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Fix invalid syntax in from_iter_instead_of_collect suggestion #7264

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Merged
bors merged 1 commit into from
May 22, 2021
Merged

Fix invalid syntax in from_iter_instead_of_collect suggestion #7264

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47 changes: 30 additions & 17 deletions clippy_lints/src/methods/from_iter_instead_of_collect.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -37,30 +37,43 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, args: &[hir::Exp
}

fn extract_turbofish(cx: &LateContext<'_>, expr: &hir::Expr<'_>, ty: Ty<'tcx>) -> String {
fn strip_angle_brackets(s: &str) -> Option<&str> {
s.strip_prefix('<')?.strip_suffix('>')
}

let call_site = expr.span.source_callsite();
if_chain! {
if let Ok(snippet) = cx.sess().source_map().span_to_snippet(call_site);
let snippet_split = snippet.split("::").collect::<Vec<_>>();
if let Some((_, elements)) = snippet_split.split_last();

then {
// is there a type specifier? (i.e.: like `<u32>` in `collections::BTreeSet::<u32>::`)
if let Some(type_specifier) = snippet_split.iter().find(|e| e.starts_with('<') && e.ends_with('>')) {
// remove the type specifier from the path elements
let without_ts = elements.iter().filter_map(|e| {
if e == type_specifier { None } else { Some((*e).to_string()) }
}).collect::<Vec<_>>();
// join and add the type specifier at the end (i.e.: `collections::BTreeSet<u32>`)
format!("{}{}", without_ts.join("::"), type_specifier)
} else {
// type is not explicitly specified so wildcards are needed
// i.e.: 2 wildcards in `std::collections::BTreeMap<&i32, &char>`
let ty_str = ty.to_string();
let start = ty_str.find('<').unwrap_or(0);
let end = ty_str.find('>').unwrap_or_else(|| ty_str.len());
let nb_wildcard = ty_str[start..end].split(',').count();
let wildcards = format!("_{}", ", _".repeat(nb_wildcard - 1));
format!("{}<{}>", elements.join("::"), wildcards)
if_chain! {
if let [type_specifier, _] = snippet_split.as_slice();
if let Some(type_specifier) = strip_angle_brackets(type_specifier);
if let Some((type_specifier, ..)) = type_specifier.split_once(" as ");
then {
type_specifier.to_string()
} else {
// is there a type specifier? (i.e.: like `<u32>` in `collections::BTreeSet::<u32>::`)
if let Some(type_specifier) = snippet_split.iter().find(|e| strip_angle_brackets(e).is_some()) {
// remove the type specifier from the path elements
let without_ts = elements.iter().filter_map(|e| {
if e == type_specifier { None } else { Some((*e).to_string()) }
}).collect::<Vec<_>>();
// join and add the type specifier at the end (i.e.: `collections::BTreeSet<u32>`)
format!("{}{}", without_ts.join("::"), type_specifier)
} else {
// type is not explicitly specified so wildcards are needed
// i.e.: 2 wildcards in `std::collections::BTreeMap<&i32, &char>`
let ty_str = ty.to_string();
let start = ty_str.find('<').unwrap_or(0);
let end = ty_str.find('>').unwrap_or_else(|| ty_str.len());
let nb_wildcard = ty_str[start..end].split(',').count();
let wildcards = format!("_{}", ", _".repeat(nb_wildcard - 1));
format!("{}<{}>", elements.join("::"), wildcards)
}
}
}
} else {
ty.to_string()
Expand Down
14 changes: 14 additions & 0 deletions tests/ui/from_iter_instead_of_collect.fixed
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Original file line number Diff line number Diff line change
Expand Up @@ -6,6 +6,20 @@
use std::collections::{BTreeMap, BTreeSet, HashMap, VecDeque};
use std::iter::FromIterator;

struct Foo(Vec<bool>);

impl FromIterator<bool> for Foo {
fn from_iter<T: IntoIterator<Item = bool>>(_: T) -> Self {
todo!()
}
}

impl<'a> FromIterator<&'a bool> for Foo {
fn from_iter<T: IntoIterator<Item = &'a bool>>(iter: T) -> Self {
iter.into_iter().copied().collect::<Self>()
}
}

fn main() {
let iter_expr = std::iter::repeat(5).take(5);
let _ = iter_expr.collect::<Vec<_>>();
Expand Down
14 changes: 14 additions & 0 deletions tests/ui/from_iter_instead_of_collect.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -6,6 +6,20 @@
use std::collections::{BTreeMap, BTreeSet, HashMap, VecDeque};
use std::iter::FromIterator;

struct Foo(Vec<bool>);

impl FromIterator<bool> for Foo {
fn from_iter<T: IntoIterator<Item = bool>>(_: T) -> Self {
todo!()
}
}

impl<'a> FromIterator<&'a bool> for Foo {
fn from_iter<T: IntoIterator<Item = &'a bool>>(iter: T) -> Self {
<Self as FromIterator<bool>>::from_iter(iter.into_iter().copied())
}
}

fn main() {
let iter_expr = std::iter::repeat(5).take(5);
let _ = Vec::from_iter(iter_expr);
Expand Down
40 changes: 23 additions & 17 deletions tests/ui/from_iter_instead_of_collect.stderr
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Original file line number Diff line number Diff line change
@@ -1,88 +1,94 @@
error: usage of `FromIterator::from_iter`
--> $DIR/from_iter_instead_of_collect.rs:11:13
--> $DIR/from_iter_instead_of_collect.rs:19:9
|
LL | let _ = Vec::from_iter(iter_expr);
| ^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `.collect()` instead of `::from_iter()`: `iter_expr.collect::<Vec<_>>()`
LL | <Self as FromIterator<bool>>::from_iter(iter.into_iter().copied())
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `.collect()` instead of `::from_iter()`: `iter.into_iter().copied().collect::<Self>()`
|
= note: `-D clippy::from-iter-instead-of-collect` implied by `-D warnings`

