.as_str() == "it_looks_like_you_are_trying_to_kill_clippy",
718 FnKind::Closure(..) => false,
722 declare_lint_pass!(CollapsibleCalls => [COLLAPSIBLE_SPAN_LINT_CALLS]);
724 impl<'tcx> LateLintPass<'tcx> for CollapsibleCalls {
725 fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>) {
726 if is_lint_allowed(cx, COLLAPSIBLE_SPAN_LINT_CALLS, expr.hir_id) {
731 if let ExprKind::Call(func, and_then_args) = expr.kind;
732 if is_expr_path_def_path(cx, func, &["clippy_utils", "diagnostics", "span_lint_and_then"]);
733 if and_then_args.len() == 5;
734 if let ExprKind::Closure(&Closure { body, .. }) = &and_then_args[4].kind;
735 let body = cx.tcx.hir().body(body);
736 let only_expr = peel_blocks_with_stmt(body.value);
737 if let ExprKind::MethodCall(ps, recv, span_call_args, _) = &only_expr.kind;
738 if let ExprKind::Path(..) = recv.kind;
740 let and_then_snippets = get_and_then_snippets(cx, and_then_args);
741 let mut sle = SpanlessEq::new(cx).deny_side_effects();
742 match ps.ident.as_str() {
743 "span_suggestion" if sle.eq_expr(&and_then_args[2], &span_call_args[0]) => {
744 suggest_suggestion(cx, expr, &and_then_snippets, &span_suggestion_snippets(cx, span_call_args));
746 "span_help" if sle.eq_expr(&and_then_args[2], &span_call_args[0]) => {
747 let help_snippet = snippet(cx, span_call_args[1].span, r#""...""#);
748 suggest_help(cx, expr, &and_then_snippets, help_snippet.borrow(), true);
750 "span_note" if sle.eq_expr(&and_then_args[2], &span_call_args[0]) => {
751 let note_snippet = snippet(cx, span_call_args[1].span, r#""...""#);
752 suggest_note(cx, expr, &and_then_snippets, note_snippet.borrow(), true);
755 let help_snippet = snippet(cx, span_call_args[0].span, r#""...""#);
756 suggest_help(cx, expr, &and_then_snippets, help_snippet.borrow(), false);
759 let note_snippet = snippet(cx, span_call_args[0].span, r#""...""#);
760 suggest_note(cx, expr, &and_then_snippets, note_snippet.borrow(), false);
769 struct AndThenSnippets<'a> {
776 fn get_and_then_snippets<'a, 'hir>(cx: &LateContext<'_>, and_then_snippets: &'hir [Expr<'hir>]) -> AndThenSnippets<'a> {
777 let cx_snippet = snippet(cx, and_then_snippets[0].span, "cx");
778 let lint_snippet = snippet(cx, and_then_snippets[1].span, "..");
779 let span_snippet = snippet(cx, and_then_snippets[2].span, "span");
780 let msg_snippet = snippet(cx, and_then_snippets[3].span, r#""...""#);
790 struct SpanSuggestionSnippets<'a> {
793 applicability: Cow<'a, str>,
796 fn span_suggestion_snippets<'a, 'hir>(
797 cx: &LateContext<'_>,
798 span_call_args: &'hir [Expr<'hir>],
799 ) -> SpanSuggestionSnippets<'a> {
800 let help_snippet = snippet(cx, span_call_args[1].span, r#""...""#);
801 let sugg_snippet = snippet(cx, span_call_args[2].span, "..");
802 let applicability_snippet = snippet(cx, span_call_args[3].span, "Applicability::MachineApplicable");
804 SpanSuggestionSnippets {
807 applicability: applicability_snippet,
811 fn suggest_suggestion(
812 cx: &LateContext<'_>,
814 and_then_snippets: &AndThenSnippets<'_>,
815 span_suggestion_snippets: &SpanSuggestionSnippets<'_>,
819 COLLAPSIBLE_SPAN_LINT_CALLS,
821 "this call is collapsible",
824 "span_lint_and_sugg({}, {}, {}, {}, {}, {}, {})",
825 and_then_snippets.cx,
826 and_then_snippets.lint,
827 and_then_snippets.span,
828 and_then_snippets.msg,
829 span_suggestion_snippets.help,
830 span_suggestion_snippets.sugg,
