Merge #3372

3372: UI test cleanup: Extract explicit_counter_loop tests r=matthiaskrgr a=phansch

cc #2038 

Co-authored-by: Philipp Hansch <dev@phansch.net>

tests/ui/explicit_counter_loop.rs

@@ -0,0 +1,122 @@
+// 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::explicit_counter_loop)]
+
+fn main() {
+    let mut vec = vec![1, 2, 3, 4];
+    let mut _index = 0;
+    for _v in &vec {
+        _index += 1
+    }
+
+    let mut _index = 1;
+    _index = 0;
+    for _v in &vec {
+        _index += 1
+    }
+}
+
+mod issue_1219 {
+    pub fn test() {
+        // should not trigger the lint because variable is used after the loop #473
+        let vec = vec![1,2,3];
+        let mut index = 0;
+        for _v in &vec { index += 1 }
+        println!("index: {}", index);
+
+        // should not trigger the lint because the count is conditional #1219
+        let text = "banana";
+        let mut count = 0;
+        for ch in text.chars() {
+            if ch == 'a' {
+                continue;
+            }
+            count += 1;
+            println!("{}", count);
+        }
+
+        // should not trigger the lint because the count is conditional
+        let text = "banana";
+        let mut count = 0;
+        for ch in text.chars() {
+            if ch == 'a' {
+                count += 1;
+            }
+            println!("{}", count);
+        }
+
+        // should trigger the lint because the count is not conditional
+        let text = "banana";
+        let mut count = 0;
+        for ch in text.chars() {
+            count += 1;
+            if ch == 'a' {
+                continue;
+            }
+            println!("{}", count);
+        }
+
+        // should trigger the lint because the count is not conditional
+        let text = "banana";
+        let mut count = 0;
+        for ch in text.chars() {
+            count += 1;
+            for i in 0..2 {
+                let _ = 123;
+            }
+            println!("{}", count);
+        }
+
+        // should not trigger the lint because the count is incremented multiple times
+        let text = "banana";
+        let mut count = 0;
+        for ch in text.chars() {
+            count += 1;
+            for i in 0..2 {
+                count += 1;
+            }
+            println!("{}", count);
+        }
+    }
+}
+
+mod issue_3308 {
+    pub fn test() {
+        // should not trigger the lint because the count is incremented multiple times
+        let mut skips = 0;
+        let erasures = vec![];
+        for i in 0..10 {
+            while erasures.contains(&(i + skips)) {
+                skips += 1;
+            }
+            println!("{}", skips);
+        }
+
+        // should not trigger the lint because the count is incremented multiple times
+        let mut skips = 0;
+        for i in 0..10 {
+            let mut j = 0;
+            while j < 5 {
+                skips += 1;
+                j += 1;
+            }
+            println!("{}", skips);
+        }
+
+        // should not trigger the lint because the count is incremented multiple times
+        let mut skips = 0;
+        for i in 0..10 {
+            for j in 0..5 {
+                skips += 1;
+            }
+            println!("{}", skips);
+        }
+    }
+}

tests/ui/explicit_counter_loop.stderr

@@ -0,0 +1,28 @@
+error: the variable `_index` is used as a loop counter. Consider using `for (_index, item) in &vec.enumerate()` or similar iterators
+  --> $DIR/explicit_counter_loop.rs:15:15
+   |
+15 |     for _v in &vec {
+   |               ^^^^
+   |
+   = note: `-D clippy::explicit-counter-loop` implied by `-D warnings`
+
+error: the variable `_index` is used as a loop counter. Consider using `for (_index, item) in &vec.enumerate()` or similar iterators
+  --> $DIR/explicit_counter_loop.rs:21:15
+   |
+21 |     for _v in &vec {
+   |               ^^^^
+
+error: the variable `count` is used as a loop counter. Consider using `for (count, item) in text.chars().enumerate()` or similar iterators
+  --> $DIR/explicit_counter_loop.rs:58:19
+   |
+58 |         for ch in text.chars() {
+   |                   ^^^^^^^^^^^^
+
+error: the variable `count` is used as a loop counter. Consider using `for (count, item) in text.chars().enumerate()` or similar iterators
+  --> $DIR/explicit_counter_loop.rs:69:19
+   |
+69 |         for ch in text.chars() {
+   |                   ^^^^^^^^^^^^
+
+error: aborting due to 4 previous errors
+