error: usage of `FromIterator::from_iter`
--> $DIR/from_iter_instead_of_collect.rs:13:13
--> $DIR/from_iter_instead_of_collect.rs:25:13
|
LL | let _ = Vec::from_iter(iter_expr);
| ^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `.collect()` instead of `::from_iter()`: `iter_expr.collect::<Vec<_>>()`

error: usage of `FromIterator::from_iter`
--> $DIR/from_iter_instead_of_collect.rs:27:13
|
LL | let _ = HashMap::<usize, &i8>::from_iter(vec![5, 5, 5, 5].iter().enumerate());
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `.collect()` instead of `::from_iter()`: `vec![5, 5, 5, 5].iter().enumerate().collect::<HashMap<usize, &i8>>()`

error: usage of `FromIterator::from_iter`
--> $DIR/from_iter_instead_of_collect.rs:18:19
--> $DIR/from_iter_instead_of_collect.rs:32:19
|
LL | assert_eq!(a, Vec::from_iter(0..3));
| ^^^^^^^^^^^^^^^^^^^^ help: use `.collect()` instead of `::from_iter()`: `(0..3).collect::<Vec<_>>()`

error: usage of `FromIterator::from_iter`
--> $DIR/from_iter_instead_of_collect.rs:19:19
--> $DIR/from_iter_instead_of_collect.rs:33:19
|
LL | assert_eq!(a, Vec::<i32>::from_iter(0..3));
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `.collect()` instead of `::from_iter()`: `(0..3).collect::<Vec<i32>>()`

error: usage of `FromIterator::from_iter`
--> $DIR/from_iter_instead_of_collect.rs:21:17
--> $DIR/from_iter_instead_of_collect.rs:35:17
|
LL | let mut b = VecDeque::from_iter(0..3);
| ^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `.collect()` instead of `::from_iter()`: `(0..3).collect::<VecDeque<_>>()`

error: usage of `FromIterator::from_iter`
--> $DIR/from_iter_instead_of_collect.rs:24:17
--> $DIR/from_iter_instead_of_collect.rs:38:17
|
LL | let mut b = VecDeque::<i32>::from_iter(0..3);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `.collect()` instead of `::from_iter()`: `(0..3).collect::<VecDeque<i32>>()`

error: usage of `FromIterator::from_iter`
--> $DIR/from_iter_instead_of_collect.rs:29:21
--> $DIR/from_iter_instead_of_collect.rs:43:21
|
LL | let mut b = collections::VecDeque::<i32>::from_iter(0..3);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `.collect()` instead of `::from_iter()`: `(0..3).collect::<collections::VecDeque<i32>>()`

error: usage of `FromIterator::from_iter`
--> $DIR/from_iter_instead_of_collect.rs:34:14
--> $DIR/from_iter_instead_of_collect.rs:48:14
|
LL | let bm = BTreeMap::from_iter(values.iter().cloned());
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `.collect()` instead of `::from_iter()`: `values.iter().cloned().collect::<BTreeMap<_, _>>()`

error: usage of `FromIterator::from_iter`
--> $DIR/from_iter_instead_of_collect.rs:35:19
--> $DIR/from_iter_instead_of_collect.rs:49:19
|
LL | let mut bar = BTreeMap::from_iter(bm.range(0..2));
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `.collect()` instead of `::from_iter()`: `bm.range(0..2).collect::<BTreeMap<_, _>>()`

error: usage of `FromIterator::from_iter`
--> $DIR/from_iter_instead_of_collect.rs:38:19
--> $DIR/from_iter_instead_of_collect.rs:52:19
|
LL | let mut bts = BTreeSet::from_iter(0..3);
| ^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `.collect()` instead of `::from_iter()`: `(0..3).collect::<BTreeSet<_>>()`

error: usage of `FromIterator::from_iter`
--> $DIR/from_iter_instead_of_collect.rs:42:17
--> $DIR/from_iter_instead_of_collect.rs:56:17
|
LL | let _ = collections::BTreeSet::from_iter(0..3);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `.collect()` instead of `::from_iter()`: `(0..3).collect::<collections::BTreeSet<_>>()`

error: usage of `FromIterator::from_iter`
--> $DIR/from_iter_instead_of_collect.rs:43:17
--> $DIR/from_iter_instead_of_collect.rs:57:17
|
LL | let _ = collections::BTreeSet::<u32>::from_iter(0..3);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `.collect()` instead of `::from_iter()`: `(0..3).collect::<collections::BTreeSet<u32>>()`

error: usage of `FromIterator::from_iter`
--> $DIR/from_iter_instead_of_collect.rs:46:15
--> $DIR/from_iter_instead_of_collect.rs:60:15
|
LL | for _i in Vec::from_iter([1, 2, 3].iter()) {}
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `.collect()` instead of `::from_iter()`: `[1, 2, 3].iter().collect::<Vec<_>>()`

error: usage of `FromIterator::from_iter`
--> $DIR/from_iter_instead_of_collect.rs:47:15
--> $DIR/from_iter_instead_of_collect.rs:61:15
|
LL | for _i in Vec::<&i32>::from_iter([1, 2, 3].iter()) {}
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `.collect()` instead of `::from_iter()`: `[1, 2, 3].iter().collect::<Vec<&i32>>()`

error: aborting due to 14 previous errors
error: aborting due to 15 previous errors