ATestReified.kt

// the A in front of the file name is just to keep this on top in the gist lol
inline fun <reified T> testReified(obj: T) {
    // None of these are possible in Java because of Type Erasure
    if (obj is Int) {
        println(5 + obj)
    } else {
        println(obj)
    }

    val x = 5
    if (x is T) {
        println("5 is type T")
    }
}

fun main(args: Array<String>) {
    testReified(5)
    testReified("5")
}

MainSimplified.java

// This file is a file that I have changed manually
// to simplify the decompiled code above. Note that
// some parts may look much different from the decompiled
// code because of two reasons:
// 1. The decompiler bugs out certain optimizations
// 2. To make the inlined calls look more like how the inline function actually looks

// First inlined call: testReified(5). Output: 10, "5 is type T"
Object param = Integer.valueOf(5);
if (param instanceof Integer) {
   System.out.println(5 + ((int) param)); // 10
} else {
   System.out.println(param);
}

int x = 5;
if(Integer.valueOf(x) instanceof Integer) {
   System.out.println("5 is type T"); // outputs
}


// Second inlined call: testReified("5"). Output: 5
Object param2 = "5";
if(param2 instanceof Integer) {
   System.out.println(5 + ((int) param));
} else {
   System.out.println(param2); // "5"
}

int x = 5;
if(Integer.valueOf(x) instanceof String) {
   var3 = "5 is type T";
   System.out.println(var3);
}

TestReified.decompiled.java

import kotlin.Metadata;
import kotlin.jvm.internal.Intrinsics;
import org.jetbrains.annotations.NotNull;

@Metadata(
   mv = {1, 1, 5},
   bv = {1, 0, 1},
   k = 2,
   d1 = {"\u0000\u0014\n\u0000\n\u0002\u0010\u0002\n\u0000\n\u0002\u0010\u0011\n\u0002\u0010\u000e\n\u0002\b\u0006\u001a\u0019\u0010\u0000\u001a\u00020\u00012\f\u0010\u0002\u001a\b\u0012\u0004\u0012\u00020\u00040\u0003¢\u0006\u0002\u0010\u0005\u001a\u001e\u0010\u0006\u001a\u00020\u0001\"\u0006\b\u0000\u0010\u0007\u0018\u00012\u0006\u0010\b\u001a\u0002H\u0007H\u0086\b¢\u0006\u0002\u0010\t¨\u0006\n"},
   d2 = {"main", "", "args", "", "", "([Ljava/lang/String;)V", "testReified", "T", "obj", "(Ljava/lang/Object;)V", "production sources for module Test"}
)
public final class TestReifiedKt {
   private static final void testReified(Object obj) {
      if(obj instanceof Integer) {
         int var2 = 5 + ((Number)obj).intValue();
         System.out.println(var2);
      } else {
         System.out.println(obj);
      }

      int x = true;
      Intrinsics.reifiedOperationMarker(3, "T");
      if(true) {
         String var3 = "5 is type T";
         System.out.println(var3);
      }

   }

   public static final void main(@NotNull String[] args) {
      Intrinsics.checkParameterIsNotNull(args, "args");
      Object obj$iv = Integer.valueOf(5);
      int var2;
      if(obj$iv instanceof Integer) {
         var2 = 5 + ((Number)obj$iv).intValue();
         System.out.println(var2);
      } else {
         System.out.println(obj$iv);
      }

      int x$iv = true;
      String var3;
      if(true) {
         var3 = "5 is type T";
         System.out.println(var3);
      }

      Object obj$iv = "5";
      if(obj$iv instanceof Integer) {
         var2 = 5 + ((Number)obj$iv).intValue();
         System.out.println(var2);
      } else {
         System.out.println(obj$iv);
      }

      int x$iv = 5;
      if(Integer.valueOf(x$iv) instanceof String) {
         var3 = "5 is type T";
         System.out.println(var3);
      }

   }
}