text: /**
   * Fixes block-shadowed let/const bindings in Safari 10/11.
   * https://kangax.github.io/compat-table/es6/#test-let_scope_shadow_resolution
   */
  export default function({ types: t }) {
    return {
      name: "transform-safari-block-shadowing",
      visitor: {
        VariableDeclarator(path) {
          // the issue only affects let and const bindings:
          const kind = path.parent.kind;
          if (kind !== "let" && kind !== "const") return;
  
          // ignore non-block-scoped bindings:
          const block = path.scope.block;
          if (t.isFunction(block) || t.isProgram(block)) return;
  
          const bindings = t.getOuterBindingIdentifiers(path.node.id);
          for (const name of Object.keys(bindings)) {
            let scope = path.scope;
  
            // ignore parent bindings (note: impossible due to let/const?)
            if (!scope.hasOwnBinding(name)) continue;
  
            // check if shadowed within the nearest function/program boundary
            while ((scope = scope.parent)) {
              if (scope.hasOwnBinding(name)) {
                path.scope.rename(name);
                break;
              }
              if (t.isFunction(scope.block) || t.isProgram(scope.block)) {
                break;
              }
            }
          }
        },
      },
    };
  }
  