Auto merge of #4069 - mikerite:while_loop_test_split, r=phansch

Reorganize "while loop" tests

cc #2038

changelog: none

tests/ui/ice-360.rs

@@ -0,0 +1,12 @@
+fn main() {}
+
+fn no_panic<T>(slice: &[T]) {
+    let mut iter = slice.iter();
+    loop {
+        let _ = match iter.next() {
+            Some(ele) => ele,
+            None => break,
+        };
+        loop {}
+    }
+}

tests/ui/ice-360.stderr

@@ -0,0 +1,24 @@
+error: this loop could be written as a `while let` loop
+  --> $DIR/ice-360.rs:5:5
+   |
+LL | /     loop {
+LL | |         let _ = match iter.next() {
+LL | |             Some(ele) => ele,
+LL | |             None => break,
+LL | |         };
+LL | |         loop {}
+LL | |     }
+   | |_____^ help: try: `while let Some(ele) = iter.next() { .. }`
+   |
+   = note: `-D clippy::while-let-loop` implied by `-D warnings`
+
+error: empty `loop {}` detected. You may want to either use `panic!()` or add `std::thread::sleep(..);` to the loop body.
+  --> $DIR/ice-360.rs:10:9
+   |
+LL |         loop {}
+   |         ^^^^^^^
+   |
+   = note: `-D clippy::empty-loop` implied by `-D warnings`
+
+error: aborting due to 2 previous errors
+

tests/ui/while_let_loop.rs

@@ -0,0 +1,119 @@
+#![warn(clippy::while_let_loop)]
+
+fn main() {
+    let y = Some(true);
+    loop {
+        if let Some(_x) = y {
+            let _v = 1;
+        } else {
+            break;
+        }
+    }
+
+    #[allow(clippy::never_loop)]
+    loop {
+        // no error, break is not in else clause
+        if let Some(_x) = y {
+            let _v = 1;
+        }
+        break;
+    }
+
+    loop {
+        match y {
+            Some(_x) => true,
+            None => break,
+        };
+    }
+
+    loop {
+        let x = match y {
+            Some(x) => x,
+            None => break,
+        };
+        let _x = x;
+        let _str = "foo";
+    }
+
+    loop {
+        let x = match y {
+            Some(x) => x,
+            None => break,
+        };
+        {
+            let _a = "bar";
+        };
+        {
+            let _b = "foobar";
+        }
+    }
+
+    loop {
+        // no error, else branch does something other than break
+        match y {
+            Some(_x) => true,
+            _ => {
+                let _z = 1;
+                break;
+            },
+        };
+    }
+
+    while let Some(x) = y {
+        // no error, obviously
+        println!("{}", x);
+    }
+
+    // #675, this used to have a wrong suggestion
+    loop {
+        let (e, l) = match "".split_whitespace().next() {
+            Some(word) => (word.is_empty(), word.len()),
+            None => break,
+        };
+
+        let _ = (e, l);
+    }
+}
+
+fn issue771() {
+    let mut a = 100;
+    let b = Some(true);
+    loop {
+        if a > 10 {
+            break;
+        }
+
+        match b {
+            Some(_) => a = 0,
+            None => break,
+        }
+    }
+}
+
+fn issue1017() {
+    let r: Result<u32, u32> = Ok(42);
+    let mut len = 1337;
+
+    loop {
+        match r {
+            Err(_) => len = 0,
+            Ok(length) => {
+                len = length;
+                break;
+            },
+        }
+    }
+}
+
+#[allow(clippy::never_loop)]
+fn issue1948() {
+    // should not trigger clippy::while_let_loop lint because break passes an expression
+    let a = Some(10);
+    let b = loop {
+        if let Some(c) = a {
+            break Some(c);
+        } else {
+            break None;
+        }
+    };
+}

tests/ui/while_let_loop.stderr

@@ -0,0 +1,63 @@
+error: this loop could be written as a `while let` loop
+  --> $DIR/while_let_loop.rs:5:5
+   |
+LL | /     loop {
+LL | |         if let Some(_x) = y {
+LL | |             let _v = 1;
+LL | |         } else {
+LL | |             break;
+LL | |         }
+LL | |     }
+   | |_____^ help: try: `while let Some(_x) = y { .. }`
+   |
+   = note: `-D clippy::while-let-loop` implied by `-D warnings`
+
+error: this loop could be written as a `while let` loop
+  --> $DIR/while_let_loop.rs:22:5
+   |
+LL | /     loop {
+LL | |         match y {
+LL | |             Some(_x) => true,
+LL | |             None => break,
+LL | |         };
+LL | |     }
+   | |_____^ help: try: `while let Some(_x) = y { .. }`
+
+error: this loop could be written as a `while let` loop
+  --> $DIR/while_let_loop.rs:29:5
+   |
+LL | /     loop {
+LL | |         let x = match y {
+LL | |             Some(x) => x,
+LL | |             None => break,
+...  |
+LL | |         let _str = "foo";
+LL | |     }
+   | |_____^ help: try: `while let Some(x) = y { .. }`
+
+error: this loop could be written as a `while let` loop
+  --> $DIR/while_let_loop.rs:38:5
+   |
+LL | /     loop {
+LL | |         let x = match y {
+LL | |             Some(x) => x,
+LL | |             None => break,
+...  |
+LL | |         }
+LL | |     }
+   | |_____^ help: try: `while let Some(x) = y { .. }`
+
+error: this loop could be written as a `while let` loop
+  --> $DIR/while_let_loop.rs:68:5
+   |
+LL | /     loop {
+LL | |         let (e, l) = match "".split_whitespace().next() {
+LL | |             Some(word) => (word.is_empty(), word.len()),
+LL | |             None => break,
+...  |
+LL | |         let _ = (e, l);
+LL | |     }
+   | |_____^ help: try: `while let Some(word) = "".split_whitespace().next() { .. }`
+
+error: aborting due to 5 previous errors
+

tests/ui/while_loop.rs → tests/ui/while_let_on_iterator.rs

@@ -1,73 +1,7 @@
-#![warn(clippy::while_let_loop, clippy::empty_loop, clippy::while_let_on_iterator)]
-#![allow(dead_code, clippy::never_loop, unused, clippy::cognitive_complexity)]
+#![warn(clippy::while_let_on_iterator)]
+#![allow(clippy::never_loop, clippy::cognitive_complexity)]
 
 fn main() {
-    let y = Some(true);
-    loop {
-        if let Some(_x) = y {
-            let _v = 1;
-        } else {
-            break;
-        }
-    }
-    loop {
-        // no error, break is not in else clause
-        if let Some(_x) = y {
-            let _v = 1;
-        }
-        break;
-    }
-    loop {
-        match y {
-            Some(_x) => true,
-            None => break,
-        };
-    }
-    loop {
-        let x = match y {
-            Some(x) => x,
-            None => break,
-        };
-        let _x = x;
-        let _str = "foo";
-    }
-    loop {
-        let x = match y {
-            Some(x) => x,
-            None => break,
-        };
-        {
-            let _a = "bar";
-        };
-        {
-            let _b = "foobar";
-        }
-    }
-    loop {
-        // no error, else branch does something other than break
-        match y {
-            Some(_x) => true,
-            _ => {
-                let _z = 1;
-                break;
-            },
-        };
-    }
-    while let Some(x) = y {
-        // no error, obviously
-        println!("{}", x);
-    }
-
-    // #675, this used to have a wrong suggestion
-    loop {
-        let (e, l) = match "".split_whitespace().next() {
-            Some(word) => (word.is_empty(), word.len()),
-            None => break,
-        };
-
-        let _ = (e, l);
-    }
-
     let mut iter = 1..20;
     while let Option::Some(x) = iter.next() {
         println!("{}", x);
@@ -116,36 +50,6 @@ fn main() {
     }
 }
 
-// regression test (#360)
-// this should not panic
-// it's ok if further iterations of the lint
-// cause this function to trigger it
-fn no_panic<T>(slice: &[T]) {
-    let mut iter = slice.iter();
-    loop {
-        let _ = match iter.next() {
-            Some(ele) => ele,
-            None => break,
-        };
-        loop {}
-    }
-}
-
-fn issue1017() {
-    let r: Result<u32, u32> = Ok(42);
-    let mut len = 1337;
-
-    loop {
-        match r {
-            Err(_) => len = 0,
-            Ok(length) => {
-                len = length;
-                break;
-            },
-        }
-    }
-}
-
 // Issue #1188
 fn refutable() {
     let a = [42, 1337];
@@ -194,18 +98,6 @@ fn nested_loops() {
     }
 }
 
-fn issue1948() {
-    // should not trigger clippy::while_let_loop lint because break passes an expression
-    let a = Some(10);
-    let b = loop {
-        if let Some(c) = a {
-            break Some(c);
-        } else {
-            break None;
-        }
-    };
-}
-
 fn issue1121() {
     use std::collections::HashSet;
     let mut values = HashSet::new();
@@ -238,18 +130,3 @@ fn issue3670() {
         let _ = elem.or_else(|| *iter.next()?);
     }
 }
-
-fn issue771() {
-    let mut a = 100;
-    let b = Some(true);
-    loop {
-        if a > 10 {
-            break;
-        }
-
-        match b {
-            Some(_) => a = 0,
-            None => break,
-        }
-    }
-}