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Merge pull request #1486 from killercup/for-loop-suggestions

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Add suggestions to `EXPLICIT_[INTO_]ITER_LOOP`
This commit is contained in:
Martin Carton 2017-01-28 14:37:59 +01:00 committed by GitHub
commit f2f6637dda
2 changed files with 86 additions and 36 deletions
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46
clippy_lints/src/loops.rs
View File

@ -588,28 +588,36 @@ fn check_for_loop_arg(cx: &LateContext, pat: &Pat, arg: &Expr, expr: &Expr) {
if &*method_name.as_str() == "iter" || &*method_name.as_str() == "iter_mut" { if &*method_name.as_str() == "iter" || &*method_name.as_str() == "iter_mut" {
if is_ref_iterable_type(cx, &args[0]) { if is_ref_iterable_type(cx, &args[0]) {
let object = snippet(cx, args[0].span, "_"); let object = snippet(cx, args[0].span, "_");
span_lint(cx, let suggestion = format!("&{}{}",
EXPLICIT_ITER_LOOP, if &*method_name.as_str() == "iter_mut" {
expr.span, "mut "
&format!("it is more idiomatic to loop over `&{}{}` instead of `{}.{}()`", } else {
if &*method_name.as_str() == "iter_mut" { ""
"mut " },
} else { object);
"" span_lint_and_then(cx,
}, EXPLICIT_ITER_LOOP,
object, arg.span,
object, &format!("it is more idiomatic to loop over `{}` instead of `{}.{}()`",
method_name)); suggestion,
object,
method_name),
|db| {
db.span_suggestion(arg.span, "to write this more concisely, try looping over", suggestion);
});
} }
} else if &*method_name.as_str() == "into_iter" && match_trait_method(cx, arg, &paths::INTO_ITERATOR) { } else if &*method_name.as_str() == "into_iter" && match_trait_method(cx, arg, &paths::INTO_ITERATOR) {
let object = snippet(cx, args[0].span, "_"); let object = snippet(cx, args[0].span, "_");
span_lint(cx, span_lint_and_then(cx,
EXPLICIT_INTO_ITER_LOOP, EXPLICIT_INTO_ITER_LOOP,
expr.span, arg.span,
&format!("it is more idiomatic to loop over `{}` instead of `{}.{}()`", &format!("it is more idiomatic to loop over `{}` instead of `{}.{}()`",
object, object,
object, object,
method_name)); method_name),
|db| {
db.span_suggestion(arg.span, "to write this more concisely, try looping over", object.to_string());
});
} else if &*method_name.as_str() == "next" && match_trait_method(cx, arg, &paths::ITERATOR) { } else if &*method_name.as_str() == "next" && match_trait_method(cx, arg, &paths::ITERATOR) {
span_lint(cx, span_lint(cx,

