syntax_data: {"ast_node_type":"other","tokens":[{"end":63,"kind":"keyword","start":0,"text":"assignments.insert((lhs_child,"}]}
source_snippet:                     assignments.insert((lhs_child, rhs_child));
context_before:                         self.register_place(ty, lhs, proj_elem.expect("child is not a projection"));
context_after:                     child = next_sibling;