Runs under Xcode, won't compile from cmd line

Using Swift
1 
import Foundation
import RegexBuilder

let timeRE : Regex  = /\d+:\d\d.\d\d/
let inputLine = "12:34.56"

   if let result = try timeRE.wholeMatch( in: inputLine )
   {
      print( "matched: \(result.0)" )
   }

Runs and matches (as expected) when I build it from Xcode. But if I switch to a terminal window, CD into the directory containing main.swift, and execute:

swiftc main.swift

main.swift:8:24: error: consecutive statements on a line must be separated by ';'
 6 | import RegexBuilder
 7 | 
 8 | let timeRE : Regex  = /\d+:\d\d.\d\d/
   |                        `- error: consecutive statements on a line must be separated by ';'
 9 | let inputLine = "12:34.56"
10 |

and a whole bunch of other errors.

2

Xcode enables the Regex literal syntax by default, command line builds do not (unless through xcodebuild). You’ll need to pass the upcoming feature flag to enable it, which I don’t have offhand.

3

swiftc -enable-bare-slash-regex main.swift

Got it. Thanks.
Interesting, I could have sworn other REs worked just fine from the command line. Maybe I only did DSLs...