syntax_data: {"ast_node_type":"other","tokens":[{"end":57,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:         // in order to get the lexical scoping correctly.
context_before:         // We have to eagerly lower the "spine" of the statements
context_after:         let stmts = self.mirror_stmts(block.hir_id.local_id, block.stmts);