831 span_suggestion_snippets.applicability
833 Applicability::MachineApplicable,
838 cx: &LateContext<'_>,
840 and_then_snippets: &AndThenSnippets<'_>,
844 let option_span = if with_span {
845 format!("Some({})", and_then_snippets.span)
852 COLLAPSIBLE_SPAN_LINT_CALLS,
854 "this call is collapsible",
857 "span_lint_and_help({}, {}, {}, {}, {}, {})",
858 and_then_snippets.cx,
859 and_then_snippets.lint,
860 and_then_snippets.span,
861 and_then_snippets.msg,
865 Applicability::MachineApplicable,
870 cx: &LateContext<'_>,
872 and_then_snippets: &AndThenSnippets<'_>,
876 let note_span = if with_span {
877 format!("Some({})", and_then_snippets.span)
884 COLLAPSIBLE_SPAN_LINT_CALLS,
886 "this call is collapsible",
889 "span_lint_and_note({}, {}, {}, {}, {}, {})",
890 and_then_snippets.cx,
891 and_then_snippets.lint,
892 and_then_snippets.span,
893 and_then_snippets.msg,
897 Applicability::MachineApplicable,
901 declare_lint_pass!(MatchTypeOnDiagItem => [MATCH_TYPE_ON_DIAGNOSTIC_ITEM]);
903 impl<'tcx> LateLintPass<'tcx> for MatchTypeOnDiagItem {
904 fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>) {
905 if is_lint_allowed(cx, MATCH_TYPE_ON_DIAGNOSTIC_ITEM, expr.hir_id) {
910 // Check if this is a call to utils::match_type()
911 if let ExprKind::Call(fn_path, [context, ty, ty_path]) = expr.kind;
912 if is_expr_path_def_path(cx, fn_path, &["clippy_utils", "ty", "match_type"]);
913 // Extract the path to the matched type
914 if let Some(segments) = path_to_matched_type(cx, ty_path);
915 let segments: Vec<&str> = segments.iter().map(Symbol::as_str).collect();
916 if let Some(ty_did) = def_path_res(cx, &segments[..]).opt_def_id();
917 // Check if the matched type is a diagnostic item
918 if let Some(item_name) = cx.tcx.get_diagnostic_name(ty_did);
920 // TODO: check paths constants from external crates.
921 let cx_snippet = snippet(cx, context.span, "_");
922 let ty_snippet = snippet(cx, ty.span, "_");
926 MATCH_TYPE_ON_DIAGNOSTIC_ITEM,
928 "usage of `clippy_utils::ty::match_type()` on a type diagnostic item",
930 format!("clippy_utils::ty::is_type_diagnostic_item({}, {}, sym::{})", cx_snippet, ty_snippet, item_name),
931 Applicability::MaybeIncorrect,
938 fn path_to_matched_type(cx: &LateContext<'_>, expr: &hir::Expr<'_>) -> Option<Vec<Symbol>> {
939 use rustc_hir::ItemKind;
942 ExprKind::AddrOf(.., expr) => return path_to_matched_type(cx, expr),
943 ExprKind::Path(qpath) => match cx.qpath_res(qpath, expr.hir_id) {
944 Res::Local(hir_id) => {
945 let parent_id = cx.tcx.hir().get_parent_node(hir_id);
946 if let Some(Node::Local(local)) = cx.tcx.hir().find(parent_id) {
947 if let Some(init) = local.init {
948 return path_to_matched_type(cx, init);
952 Res::Def(DefKind::Const | DefKind::Static(..), def_id) => {
953 if let Some(Node::Item(item)) = cx.tcx.hir().get_if_local(def_id) {
954 if let ItemKind::Const(.., body_id) | ItemKind::Static(.., body_id) = item.kind {
955 let body = cx.tcx.hir().body(body_id);
956 return path_to_matched_type(cx, body.value);
962 ExprKind::Array(exprs) => {
963 let segments: Vec<Symbol> = exprs
966 if let ExprKind::Lit(lit) = &expr.kind {
967 if let LitKind::Str(sym, _) = lit.node {
976 if segments.len() == exprs.len() {
977 return Some(segments);
986 // This is not a complete resolver for paths. It works on all the paths currently used in the paths
987 // module. That's all it does and all it needs to do.
