Usage of parameter properties results in incorrect diagnostics

[saulecabrera]

Using parameter properties outside of a constructor results in an incorrect diagnostic:

class A {
  value: i32 = 0;
  set bet(pubic v: i32) {}
}

This also happens with normal functions and arrow functions and when using private and protected

Actual

The following diagnostic is emitted: ) expected

Expected
Something more informative, such as:

A parameter property is only allowed in a constructor implementation.