syntax_data: {"ast_node_type":"other","tokens":[{"end":83,"kind":"keyword","start":0,"text":"///"}]}
source_snippet:     /// crate. The source code of such an "imported `SourceFile`" is not available,
context_before:     /// Allocates a new `SourceFile` representing a source file from an external
context_after:     /// but we still know enough to generate accurate debuginfo location