TypeScript AutoComplete: Overloading functions erratic behavior

[brenapp]

Issue Type: Bug

I'm making TypeScript definitions for my JavaScript library. For the purpose of this issue, it consists of six endpoints, each with their own request and response interfaces which contain all the parameters and returned fields for the said endpoint. They come together with the .get(endpoint: string, params) function, which is overloaded to use each correct interface. I ran into this issue when testing these definitions.

Expected Behavior: AutoComplete should suggest from the correct overloaded function (and therefore, the correct interface) when that one is provided

Actual Behavior: Tooltip displays the correct overload before any keys are added to the parameters object, but reverts to the first upon any being added. Take a look:

Notice in the tooltip, how once the awards endpoint has been selected, VSCode correctly displays the suggested overload for .get(), but once a key is typed, it reverts to the first definition in both the suggestions and the tooltip

Steps to Reproduce:

1. Download the appropriate definition file here
2. import { get } from "vexdb"
3. Get an endpoint and see vscode revert to the first overload in the parameter suggestion (like above)

Note: I'm relatively new to TypeScript, so it's very possible I may be doing something wrong here, or going against standard best practices. If that's the case, please feel free to close this issue. The reason I feel confident enough to file this is because the definition file compiles fine, and the experience mostly works, it just appears to be a small mistake on the part of VSCode

VS Code version: Code 1.24.1 (24f6262, 2018-06-13T17:41:50.128Z)
OS version: Darwin x64 16.7.0

System Info

Item	Value
CPUs	Intel(R) Core(TM) i5-4278U CPU @ 2.60GHz (4 x 2600)
GPU Status	2d_canvas: enabled flash_3d: enabled flash_stage3d: enabled flash_stage3d_baseline: enabled gpu_compositing: enabled multiple_raster_threads: enabled_on native_gpu_memory_buffers: enabled rasterization: enabled video_decode: enabled video_encode: enabled vpx_decode: enabled webgl: enabled webgl2: enabled
Load (avg)	2, 2, 2
Memory (System)	8.00GB (0.06GB free)
Process Argv	/Applications/Visual Studio Code.app/Contents/MacOS/Electron
Screen Reader	no
VM	0%

Extensions (15)

Extension	Author (truncated)	Version
code-gnu-global	aus	0.2.2
tslint	eg2	1.0.33
prettier-vscode	esb	1.5.0
auto-close-tag	for	0.5.6
auto-rename-tag	for	0.0.15
types-autoinstaller	jvi	2.4.0
auto-comment-blocks	kev	1.0.1
rainbow-csv	mec	0.4.2
dotenv	mik	1.0.1
python	ms-	2018.6.0
cpptools	ms-	0.17.5
debugger-for-chrome	msj	4.6.0
language-stylus	sys	1.9.2
vsfire	tob	1.3.2
vscode-import-cost	wix	2.7.2

(1 theme extensions excluded)

[mjbvz]

Thanks. Opened microsoft/TypeScript#25208 to track this upstream