Regression: property used before initialization inside function

[ajafff]

TypeScript Version: 3.8.0-dev.20200125

Search Terms:

Code

// @target: esnext
// @useDefineForClassFields. true
class C {
    bar = () => this.foo1 + this.foo2;
    foo1 = '';
    constructor(public foo2: string) {}
}

Expected behavior:

Accessing foo1 and foo2 should not be an error as the function is not immediately invoked and therefore the properties are initialized when accessed. This worked before #36425.

Actual behavior:

used before initialization error on this.foo1 and this.foo2

Playground Link: https://www.typescriptlang.org/play/?useDefineForClassFields=true&target=99&ts=3.8.0-dev.20200125&ssl=9&ssc=2&pln=5&pc=2#code/MYGwhgzhAEDC0G8BQ1XQEZgE7QLzQAoBKPAPmgBcALASwgDoAzAe2YEZoBqS2hl5gEwBuFGn4d8Ackki00YMwB2EClgCuwCsywEADmvQgawaPwEAuaCqw1FAcxIIAvkidA

Related Issues: #36425 @sandersn