syntax_data: {"ast_node_type":"variable","tokens":[{"end":68,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:     let invalid_discr_block_data = BasicBlockData::new(None, false);
context_before:     // Insert a new target block that is branched to in case of an invalid discriminant.
context_after:     let invalid_discr_block = basic_blocks.push(invalid_discr_block_data);