syntax_data: {"ast_node_type":"other","tokens":[{"end":85,"kind":"keyword","start":0,"text":"msg:"}]}
source_snippet:             msg: Box::new(AssertKind::InvalidEnumConstruction(Operand::Copy(discr))),
context_before:             target: new_block,
context_after:             // This calls panic_invalid_enum_construction, which is #[rustc_nounwind].