Prettier 2.8.5
Playground link

--parser typescript

Input:

class A {
  @dec() accessor #field;
}

Output:

SyntaxError: Decorators are not valid here. (2:3)
  1 | class A {
> 2 |   @dec() accessor #field;
    |   ^^^^^^
  3 | }

Expected behavior:

No SyntaxError. Change the parser from "typescript" to "babel-ts" will make it work.

Prettier 2.8.4 works fine, seems 2.8.5 introduced this.