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Auto merge of #11370 - modelflat:suggest-relpath-in-redundant-closure-for-method-calls, r=blyxyas

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[fix] [`redundant_closure_for_method_calls`] Suggest relative paths for local modules

Fixes #10854.

Currently, `redundant_closure_for_method_calls` suggest incorrect paths when a method defined on a struct within inline mod is referenced (see the description in the aforementioned issue for an example; also see [this playground link](https://play.rust-lang.org/?version=stable&mode=release&edition=2021&gist=f7d3c5b2663c9bd3ab7abdb0bd38ee43) for the current-version output for the test cases added in this PR). It will now try to construct a relative path path to the module and suggest it instead.

changelog: [`redundant_closure_for_method_calls`] Fix incorrect path suggestions for types within local modules
This commit is contained in:
bors 2024-01-29 14:53:54 +00:00
commit 3cd713a9f8
5 changed files with 271 additions and 33 deletions
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36
clippy_lints/src/eta_reduction.rs
View file

@ -3,15 +3,14 @@ use clippy_utils::higher::VecArgs;
use clippy_utils::source::snippet_opt;
use clippy_utils::ty::type_diagnostic_name;
use clippy_utils::usage::{local_used_after_expr, local_used_in};
use clippy_utils::{higher, is_adjusted, path_to_local, path_to_local_id};
use clippy_utils::{get_path_from_caller_to_method_type, higher, is_adjusted, path_to_local, path_to_local_id};
use rustc_errors::Applicability;
use rustc_hir::def_id::DefId;
use rustc_hir::{BindingAnnotation, Expr, ExprKind, FnRetTy, Param, PatKind, QPath, TyKind, Unsafety};
use rustc_infer::infer::TyCtxtInferExt;
use rustc_lint::{LateContext, LateLintPass};
use rustc_middle::ty::{
self, Binder, ClosureArgs, ClosureKind, EarlyBinder, FnSig, GenericArg, GenericArgKind, GenericArgsRef,
ImplPolarity, List, Region, RegionKind, Ty, TypeVisitableExt, TypeckResults,
self, Binder, ClosureArgs, ClosureKind, FnSig, GenericArg, GenericArgKind, ImplPolarity, List, Region, RegionKind,
Ty, TypeVisitableExt, TypeckResults,
};
use rustc_session::declare_lint_pass;
use rustc_span::symbol::sym;
@ -203,11 +202,12 @@ impl<'tcx> LateLintPass<'tcx> for EtaReduction {
"redundant closure",
|diag| {
let args = typeck.node_args(body.value.hir_id);
let name = get_ufcs_type_name(cx, method_def_id, args);
let caller = self_.hir_id.owner.def_id;
let type_name = get_path_from_caller_to_method_type(cx.tcx, caller, method_def_id, args);
diag.span_suggestion(
expr.span,
"replace the closure with the method itself",
format!("{}::{}", name, path.ident.name),
format!("{}::{}", type_name, path.ident.name),
Applicability::MachineApplicable,
);
},
@ -309,27 +309,3 @@ fn has_late_bound_to_non_late_bound_regions(from_sig: FnSig<'_>, to_sig: FnSig<'
.zip(to_sig.inputs_and_output)
.any(|(from_ty, to_ty)| check_ty(from_ty, to_ty))
}
fn get_ufcs_type_name<'tcx>(cx: &LateContext<'tcx>, method_def_id: DefId, args: GenericArgsRef<'tcx>) -> String {
let assoc_item = cx.tcx.associated_item(method_def_id);
let def_id = assoc_item.container_id(cx.tcx);
match assoc_item.container {
ty::TraitContainer => cx.tcx.def_path_str(def_id),
ty::ImplContainer => {
let ty = cx.tcx.type_of(def_id).instantiate_identity();
match ty.kind() {
ty::Adt(adt, _) => cx.tcx.def_path_str(adt.did()),
ty::Array(..)
| ty::Dynamic(..)
| ty::Never
| ty::RawPtr(_)
| ty::Ref(..)
| ty::Slice(_)
| ty::Tuple(_) => {
format!("<{}>", EarlyBinder::bind(ty).instantiate(cx.tcx, args))
},
_ => ty.to_string(),
}
},
}
}

