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Check clone_or_copy_needed in unnecessary_filter_map::check

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This commit is contained in:
Samuel E. Moelius III 2022-02-28 05:00:36 -05:00
parent cfd32522c0
commit d123ffc6c7
3 changed files with 95 additions and 90 deletions
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7
clippy_lints/src/methods/unnecessary_filter_map.rs
View file

@ -1,4 +1,6 @@
use super::utils::clone_or_copy_needed;
use clippy_utils::diagnostics::span_lint;
use clippy_utils::ty::is_copy;
use clippy_utils::usage::mutated_variables;
use clippy_utils::{is_lang_ctor, is_trait_method, path_to_local_id};
use rustc_hir as hir;
@ -20,6 +22,7 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, arg: &hir::Expr<
let arg_id = body.params[0].pat.hir_id;
let mutates_arg =
mutated_variables(&body.value, cx).map_or(true, |used_mutably| used_mutably.contains(&arg_id));
let (clone_or_copy_needed, _) = clone_or_copy_needed(cx, body.params[0].pat, &body.value);
let (mut found_mapping, mut found_filtering) = check_expression(cx, arg_id, &body.value);
@ -28,10 +31,10 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, arg: &hir::Expr<
found_mapping |= return_visitor.found_mapping;
found_filtering |= return_visitor.found_filtering;
let in_ty = cx.typeck_results().node_type(body.params[0].hir_id);
let sugg = if !found_filtering {
"map"
} else if !found_mapping && !mutates_arg {
let in_ty = cx.typeck_results().node_type(body.params[0].hir_id);
} else if !found_mapping && !mutates_arg && (!clone_or_copy_needed || is_copy(cx, in_ty)) {
match cx.typeck_results().expr_ty(&body.value).kind() {
ty::Adt(adt, subst) if cx.tcx.is_diagnostic_item(sym::Option, adt.did) && in_ty == subst.type_at(0) => {
"filter"

91
clippy_lints/src/methods/unnecessary_iter_cloned.rs
View file

@ -1,14 +1,12 @@
use super::utils::clone_or_copy_needed;
use clippy_utils::diagnostics::span_lint_and_then;
use clippy_utils::higher::ForLoop;
use clippy_utils::source::snippet_opt;
use clippy_utils::ty::{get_associated_type, get_iterator_item_ty, implements_trait};
use clippy_utils::{fn_def_id, get_parent_expr, path_to_local_id, usage};
use clippy_utils::{fn_def_id, get_parent_expr};
use rustc_errors::Applicability;
use rustc_hir::intravisit::{walk_expr, Visitor};
use rustc_hir::{def_id::DefId, BorrowKind, Expr, ExprKind, HirId, LangItem, Mutability, Pat};
use rustc_hir::{def_id::DefId, Expr, ExprKind, LangItem};
use rustc_lint::LateContext;
use rustc_middle::hir::nested_filter;
use rustc_middle::ty;
use rustc_span::{sym, Symbol};
use super::UNNECESSARY_TO_OWNED;
@ -100,89 +98,6 @@ pub fn check_for_loop_iter(
false
}
/// The core logic of `check_for_loop_iter` above, this function wraps a use of
/// `CloneOrCopyVisitor`.
fn clone_or_copy_needed<'tcx>(
cx: &LateContext<'tcx>,
pat: &Pat<'tcx>,
body: &'tcx Expr<'tcx>,
) -> (bool, Vec<&'tcx Expr<'tcx>>) {
let mut visitor = CloneOrCopyVisitor {
cx,
binding_hir_ids: pat_bindings(pat),
clone_or_copy_needed: false,
addr_of_exprs: Vec::new(),
};
visitor.visit_expr(body);
(visitor.clone_or_copy_needed, visitor.addr_of_exprs)
}
/// Returns a vector of all `HirId`s bound by the pattern.
fn pat_bindings(pat: &Pat<'_>) -> Vec<HirId> {
let mut collector = usage::ParamBindingIdCollector {
binding_hir_ids: Vec::new(),
};
collector.visit_pat(pat);
collector.binding_hir_ids
}
/// `clone_or_copy_needed` will be false when `CloneOrCopyVisitor` is done visiting if the only
/// operations performed on `binding_hir_ids` are:
/// * to take non-mutable references to them
/// * to use them as non-mutable `&self` in method calls
/// If any of `binding_hir_ids` is used in any other way, then `clone_or_copy_needed` will be true
/// when `CloneOrCopyVisitor` is done visiting.
struct CloneOrCopyVisitor<'cx, 'tcx> {
cx: &'cx LateContext<'tcx>,
binding_hir_ids: Vec<HirId>,
clone_or_copy_needed: bool,
addr_of_exprs: Vec<&'tcx Expr<'tcx>>,
}
impl<'cx, 'tcx> Visitor<'tcx> for CloneOrCopyVisitor<'cx, 'tcx> {
type NestedFilter = nested_filter::OnlyBodies;
fn nested_visit_map(&mut self) -> Self::Map {
self.cx.tcx.hir()
}
fn visit_expr(&mut self, expr: &'tcx Expr<'tcx>) {
walk_expr(self, expr);
if self.is_binding(expr) {
if let Some(parent) = get_parent_expr(self.cx, expr) {
match parent.kind {
ExprKind::AddrOf(BorrowKind::Ref, Mutability::Not, _) => {
self.addr_of_exprs.push(parent);
return;
},
ExprKind::MethodCall(_, args, _) => {
if_chain! {
if args.iter().skip(1).all(|arg| !self.is_binding(arg));
if let Some(method_def_id) = self.cx.typeck_results().type_dependent_def_id(parent.hir_id);
let method_ty = self.cx.tcx.type_of(method_def_id);
let self_ty = method_ty.fn_sig(self.cx.tcx).input(0).skip_binder();
if matches!(self_ty.kind(), ty::Ref(_, _, Mutability::Not));
then {
return;
}
}
},
_ => {},
}
}
self.clone_or_copy_needed = true;
}
}
}
impl<'cx, 'tcx> CloneOrCopyVisitor<'cx, 'tcx> {
fn is_binding(&self, expr: &Expr<'tcx>) -> bool {
self.binding_hir_ids
.iter()
.any(|hir_id| path_to_local_id(expr, *hir_id))
}
}
/// Returns true if the named method is `IntoIterator::into_iter`.
pub fn is_into_iter(cx: &LateContext<'_>, callee_def_id: DefId) -> bool {
cx.tcx.lang_items().require(LangItem::IntoIterIntoIter) == Ok(callee_def_id)

