Add KCallable.returnType

core/builtins/src/kotlin/reflect/KCallable.kt

@@ -39,6 +39,11 @@ public interface KCallable<out R> {
      */
     public val parameters: List<KParameter>
 
+    /**
+     * The type of values returned by this callable.
+     */
+    public val returnType: KType
+
     /**
      * Calls this callable with the specified arguments and returns the result.
      * Throws an exception if the number of specified arguments is not equal to the size of [parameters],

core/reflection.jvm/src/kotlin/reflect/jvm/internal/KCallableImpl.kt

@@ -20,6 +20,7 @@ import org.jetbrains.kotlin.descriptors.CallableMemberDescriptor
 import java.util.ArrayList
 import kotlin.reflect.KCallable
 import kotlin.reflect.KParameter
+import kotlin.reflect.KType
 
 interface KCallableImpl<out R> : KCallable<R> {
     val descriptor: CallableMemberDescriptor
@@ -44,4 +45,7 @@ interface KCallableImpl<out R> : KCallable<R> {
             result.trimToSize()
             return result
         }
+
+    override val returnType: KType
+        get() = KTypeImpl(descriptor.returnType!!)
 }

core/runtime.jvm/src/kotlin/jvm/internal/CallableReference.java

@@ -20,6 +20,7 @@ import kotlin.jvm.KotlinReflectionNotSupportedError;
 import kotlin.reflect.KCallable;
 import kotlin.reflect.KDeclarationContainer;
 import kotlin.reflect.KParameter;
+import kotlin.reflect.KType;
 import org.jetbrains.annotations.NotNull;
 
 import java.util.List;
@@ -69,6 +70,11 @@ public abstract class CallableReference implements KCallable {
         throw error();
     }
 
+    @Override
+    public KType getReturnType() {
+        throw error();
+    }
+
     @Override
     public Object call(@NotNull Object... args) {
         throw error();

core/runtime.jvm/src/kotlin/jvm/internal/FunctionReference.java

@@ -66,6 +66,11 @@ public class FunctionReference
         throw error();
     }
 
+    @Override
+    public KType getReturnType() {
+        throw error();
+    }
+
     @Override
     public Object call(@NotNull Object... args) {
         throw error();