// The branch on needs_drop() is an -O1 performance optimization.
// Without the branch, dropping TypedArena<u8> takes linear time.
if mem::needs_drop::<T>() {
// The branch on needs_drop() is an -O1 performance optimization.
// Without the branch, dropping TypedArena<u8> takes linear time.
if mem::needs_drop::<T>() {