Fix #1219 false positive for explicit_counter_loop

Author: JoshMcguigan

clippy_lints/src/loops.rs

@@ -1950,6 +1950,9 @@ impl<'a, 'tcx> Visitor<'tcx> for IncrementVisitor<'a, 'tcx> {
             walk_expr(self, expr);
             self.depth -= 1;
             return;
+        } else if let ExprKind::Continue(_) = expr.node {
+            self.done = true;
+            return;
         }
         walk_expr(self, expr);
     }

tests/ui/for_loop.rs

@@ -601,5 +601,16 @@ mod issue_1219 {
             }
             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);
+        }
     }
 }

tests/ui/for_loop.stderr

@@ -487,5 +487,11 @@ error: it looks like you're manually copying between slices
 547 |     for i in 0..src.len() {
     |              ^^^^^^^^^^^^ help: try replacing the loop by: `dst[..src.len()].clone_from_slice(&src[..])`
 
-error: aborting due to 59 previous errors
+error: the variable `count` is used as a loop counter. Consider using `for (count, item) in text.chars().enumerate()` or similar iterators
+   --> $DIR/for_loop.rs:608:19
+    |
+608 |         for ch in text.chars() {
+    |                   ^^^^^^^^^^^^
+
+error: aborting due to 60 previous errors