Critical: async_bufreader::BufReader::poll_fill_buf: Destroys data.

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Line 174 s/this.buffer/this.buffer[*this.cap..]/.

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nom-bufreader/src/async_bufreader.rs

Line 174 in c2e48f5

let read = ready!(this.inner.poll_read(cx, this.buffer))?;

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"AND", you can't use ready! as this is called multiple times in succession. Returning Ready and then Pending is a panic.

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diff --git a/src/async_bufreader.rs b/src/async_bufreader.rs
index bb5557c..836c6fa 100644
--- a/src/async_bufreader.rs
+++ b/src/async_bufreader.rs
@@ -171,9 +171,16 @@ impl<R: AsyncRead> AsyncBufRead for BufReader<R> {
             }
         }
 
-        let read = ready!(this.inner.poll_read(cx, this.buffer))?;
-        *this.cap += read;
-
+        match this.inner.poll_read(cx, &mut this.buffer[*this.cap..]) {
+            Poll::Pending => {
+                /* This is supposed to let the compiler know pos can never be greater than cap... or something */
+                if *this.pos < *this.cap {
+                } else {
+                    return Poll::Pending;
+                }
+            }
+            Poll::Ready(read) => *this.cap += read?,
+        }
         Poll::Ready(Ok(&this.buffer[*this.pos..*this.cap]))
     }