Auto merge of #3605 - phansch:small_methods_ui_test_improvement, r=flip1995

UI test cleanup: Extract iter_skip_next from methods.rs

cc #2038

tests/ui/iter_skip_next.rs

@@ -0,0 +1,61 @@
+// Copyright 2014-2018 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![warn(clippy::iter_skip_next)]
+#![allow(clippy::blacklisted_name)]
+
+/// Struct to generate false positive for Iterator-based lints
+#[derive(Copy, Clone)]
+struct IteratorFalsePositives {
+    foo: u32,
+}
+
+impl IteratorFalsePositives {
+    fn filter(self) -> IteratorFalsePositives {
+        self
+    }
+
+    fn next(self) -> IteratorFalsePositives {
+        self
+    }
+
+    fn find(self) -> Option<u32> {
+        Some(self.foo)
+    }
+
+    fn position(self) -> Option<u32> {
+        Some(self.foo)
+    }
+
+    fn rposition(self) -> Option<u32> {
+        Some(self.foo)
+    }
+
+    fn nth(self, n: usize) -> Option<u32> {
+        Some(self.foo)
+    }
+
+    fn skip(self, _: usize) -> IteratorFalsePositives {
+        self
+    }
+}
+
+/// Checks implementation of `ITER_SKIP_NEXT` lint
+fn iter_skip_next() {
+    let mut some_vec = vec![0, 1, 2, 3];
+    let _ = some_vec.iter().skip(42).next();
+    let _ = some_vec.iter().cycle().skip(42).next();
+    let _ = (1..10).skip(10).next();
+    let _ = &some_vec[..].iter().skip(3).next();
+    let foo = IteratorFalsePositives { foo: 0 };
+    let _ = foo.skip(42).next();
+    let _ = foo.filter().skip(42).next();
+}
+
+fn main() {}

tests/ui/iter_skip_next.stderr

@@ -0,0 +1,28 @@
+error: called `skip(x).next()` on an iterator. This is more succinctly expressed by calling `nth(x)`
+  --> $DIR/iter_skip_next.rs:52:13
+   |
+LL |     let _ = some_vec.iter().skip(42).next();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: `-D clippy::iter-skip-next` implied by `-D warnings`
+
+error: called `skip(x).next()` on an iterator. This is more succinctly expressed by calling `nth(x)`
+  --> $DIR/iter_skip_next.rs:53:13
+   |
+LL |     let _ = some_vec.iter().cycle().skip(42).next();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: called `skip(x).next()` on an iterator. This is more succinctly expressed by calling `nth(x)`
+  --> $DIR/iter_skip_next.rs:54:13
+   |
+LL |     let _ = (1..10).skip(10).next();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^
+
+error: called `skip(x).next()` on an iterator. This is more succinctly expressed by calling `nth(x)`
+  --> $DIR/iter_skip_next.rs:55:14
+   |
+LL |     let _ = &some_vec[..].iter().skip(3).next();
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 4 previous errors
+

tests/ui/methods.rs

@@ -390,18 +390,6 @@ fn iter_nth() {
     let ok_mut = false_positive.iter_mut().nth(3);
 }
 
-/// Checks implementation of `ITER_SKIP_NEXT` lint
-fn iter_skip_next() {
-    let mut some_vec = vec![0, 1, 2, 3];
-    let _ = some_vec.iter().skip(42).next();
-    let _ = some_vec.iter().cycle().skip(42).next();
-    let _ = (1..10).skip(10).next();
-    let _ = &some_vec[..].iter().skip(3).next();
-    let foo = IteratorFalsePositives { foo : 0 };
-    let _ = foo.skip(42).next();
-    let _ = foo.filter().skip(42).next();
-}
-
 #[allow(clippy::similar_names)]
 fn main() {
     let opt = Some(0);

tests/ui/methods.stderr

@@ -367,39 +367,13 @@ error: called `.iter_mut().nth()` on a VecDeque. Calling `.get_mut()` is both fa
 LL |         let bad_vec_deque = some_vec_deque.iter_mut().nth(3);
    |                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error: called `skip(x).next()` on an iterator. This is more succinctly expressed by calling `nth(x)`
-  --> $DIR/methods.rs:396:13
-   |
-LL |     let _ = some_vec.iter().skip(42).next();
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: `-D clippy::iter-skip-next` implied by `-D warnings`
-
-error: called `skip(x).next()` on an iterator. This is more succinctly expressed by calling `nth(x)`
-  --> $DIR/methods.rs:397:13
-   |
-LL |     let _ = some_vec.iter().cycle().skip(42).next();
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-error: called `skip(x).next()` on an iterator. This is more succinctly expressed by calling `nth(x)`
-  --> $DIR/methods.rs:398:13
-   |
-LL |     let _ = (1..10).skip(10).next();
-   |             ^^^^^^^^^^^^^^^^^^^^^^^
-
-error: called `skip(x).next()` on an iterator. This is more succinctly expressed by calling `nth(x)`
-  --> $DIR/methods.rs:399:14
-   |
-LL |     let _ = &some_vec[..].iter().skip(3).next();
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
 error: used unwrap() on an Option value. If you don't want to handle the None case gracefully, consider using expect() to provide a better panic message
-  --> $DIR/methods.rs:408:13
+  --> $DIR/methods.rs:396:13
    |
 LL |     let _ = opt.unwrap();
    |             ^^^^^^^^^^^^
    |
    = note: `-D clippy::option-unwrap-used` implied by `-D warnings`
 
-error: aborting due to 50 previous errors
+error: aborting due to 46 previous errors