False positive "Lexical declarations require ECMAScript 6" and "TypeScript 1.x feature. Current language is 1.4" error messages

Question

After updating TypeScript to version 1.7 (the latest version at this time) I've been seeing Resharper point out errors, for example when using namespace, const and let, even though they should be supported by this version of TypeScript.

For example:

TypeScript 1.x feature. Current language is 1.4

and

Lexical declarations (let and const) require ECMAScript 6 compiler target. Current target is ECMAScript 5.

Answer 1

It seems my version of Resharper (10.0.1) is unable to detect the TypeScript version.

To resolve this you can specify the version manually. Since this version of Resharper (the latest at this time of posting) doesn't support TypeScript 1.7, TypeScript 1.6 needs to be used.