tests/ui/for_loop.rs

@@ -84,7 +84,7 @@ impl Unrelated {
 }
 
 #[warn(clippy::needless_range_loop, clippy::explicit_iter_loop, clippy::explicit_into_iter_loop, clippy::iter_next_loop, clippy::reverse_range_loop,
-       clippy::explicit_counter_loop, clippy::for_kv_map)]
+       clippy::for_kv_map)]
 #[warn(clippy::unused_collect)]
 #[allow(clippy::linkedlist, clippy::shadow_unrelated, clippy::unnecessary_mut_passed, clippy::cyclomatic_complexity, clippy::similar_names)]
 #[allow(clippy::many_single_char_names, unused_variables)]
@@ -275,16 +275,6 @@ fn main() {
     let _y = vec.iter().cloned().map(|x| out.push(x)).collect::<Vec<_>>(); // this is fine
 
     // Loop with explicit counter variable
-    let mut _index = 0;
-    for _v in &vec {
-        _index += 1
-    }
-
-    let mut _index = 1;
-    _index = 0;
-    for _v in &vec {
-        _index += 1
-    }
 
     // Potential false positives
     let mut _index = 0;
@@ -594,103 +584,3 @@ mod issue_2496 {
         unimplemented!()
     }
 }
-
-mod issue_1219 {
-    #[warn(clippy::explicit_counter_loop)]
-    pub fn test() {
-        // should not trigger the lint because variable is used after the loop #473
-        let vec = vec![1,2,3];
-        let mut index = 0;
-        for _v in &vec { index += 1 }
-        println!("index: {}", index);
-
-        // should not trigger the lint because the count is conditional #1219
-        let text = "banana";
-        let mut count = 0;
-        for ch in text.chars() {
-            if ch == 'a' {
-                continue;
-            }
-            count += 1;
-            println!("{}", count);
-        }
-
-        // should not trigger the lint because the count is conditional
-        let text = "banana";
-        let mut count = 0;
-        for ch in text.chars() {
-            if ch == 'a' {
-                count += 1;
-            }
-            println!("{}", count);
-        }
-
-        // should trigger the lint because the count is not conditional
-        let text = "banana";
-        let mut count = 0;
-        for ch in text.chars() {
-            count += 1;
-            if ch == 'a' {
-                continue;
-            }
-            println!("{}", count);
-        }
-
-        // should trigger the lint because the count is not conditional
-        let text = "banana";
-        let mut count = 0;
-        for ch in text.chars() {
-            count += 1;
-            for i in 0..2 {
-                let _ = 123;
-            }
-            println!("{}", count);
-        }
-
-        // should not trigger the lint because the count is incremented multiple times
-        let text = "banana";
-        let mut count = 0;
-        for ch in text.chars() {
-            count += 1;
-            for i in 0..2 {
-                count += 1;
-            }
-            println!("{}", count);
-        }
-    }
-}
-
-mod issue_3308 {
-    #[warn(clippy::explicit_counter_loop)]
-    pub fn test() {
-        // should not trigger the lint because the count is incremented multiple times
-        let mut skips = 0;
-        let erasures = vec![];
-        for i in 0..10 {
-            while erasures.contains(&(i + skips)) {
-                skips += 1;
-            }
-            println!("{}", skips);
-        }
-
-        // should not trigger the lint because the count is incremented multiple times
-        let mut skips = 0;
-        for i in 0..10 {
-            let mut j = 0;
-            while j < 5 {
-                skips += 1;
-                j += 1;
-            }
-            println!("{}", skips);
-        }
-
-        // should not trigger the lint because the count is incremented multiple times
-        let mut skips = 0;
-        for i in 0..10 {
-            for j in 0..5 {
-                skips += 1;
-            }
-            println!("{}", skips);
-        }
-    }
-}