• VSCode Version: 1.18.0
• OS Version: Windows 10 FCU

Steps to Reproduce:

1. You have a tasks.json file with a bunch of tasks and separate OS configurations for the path to the exe defined once at the top of the file.
2. In a few tasks you need to pass the path to an output dir, so you try ${workspaceFolder}/debug which works on Linux/macOS but not on Windows because the underlying utility we use (rcedit) rejects the path.

What I'd like to be able to do is specify ${workspaceFolder}${dirSep}debug and not have to worry about the vagaries of OS dir separators.

Reproduces without extensions: N/A