Prop.java:
#    0| [CompilationUnit] Prop
#    2|   1: [Class] Prop
#    4|     2: [Method] getFoo
#    4|       3: [TypeAccess] String
#    4|       5: [BlockStmt] { ... }
#    5|         0: [ReturnStmt] return ...
#    5|           0: [StringLiteral] "foo"
Use.kt:
#    0| [CompilationUnit] Use
#    0|   1: [Class] UseKt
#    2|     1: [Method] use
#    2|       3: [TypeAccess] String
#-----|       4: (Parameters)
#    2|         0: [Parameter] prop
#    2|           0: [TypeAccess] Prop
#    2|       5: [BlockStmt] { ... }
#    3|         0: [ReturnStmt] return ...
#    3|           0: [ImplicitNotNullExpr] <implicit not null>
#    3|             0: [TypeAccess] String
#    3|             1: [MethodCall] getFoo(...)
#    3|               -1: [VarAccess] prop