No typescript highlighting for arrow function with line break before first param

[arznaar]

Code below compiles correctly to javascript and runs without error.

• VSCode Version: 1.17.2
• Typescript version: 2.5.3
• OS Version: Windows 10 version 1703 build 15063.540
• Reproduces without extensions: Yes

Steps to Reproduce:

Write first param for the arrow function on the next line. Example:

const goodMethod = (param1: string, param2: string) => {
}

const badMethod = (
    param1: string,
    param2: string
) => {
}

[mjbvz]

This issue was moved to microsoft/TypeScript-TmLanguage#539