Regression bug - false typescript error with regards to generics and generics inference

[noam-honig]

Issue Type: Bug

I use a complex structure of classes, interfaces and generics.

The generic type is inferred by the first paramter of the class constructor.
In the current version I get a syntax highlight error that I did not receive in older versions (few month ago).

Here are some screenshots - and the code is below:

And the errors are:

and:

Here's the type script code with two members - one that get's the syntax error and one that works.

class ClassA<classType>  {
  constructor(private entity?: classType, public settings?: SettingsInterface<classType>) {

  }
}
export interface valueInterface<classType> {
  func?: (row: classType) => any;
  value?: string;
}
export interface SettingsInterface<classType> {
  values?: (row: classType) => valueInterface<classType>[],
}
class myClass{
    theName='myClass';
}

var thisGetsTheFalseError = new ClassA(new myClass(), {
  values: o => [
    {
      value: o.theName,
      func: x => 'asdfkjhgfdfghjkjhgfdfghjklkjhgfdfghjklkjhgfghj'
    }
  ]
});
var thisIsOk = new ClassA<myClass>(new myClass(), {
  values: o => [
    {
      value: o.theName,
      func: x => 'asdfkjhgfdfghjkjhgfdfghjklkjhgfdfghjklkjhgfghj'
    }
  ]
});

VS Code version: Code 1.28.2 (7f3ce96ff4729c91352ae6def877e59c561f4850, 2018-10-17T00:23:51.859Z)
OS version: Windows_NT x64 10.0.17134

System Info

Item	Value
CPUs	Intel(R) Core(TM) i7-5930K CPU @ 3.50GHz (12 x 3500)
GPU Status	2d_canvas: enabled checker_imaging: disabled_off flash_3d: enabled flash_stage3d: enabled flash_stage3d_baseline: enabled gpu_compositing: enabled multiple_raster_threads: enabled_on native_gpu_memory_buffers: disabled_software rasterization: enabled video_decode: enabled video_encode: enabled webgl: enabled webgl2: enabled
Memory (System)	31.84GB (17.33GB free)
Process Argv	--folder-uri file:///c%3A/Repos/radweb
Screen Reader	no
VM	0%

Extensions (4)

Extension	Author (truncated)	Version
ng-template	Ang	0.1.10
githistory	don	0.4.3
gitlens	eam	8.5.6
debugger-for-chrome	msj	4.11.0

[noam-honig]

Just to clarify - it's not a typescript build error (at least in the typescript version I'm building with) - it's an error syntax highlight in VS Code

[noam-honig]

One more clarification - I confirmed that in typescript 3.1.6 it's a build error.
Previously in TypeScript 2.5.3 - it worked as expected without any build errors or syntax highlight errors.

[RyanCavanaugh]

Regression starting at 3.1

[noam-honig]

@weswigham I've retested this using the latest vscode and typescript 3.5.1 and it's still not working - how can I test if it was fixed?

[weswigham]

You'd have to use the nightly - typescript@next - and configure vscode to use the installed version of typescript.