code: protected void memberEnter(JCTree tree, Env<AttrContext> env) {
          Env<AttrContext> prevEnv = this.env;
          try {
              this.env = env;
              tree.accept(this);
          }  catch (CompletionFailure ex) {
              chk.completionError(tree.pos(), ex);
          } finally {
              this.env = prevEnv;
          }
      }
docs: Enter field and method definitions and process import
  clauses, catching any completion failure exceptions.