Removes the hard distinction between fields, i.e.

class Foo {
  a: i32;
}

and properties, i.e.

class Foo {
  get a(): i32 { return 42; }
  set a(value: i32) { }
}

by making fields special kinds of properties, differing in having an associated memory offset. As a result, fields (which get built-in getters and setters) and properties (with explicit getters and setters) can override each other, lifting the annoying limitation that interface fields can only be implemented with properties. Since interchangeable fields and properties are more powerful than what is possible in JS/TS, compatibility with TS becomes a matter of disallowing what wouldn't be supported there due to JS nature.

• I've read the contributing guidelines
• I've added my name and email to the NOTICE file