Before You File a Proposal Please Confirm You Have Done The Following...

• I have searched for related issues and found none that match my proposal.
• I have searched the current rule list and found no rules that match my proposal.
• I have read the FAQ and my problem is not listed.

My proposal is suitable for this project

• My proposal specifically checks TypeScript syntax, or it proposes a check that requires type information to be accurate.
• My proposal is not a "formatting rule"; meaning it does not just enforce how code is formatted (whitespace, brace placement, etc).
• I believe my proposal would be useful to the broader TypeScript community (meaning it is not a niche proposal).

Description

My rule would check that there are no unnecessary assignments of parameter properties in constructors.

Fail Cases

class Foo {
  constructor(public bar: string) {
    this.bar = bar; // <-- warn here
  }
}

class Foo2 {
  baz: string;
  constructor(public bar: string, baz: string) {
    this.bar = bar; // <-- warn here
    this.baz = baz;
  }
}

Pass Cases

class Foo {
  constructor(public bar: string) {}
}

class Foo2 {
  baz: string;
  constructor(public bar: string, baz: string) {
    this.baz = baz;
  }
}

Additional Info

You can see in this TypeScript playground that assignment of parameter properties produces duplicate assignment: