Suggest calling iter if needed in explicit_counter_loop

This commit is contained in:
HMPerson1 2019-10-18 00:03:27 -04:00
parent 77092a54d7
commit 72f3439346
No known key found for this signature in database
GPG key ID: 1FB477DDD27821CE
3 changed files with 67 additions and 21 deletions

View file

@ -27,9 +27,10 @@ use syntax_pos::{BytePos, Symbol};
use crate::utils::paths;
use crate::utils::{
get_enclosing_block, get_parent_expr, has_iter_method, higher, is_integer_const, is_refutable, last_path_segment,
match_trait_method, match_type, match_var, multispan_sugg, snippet, snippet_opt, snippet_with_applicability,
span_help_and_lint, span_lint, span_lint_and_sugg, span_lint_and_then, SpanlessEq,
get_enclosing_block, get_parent_expr, get_trait_def_id, has_iter_method, higher, implements_trait,
is_integer_const, is_refutable, last_path_segment, match_trait_method, match_type, match_var, multispan_sugg,
snippet, snippet_opt, snippet_with_applicability, span_help_and_lint, span_lint, span_lint_and_sugg,
span_lint_and_then, SpanlessEq,
};
declare_clippy_lint! {
@ -1470,17 +1471,7 @@ fn check_for_loop_explicit_counter<'a, 'tcx>(
"for ({}, {}) in {}.enumerate()",
name,
snippet_with_applicability(cx, pat.span, "item", &mut applicability),
if higher::range(cx, arg).is_some() {
format!(
"({})",
snippet_with_applicability(cx, arg.span, "_", &mut applicability)
)
} else {
format!(
"{}",
sugg::Sugg::hir_with_applicability(cx, arg, "_", &mut applicability).maybe_par()
)
}
make_iterator_snippet(cx, arg, &mut applicability),
),
applicability,
);
@ -1490,6 +1481,39 @@ fn check_for_loop_explicit_counter<'a, 'tcx>(
}
}
/// If `arg` was the argument to a `for` loop, return the "cleanest" way of writing the
/// actual `Iterator` that the loop uses.
fn make_iterator_snippet(cx: &LateContext<'_, '_>, arg: &Expr, applic_ref: &mut Applicability) -> String {
let impls_iterator = get_trait_def_id(cx, &paths::ITERATOR)
.map_or(false, |id| implements_trait(cx, cx.tables.expr_ty(arg), id, &[]));
if impls_iterator {
format!(
"{}",
sugg::Sugg::hir_with_applicability(cx, arg, "_", applic_ref).maybe_par()
)
} else {
// (&x).into_iter() ==> x.iter()
// (&mut x).into_iter() ==> x.iter_mut()
match &arg.kind {
ExprKind::AddrOf(mutability, arg_inner) if has_iter_method(cx, cx.tables.expr_ty(&arg_inner)).is_some() => {
let meth_name = match mutability {
MutMutable => "iter_mut",
MutImmutable => "iter",
};
format!(
"{}.{}()",
sugg::Sugg::hir_with_applicability(cx, &arg_inner, "_", applic_ref).maybe_par(),
meth_name,
)
},
_ => format!(
"{}.into_iter()",
sugg::Sugg::hir_with_applicability(cx, arg, "_", applic_ref).maybe_par()
),
}
}
}
/// Checks for the `FOR_KV_MAP` lint.
fn check_for_loop_over_map_kv<'a, 'tcx>(
cx: &LateContext<'a, 'tcx>,

View file

@ -12,6 +12,16 @@ fn main() {
for _v in &vec {
_index += 1
}
let mut _index = 0;
for _v in &mut vec {
_index += 1;
}
let mut _index = 0;
for _v in vec {
_index += 1;
}
}
mod issue_1219 {

View file

@ -2,7 +2,7 @@ error: the variable `_index` is used as a loop counter.
--> $DIR/explicit_counter_loop.rs:6:15
|
LL | for _v in &vec {
| ^^^^ help: consider using: `for (_index, _v) in (&vec).enumerate()`
| ^^^^ help: consider using: `for (_index, _v) in vec.iter().enumerate()`
|
= note: `-D clippy::explicit-counter-loop` implied by `-D warnings`
@ -10,25 +10,37 @@ error: the variable `_index` is used as a loop counter.
--> $DIR/explicit_counter_loop.rs:12:15
|
LL | for _v in &vec {
| ^^^^ help: consider using: `for (_index, _v) in (&vec).enumerate()`
| ^^^^ help: consider using: `for (_index, _v) in vec.iter().enumerate()`
error: the variable `_index` is used as a loop counter.
--> $DIR/explicit_counter_loop.rs:17:15
|
LL | for _v in &mut vec {
| ^^^^^^^^ help: consider using: `for (_index, _v) in vec.iter_mut().enumerate()`
error: the variable `_index` is used as a loop counter.
--> $DIR/explicit_counter_loop.rs:22:15
|
LL | for _v in vec {
| ^^^ help: consider using: `for (_index, _v) in vec.into_iter().enumerate()`
error: the variable `count` is used as a loop counter.
--> $DIR/explicit_counter_loop.rs:51:19
--> $DIR/explicit_counter_loop.rs:61:19
|
LL | for ch in text.chars() {
| ^^^^^^^^^^^^ help: consider using: `for (count, ch) in text.chars().enumerate()`
error: the variable `count` is used as a loop counter.
--> $DIR/explicit_counter_loop.rs:62:19
--> $DIR/explicit_counter_loop.rs:72:19
|
LL | for ch in text.chars() {
| ^^^^^^^^^^^^ help: consider using: `for (count, ch) in text.chars().enumerate()`
error: the variable `count` is used as a loop counter.
--> $DIR/explicit_counter_loop.rs:120:19
--> $DIR/explicit_counter_loop.rs:130:19
|
LL | for _i in 3..10 {
| ^^^^^ help: consider using: `for (count, _i) in (3..10).enumerate()`
| ^^^^^ help: consider using: `for (count, _i) in 3..10.enumerate()`
error: aborting due to 5 previous errors
error: aborting due to 7 previous errors