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FOR_KV_MAP can now lint on mutable maps due to values_mut() #1430

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Merged
merged 2 commits into from
Jan 10, 2017
Merged

FOR_KV_MAP can now lint on mutable maps due to values_mut() #1430

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e066997
FOR_KV_MAP can now lint on mutable maps due to values_mut()
oli-obk Jan 10, 2017
87db342
run rustfmt
Manishearth Jan 10, 2017
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29 changes: 18 additions & 11 deletions clippy_lints/src/loops.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -16,7 +16,7 @@ use utils::sugg;

use utils::{snippet, span_lint, get_parent_expr, match_trait_method, match_type, multispan_sugg, in_external_macro,
is_refutable, span_help_and_lint, is_integer_literal, get_enclosing_block, span_lint_and_then, higher,
walk_ptrs_ty, last_path_segment};
last_path_segment};
use utils::paths;

/// **What it does:** Checks for looping over the range of `0..len` of some
Expand Down Expand Up @@ -712,19 +712,26 @@ fn check_for_loop_over_map_kv<'a, 'tcx>(

if let PatKind::Tuple(ref pat, _) = pat.node {
if pat.len() == 2 {
let (new_pat_span, kind) = match (&pat[0].node, &pat[1].node) {
(key, _) if pat_is_wild(cx, key, body) => (pat[1].span, "value"),
(_, value) if pat_is_wild(cx, value, body) => (pat[0].span, "key"),
let arg_span = arg.span;
let (new_pat_span, kind, ty, mutbl) = match cx.tcx.tables().expr_ty(arg).sty {
ty::TyRef(_, ref tam) => {
match (&pat[0].node, &pat[1].node) {
(key, _) if pat_is_wild(cx, key, body) => (pat[1].span, "value", tam.ty, tam.mutbl),
(_, value) if pat_is_wild(cx, value, body) => (pat[0].span, "key", tam.ty, MutImmutable),
_ => return,
}
},
_ => return,
};

let (arg_span, arg) = match arg.node {
ExprAddrOf(MutImmutable, ref expr) => (arg.span, &**expr),
ExprAddrOf(MutMutable, _) => return, // for _ in &mut _, there is no {values,keys}_mut method
_ => (arg.span, arg),
let mutbl = match mutbl {
MutImmutable => "",
MutMutable => "_mut",
};
let arg = match arg.node {
ExprAddrOf(_, ref expr) => &**expr,
_ => arg,
};

let ty = walk_ptrs_ty(cx.tcx.tables().expr_ty(arg));
if match_type(cx, ty, &paths::HASHMAP) || match_type(cx, ty, &paths::BTREEMAP) {
span_lint_and_then(cx,
FOR_KV_MAP,
Expand All @@ -735,7 +742,7 @@ fn check_for_loop_over_map_kv<'a, 'tcx>(
multispan_sugg(db,
"use the corresponding method".into(),
&[(pat_span, &snippet(cx, new_pat_span, kind)),
(arg_span, &format!("{}.{}s()", map.maybe_par(), kind))]);
(arg_span, &format!("{}.{}s{}()", map.maybe_par(), kind, mutbl))]);
});
}
}
Expand Down
16 changes: 14 additions & 2 deletions tests/compile-fail/for_loop.rs
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Expand Up @@ -87,7 +87,7 @@ impl Unrelated {
}
}

#[deny(needless_range_loop, explicit_iter_loop, explicit_into_iter_loop, iter_next_loop, reverse_range_loop, explicit_counter_loop)]
#[deny(needless_range_loop, explicit_iter_loop, explicit_into_iter_loop, iter_next_loop, reverse_range_loop, explicit_counter_loop, for_kv_map)]
#[deny(unused_collect)]
#[allow(linkedlist, shadow_unrelated, unnecessary_mut_passed, cyclomatic_complexity, similar_names)]
#[allow(many_single_char_names)]
Expand Down Expand Up @@ -417,11 +417,23 @@ fn main() {

let mut m : HashMap<u64, u64> = HashMap::new();
for (_, v) in &mut m {
// Ok, there is no values_mut method or equivalent
//~^ you seem to want to iterate on a map's values
//~| HELP use the corresponding method
//~| HELP use the corresponding method
//~| SUGGESTION for v in m.values_mut()
let _v = v;
}

let m: &mut HashMap<u64, u64> = &mut HashMap::new();
for (_, v) in &mut *m {
//~^ you seem to want to iterate on a map's values
//~| HELP use the corresponding method
//~| HELP use the corresponding method
//~| SUGGESTION for v in (*m).values_mut()
let _v = v;
}

let m : HashMap<u64, u64> = HashMap::new();
let rm = &m;
for (k, _value) in rm {
//~^ you seem to want to iterate on a map's keys
Expand Down