76
tests/compile-fail/for_loop.rs
View File

@ -286,39 +286,81 @@ fn main() {
id_col[i] = 1f64; id_col[i] = 1f64;
} }
/* for _v in vec.iter() { }
for i in (10..0).map(|x| x * 2) { //~^ ERROR it is more idiomatic to loop over `&vec`
println!("{}", i); //~| HELP to write this more concisely, try looping over
}*/ //~| SUGGESTION for _v in &vec {
for _v in vec.iter() { } //~ERROR it is more idiomatic to loop over `&vec`
for _v in vec.iter_mut() { } //~ERROR it is more idiomatic to loop over `&mut vec`
for _v in vec.iter_mut() { }
//~^ ERROR it is more idiomatic to loop over `&mut vec`
//~| HELP to write this more concisely, try looping over
//~| SUGGESTION for _v in &mut vec {
let out_vec = vec![1,2,3]; let out_vec = vec![1,2,3];
for _v in out_vec.into_iter() { } //~ERROR it is more idiomatic to loop over `out_vec` instead of `out_vec.into_iter()` for _v in out_vec.into_iter() { }
//~^ ERROR it is more idiomatic to loop over `out_vec` instead of `out_vec.into_iter()`
//~| HELP to write this more concisely, try looping over
//~| SUGGESTION for _v in out_vec {
for _v in &vec { } // these are fine for _v in &vec { } // these are fine
for _v in &mut vec { } // these are fine for _v in &mut vec { } // these are fine
for _v in [1, 2, 3].iter() { } //~ERROR it is more idiomatic to loop over `&[ for _v in [1, 2, 3].iter() { }
//~^ ERROR it is more idiomatic to loop over `&[
//~| HELP to write this more concisely, try looping over
//~| SUGGESTION for _v in &[1, 2, 3] {
for _v in (&mut [1, 2, 3]).iter() { } // no error for _v in (&mut [1, 2, 3]).iter() { } // no error
for _v in [0; 32].iter() {} //~ERROR it is more idiomatic to loop over `&[
for _v in [0; 32].iter() {}
//~^ ERROR it is more idiomatic to loop over `&[
//~| HELP to write this more concisely, try looping over
//~| SUGGESTION for _v in &[0; 32] {
for _v in [0; 33].iter() {} // no error for _v in [0; 33].iter() {} // no error
let ll: LinkedList<()> = LinkedList::new(); let ll: LinkedList<()> = LinkedList::new();
for _v in ll.iter() { } //~ERROR it is more idiomatic to loop over `&ll` for _v in ll.iter() { }
//~^ ERROR it is more idiomatic to loop over `&ll`
//~| HELP to write this more concisely, try looping over
//~| SUGGESTION for _v in &ll {
let vd: VecDeque<()> = VecDeque::new(); let vd: VecDeque<()> = VecDeque::new();
for _v in vd.iter() { } //~ERROR it is more idiomatic to loop over `&vd` for _v in vd.iter() { }
//~^ ERROR it is more idiomatic to loop over `&vd`
//~| HELP to write this more concisely, try looping over
//~| SUGGESTION for _v in &vd {
let bh: BinaryHeap<()> = BinaryHeap::new(); let bh: BinaryHeap<()> = BinaryHeap::new();
for _v in bh.iter() { } //~ERROR it is more idiomatic to loop over `&bh` for _v in bh.iter() { }
//~^ ERROR it is more idiomatic to loop over `&bh`
//~| HELP to write this more concisely, try looping over
//~| SUGGESTION for _v in &bh {
let hm: HashMap<(), ()> = HashMap::new(); let hm: HashMap<(), ()> = HashMap::new();
for _v in hm.iter() { } //~ERROR it is more idiomatic to loop over `&hm` for _v in hm.iter() { }
//~^ ERROR it is more idiomatic to loop over `&hm`
//~| HELP to write this more concisely, try looping over
//~| SUGGESTION for _v in &hm {
let bt: BTreeMap<(), ()> = BTreeMap::new(); let bt: BTreeMap<(), ()> = BTreeMap::new();
for _v in bt.iter() { } //~ERROR it is more idiomatic to loop over `&bt` for _v in bt.iter() { }
//~^ ERROR it is more idiomatic to loop over `&bt`
//~| HELP to write this more concisely, try looping over
//~| SUGGESTION for _v in &bt {
let hs: HashSet<()> = HashSet::new(); let hs: HashSet<()> = HashSet::new();
for _v in hs.iter() { } //~ERROR it is more idiomatic to loop over `&hs` for _v in hs.iter() { }
//~^ ERROR it is more idiomatic to loop over `&hs`
//~| HELP to write this more concisely, try looping over
//~| SUGGESTION for _v in &hs {
let bs: BTreeSet<()> = BTreeSet::new(); let bs: BTreeSet<()> = BTreeSet::new();
for _v in bs.iter() { } //~ERROR it is more idiomatic to loop over `&bs` for _v in bs.iter() { }
//~^ ERROR it is more idiomatic to loop over `&bs`
//~| HELP to write this more concisely, try looping over
//~| SUGGESTION for _v in &bs {
for _v in vec.iter().next() { } //~ERROR you are iterating over `Iterator::next()` for _v in vec.iter().next() { } //~ERROR you are iterating over `Iterator::next()`