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factor out the rvalue lifetime rule

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remove region_scope_tree from RegionCtxt

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Co-authored-by: Niko Matsakis <niko@alum.mit.edu>
This commit is contained in:
Ding Xiang Fei 2022-04-01 21:12:18 +08:00
parent fc965c7300
commit e885157f03
2 changed files with 76 additions and 46 deletions
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76
clippy_lints/src/loops/needless_range_loop.rs
View file

@ -3,7 +3,9 @@ use clippy_utils::diagnostics::{multispan_sugg, span_lint_and_then};
use clippy_utils::source::snippet;
use clippy_utils::ty::has_iter_method;
use clippy_utils::visitors::is_local_used;
use clippy_utils::{contains_name, higher, is_integer_const, match_trait_method, paths, sugg, SpanlessEq};
use clippy_utils::{
contains_name, higher, is_integer_const, match_trait_method, paths, sugg, SpanlessEq,
};
use if_chain::if_chain;
use rustc_ast::ast;
use rustc_data_structures::fx::{FxHashMap, FxHashSet};
@ -27,12 +29,7 @@ pub(super) fn check<'tcx>(
body: &'tcx Expr<'_>,
expr: &'tcx Expr<'_>,
) {
if let Some(higher::Range {
start: Some(start),
ref end,
limits,
}) = higher::Range::hir(arg)
{
if let Some(higher::Range { start: Some(start), ref end, limits }) = higher::Range::hir(arg) {
// the var must be a single name
if let PatKind::Binding(_, canonical_id, ident, _) = pat.kind {
let mut visitor = VarVisitor {
@ -58,7 +55,11 @@ pub(super) fn check<'tcx>(
// ensure that the indexed variable was declared before the loop, see #601
if let Some(indexed_extent) = indexed_extent {
let parent_def_id = cx.tcx.hir().get_parent_item(expr.hir_id);
let region_scope_tree = cx.tcx.region_scope_tree(parent_def_id);
let parent_body_id = cx
.tcx
.hir()
.body_owned_by(cx.tcx.hir().local_def_id_to_hir_id(parent_def_id));
let region_scope_tree = &cx.tcx.typeck_body(parent_body_id).region_scope_tree;
let pat_extent = region_scope_tree.var_scope(pat.hir_id.local_id).unwrap();
if region_scope_tree.is_subscope_of(indexed_extent, pat_extent) {
return;
@ -107,17 +108,22 @@ pub(super) fn check<'tcx>(
}
}
if is_len_call(end, indexed) || is_end_eq_array_len(cx, end, limits, indexed_ty) {
if is_len_call(end, indexed) || is_end_eq_array_len(cx, end, limits, indexed_ty)
{
String::new()
} else if visitor.indexed_mut.contains(&indexed) && contains_name(indexed, take_expr) {
} else if visitor.indexed_mut.contains(&indexed)
&& contains_name(indexed, take_expr)
{
return;
} else {
match limits {
ast::RangeLimits::Closed => {
let take_expr = sugg::Sugg::hir(cx, take_expr, "<count>");
format!(".take({})", take_expr + sugg::ONE)
},
ast::RangeLimits::HalfOpen => format!(".take({})", snippet(cx, take_expr.span, "..")),
}
ast::RangeLimits::HalfOpen => {
format!(".take({})", snippet(cx, take_expr.span, ".."))
}
}
}
} else {
@ -143,7 +149,10 @@ pub(super) fn check<'tcx>(
cx,
NEEDLESS_RANGE_LOOP,
arg.span,
&format!("the loop variable `{}` is used to index `{}`", ident.name, indexed),
&format!(
"the loop variable `{}` is used to index `{}`",
ident.name, indexed
),
|diag| {
multispan_sugg(
diag,
@ -152,7 +161,10 @@ pub(super) fn check<'tcx>(
(pat.span, format!("({}, <item>)", ident.name)),
(
arg.span,
format!("{}.{}().enumerate(){}{}", indexed, method, method_1, method_2),
format!(
"{}.{}().enumerate(){}{}",
indexed, method, method_1, method_2
),
),
],
);
@ -169,7 +181,10 @@ pub(super) fn check<'tcx>(
cx,
NEEDLESS_RANGE_LOOP,
arg.span,
&format!("the loop variable `{}` is only used to index `{}`", ident.name, indexed),
&format!(
"the loop variable `{}` is only used to index `{}`",
ident.name, indexed
),
|diag| {
multispan_sugg(
diag,
@ -246,7 +261,12 @@ struct VarVisitor<'a, 'tcx> {
}
impl<'a, 'tcx> VarVisitor<'a, 'tcx> {
fn check(&mut self, idx: &'tcx Expr<'_>, seqexpr: &'tcx Expr<'_>, expr: &'tcx Expr<'_>) -> bool {
fn check(
&mut self,
idx: &'tcx Expr<'_>,
seqexpr: &'tcx Expr<'_>,
expr: &'tcx Expr<'_>,
) -> bool {
if_chain! {
// the indexed container is referenced by a name
if let ExprKind::Path(ref seqpath) = seqexpr.kind;
@ -262,7 +282,16 @@ impl<'a, 'tcx> VarVisitor<'a, 'tcx> {
match res {
Res::Local(hir_id) => {
let parent_def_id = self.cx.tcx.hir().get_parent_item(expr.hir_id);
let extent = self.cx.tcx.region_scope_tree(parent_def_id).var_scope(hir_id.local_id).unwrap();
let parent_body_id = self.cx
.tcx
.hir()
.body_owned_by(self.cx.tcx.hir().local_def_id_to_hir_id(parent_def_id));
let extent = self.cx
.tcx
.typeck_body(parent_body_id)
.region_scope_tree
.var_scope(hir_id.local_id)
.unwrap();
if index_used_directly {
self.indexed_directly.insert(
seqvar.segments[0].ident.name,
@ -331,13 +360,13 @@ impl<'a, 'tcx> Visitor<'tcx> for VarVisitor<'a, 'tcx> {
self.visit_expr(lhs);
self.prefer_mutable = false;
self.visit_expr(rhs);
},
}
ExprKind::AddrOf(BorrowKind::Ref, mutbl, expr) => {
if mutbl == Mutability::Mut {
self.prefer_mutable = true;
}
self.visit_expr(expr);
},
}
ExprKind::Call(f, args) => {
self.visit_expr(f);
for expr in args {
@ -350,10 +379,11 @@ impl<'a, 'tcx> Visitor<'tcx> for VarVisitor<'a, 'tcx> {
}
self.visit_expr(expr);
}
},
}
ExprKind::MethodCall(_, args, _) => {
let def_id = self.cx.typeck_results().type_dependent_def_id(expr.hir_id).unwrap();
for (ty, expr) in iter::zip(self.cx.tcx.fn_sig(def_id).inputs().skip_binder(), args) {
for (ty, expr) in iter::zip(self.cx.tcx.fn_sig(def_id).inputs().skip_binder(), args)
{
self.prefer_mutable = false;
if let ty::Ref(_, _, mutbl) = *ty.kind() {
if mutbl == Mutability::Mut {
@ -362,11 +392,11 @@ impl<'a, 'tcx> Visitor<'tcx> for VarVisitor<'a, 'tcx> {
}
self.visit_expr(expr);
}
},
}
ExprKind::Closure(_, _, body_id, ..) => {
let body = self.cx.tcx.hir().body(body_id);
self.visit_expr(&body.value);
},
}
_ => walk_expr(self, expr),
}
self.prefer_mutable = old;