syntax_data: {"ast_node_type":"variable","tokens":[{"end":69,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:     let mut variant_source_info: IndexVec<VariantIdx, SourceInfo> = [
context_before:     let body_span = body.source_scopes[OUTERMOST_SOURCE_SCOPE].span;
context_after:         SourceInfo::outermost(body_span.shrink_to_lo()),