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Add suggestions to EXPLICIT_[INTO_]ITER_LOOP

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Also reduces the highlighted span to the expr containing the
`.[into_]iter()` call (so the suggestion is probably applicable by
rustfix.)

Fixes #1484
This commit is contained in:
Pascal Hertleif 2017-01-28 14:02:49 +01:00
parent d825f194fd
commit 8cbf548f7e
2 changed files with 90 additions and 33 deletions
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48
clippy_lints/src/loops.rs
View File

@ -588,28 +588,38 @@ 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 is_ref_iterable_type(cx, &args[0]) {
let object = snippet(cx, args[0].span, "_");
span_lint(cx,
EXPLICIT_ITER_LOOP,
expr.span,
&format!("it is more idiomatic to loop over `&{}{}` instead of `{}.{}()`",
if &*method_name.as_str() == "iter_mut" {
"mut "
} else {
""
},
object,
object,
method_name));
let suggestion = format!("&{}{}",
if &*method_name.as_str() == "iter_mut" {
"mut "
} else {
""
},
object);
span_lint_and_then(cx,
EXPLICIT_ITER_LOOP,
arg.span,
&format!("it is more idiomatic to loop over `{}` instead of `{}.{}()`",
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) {
let object = snippet(cx, args[0].span, "_");
span_lint(cx,
EXPLICIT_INTO_ITER_LOOP,
expr.span,
&format!("it is more idiomatic to loop over `{}` instead of `{}.{}()`",
object,
object,
method_name));
span_lint_and_then(cx,
EXPLICIT_INTO_ITER_LOOP,
arg.span,
&format!("it is more idiomatic to loop over `{}` instead of `{}.{}()`",
object,
object,
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) {
span_lint(cx,

75
tests/compile-fail/for_loop.rs
View File

@ -286,39 +286,86 @@ fn main() {
id_col[i] = 1f64;
}
/*
// This is fine.
for i in (10..0).map(|x| x * 2) {
println!("{}", i);
}*/
}
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() { }
//~^ ERROR it is more idiomatic to loop over `&vec`
//~| HELP to write this more concisely, try looping over
//~| SUGGESTION &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 vec
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 out_vec
for _v in &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 &[1, 2, 3]
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 &[0; 32]
for _v in [0; 33].iter() {} // no error
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 &ll
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 &vd
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 &bh
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 &hm
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 &bt
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 &hs
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 &bs
for _v in vec.iter().next() { } //~ERROR you are iterating over `Iterator::next()`