syntax_data: {"ast_node_type":"other","tokens":[{"end":81,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:         // Note that filename may not be a valid path, eg it may be `<anon>` etc,
context_before:     ) -> Result<Arc<SourceFile>, OffsetOverflowError> {
context_after:         // but this is okay because the directory determined by `path.pop()` will