syntax_data: {"ast_node_type":"other","tokens":[{"end":77,"kind":"keyword","start":0,"text":"///"}]}
source_snippet:     /// moving/copying/ref'ing the source as appropriate. Tests the guard, if
context_before:     /// Initializes each of the bindings from the candidate by
context_after:     /// any, and then branches to the arm. Returns the block for the case where