diff --git a/clippy_lints/src/let_and_return.rs b/clippy_lints/src/let_and_return.rs index ddc41f89f..fa560ffb9 100644 --- a/clippy_lints/src/let_and_return.rs +++ b/clippy_lints/src/let_and_return.rs @@ -1,6 +1,5 @@ use if_chain::if_chain; use rustc_errors::Applicability; -use rustc_hir::def_id::DefId; use rustc_hir::intravisit::{walk_expr, NestedVisitorMap, Visitor}; use rustc_hir::{Block, Expr, ExprKind, PatKind, StmtKind}; use rustc_lint::{LateContext, LateLintPass, LintContext}; @@ -9,7 +8,7 @@ use rustc_middle::lint::in_external_macro; use rustc_middle::ty::subst::GenericArgKind; use rustc_session::{declare_lint_pass, declare_tool_lint}; -use crate::utils::{in_macro, match_qpath, snippet_opt, span_lint_and_then}; +use crate::utils::{fn_def_id, in_macro, match_qpath, snippet_opt, span_lint_and_then}; declare_clippy_lint! { /// **What it does:** Checks for `let`-bindings, which are subsequently @@ -97,22 +96,6 @@ struct BorrowVisitor<'a, 'tcx> { borrows: bool, } -impl BorrowVisitor<'_, '_> { - fn fn_def_id(&self, expr: &Expr<'_>) -> Option { - match &expr.kind { - ExprKind::MethodCall(..) => self.cx.tables().type_dependent_def_id(expr.hir_id), - ExprKind::Call( - Expr { - kind: ExprKind::Path(qpath), - .. - }, - .., - ) => self.cx.qpath_res(qpath, expr.hir_id).opt_def_id(), - _ => None, - } - } -} - impl<'tcx> Visitor<'tcx> for BorrowVisitor<'_, 'tcx> { type Map = Map<'tcx>; @@ -121,7 +104,7 @@ impl<'tcx> Visitor<'tcx> for BorrowVisitor<'_, 'tcx> { return; } - if let Some(def_id) = self.fn_def_id(expr) { + if let Some(def_id) = fn_def_id(self.cx, expr) { self.borrows = self .cx .tcx diff --git a/clippy_lints/src/unnecessary_sort_by.rs b/clippy_lints/src/unnecessary_sort_by.rs index d94077681..91c1789a2 100644 --- a/clippy_lints/src/unnecessary_sort_by.rs +++ b/clippy_lints/src/unnecessary_sort_by.rs @@ -5,24 +5,23 @@ use if_chain::if_chain; use rustc_errors::Applicability; use rustc_hir::{Expr, ExprKind, Mutability, Param, Pat, PatKind, Path, PathSegment, QPath}; use rustc_lint::{LateContext, LateLintPass}; +use rustc_middle::ty::{self, subst::GenericArgKind}; use rustc_session::{declare_lint_pass, declare_tool_lint}; use rustc_span::symbol::Ident; declare_clippy_lint! { /// **What it does:** - /// Detects when people use `Vec::sort_by` and pass in a function + /// Detects uses of `Vec::sort_by` passing in a closure /// which compares the two arguments, either directly or indirectly. /// /// **Why is this bad?** /// It is more clear to use `Vec::sort_by_key` (or `Vec::sort` if - /// possible) than to use `Vec::sort_by` and and a more complicated + /// possible) than to use `Vec::sort_by` and a more complicated /// closure. /// /// **Known problems:** - /// If the suggested `Vec::sort_by_key` uses Reverse and it isn't - /// imported by a use statement in the current frame, then a `use` - /// statement that imports it will need to be added (which this lint - /// can't do). + /// If the suggested `Vec::sort_by_key` uses Reverse and it isn't already + /// imported by a use statement, then it will need to be added manually. /// /// **Example:** /// @@ -201,28 +200,41 @@ fn detect_lint(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option { }; let vec_name = Sugg::hir(cx, &args[0], "..").to_string(); let unstable = name == "sort_unstable_by"; + if_chain! { if let ExprKind::Path(QPath::Resolved(_, Path { segments: [PathSegment { ident: left_name, .. }], .. })) = &left_expr.kind; if left_name == left_ident; then { - Some(LintTrigger::Sort(SortDetection { vec_name, unstable })) - } - else { - Some(LintTrigger::SortByKey(SortByKeyDetection { - vec_name, - unstable, - closure_arg, - closure_body, - reverse - })) + return Some(LintTrigger::Sort(SortDetection { vec_name, unstable })) + } else { + if !key_returns_borrow(cx, left_expr) { + return Some(LintTrigger::SortByKey(SortByKeyDetection { + vec_name, + unstable, + closure_arg, + closure_body, + reverse + })) + } } } - } else { - None } } + + None +} + +fn key_returns_borrow(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool { + if let Some(def_id) = utils::fn_def_id(cx, expr) { + let output = cx.tcx.fn_sig(def_id).output(); + let ty = output.skip_binder(); + return matches!