syntax_data: {"ast_node_type":"other","tokens":[{"end":79,"kind":"keyword","start":0,"text":".unwrap_or_else(||"}]}
source_snippet:         .unwrap_or_else(|| span_bug!(span, "can't build MIR for {:?}", fn_def))
context_before:         .hir_fn_decl_by_hir_id(fn_id)
context_after:         .output