message: Assert the size of an assign
  Summary: Useful to track, even if we don't care too much.
diff: @@ -40,6 +40,7 @@ pub type AstStmt = Spanned<Stmt>;
  // but we equally don't want to regress without noticing.
  assert_eq_size!(AstStmt, [usize; 11]);
  assert_eq_size!(AstExpr, [usize; 7]);
  +assert_eq_size!(AstAssign, [usize; 7]);
  /// A representation of a Starlark module abstract syntax tree.
  ///
  