STEP 0:
    modifications:
        U : l2.0.kt -> l2.kt
    added file: l1.kt, l2.kt
STEP 1:
    modifications:
        U : l2.1.kt -> l2.kt
    modified ir: l2.kt
STEP 2:
    modifications:
        U : l2.2.kt -> l2.kt
    modified ir: l2.kt
STEP 3:
    modifications:
        U : l2.0.kt -> l2.kt
    modified ir: l2.kt
