Requires

• Add filter for Kotlin safe call operators chains #1810
• IFilterOutput.replaceBranches should allow the use of individual branches of instructions #1813

For the following Example.kt

data class B(val c: String)
fun example(b: B?): String =
    b?.c ?: ""

Kotlin compiler generates

  public static final java.lang.String example(B);
    descriptor: (LB;)Ljava/lang/String;
    flags: (0x0019) ACC_PUBLIC, ACC_STATIC, ACC_FINAL
    Code:
      stack=2, locals=1, args_size=1
         0: aload_0
         1: dup
         2: ifnull        12
         5: invokevirtual #14                 // Method B.getC:()Ljava/lang/String;
         8: dup
         9: ifnonnull     15
        12: pop
        13: ldc           #16                 // String
        15: areturn

To be able to achieve full coverage branches of ifnull and ifnonnull instructions should be replaced as following

non-null case should be considered covered when

• branch 1 of ifnonnull instruction was executed

There is no instruction whose execution status allows to determine that only non-null case was executed, so the current replaceBranches is not usable and that's why #1813 is required.

null case should be considered covered when

• branch 1 of ifnull instruction was executed
• or branch 0 of ifnonnull instruction was executed

Fixes #1351