988 pub fn check_path(cx: &LateContext<'_>, path: &[&str]) -> bool {
989 if def_path_res(cx, path) != Res::Err {
993 // Some implementations can't be found by `path_to_res`, particularly inherent
994 // implementations of native types. Check lang items.
995 let path_syms: Vec<_> = path.iter().map(|p| Symbol::intern(p)).collect();
996 let lang_items = cx.tcx.lang_items();
997 // This list isn't complete, but good enough for our current list of paths.
998 let incoherent_impls = [
999 SimplifiedTypeGen::FloatSimplifiedType(FloatTy::F32),
1000 SimplifiedTypeGen::FloatSimplifiedType(FloatTy::F64),
1001 SimplifiedTypeGen::SliceSimplifiedType,
1002 SimplifiedTypeGen::StrSimplifiedType,
1005 .flat_map(|&ty| cx.tcx.incoherent_impls(ty));
1006 for item_def_id in lang_items.items().iter().flatten().chain(incoherent_impls) {
1007 let lang_item_path = cx.get_def_path(*item_def_id);
1008 if path_syms.starts_with(&lang_item_path) {
1009 if let [item] = &path_syms[lang_item_path.len()..] {
1011 cx.tcx.def_kind(*item_def_id),
1012 DefKind::Mod | DefKind::Enum | DefKind::Trait
1014 for child in cx.tcx.module_children(*item_def_id) {
1015 if child.ident.name == *item {
1020 for child in cx.tcx.associated_item_def_ids(*item_def_id) {
1021 if cx.tcx.item_name(*child) == *item {
1033 declare_lint_pass!(InvalidPaths => [INVALID_PATHS]);
1035 impl<'tcx> LateLintPass<'tcx> for InvalidPaths {
1036 fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx Item<'_>) {
1037 let local_def_id = &cx.tcx.parent_module(item.hir_id());
1038 let mod_name = &cx.tcx.item_name(local_def_id.to_def_id());
1040 if mod_name.as_str() == "paths";
1041 if let hir::ItemKind::Const(ty, body_id) = item.kind;
1042 let ty = hir_ty_to_ty(cx.tcx, ty);
1043 if let ty::Array(el_ty, _) = &ty.kind();
1044 if let ty::Ref(_, el_ty, _) = &el_ty.kind();
1046 let body = cx.tcx.hir().body(body_id);
1047 let typeck_results = cx.tcx.typeck_body(body_id);
1048 if let Some(Constant::Vec(path)) = constant_simple(cx, typeck_results, body.value);
1049 let path: Vec<&str> = path.iter().map(|x| {
1050 if let Constant::Str(s) = x {
1053 // We checked the type of the constant above
1057 if !check_path(cx, &path[..]);
1059 span_lint(cx, INVALID_PATHS, item.span, "invalid path");
1066 pub struct InterningDefinedSymbol {
1067 // Maps the symbol value to the constant DefId.