134
clippy_utils/src/lib.rs
View file

@ -75,6 +75,7 @@ use core::mem;
use core::ops::ControlFlow;
use std::collections::hash_map::Entry;
use std::hash::BuildHasherDefault;
use std::iter::{once, repeat};
use std::sync::{Mutex, MutexGuard, OnceLock};
use itertools::Itertools;
@ -84,6 +85,7 @@ use rustc_data_structures::packed::Pu128;
use rustc_data_structures::unhash::UnhashMap;
use rustc_hir::def::{DefKind, Res};
use rustc_hir::def_id::{CrateNum, DefId, LocalDefId, LocalModDefId, LOCAL_CRATE};
use rustc_hir::definitions::{DefPath, DefPathData};
use rustc_hir::hir_id::{HirIdMap, HirIdSet};
use rustc_hir::intravisit::{walk_expr, FnKind, Visitor};
use rustc_hir::LangItem::{OptionNone, OptionSome, ResultErr, ResultOk};
@ -102,8 +104,8 @@ use rustc_middle::ty::binding::BindingMode;
use rustc_middle::ty::fast_reject::SimplifiedType;
use rustc_middle::ty::layout::IntegerExt;
use rustc_middle::ty::{
self as rustc_ty, Binder, BorrowKind, ClosureKind, FloatTy, IntTy, ParamEnv, ParamEnvAnd, Ty, TyCtxt, TypeAndMut,
TypeVisitableExt, UintTy, UpvarCapture,
self as rustc_ty, Binder, BorrowKind, ClosureKind, EarlyBinder, FloatTy, GenericArgsRef, IntTy, ParamEnv,
ParamEnvAnd, Ty, TyCtxt, TypeAndMut, TypeVisitableExt, UintTy, UpvarCapture,
};
use rustc_span::hygiene::{ExpnKind, MacroKind};
use rustc_span::source_map::SourceMap;
@ -3264,3 +3266,131 @@ pub fn is_never_expr<'tcx>(cx: &LateContext<'tcx>, e: &'tcx Expr<'_>) -> Option<
})
}
}
/// Produces a path from a local caller to the type of the called method. Suitable for user
/// output/suggestions.
///
/// Returned path can be either absolute (for methods defined non-locally), or relative (for local
/// methods).
pub fn get_path_from_caller_to_method_type<'tcx>(
tcx: TyCtxt<'tcx>,
from: LocalDefId,
method: DefId,
args: GenericArgsRef<'tcx>,
) -> String {
let assoc_item = tcx.associated_item(method);
let def_id = assoc_item.container_id(tcx);
match assoc_item.container {
rustc_ty::TraitContainer => get_path_to_callee(tcx, from, def_id),
rustc_ty::ImplContainer => {
let ty = tcx.type_of(def_id).instantiate_identity();
get_path_to_ty(tcx, from, ty, args)
},
}
}
fn get_path_to_ty<'tcx>(tcx: TyCtxt<'tcx>, from: LocalDefId, ty: Ty<'tcx>, args: GenericArgsRef<'tcx>) -> String {
match ty.kind() {
rustc_ty::Adt(adt, _) => get_path_to_callee(tcx, from, adt.did()),
// TODO these types need to be recursively resolved as well
rustc_ty::Array(..)
| rustc_ty::Dynamic(..)
| rustc_ty::Never
| rustc_ty::RawPtr(_)
| rustc_ty::Ref(..)
| rustc_ty::Slice(_)
| rustc_ty::Tuple(_) => format!("<{}>", EarlyBinder::bind(ty).instantiate(tcx, args)),
_ => ty.to_string(),
}
}
/// Produce a path from some local caller to the callee. Suitable for user output/suggestions.
fn get_path_to_callee(tcx: TyCtxt<'_>, from: LocalDefId, callee: DefId) -> String {
// only search for a relative path if the call is fully local
if callee.is_local() {
let callee_path = tcx.def_path(callee);
let caller_path = tcx.def_path(from.to_def_id());
maybe_get_relative_path(&caller_path, &callee_path, 2)
} else {
tcx.def_path_str(callee)
}
}
/// Tries to produce a relative path from `from` to `to`; if such a path would contain more than
/// `max_super` `super` items, produces an absolute path instead. Both `from` and `to` should be in
/// the local crate.
///
/// Suitable for user output/suggestions.
///
/// This ignores use items, and assumes that the target path is visible from the source
/// path (which _should_ be a reasonable assumption since we in order to be able to use an object of
/// certain type T, T is required to be visible).
///
/// TODO make use of `use` items. Maybe we should have something more sophisticated like
/// rust-analyzer does? <https://docs.rs/ra_ap_hir_def/0.0.169/src/ra_ap_hir_def/find_path.rs.html#19-27>
fn maybe_get_relative_path(from: &DefPath, to: &DefPath, max_super: usize) -> String {
use itertools::EitherOrBoth::{Both, Left, Right};
// 1. skip the segments common for both paths (regardless of their type)
let unique_parts = to
.data
.iter()
.zip_longest(from.data.iter())
.skip_while(|el| matches!(el, Both(l, r) if l == r))
.map(|el| match el {
Both(l, r) => Both(l.data, r.data),
Left(l) => Left(l.data),
Right(r) => Right(r.data),
});
// 2. for the remaning segments, construct relative path using only mod names and `super`
let mut go_up_by = 0;
let mut path = Vec::new();
for el in unique_parts {
match el {
Both(l, r) => {
// consider:
// a::b::sym:: :: refers to
// c::d::e ::f::sym
// result should be super::super::c::d::e::f
//
// alternatively:
// a::b::c ::d::sym refers to
// e::f::sym:: ::
// result should be super::super::super::super::e::f
if let DefPathData::TypeNs(s) = l {
path.push(s.to_string());
}
if let DefPathData::TypeNs(_) = r {
go_up_by += 1;
}
},
// consider:
// a::b::sym:: :: refers to
// c::d::e ::f::sym
// when looking at `f`
Left(DefPathData::TypeNs(sym)) => path.push(sym.to_string()),
// consider:
// a::b::c ::d::sym refers to
// e::f::sym:: ::
// when looking at `d`
Right(DefPathData::TypeNs(_)) => go_up_by += 1,
_ => {},
}
}
if go_up_by > max_super {
// `super` chain would be too long, just use the absolute path instead
once(String::from("crate"))
.chain(to.data.iter().filter_map(|el| {
if let DefPathData::TypeNs(sym) = el.data {
Some(sym.to_string())
} else {
None
}
}))
.join("::")
} else {
repeat(String::from("super")).take(go_up_by).chain(path).join("::")
}
}

