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Refactor check_for_loop_over_map_kv to its own module

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nahuakang 2021-02-08 21:04:33 +01:00 • committed by Yoshitomo Nakanishi
parent 408368a82c
commit 7b0f588b77
2 changed files with 71 additions and 65 deletions
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69
clippy_lints/src/loops/for_loop_over_map_kv.rs Normal file
View file

@ -0,0 +1,69 @@
use crate::utils::visitors::LocalUsedVisitor;
use crate::utils::{is_type_diagnostic_item, match_type, multispan_sugg, paths, snippet, span_lint_and_then, sugg};
use rustc_hir::{BorrowKind, Expr, ExprKind, Mutability, Pat, PatKind};
use rustc_lint::LateContext;
use rustc_middle::ty;
/// Checks for the `FOR_KV_MAP` lint.
pub(super) fn check_for_loop_over_map_kv<'tcx>(
cx: &LateContext<'tcx>,
pat: &'tcx Pat<'_>,
arg: &'tcx Expr<'_>,
body: &'tcx Expr<'_>,
expr: &'tcx Expr<'_>,
) {
let pat_span = pat.span;
if let PatKind::Tuple(ref pat, _) = pat.kind {
if pat.len() == 2 {
let arg_span = arg.span;
let (new_pat_span, kind, ty, mutbl) = match *cx.typeck_results().expr_ty(arg).kind() {
ty::Ref(_, ty, mutbl) => match (&pat[0].kind, &pat[1].kind) {
(key, _) if pat_is_wild(key, body) => (pat[1].span, "value", ty, mutbl),
(_, value) if pat_is_wild(value, body) => (pat[0].span, "key", ty, Mutability::Not),
_ => return,
},
_ => return,
};
let mutbl = match mutbl {
Mutability::Not => "",
Mutability::Mut => "_mut",
};
let arg = match arg.kind {
ExprKind::AddrOf(BorrowKind::Ref, _, ref expr) => &**expr,
_ => arg,
};
if is_type_diagnostic_item(cx, ty, sym!(hashmap_type)) || match_type(cx, ty, &paths::BTREEMAP) {
span_lint_and_then(
cx,
super::FOR_KV_MAP,
expr.span,
&format!("you seem to want to iterate on a map's {}s", kind),
|diag| {
let map = sugg::Sugg::hir(cx, arg, "map");
multispan_sugg(
diag,
"use the corresponding method",
vec![
(pat_span, snippet(cx, new_pat_span, kind).into_owned()),
(arg_span, format!("{}.{}s{}()", map.maybe_par(), kind, mutbl)),
],
);
},
);
}
}
}
}
/// Returns `true` if the pattern is a `PatWild` or an ident prefixed with `_`.
fn pat_is_wild<'tcx>(pat: &'tcx PatKind<'_>, body: &'tcx Expr<'_>) -> bool {
match *pat {
PatKind::Wild => true,
PatKind::Binding(_, id, ident, None) if ident.as_str().starts_with('_') => {
!LocalUsedVisitor::new(id).check_expr(body)
},
_ => false,
}
}

67
clippy_lints/src/loops/mod.rs
View file

@ -1,4 +1,5 @@
mod for_loop_arg;
mod for_loop_over_map_kv;
mod manual_flatten;
mod utils;
@ -863,7 +864,7 @@ fn check_for_loop<'tcx>(
check_for_loop_explicit_counter(cx, pat, arg, body, expr);
}
for_loop_arg::check_for_loop_arg(cx, pat, arg, expr);
check_for_loop_over_map_kv(cx, pat, arg, body, expr);
for_loop_over_map_kv::check_for_loop_over_map_kv(cx, pat, arg, body, expr);
check_for_mut_range_bound(cx, arg, body);
check_for_single_element_loop(cx, pat, arg, body, expr);
detect_same_item_push(cx, pat, arg, body, expr);
@ -1732,59 +1733,6 @@ fn check_for_loop_explicit_counter<'tcx>(
}
}
/// Checks for the `FOR_KV_MAP` lint.
fn check_for_loop_over_map_kv<'tcx>(
cx: &LateContext<'tcx>,
pat: &'tcx Pat<'_>,
arg: &'tcx Expr<'_>,
body: &'tcx Expr<'_>,
expr: &'tcx Expr<'_>,
) {
let pat_span = pat.span;
if let PatKind::Tuple(ref pat, _) = pat.kind {
if pat.len() == 2 {
let arg_span = arg.span;
let (new_pat_span, kind, ty, mutbl) = match *cx.typeck_results().expr_ty(arg).kind() {
ty::Ref(_, ty, mutbl) => match (&pat[0].kind, &pat[1].kind) {
(key, _) if pat_is_wild(cx, key, body) => (pat[1].span, "value", ty, mutbl),
(_, value) if pat_is_wild(cx, value, body) => (pat[0].span, "key", ty, Mutability::Not),
_ => return,
},
_ => return,
};
let mutbl = match mutbl {
Mutability::Not => "",
Mutability::Mut => "_mut",
};
let arg = match arg.kind {
ExprKind::AddrOf(BorrowKind::Ref, _, ref expr) => &**expr,
_ => arg,
};
if is_type_diagnostic_item(cx, ty, sym!(hashmap_type)) || match_type(cx, ty, &paths::BTREEMAP) {
span_lint_and_then(
cx,
FOR_KV_MAP,
expr.span,
&format!("you seem to want to iterate on a map's {}s", kind),
|diag| {
let map = sugg::Sugg::hir(cx, arg, "map");
multispan_sugg(
diag,
"use the corresponding method",
vec![
(pat_span, snippet(cx, new_pat_span, kind).into_owned()),
(arg_span, format!("{}.{}s{}()", map.maybe_par(), kind, mutbl)),
],
);
},
);
}
}
}
}
fn check_for_single_element_loop<'tcx>(
cx: &LateContext<'tcx>,
pat: &'tcx Pat<'_>,
@ -1927,17 +1875,6 @@ fn check_for_mutation<'tcx>(
delegate.mutation_span()
}
/// Returns `true` if the pattern is a `PatWild` or an ident prefixed with `_`.
fn pat_is_wild<'tcx>(cx: &LateContext<'tcx>, pat: &'tcx PatKind<'_>, body: &'tcx Expr<'_>) -> bool {
match *pat {
PatKind::Wild => true,
PatKind::Binding(_, id, ident, None) if ident.as_str().starts_with('_') => {
!LocalUsedVisitor::new(cx, id).check_expr(body)
},
_ => false,
}
}
struct VarVisitor<'a, 'tcx> {
/// context reference
cx: &'a LateContext<'tcx>,