Test.java:
#    0| [CompilationUnit] Test
#    1|   1: [Class] Test
#    2|     2: [Method] foo
#    2|       3: [TypeAccess] void
#-----|       4: (Parameters)
#    2|         0: [Parameter] s
#    2|           0: [TypeAccess] String
#    2|       5: [BlockStmt] stmt
#    3|         0: [LocalVariableDeclStmt] stmt
#    3|           0: [TypeAccess] int
#    3|           1: [LocalVariableDeclExpr] x
#    3|             0: [SwitchExpr] switch (...)
#    3|               -1: [VarAccess] s
#    4|               0: [ConstCase] stmt
#    4|                 -1: [IntegerLiteral] 1
#    4|                 0: [StringLiteral] "a"
#    4|                 1: [StringLiteral] "b"
#    5|               1: [ConstCase] stmt
#    5|                 -1: [IntegerLiteral] 2
#    5|                 0: [StringLiteral] "c"
#    6|               2: [DefaultCase] stmt
#    6|                 -1: [IntegerLiteral] 3