Iceman

@swift-main -warn-concurrency var const: Int { 42 } let const2: Int = 42 actor A { init() { _ = const _ = const2 } }

stderr:

<stdin>:6:9: warning: reference to var 'const' is not concurrency-safe because it involves shared mutable state _ = const ^ <stdin>:1:5: note: var declared here var const: Int { 42 } ^