Completion hits too complex in chained `+` in result builder

[hamishknight]

The following hits "too complex" and produces no completions:

import SwiftUI

func foo() -> some View {
  Group {
    Group {
      Group {
        Text("")
        + Text("")
          .foregroundColor(Color(""))
        + Text("")
        + Text("")
        + Text("")
          .#^CC^#
      }
    }
  }
}

The expression without .#^CC^# does type-check, although it takes several seconds