IntelliJ IDEA 编译报错：Error:java: C

确认以下几点:

1. Target bytecode version

   
   Target bytecode version

2. Project Language Level

   
   Project Language Level

3. Module Language Level

   
   Module Language Level

4. Rebuild Project

   
   Rebuild Project

如果还是不行, 可以继续尝试:

• 将Compiler改成Eclipse来编译项目(Annotation Processor 可能出问题)
  Use Compiler
• 改回为Javac, 再重新编译
• 取消选项Use compiler from module target JDK when possible
  Use compiler from module target JDK when possible