syntax_data: {"ast_node_type":"other","tokens":[{"end":96,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:                         // stashing the span of the braces somewhere (like in the match source).
context_before:                         // This is horrendous, and we should deal with it by just
context_after:                         scrut.span.find_ancestor_in_same_ctxt(expr_span).and_then(|scrut_span| {