87
clippy_lints/src/methods/utils.rs
View file

@ -1,10 +1,14 @@
use clippy_utils::source::snippet_with_applicability;
use clippy_utils::ty::is_type_diagnostic_item;
use clippy_utils::{get_parent_expr, path_to_local_id, usage};
use if_chain::if_chain;
use rustc_ast::ast;
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_hir::intravisit::{walk_expr, Visitor};
use rustc_hir::{BorrowKind, Expr, ExprKind, HirId, Mutability, Pat};
use rustc_lint::LateContext;
use rustc_middle::hir::nested_filter;
use rustc_middle::ty::{self, Ty};
use rustc_span::symbol::sym;
@ -79,3 +83,86 @@ pub(super) fn get_hint_if_single_char_arg(
}
}
}
/// The core logic of `check_for_loop_iter` in `unnecessary_iter_cloned.rs`, this function wraps a
/// use of `CloneOrCopyVisitor`.
pub(super) fn clone_or_copy_needed<'tcx>(
cx: &LateContext<'tcx>,
pat: &Pat<'tcx>,
body: &'tcx Expr<'tcx>,
) -> (bool, Vec<&'tcx Expr<'tcx>>) {
let mut visitor = CloneOrCopyVisitor {
cx,
binding_hir_ids: pat_bindings(pat),
clone_or_copy_needed: false,
addr_of_exprs: Vec::new(),
};
visitor.visit_expr(body);
(visitor.clone_or_copy_needed, visitor.addr_of_exprs)
}
/// Returns a vector of all `HirId`s bound by the pattern.
fn pat_bindings(pat: &Pat<'_>) -> Vec<HirId> {
let mut collector = usage::ParamBindingIdCollector {
binding_hir_ids: Vec::new(),
};
collector.visit_pat(pat);
collector.binding_hir_ids
}
/// `clone_or_copy_needed` will be false when `CloneOrCopyVisitor` is done visiting if the only
/// operations performed on `binding_hir_ids` are:
/// * to take non-mutable references to them
/// * to use them as non-mutable `&self` in method calls
/// If any of `binding_hir_ids` is used in any other way, then `clone_or_copy_needed` will be true
/// when `CloneOrCopyVisitor` is done visiting.
struct CloneOrCopyVisitor<'cx, 'tcx> {
cx: &'cx LateContext<'tcx>,
binding_hir_ids: Vec<HirId>,
clone_or_copy_needed: bool,
addr_of_exprs: Vec<&'tcx Expr<'tcx>>,
}
impl<'cx, 'tcx> Visitor<'tcx> for CloneOrCopyVisitor<'cx, 'tcx> {
type NestedFilter = nested_filter::OnlyBodies;
fn nested_visit_map(&mut self) -> Self::Map {
self.cx.tcx.hir()
}
fn visit_expr(&mut self, expr: &'tcx Expr<'tcx>) {
walk_expr(self, expr);
if self.is_binding(expr) {
if let Some(parent) = get_parent_expr(self.cx, expr) {
match parent.kind {
ExprKind::AddrOf(BorrowKind::Ref, Mutability::Not, _) => {
self.addr_of_exprs.push(parent);
return;
},
ExprKind::MethodCall(_, args, _) => {
if_chain! {
if args.iter().skip(1).all(|arg| !self.is_binding(arg));
if let Some(method_def_id) = self.cx.typeck_results().type_dependent_def_id(parent.hir_id);
let method_ty = self.cx.tcx.type_of(method_def_id);
let self_ty = method_ty.fn_sig(self.cx.tcx).input(0).skip_binder();
if matches!(self_ty.kind(), ty::Ref(_, _, Mutability::Not));
then {
return;
}
}
},
_ => {},
}
}
self.clone_or_copy_needed = true;
}
}
}
impl<'cx, 'tcx> CloneOrCopyVisitor<'cx, 'tcx> {
fn is_binding(&self, expr: &Expr<'tcx>) -> bool {
self.binding_hir_ids
.iter()
.any(|hir_id| path_to_local_id(expr, *hir_id))
}
}