syntax_data: {"ast_node_type":"function","tokens":[{"end":59,"kind":"keyword","start":0,"text":"fn"}]}
source_snippet: fn file_contains(file: &SourceFile, pos: BytePos) -> bool {
context_before: #[inline]
context_after:     // `SourceMap::lookup_source_file_idx` and `SourceFile::contains` both consider the position