1068 symbol_map: FxHashMap<u32, DefId>,
1071 impl_lint_pass!(InterningDefinedSymbol => [INTERNING_DEFINED_SYMBOL, UNNECESSARY_SYMBOL_STR]);
1073 impl<'tcx> LateLintPass<'tcx> for InterningDefinedSymbol {
1074 fn check_crate(&mut self, cx: &LateContext<'_>) {
1075 if !self.symbol_map.is_empty() {
1079 for &module in &[&paths::KW_MODULE, &paths::SYM_MODULE] {
1080 if let Some(def_id) = def_path_res(cx, module).opt_def_id() {
1081 for item in cx.tcx.module_children(def_id).iter() {
1083 if let Res::Def(DefKind::Const, item_def_id) = item.res;
1084 let ty = cx.tcx.type_of(item_def_id);
1085 if match_type(cx, ty, &paths::SYMBOL);
1086 if let Ok(ConstValue::Scalar(value)) = cx.tcx.const_eval_poly(item_def_id);
1087 if let Ok(value) = value.to_u32();
1089 self.symbol_map.insert(value, item_def_id);
1097 fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
1099 if let ExprKind::Call(func, [arg]) = &expr.kind;
1100 if let ty::FnDef(def_id, _) = cx.typeck_results().expr_ty(func).kind();
1101 if match_def_path(cx, *def_id, &paths::SYMBOL_INTERN);
1102 if let Some(Constant::Str(arg)) = constant_simple(cx, cx.typeck_results(), arg);
1103 let value = Symbol::intern(&arg).as_u32();
1104 if let Some(&def_id) = self.symbol_map.get(&value);
1108 INTERNING_DEFINED_SYMBOL,
1109 is_expn_of(expr.span, "sym").unwrap_or(expr.span),
1110 "interning a defined symbol",
1112 cx.tcx.def_path_str(def_id),
1113 Applicability::MachineApplicable,
1117 if let ExprKind::Binary(op, left, right) = expr.kind {
1118 if matches!(op.node, BinOpKind::Eq | BinOpKind::Ne) {
1120 (left, self.symbol_str_expr(left, cx)),
1121 (right, self.symbol_str_expr(right, cx)),
1124 // both operands are a symbol string
1125 [(_, Some(left)), (_, Some(right))] => {
1128 UNNECESSARY_SYMBOL_STR,
1130 "unnecessary `Symbol` to string conversion",
1134 left.as_symbol_snippet(cx),
1136 right.as_symbol_snippet(cx),
1138 Applicability::MachineApplicable,
1141 // one of the operands is a symbol string
1142 [(expr, Some(symbol)), _] | [_, (expr, Some(symbol))] => {
1143 // creating an owned string for comparison
1144 if matches!(symbol, SymbolStrExpr::Expr { is_to_owned: true, .. }) {
1147 UNNECESSARY_SYMBOL_STR,
1149 "unnecessary string allocation",
1151 format!("{}.as_str()", symbol.as_symbol_snippet(cx)),
1152 Applicability::MachineApplicable,
1157 [(_, None), (_, None)] => {},
1164 impl InterningDefinedSymbol {
1165 fn symbol_str_expr<'tcx>(&self, expr: &'tcx Expr<'tcx>, cx: &LateContext<'tcx>) -> Option<SymbolStrExpr<'tcx>> {
1166 static IDENT_STR_PATHS: &[&[&str]] = &[&paths::IDENT_AS_STR, &paths::TO_STRING_METHOD];
1167 static SYMBOL_STR_PATHS: &[&[&str]] = &[
1168 &paths::SYMBOL_AS_STR,
1169 &paths::SYMBOL_TO_IDENT_STRING,
1170 &paths::TO_STRING_METHOD,
1172 let call = if_chain! {
1173 if let ExprKind::AddrOf(_, _, e) = expr.kind;
1174 if let ExprKind::Unary(UnOp::Deref, e) = e.kind;
1175 then { e } else { expr }
1179 if let ExprKind::MethodCall(_, item, [], _) = call.kind;
1180 if let Some(did) = cx.typeck_results().type_dependent_def_id(call.hir_id);
1181 let ty = cx.typeck_results().expr_ty(item);
1182 // ...on either an Ident or a Symbol
1183 if let Some(is_ident) = if match_type(cx, ty, &paths::SYMBOL) {
1185 } else if match_type(cx, ty, &paths::IDENT) {
1190 // ...which converts it to a string
1191 let paths = if is_ident { IDENT_STR_PATHS } else { SYMBOL_STR_PATHS };
1192 if let Some(path) = paths.iter().find(|path| match_def_path(cx, did, path));
