Fix `needless_continue` false positive

2 files changed, 110 insertions, 4 deletions

diff --git a/tests/ui/needless_continue.rs b/tests/ui/needless_continue.rs
index 8bb1ba6edb5..5da95647f2c 100644
--- a/tests/ui/needless_continue.rs
+++ b/tests/ui/needless_continue.rs
@@ -1,3 +1,5 @@
+#![warn(clippy::needless_continue)]
+
 macro_rules! zero {
     ($x:expr) => {
         $x == 0
@@ -10,7 +12,6 @@ macro_rules! nonzero {
     };
 }
 
-#[warn(clippy::needless_continue)]
 fn main() {
     let mut i = 1;
     while i < 10 {
@@ -49,3 +50,66 @@ fn main() {
         println!("bleh");
     }
 }
+
+mod issue_2329 {
+    fn condition() -> bool {
+        unimplemented!()
+    }
+    fn update_condition() {}
+
+    // only the outer loop has a label
+    fn foo() {
+        'outer: loop {
+            println!("Entry");
+            while condition() {
+                update_condition();
+                if condition() {
+                    println!("foo-1");
+                } else {
+                    continue 'outer; // should not lint here
+                }
+                println!("foo-2");
+
+                update_condition();
+                if condition() {
+                    continue 'outer; // should not lint here
+                } else {
+                    println!("foo-3");
+                }
+                println!("foo-4");
+            }
+        }
+    }
+
+    // both loops have labels
+    fn bar() {
+        'outer: loop {
+            println!("Entry");
+            'inner: while condition() {
+                update_condition();
+                if condition() {
+                    println!("bar-1");
+                } else {
+                    continue 'outer; // should not lint here
+                }
+                println!("bar-2");
+
+                update_condition();
+                if condition() {
+                    println!("bar-3");
+                } else {
+                    continue 'inner; // should lint here
+                }
+                println!("bar-4");
+
+                update_condition();
+                if condition() {
+                    continue; // should lint here
+                } else {
+                    println!("bar-5");
+                }
+                println!("bar-6");
+            }
+        }
+    }
+}
diff --git a/tests/ui/needless_continue.stderr b/tests/ui/needless_continue.stderr
index 763eaf3a70e..340ae66dae4 100644
--- a/tests/ui/needless_continue.stderr
+++ b/tests/ui/needless_continue.stderr
@@ -1,6 +1,6 @@
 error: This else block is redundant.
 
-  --> $DIR/needless_continue.rs:27:16
+  --> $DIR/needless_continue.rs:28:16
    |
 LL |           } else {
    |  ________________^
@@ -37,7 +37,7 @@ LL | |         }
 
 error: There is no need for an explicit `else` block for this `if` expression
 
-  --> $DIR/needless_continue.rs:42:9
+  --> $DIR/needless_continue.rs:43:9
    |
 LL | /         if (zero!(i % 2) || nonzero!(i % 5)) && i % 3 != 0 {
 LL | |             continue;
@@ -55,5 +55,47 @@ LL | |         }
            println!("Jabber");
            ...
 
-error: aborting due to 2 previous errors
+error: This else block is redundant.
+
+  --> $DIR/needless_continue.rs:100:24
+   |
+LL |                   } else {
+   |  ________________________^
+LL | |                     continue 'inner; // should lint here
+LL | |                 }
+   | |_________________^
+   |
+   = help: Consider dropping the else clause and merging the code that follows (in the loop) with the if block, like so:
+           if condition() {
+           println!("bar-3");
+           // Merged code follows...println!("bar-4");
+           update_condition();
+           if condition() {
+               continue; // should lint here
+           } else {
+               println!("bar-5");
+           }
+           println!("bar-6");
+           }
+           
+
+error: There is no need for an explicit `else` block for this `if` expression
+
+  --> $DIR/needless_continue.rs:106:17
+   |
+LL | /                 if condition() {
+LL | |                     continue; // should lint here
+LL | |                 } else {
+LL | |                     println!("bar-5");
+LL | |                 }
+   | |_________________^
+   |
+   = help: Consider dropping the else clause, and moving out the code in the else block, like so:
+           if condition() {
+               continue;
+           }
+           println!("bar-5");
+           ...
+
+error: aborting due to 4 previous errors