Logical Assignment Operator should be a definite assignment kind

[Kingwl]

TypeScript Version: 3.7.x-dev.201xxxxx

Search Terms:
assignment operator, type
Code
#37255 (comment)

// A *self-contained* demonstration of the problem follows...
// Test this by running `tsc` on the command-line, rather than through another build tool such as Gulp, Webpack, etc.
let x: { a?: boolean } = {};

x.a ??= true;
x.a &&= false;
^^^ Type 'false' is not assignable to type 'true'.(2322)

Expected behavior:
Works

Actual behavior:
Type 'false' is not assignable to type 'true'.(2322)

Playground Link:

Related Issues: