Check bounds when calling Comment::get_child (fix rust-lang#142)

Author: catdesk

src/clang.rs

@@ -796,9 +796,13 @@ impl Comment {
     }
 
     /// Get this comment's `idx`th child comment
-    pub fn get_child(&self, idx: c_uint) -> Comment {
-        unsafe {
-            Comment { x: clang_Comment_getChild(self.x, idx) }
+    pub fn get_child(&self, idx: c_uint) -> Option<Comment> {
+        if idx  >= self.num_children() {
+            None
+        } else {
+            unsafe {
+                Some(Comment { x: clang_Comment_getChild(self.x, idx) })
+            }
         }
     }
 

src/ir/annotations.rs

@@ -153,7 +153,8 @@ impl Annotations {
         }
 
         for i in 0..comment.num_children() {
-            self.parse(&comment.get_child(i), matched);
+            let child = &comment.get_child(i).expect("index higher than number of children");
+            self.parse(child, matched);
         }
     }
 }