Parser doesn't expect 3 part version in `@available`

IDE: Visual Studio X/Fire
Version: (develop)
Target (If relevant): Island(OSX)
The Elements parser doesn’t expect 3 part version in @available, and gets quite confused.

Expected Behavior:
Errors about lack of context, or in actual use, compiling fine.
Actual Behavior:
see below, the E1 is the most important error here.

@available(macOS 10.12.2, iOS 10.2, tvOS 10.1, watchOS 3.1.1, *) // E1 closing parenthesis expected, got dot
																 // E5 Attributes are not allowed here
																 // E477 Declaration expected
																 // E63 Type mismatch

Thanks, logged as bugs://83572

bugs://83572 got closed with status fixed.