index.wxml
<import src="{{viewPath}}"></import>
<view>{{viewPath}}</view>
<template wx:if="{{viewName}}" is="{{viewName}}"></template>

index.js
viewPath = "/views/demo.wxml"
viewName = "demo"

报错
WXMLRT_$gwx:./pages/index/index.wxml:import:2:2: Path `{{viewPath}}` not found from `./pages/index/index.wxml`.

<import src="{{viewPath}}"></import> 改成
<import src="/views/demo.wxml"></import> 正常