syntax_data: {"ast_node_type":"other","tokens":[{"end":63,"kind":"keyword","start":0,"text":"this.source_scope"}]}
source_snippet:                             this.source_scope = variable_scope;
context_before:                                 this.new_source_scope(then_span, LintLevel::Inherited);
context_after:                             SourceInfo { span: then_span, scope: variable_scope }