1194 let is_to_owned = path.last().unwrap().ends_with("string");
1195 return Some(SymbolStrExpr::Expr {
1202 // is a string constant
1203 if let Some(Constant::Str(s)) = constant_simple(cx, cx.typeck_results(), expr) {
1204 let value = Symbol::intern(&s).as_u32();
1205 // ...which matches a symbol constant
1206 if let Some(&def_id) = self.symbol_map.get(&value) {
1207 return Some(SymbolStrExpr::Const(def_id));
1214 enum SymbolStrExpr<'tcx> {
1215 /// a string constant with a corresponding symbol constant
1217 /// a "symbol to string" expression like `symbol.as_str()`
1219 /// part that evaluates to `Symbol` or `Ident`
1220 item: &'tcx Expr<'tcx>,
1222 /// whether an owned `String` is created like `to_ident_string()`
1227 impl<'tcx> SymbolStrExpr<'tcx> {
1228 /// Returns a snippet that evaluates to a `Symbol` and is const if possible
1229 fn as_symbol_snippet(&self, cx: &LateContext<'_>) -> Cow<'tcx, str> {
1231 Self::Const(def_id) => cx.tcx.def_path_str(def_id).into(),
1232 Self::Expr { item, is_ident, .. } => {
1233 let mut snip = snippet(cx, item.span.source_callsite(), "..");
1236 snip.to_mut().push_str(".name");
1244 declare_lint_pass!(IfChainStyle => [IF_CHAIN_STYLE]);
1246 impl<'tcx> LateLintPass<'tcx> for IfChainStyle {
1247 fn check_block(&mut self, cx: &LateContext<'tcx>, block: &'tcx hir::Block<'_>) {
1248 let (local, after, if_chain_span) = if_chain! {
1249 if let [Stmt { kind: StmtKind::Local(local), .. }, after @ ..] = block.stmts;
1250 if let Some(if_chain_span) = is_expn_of(block.span, "if_chain");
1251 then { (local, after, if_chain_span) } else { return }
1253 if is_first_if_chain_expr(cx, block.hir_id, if_chain_span) {
1257 if_chain_local_span(cx, local, if_chain_span),
1258 "`let` expression should be above the `if_chain!`",
1260 } else if local.span.ctxt() == block.span.ctxt() && is_if_chain_then(after, block.expr, if_chain_span) {
1264 if_chain_local_span(cx, local, if_chain_span),
1265 "`let` expression should be inside `then { .. }`",
1270 fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>) {
1271 let (cond, then, els) = if let Some(higher::IfOrIfLet { cond, r#else, then }) = higher::IfOrIfLet::hir(expr) {
1272 (cond, then, r#else.is_some())
1276 let then_block = match then.kind {
1277 ExprKind::Block(block, _) => block,
1280 let if_chain_span = is_expn_of(expr.span, "if_chain");
1282 check_nested_if_chains(cx, expr, then_block, if_chain_span);
1284 let if_chain_span = match if_chain_span {
1288 // check for `if a && b;`
1290 if let ExprKind::Binary(op, _, _) = cond.kind;
1291 if op.node == BinOpKind::And;
1292 if cx.sess().source_map().is_multiline(cond.span);
1294 span_lint(cx, IF_CHAIN_STYLE, cond.span, "`if a && b;` should be `if a; if b;`");
1297 if is_first_if_chain_expr(cx, expr.hir_id, if_chain_span)
1298 && is_if_chain_then(then_block.stmts, then_block.expr, if_chain_span)
1300 span_lint(cx, IF_CHAIN_STYLE, expr.span, "`if_chain!` only has one `if`");
1305 fn check_nested_if_chains(
1306 cx: &LateContext<'_>,
1308 then_block: &Block<'_>,
1309 if_chain_span: Option<Span>,
1312 let (head, tail) = match *then_block {
1313 Block { stmts, expr: Some(tail), .. } => (stmts, tail),
1317 Stmt { kind: StmtKind::Expr(tail) | StmtKind::Semi(tail), .. }
1324 if let Some(higher::IfOrIfLet { r#else: None, .. }) = higher::IfOrIfLet::hir(tail);
1325 let sm = cx.sess().source_map();
1328 .all(|stmt| matches!(stmt.kind, StmtKind::Local(..)) && !sm.is_multiline(stmt.span));
1329 if if_chain_span.is_some() || !is_else_clause(cx.tcx, if_expr);
