syntax_data: {"ast_node_type":"other","tokens":[{"end":35,"kind":"keyword","start":0,"text":"if"}]}
source_snippet:             if a_mutbl != b_mutbl {
context_before:         (ty::RawPtr(a_ty, a_mutbl), ty::RawPtr(b_ty, b_mutbl)) => {
context_after:                 return Err(TypeError::Mutability);