syntax_data: {"ast_node_type":"struct","tokens":[{"end":72,"kind":"keyword","start":0,"text":"the"}]}
source_snippet: the `Foo` in the *second* field of the struct is culpable. This requires
context_before: For the diagnostic output (in `Value::from_cycle_error`), we want to detect that
context_after: traversing the HIR of the struct and calling `params_in_repr(Bar)`. But we can't