exit status: 1 with stderr:
<stdin>:4:9: error: use of local variable 'a' before its declaration a += 2 ^ <stdin>:7:9: note: 'a' declared here var a: Int = 42 ^ <stdin>:5:15: error: use of local variable 'a' before its declaration print(a) ^ <stdin>:7:9: note: 'a' declared here var a: Int = 42 ^