Compile errors in the editor

[jrieken]

Since today (Insiders-1.8.0 0d65ced) I see compile errors in the editor that don't show up when running gulp watch. Unsure if this is new TypeScript behaviour or bugs? Samples are

• https://github.com/Microsoft/vscode/blob/master/src/vs/workbench/api/node/extHostConfiguration.ts#L110
• https://github.com/Microsoft/vscode/blob/master/src/vs/editor/contrib/snippet/common/snippetParser.ts#L208

[kieferrm]

This is the condensed version of snippetParser.ts that still creates the problem:

export abstract class Marker {
	static toString(markers: Marker[]): string {
		return '';
	}
}

export class Placeholder extends Marker {
	constructor(public name: string = '', public defaultValue: Marker[]) {
		super();
	}
}

function foo(marker: Marker) {
	if (marker instanceof Placeholder) {
		console.log(marker.name);
		console.log(marker.defaultValue);
	}
}

foo(null);

[kieferrm]

This is the error we are getting:

[jrieken]

Thanks for drilling into this. I might push a change to rename my method...

[kieferrm]

Here is the second one:

export interface Foo {
	property: boolean;
	[key: string]: any;
}

function freezer(bar: Foo): Foo {
	return Object.freeze(bar);
}

freezer(null);

The issue is caused when an index is combined with anything else no matter if a property or method.

The error we get is:

[mjbvz]

Opened two more issues against TS to track other issue we are seeing when compiling VSCode with 2.1.4:

• Promise.then with Any Return Type Produces Incorrect error TypeScript#12725
• Cannot use === with Enum Literal Type TypeScript#12729

I'm going to submit quick workarounds fixes to our code for those two problems. They just require additional casts

[mjbvz]

Fixed those two errors with #16861

[mjbvz]

I believe this was resolved by #16861 and 499a648.

We also followed up with the TS team. Most of the errors are by design and are breaking changes in TS 2.1