syntax_data: {"ast_node_type":"other","tokens":[{"end":87,"kind":"keyword","start":0,"text":"//"}]}
source_snippet: // Only `cfg(target_feature)` and `#[target_feature]` actually do any stability gating.
context_before: // on stable. Using a feature not on the list of Rust target features only emits a warning.
context_after: // `cfg(target_feature)` for unstable features just works on nightly without any feature gate.