diff --git a/compiler/backend/src/org/jetbrains/kotlin/codegen/CallReceiver.java b/compiler/backend/src/org/jetbrains/kotlin/codegen/CallReceiver.java
index 27da29f5dd7..ec46d15e72a 100644
--- a/compiler/backend/src/org/jetbrains/kotlin/codegen/CallReceiver.java
+++ b/compiler/backend/src/org/jetbrains/kotlin/codegen/CallReceiver.java
@@ -29,19 +29,22 @@ import org.jetbrains.org.objectweb.asm.commons.InstructionAdapter;
 public class CallReceiver extends StackValue {
     private final StackValue dispatchReceiver;
     private final StackValue extensionReceiver;
+    private final Type secondReceiverType;
 
     private CallReceiver(
             @NotNull StackValue dispatchReceiver,
             @NotNull StackValue extensionReceiver,
-            @NotNull Type type
+            @NotNull Type type,
+            @Nullable Type secondReceiverType
     ) {
         super(type, dispatchReceiver.canHaveSideEffects() || extensionReceiver.canHaveSideEffects());
         this.dispatchReceiver = dispatchReceiver;
         this.extensionReceiver = extensionReceiver;
+        this.secondReceiverType = secondReceiverType;
     }
 
     public StackValue withoutReceiverArgument() {
-        return new CallReceiver(dispatchReceiver, none(), type);
+        return new CallReceiver(dispatchReceiver, none(), type, secondReceiverType);
     }
 
     public static StackValue generateCallReceiver(
@@ -57,8 +60,12 @@ public class CallReceiver extends StackValue {
         GenerationState state = codegen.getState();
 
         Type type;
+        Type secondReceiverType = null;
         if (extensionReceiverParameter != null) {
             type = calcExtensionReceiverType(resolvedCall, extensionReceiverParameter, typeMapper, callableMethod, state);
+            if (dispatchReceiverParameter != null) {
+                secondReceiverType = calcDispatchReceiverType(resolvedCall, dispatchReceiverParameter, typeMapper, callableMethod);
+            }
         }
         else if (dispatchReceiverParameter != null) {
             type = calcDispatchReceiverType(resolvedCall, dispatchReceiverParameter, typeMapper, callableMethod);
@@ -72,7 +79,7 @@ public class CallReceiver extends StackValue {
 
         assert type != null : "Could not map receiver type for " + resolvedCall;
 
-        return new CallReceiver(dispatchReceiver, extensionReceiver, type);
+        return new CallReceiver(dispatchReceiver, extensionReceiver, type, secondReceiverType);
     }
 
     private static Type calcDispatchReceiverType(
@@ -135,10 +142,13 @@ public class CallReceiver extends StackValue {
             currentExtensionReceiver = StackValue.onStack(currentExtensionReceiver.type);
         }
 
-        dispatchReceiver.put(hasExtensionReceiver ? dispatchReceiver.type : type, v);
+        Type dispatchReceiverType = secondReceiverType != null ? secondReceiverType :
+                                    hasExtensionReceiver ? dispatchReceiver.type :
+                                    type;
+        dispatchReceiver.put(dispatchReceiverType, v);
 
         currentExtensionReceiver
-                .moveToTopOfStack(hasExtensionReceiver ? type : currentExtensionReceiver.type, v, dispatchReceiver.type.getSize());
+                .moveToTopOfStack(hasExtensionReceiver ? type : currentExtensionReceiver.type, v, dispatchReceiverType.getSize());
     }
 
     @Override
diff --git a/compiler/testData/codegen/box/smartCasts/kt17725.kt b/compiler/testData/codegen/box/smartCasts/kt17725.kt
new file mode 100644
index 00000000000..71334c4f85b
--- /dev/null
+++ b/compiler/testData/codegen/box/smartCasts/kt17725.kt
@@ -0,0 +1,10 @@
+class Bob {
+    fun Bob.bar() = "OK"
+}
+
+fun Any.foo() = when(this) {
+    is Bob -> bar()
+    else -> throw AssertionError()
+}
+
+fun box(): String = Bob().foo()
\ No newline at end of file
diff --git a/compiler/tests-ir-jvm/tests/org/jetbrains/kotlin/codegen/ir/IrBlackBoxCodegenTestGenerated.java b/compiler/tests-ir-jvm/tests/org/jetbrains/kotlin/codegen/ir/IrBlackBoxCodegenTestGenerated.java
index 444c795607b..caee19fe08a 100644
--- a/compiler/tests-ir-jvm/tests/org/jetbrains/kotlin/codegen/ir/IrBlackBoxCodegenTestGenerated.java
+++ b/compiler/tests-ir-jvm/tests/org/jetbrains/kotlin/codegen/ir/IrBlackBoxCodegenTestGenerated.java
@@ -17600,6 +17600,12 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
             doTest(fileName);
         }
 
+        @TestMetadata("kt17725.kt")
+        public void testKt17725() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/smartCasts/kt17725.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("kt19058.kt")
         public void testKt19058() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/smartCasts/kt19058.kt");
diff --git a/compiler/tests/org/jetbrains/kotlin/codegen/BlackBoxCodegenTestGenerated.java b/compiler/tests/org/jetbrains/kotlin/codegen/BlackBoxCodegenTestGenerated.java
index 54242d1b47b..29505ec4ae9 100644
--- a/compiler/tests/org/jetbrains/kotlin/codegen/BlackBoxCodegenTestGenerated.java
+++ b/compiler/tests/org/jetbrains/kotlin/codegen/BlackBoxCodegenTestGenerated.java
@@ -17600,6 +17600,12 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             doTest(fileName);
         }
 
+        @TestMetadata("kt17725.kt")
+        public void testKt17725() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/smartCasts/kt17725.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("kt19058.kt")
         public void testKt19058() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/smartCasts/kt19058.kt");
diff --git a/compiler/tests/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java b/compiler/tests/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java
index b922373dadc..b4f1118b4ee 100644
--- a/compiler/tests/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java
+++ b/compiler/tests/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java
@@ -17600,6 +17600,12 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
             doTest(fileName);
         }
 
+        @TestMetadata("kt17725.kt")
+        public void testKt17725() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/smartCasts/kt17725.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("kt19058.kt")
         public void testKt19058() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/smartCasts/kt19058.kt");
diff --git a/js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/JsCodegenBoxTestGenerated.java b/js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/JsCodegenBoxTestGenerated.java
index 17b1e3b5c96..ee75a75a52e 100644
--- a/js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/JsCodegenBoxTestGenerated.java
+++ b/js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/JsCodegenBoxTestGenerated.java
@@ -21506,6 +21506,12 @@ public class JsCodegenBoxTestGenerated extends AbstractJsCodegenBoxTest {
             doTest(fileName);
         }
 
+        @TestMetadata("kt17725.kt")
+        public void testKt17725() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/smartCasts/kt17725.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("kt19100.kt")
         public void testKt19100() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/smartCasts/kt19100.kt");