(ty.kind, ty::Ref(..)) + || ty.walk().any(|arg| matches!(arg.unpack(), GenericArgKind::Lifetime(_))); + } + + false } impl LateLintPass<'_> for UnnecessarySortBy { diff --git a/clippy_lints/src/utils/mod.rs b/clippy_lints/src/utils/mod.rs index 3a3b79925..93075b9f0 100644 --- a/clippy_lints/src/utils/mod.rs +++ b/clippy_lints/src/utils/mod.rs @@ -1363,6 +1363,21 @@ pub fn fn_has_unsatisfiable_preds(cx: &LateContext<'_>, did: DefId) -> bool { ) } +/// Returns the `DefId` of the callee if the given expression is a function or method call. +pub fn fn_def_id(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option { + match &expr.kind { + ExprKind::MethodCall(..) => cx.tables().type_dependent_def_id(expr.hir_id), + ExprKind::Call( + Expr { + kind: ExprKind::Path(qpath), + .. + }, + .., + ) => cx.tables().qpath_res(qpath, expr.hir_id).opt_def_id(), + _ => None, + } +} + pub fn run_lints(cx: &LateContext<'_>, lints: &[&'static Lint], id: HirId) -> bool { lints.iter().any(|lint| { matches!( diff --git a/tests/ui/unnecessary_sort_by.fixed b/tests/ui/unnecessary_sort_by.fixed index 779fd5770..c017d1cf9 100644 --- a/tests/ui/unnecessary_sort_by.fixed +++ b/tests/ui/unnecessary_sort_by.fixed @@ -2,11 +2,11 @@ use std::cmp::Reverse; -fn id(x: isize) -> isize { - x -} +fn unnecessary_sort_by() { + fn id(x: isize) -> isize { + x + } -fn main() { let mut vec: Vec = vec![3, 6, 1, 2, 5]; // Forward examples vec.sort(); @@ -24,3 +24,41 @@ fn main() { vec.sort_by(|_, b| b.cmp(c)); vec.sort_unstable_by(|a, _| a.cmp(c)); } + +// Should not be linted to avoid hitting https://github.com/rust-lang/rust/issues/34162 +mod issue_5754 { + struct Test(String); + + #[derive(PartialOrd, Ord, PartialEq, Eq)] + struct Wrapper<'a>(&'a str); + + impl Test { + fn name(&self) -> &str { + &self.0 + } + + fn wrapped(&self) -> Wrapper<'_> { + Wrapper(&self.0) + } + } + + pub fn test() { + let mut args: Vec = vec![]; + + // Forward + args.sort_by(|a, b| a.name().cmp(b.name())); + args.sort_by(|a, b| a.wrapped().cmp(&b.wrapped())); + args.sort_unstable_by(|a, b| a.name().cmp(b.name())); + args.sort_unstable_by(|a, b| a.wrapped().cmp(&b.wrapped())); + // Reverse + args.sort_by(|a, b| b.name().cmp(a.name())); + args.sort_by(|a, b| b.wrapped().cmp(&a.wrapped())); + args.sort_unstable_by(|a, b| b.name().cmp(a.name())); + args.sort_unstable_by(|a, b| b.wrapped().cmp(&a.wrapped())); + } +} + +fn main() { + unnecessary_sort_by(); + issue_5754::test(); +} diff --git a/tests/ui/unnecessary_sort_by.rs b/tests/ui/unnecessary_sort_by.rs index 0485a5630..1929c72b2 100644 --- a/tests/ui/unnecessary_sort_by.rs +++ b/tests/ui/unnecessary_sort_by.rs @@ -2,11 +2,11 @@ use std::cmp::Reverse; -fn id(x: isize) -> isize { - x -} +fn unnecessary_sort_by() { + fn id(x: isize) -> isize { + x + } -fn main() { let mut vec: Vec = vec![3, 6, 1, 2, 5]; // Forward examples vec.sort_by(|a, b| a.cmp(b)); @@ -24,3 +24,41 @@ fn main() { vec.sort_by(|_, b| b.cmp(c)); vec.sort_unstable_by(|a, _| a.cmp(c)); } + +// Should not be linted to avoid hitting https://github.com/rust-lang/rust/issues/34162 +mod issue_5754 { + struct Test(String); + + #[derive(PartialOrd, Ord, PartialEq, Eq)] + struct Wrapper<'a>(&'a str); + + impl Test { + fn name(&self) -> &str { + &self.0 + } + + fn wrapped(&self) -> Wrapper<'_> { + Wrapper(&self.0) + } + } + + pub fn test() { + let mut args: Vec = vec![]; + + // Forward + args.sort_by(|a, b| a.name().cmp(b.name())); + args.sort_by(|a, b| a.wrapped().cmp(&b.wrapped())); + args.sort_unstable_by(|a, b| a.name().cmp(b.name())); + args.sort_unstable_by(|a, b| a.wrapped().cmp(&b.wrapped())); + // Reverse + args.sort_by(|a, b| b.name().cmp(a.name())); + args.sort_by(|a, b| b.wrapped().cmp(&a.wrapped())); + args.sort_unstable_by(|a, b| b.name().cmp(a.name())); + args.sort_unstable_by(|a, b| b.wrapped().cmp(&a.wrapped())); + } +} + +fn main() { + unnecessary_sort_by(); + issue_5754::test(); +}