diff options
| -rw-r--r-- | clippy_lints/src/methods/mod.rs | 38 | ||||
| -rw-r--r-- | tests/ui/from_iter_instead_of_collect.fixed | 48 | ||||
| -rw-r--r-- | tests/ui/from_iter_instead_of_collect.rs | 41 | ||||
| -rw-r--r-- | tests/ui/from_iter_instead_of_collect.stderr | 86 |
4 files changed, 201 insertions, 12 deletions
diff --git a/clippy_lints/src/methods/mod.rs b/clippy_lints/src/methods/mod.rs index d3db9c666df..0af5d124359 100644 --- a/clippy_lints/src/methods/mod.rs +++ b/clippy_lints/src/methods/mod.rs @@ -4142,20 +4142,54 @@ fn lint_from_iter(cx: &LateContext<'_>, expr: &hir::Expr<'_>, args: &[hir::Expr< if implements_trait(cx, ty, from_iter_id, &[]) && implements_trait(cx, arg_ty, iter_id, &[]); then { // `expr` implements `FromIterator` trait - let iter_expr = snippet(cx, args[0].span, ".."); + let iter_expr = sugg::Sugg::hir(cx, &args[0], "..").maybe_par(); + let turbofish = extract_turbofish(cx, expr, ty); + let sugg = format!("{}.collect::<{}>()", iter_expr, turbofish); span_lint_and_sugg( cx, FROM_ITER_INSTEAD_OF_COLLECT, expr.span, "usage of `FromIterator::from_iter`", "use `.collect()` instead of `::from_iter()`", - format!("{}.collect()", iter_expr), + sugg, Applicability::MaybeIncorrect, ); } } } +fn extract_turbofish(cx: &LateContext<'_>, expr: &hir::Expr<'_>, ty: Ty<'tcx>) -> String { + if_chain! { + let call_site = expr.span.source_callsite(); + 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) + } + } else { + ty.to_string() + } + } +} + fn fn_header_equals(expected: hir::FnHeader, actual: hir::FnHeader) -> bool { expected.constness == actual.constness && expected.unsafety == actual.unsafety diff --git a/tests/ui/from_iter_instead_of_collect.fixed b/tests/ui/from_iter_instead_of_collect.fixed new file mode 100644 index 00000000000..b5f548810e6 --- /dev/null +++ b/tests/ui/from_iter_instead_of_collect.fixed @@ -0,0 +1,48 @@ +// run-rustfix + +#![warn(clippy::from_iter_instead_of_collect)] +#![allow(unused_imports)] + +use std::collections::{BTreeMap, BTreeSet, HashMap, VecDeque}; +use std::iter::FromIterator; + +fn main() { + let iter_expr = std::iter::repeat(5).take(5); + let _ = iter_expr.collect::<Vec<_>>(); + + let _ = vec![5, 5, 5, 5].iter().enumerate().collect::<HashMap<usize, &i8>>(); + + Vec::from_iter(vec![42u32]); + + let a = vec![0, 1, 2]; + assert_eq!(a, (0..3).collect::<Vec<_>>()); + assert_eq!(a, (0..3).collect::<Vec<i32>>()); + + let mut b = (0..3).collect::<VecDeque<_>>(); + b.push_back(4); + + let mut b = (0..3).collect::<VecDeque<i32>>(); + b.push_back(4); + + { + use std::collections; + let mut b = (0..3).collect::<collections::VecDeque<i32>>(); + b.push_back(4); + } + + let values = [(0, 'a'), (1, 'b'), (2, 'c'), (3, 'd')]; + let bm = values.iter().cloned().collect::<BTreeMap<_, _>>(); + let mut bar = bm.range(0..2).collect::<BTreeMap<_, _>>(); + bar.insert(&4, &'e'); + + let mut bts = (0..3).collect::<BTreeSet<_>>(); + bts.insert(2); + { + use std::collections; + let _ = (0..3).collect::<collections::BTreeSet<_>>(); + let _ = (0..3).collect::<collections::BTreeSet<u32>>(); + } + + for _i in [1, 2, 3].iter().collect::<Vec<_>>() {} + for _i in [1, 2, 3].iter().collect::<Vec<&i32>>() {} +} diff --git a/tests/ui/from_iter_instead_of_collect.rs b/tests/ui/from_iter_instead_of_collect.rs index 045eb3133d3..b842b5451d1 100644 --- a/tests/ui/from_iter_instead_of_collect.rs +++ b/tests/ui/from_iter_instead_of_collect.rs @@ -1,13 +1,48 @@ +// run-rustfix + #![warn(clippy::from_iter_instead_of_collect)] +#![allow(unused_imports)] -use std::collections::HashMap; +use std::collections::{BTreeMap, BTreeSet, HashMap, VecDeque}; use std::iter::FromIterator; fn main() { let iter_expr = std::iter::repeat(5).take(5); - Vec::from_iter(iter_expr); + let _ = Vec::from_iter(iter_expr); - HashMap::<usize, &i8>::from_iter(vec![5, 5, 5, 5].iter().enumerate()); + let _ = HashMap::<usize, &i8>::from_iter(vec![5, 5, 5, 5].iter().enumerate()); Vec::from_iter(vec![42u32]); + + let a = vec![0, 1, 2]; + assert_eq!(a, Vec::from_iter(0..3)); + assert_eq!(a, Vec::<i32>::from_iter(0..3)); + + let mut b = VecDeque::from_iter(0..3); + b.push_back(4); + + let mut b = VecDeque::<i32>::from_iter(0..3); + b.push_back(4); + + { + use std::collections; + let mut b = collections::VecDeque::<i32>::from_iter(0..3); + b.push_back(4); + } + + let values = [(0, 'a'), (1, 'b'), (2, 'c'), (3, 'd')]; + let bm = BTreeMap::from_iter(values.iter().cloned()); + let mut bar = BTreeMap::from_iter(bm.range(0..2)); + bar.insert(&4, &'e'); + + let mut bts = BTreeSet::from_iter(0..3); + bts.insert(2); + { + use std::collections; + let _ = collections::BTreeSet::from_iter(0..3); + let _ = collections::BTreeSet::<u32>::from_iter(0..3); + } + + for _i in Vec::from_iter([1, 2, 3].iter()) {} + for _i in Vec::<&i32>::from_iter([1, 2, 3].iter()) {} } diff --git a/tests/ui/from_iter_instead_of_collect.stderr b/tests/ui/from_iter_instead_of_collect.stderr index 46bdc2f4e19..434734c9a21 100644 --- a/tests/ui/from_iter_instead_of_collect.stderr +++ b/tests/ui/from_iter_instead_of_collect.stderr @@ -1,16 +1,88 @@ error: usage of `FromIterator::from_iter` - --> $DIR/from_iter_instead_of_collect.rs:8:5 + --> $DIR/from_iter_instead_of_collect.rs:11:13 | -LL | Vec::from_iter(iter_expr); - | ^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `.collect()` instead of `::from_iter()`: `iter_expr.collect()` +LL | let _ = Vec::from_iter(iter_expr); + | ^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `.collect()` instead of `::from_iter()`: `iter_expr.collect::<Vec<_>>()` | = 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:10:5 + --> $DIR/from_iter_instead_of_collect.rs:13:13 | -LL | 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()` +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: aborting due to 2 previous errors +error: usage of `FromIterator::from_iter` + --> $DIR/from_iter_instead_of_collect.rs:18:19 + | +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 + | +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 + | +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 + | +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 + | +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 + | +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 + | +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 + | +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 + | +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 + | +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 + | +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 + | +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 |