Property initializer should get the same completion as property assignment

[mjbvz]

From @unional on April 22, 2017 9:12

• VSCode Version: 1.11.2
• OS Version: OSX

abstract class Foo {
  options: {
    x: string
  }
}

class Koo extends Foo { // already know options is missing x
  options = {
    // should get `x` as property
  }
  do() {
    this.options = {
      // does recognize `x` as property
    }
  }
}

Copied from original issue: microsoft/vscode#25181

[sandersn]

Typescript sees Koo's options as distinct from Foo's options when declaring them. It just checks that Koo's options is assignable to Foo's options after it has been created.

In contrast, this.options is referring to something that is already declared. Note that if you provide a more specific type for Koo's options, like options = { x: "string literal type" }, then the completion for this.options in Koo will have that more specific type.

[sandersn]

A full explanation of the approaches we have tried is at #6118. Both would provide completions here, but neither works well as part of the language.

[sandersn]

Duplicate of #3667