1330 then {} else { return }
1332 let (span, msg) = match (if_chain_span, is_expn_of(tail.span, "if_chain")) {
1333 (None, Some(_)) => (if_expr.span, "this `if` can be part of the inner `if_chain!`"),
1334 (Some(_), None) => (tail.span, "this `if` can be part of the outer `if_chain!`"),
1335 (Some(a), Some(b)) if a != b => (b, "this `if_chain!` can be merged with the outer `if_chain!`"),
1338 span_lint_and_then(cx, IF_CHAIN_STYLE, span, msg, |diag| {
1339 let (span, msg) = match head {
1341 [stmt] => (stmt.span, "this `let` statement can also be in the `if_chain!`"),
1344 "these `let` statements can also be in the `if_chain!`",
1347 diag.span_help(span, msg);
1351 fn is_first_if_chain_expr(cx: &LateContext<'_>, hir_id: HirId, if_chain_span: Span) -> bool {
1354 .parent_iter(hir_id)
1357 !matches!(node, Node::Expr(Expr { kind: ExprKind::Block(..), .. }) | Node::Stmt(_))
1359 .map_or(false, |(id, _)| {
1360 is_expn_of(cx.tcx.hir().span(id), "if_chain") != Some(if_chain_span)
1364 /// Checks a trailing slice of statements and expression of a `Block` to see if they are part
1365 /// of the `then {..}` portion of an `if_chain!`
1366 fn is_if_chain_then(stmts: &[Stmt<'_>], expr: Option<&Expr<'_>>, if_chain_span: Span) -> bool {
1367 let span = if let [stmt, ..] = stmts {
1369 } else if let Some(expr) = expr {
1375 is_expn_of(span, "if_chain").map_or(true, |span| span != if_chain_span)
1378 /// Creates a `Span` for `let x = ..;` in an `if_chain!` call.
1379 fn if_chain_local_span(cx: &LateContext<'_>, local: &Local<'_>, if_chain_span: Span) -> Span {
1380 let mut span = local.pat.span;
1381 if let Some(init) = local.init {
1382 span = span.to(init.span);
1384 span.adjust(if_chain_span.ctxt().outer_expn());
1385 let sm = cx.sess().source_map();
1386 let span = sm.span_extend_to_prev_str(span, "let", false, true).unwrap_or(span);
1387 let span = sm.span_extend_to_next_char(span, ';', false);
1389 span.lo() - BytePos(3),
1390 span.hi() + BytePos(1),
1396 declare_lint_pass!(MsrvAttrImpl => [MISSING_MSRV_ATTR_IMPL]);
1398 impl LateLintPass<'_> for MsrvAttrImpl {
1399 fn check_item(&mut self, cx: &LateContext<'_>, item: &hir::Item<'_>) {
1401 if let hir::ItemKind::Impl(hir::Impl {
1402 of_trait: Some(lint_pass_trait_ref),
1407 if let Some(lint_pass_trait_def_id) = lint_pass_trait_ref.trait_def_id();
1408 let is_late_pass = match_def_path(cx, lint_pass_trait_def_id, &paths::LATE_LINT_PASS);
1409 if is_late_pass || match_def_path(cx, lint_pass_trait_def_id, &paths::EARLY_LINT_PASS);
1410 let self_ty = hir_ty_to_ty(cx.tcx, self_ty);
1411 if let ty::Adt(self_ty_def, _) = self_ty.kind();
1412 if self_ty_def.is_struct();
1413 if self_ty_def.all_fields().any(|f| {
1417 .filter(|t| matches!(t.unpack(), GenericArgKind::Type(_)))
1418 .any(|t| match_type(cx, t.expect_ty(), &paths::RUSTC_VERSION))
1420 if !items.iter().any(|item| item.ident.name == sym!(enter_lint_attrs));
1422 let context = if is_late_pass { "LateContext" } else { "EarlyContext" };
1423 let lint_pass = if is_late_pass { "LateLintPass" } else { "EarlyLintPass" };
1424 let span = cx.sess().source_map().span_through_char(item.span, '{');
1427 MISSING_MSRV_ATTR_IMPL,
1429 &format!("`extract_msrv_attr!` macro missing from `{lint_pass}` implementation"),
1430 &format!("add `extract_msrv_attr!({context})` to the `{lint_pass}` implementation"),
1431 format!("{}\n extract_msrv_attr!({context});", snippet(cx, span, "..")),
1432 Applicability::MachineApplicable,