syntax_data: {"ast_node_type":"other","tokens":[{"end":42,"kind":"keyword","start":0,"text":"DistinctSources(Box<DistinctSources>),"}]}
source_snippet:     DistinctSources(Box<DistinctSources>),
context_before:     IllFormedSpan(Span),
context_after:     MalformedForSourcemap(MalformedSourceMapPositions),