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fix explicit_into_iter_loop on references 

fixes #1398
This commit is contained in:
Oliver Schneider 2017-01-09 16:59:55 +01:00
parent 55ea08102a
commit 0bea3e76d4
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GPG Key ID: A69F8D225B3AD7D9
2 changed files with 44 additions and 26 deletions
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67
clippy_lints/src/loops.rs
View File

@ -644,48 +644,63 @@ fn check_for_loop_reverse_range(cx: &LateContext, arg: &Expr, expr: &Expr) {
}
}
fn lint_iter_method(cx: &LateContext, args: &[Expr], arg: &Expr, expr: &Expr, method_name: &str) {
let object = snippet(cx, args[0].span, "_");
let suggestion = format!("&{}{}",
if method_name == "iter_mut" {
"mut "
} else {
""
},
object);
span_lint_and_then(cx,
EXPLICIT_ITER_LOOP,
expr.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));
}
fn check_for_loop_arg(cx: &LateContext, pat: &Pat, arg: &Expr, expr: &Expr) {
let mut next_loop_linted = false; // whether or not ITER_NEXT_LOOP lint was used
if let ExprMethodCall(ref method, _, ref args) = arg.node {
// just the receiver, no arguments
if args.len() == 1 {
let method_name = method.node;
let method_name = &*method.node.as_str();
// check for looping over x.iter() or x.iter_mut(), could use &x or &mut x
if &*method_name.as_str() == "iter" || &*method_name.as_str() == "iter_mut" {
if method_name == "iter" || method_name == "iter_mut" {
if is_ref_iterable_type(cx, &args[0]) {
lint_iter_method(cx, args, arg, expr, method_name);
}
} else if method_name == "into_iter" && match_trait_method(cx, arg, &paths::INTO_ITERATOR) {
let method_call = ty::MethodCall::expr(arg.id);
let fn_ty = cx.tables
.method_map
.get(&method_call)
.map(|method_callee| method_callee.ty)
.expect("method calls need an entry in the method map");
let fn_arg_tys = fn_ty.fn_args();
assert_eq!(fn_arg_tys.skip_binder().len(), 1);
if fn_arg_tys.skip_binder()[0].is_region_ptr() {
lint_iter_method(cx, args, arg, expr, method_name);
} else {
let object = snippet(cx, args[0].span, "_");
let suggestion = format!("&{}{}",
if &*method_name.as_str() == "iter_mut" {
"mut "
} else {
""
},
object);
span_lint_and_then(cx,
EXPLICIT_ITER_LOOP,
EXPLICIT_INTO_ITER_LOOP,
arg.span,
&format!("it is more idiomatic to loop over `{}` instead of `{}.{}()`",
suggestion,
object,
object,
method_name),
|db| {
db.span_suggestion(arg.span, "to write this more concisely, try looping over", suggestion);
db.span_suggestion(arg.span,
"to write this more concisely, try looping over",
object.to_string());
});
}
} 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_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) {
} else if method_name == "next" && match_trait_method(cx, arg, &paths::ITERATOR) {
span_lint(cx,
ITER_NEXT_LOOP,
expr.span,

3
tests/ui/for_loop.rs
View File

@ -302,6 +302,9 @@ fn main() {
let array = [1, 2, 3];
for _v in array.into_iter() {} //~ERROR it is more idiomatic to loop over `&array`
for _v in &vec { } // these are fine
for _v in &mut vec { } // these are fine