title: Unable to resolve signature of property decorator when called as an expression
body: <pre><code>import { isEmail, isEmpty, isPhoneNumber, Length } from &quot;class-validator&quot;
  import { Field, InputType } from &quot;type-graphql&quot;;
  
  @InputType()
  export class RegisterInput {
      @Field()
      @Length(2, 15, { message: &quot;Username Must Be At Least 2 characters&quot; })
      username?: string;
  
      @Field()
      @isEmail()
      email?: string;
  
      @Field()
      @Length(1, 20)
      @isPhoneNumber()
      phoneNumber?: string;
  
      @isEmpty()
      password?: string
  
  }
  </code></pre>
  <p>The thing is @isEmail() and @isPhoneNumber() and @isEmpty() throw the same error:</p>
  <pre><code>Unable to resolve signature of property decorator when called as an expression.
    This expression is not callable.
      Type 'Boolean' has no call signatures.ts(1240)
  </code></pre>
  <p>Please help me out I've been stuck with this bug the whole day</p>