New upstream version 1.52.1+dfsg1

[rustc.git] / src / tools / clippy / tests / ui / from_iter_instead_of_collect.rs

diff --git a/src/tools/clippy/tests/ui/from_iter_instead_of_collect.rs b/src/tools/clippy/tests/ui/from_iter_instead_of_collect.rs
new file mode 100644 (file)
index 0000000..b842b54
--- /dev/null
+++ b/src/tools/clippy/tests/ui/from_iter_instead_of_collect.rs
@@ -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 _ = Vec::from_iter(iter_expr);
+
+    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()) {}
+}