use crate::utils;
-use crate::utils::paths;
use crate::utils::sugg::Sugg;
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::sym;
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:**
///
/// Detect if the two expressions are mirrored (identical, except one
/// contains a and the other replaces it with b)
fn mirrored_exprs(
- cx: &LateContext<'_, '_>,
+ cx: &LateContext<'_>,
a_expr: &Expr<'_>,
a_ident: &Ident,
b_expr: &Expr<'_>,
// The two exprs are method calls.
// Check to see that the function is the same and the arguments are mirrored
// This is enough because the receiver of the method is listed in the arguments
- (ExprKind::MethodCall(left_segment, _, left_args, _), ExprKind::MethodCall(right_segment, _, right_args, _)) => {
+ (
+ ExprKind::MethodCall(left_segment, _, left_args, _),
+ ExprKind::MethodCall(right_segment, _, right_args, _),
+ ) => {
left_segment.ident == right_segment.ident
&& left_args
.iter()
}
}
-fn detect_lint(cx: &LateContext<'_, '_>, expr: &Expr<'_>) -> Option<LintTrigger> {
+fn detect_lint(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<LintTrigger> {
if_chain! {
if let ExprKind::MethodCall(name_ident, _, args, _) = &expr.kind;
if let name = name_ident.ident.name.to_ident_string();
if name == "sort_by" || name == "sort_unstable_by";
if let [vec, Expr { kind: ExprKind::Closure(_, _, closure_body_id, _, _), .. }] = args;
- if utils::match_type(cx, &cx.tables.expr_ty(vec), &paths::VEC);
+ if utils::is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(vec), sym::vec_type);
if let closure_body = cx.tcx.hir().body(*closure_body_id);
if let &[
Param { pat: Pat { kind: PatKind::Binding(_, _, left_ident, _), .. }, ..},
Param { pat: Pat { kind: PatKind::Binding(_, _, right_ident, _), .. }, .. }
] = &closure_body.params;
if let ExprKind::MethodCall(method_path, _, [ref left_expr, ref right_expr], _) = &closure_body.value.kind;
- if method_path.ident.name.to_ident_string() == "cmp";
+ if method_path.ident.name == sym::cmp;
then {
let (closure_body, closure_arg, reverse) = if mirrored_exprs(
&cx,
};
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
- }))
+
+ if let ExprKind::Path(QPath::Resolved(_, Path {
+ segments: [PathSegment { ident: left_name, .. }], ..
+ })) = &left_expr.kind {
+ if left_name == left_ident {
+ return Some(LintTrigger::Sort(SortDetection { vec_name, unstable }));
}
}
- } else {
- None
+
+ if !expr_borrows(cx, left_expr) {
+ return Some(LintTrigger::SortByKey(SortByKeyDetection {
+ vec_name,
+ closure_arg,
+ closure_body,
+ reverse,
+ unstable,
+ }));
+ }
}
}
+
+ None
+}
+
+fn expr_borrows(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
+ let ty = cx.typeck_results().expr_ty(expr);
+ matches!(ty.kind(), ty::Ref(..)) || ty.walk().any(|arg| matches!(arg.unpack(), GenericArgKind::Lifetime(_)))
}
-impl LateLintPass<'_, '_> for UnnecessarySortBy {
- fn check_expr(&mut self, cx: &LateContext<'_, '_>, expr: &Expr<'_>) {
+impl LateLintPass<'_> for UnnecessarySortBy {
+ fn check_expr(&mut self, cx: &LateContext<'_>, expr: &Expr<'_>) {
match detect_lint(cx, expr) {
Some(LintTrigger::SortByKey(trigger)) => utils::span_lint_and_sugg(
cx,
"use Vec::sort_by_key here instead",
"try",
format!(
- "{}.sort{}_by_key(|&{}| {})",
+ "{}.sort{}_by_key(|{}| {})",
trigger.vec_name,
if trigger.unstable { "_unstable" } else { "" },
trigger.closure_arg,
projects / rust.git / blobdiff