54
tests/ui/eta.fixed
View file

@ -417,3 +417,57 @@ fn _closure_with_types() {
let _ = f2(|x: u32| f(x));
let _ = f2(|x| -> u32 { f(x) });
}
/// https://github.com/rust-lang/rust-clippy/issues/10854
/// This is to verify that redundant_closure_for_method_calls resolves suggested paths to relative.
mod issue_10854 {
pub mod test_mod {
pub struct Test;
impl Test {
pub fn method(self) -> i32 {
0
}
}
pub fn calls_test(test: Option<Test>) -> Option<i32> {
test.map(Test::method)
}
pub fn calls_outer(test: Option<super::Outer>) -> Option<i32> {
test.map(super::Outer::method)
}
}
pub struct Outer;
impl Outer {
pub fn method(self) -> i32 {
0
}
}
pub fn calls_into_mod(test: Option<test_mod::Test>) -> Option<i32> {
test.map(test_mod::Test::method)
}
mod a {
pub mod b {
pub mod c {
pub fn extreme_nesting(test: Option<super::super::super::d::Test>) -> Option<i32> {
test.map(crate::issue_10854::d::Test::method)
}
}
}
}
mod d {
pub struct Test;
impl Test {
pub fn method(self) -> i32 {
0
}
}
}
}

54
tests/ui/eta.rs
View file

@ -417,3 +417,57 @@ fn _closure_with_types() {
let _ = f2(|x: u32| f(x));
let _ = f2(|x| -> u32 { f(x) });
}
/// https://github.com/rust-lang/rust-clippy/issues/10854
/// This is to verify that redundant_closure_for_method_calls resolves suggested paths to relative.
mod issue_10854 {
pub mod test_mod {
pub struct Test;
impl Test {
pub fn method(self) -> i32 {
0
}
}
pub fn calls_test(test: Option<Test>) -> Option<i32> {
test.map(|t| t.method())
}
pub fn calls_outer(test: Option<super::Outer>) -> Option<i32> {
test.map(|t| t.method())
}
}
pub struct Outer;
impl Outer {
pub fn method(self) -> i32 {
0
}
}
pub fn calls_into_mod(test: Option<test_mod::Test>) -> Option<i32> {
test.map(|t| t.method())
}
mod a {
pub mod b {
pub mod c {
pub fn extreme_nesting(test: Option<super::super::super::d::Test>) -> Option<i32> {
test.map(|t| t.method())
}
}
}
}
mod d {
pub struct Test;
impl Test {
pub fn method(self) -> i32 {
0
}
}
}
}

26
tests/ui/eta.stderr
View file

@ -166,5 +166,29 @@ error: redundant closure
LL | let _ = f(&0, |x, y| f2(x, y));
| ^^^^^^^^^^^^^^^ help: replace the closure with the function itself: `f2`
error: aborting due to 27 previous errors
error: redundant closure
--> $DIR/eta.rs:434:22
|
LL | test.map(|t| t.method())
| ^^^^^^^^^^^^^^ help: replace the closure with the method itself: `Test::method`
error: redundant closure
--> $DIR/eta.rs:438:22
|
LL | test.map(|t| t.method())
| ^^^^^^^^^^^^^^ help: replace the closure with the method itself: `super::Outer::method`
error: redundant closure
--> $DIR/eta.rs:451:18
|
LL | test.map(|t| t.method())
| ^^^^^^^^^^^^^^ help: replace the closure with the method itself: `test_mod::Test::method`
error: redundant closure
--> $DIR/eta.rs:458:30
|
LL | test.map(|t| t.method())
| ^^^^^^^^^^^^^^ help: replace the closure with the method itself: `crate::issue_10854::d::Test::method`
error: aborting due to 31 previous errors