diff --git a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/ExpectDeclarationsRemoveLowering.kt b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/ExpectDeclarationsRemoveLowering.kt
new file mode 100644
index 00000000000..2ad2c48dd6b
--- /dev/null
+++ b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/ExpectDeclarationsRemoveLowering.kt
@@ -0,0 +1,25 @@
+/*
+ * Copyright 2010-2018 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.backend.common.lower
+
+import org.jetbrains.kotlin.backend.common.BackendContext
+import org.jetbrains.kotlin.backend.common.FileLoweringPass
+import org.jetbrains.kotlin.ir.declarations.IrFile
+import org.jetbrains.kotlin.ir.util.ExpectDeclarationRemover
+import org.jetbrains.kotlin.ir.util.patchDeclarationParents
+import org.jetbrains.kotlin.ir.visitors.acceptVoid
+
+/**
+ * This pass removes all declarations with `isExpect == true`.
+ */
+class ExpectDeclarationsRemoveLowering(val context: BackendContext) : FileLoweringPass {
+
+    val visitor = ExpectDeclarationRemover(context.ir.symbols.externalSymbolTable, true)
+
+    override fun lower(irFile: IrFile) {
+        irFile.acceptVoid(visitor)
+    }
+}
diff --git a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/JsLoweringPhases.kt b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/JsLoweringPhases.kt
index 51471f9e878..dae90a7e1a7 100644
--- a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/JsLoweringPhases.kt
+++ b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/JsLoweringPhases.kt
@@ -87,7 +87,7 @@ private val moveBodilessDeclarationsToSeparatePlacePhase = makeCustomJsModulePha
 )
 
 private val expectDeclarationsRemovingPhase = makeJsModulePhase(
-    ::ExpectDeclarationsRemoving,
+    ::ExpectDeclarationsRemoveLowering,
     name = "ExpectDeclarationsRemoving",
     description = "Remove expect declaration from module fragment"
 )
diff --git a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/inline/DeepCopyIrTreeWithDescriptors.kt b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/inline/DeepCopyIrTreeWithDescriptors.kt
index ef1712dc87b..8a2fd9517e6 100644
--- a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/inline/DeepCopyIrTreeWithDescriptors.kt
+++ b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/inline/DeepCopyIrTreeWithDescriptors.kt
@@ -157,8 +157,10 @@ internal class DeepCopyIrTreeWithSymbolsForInliner(
             if (type !is IrSimpleType) return type
 
             val substitutedType = typeArguments?.get(type.classifier)
-            if (substitutedType != null) {
-                substitutedType as IrSimpleType
+
+            if (substitutedType is IrDynamicType) return substitutedType
+
+            if (substitutedType is IrSimpleType) {
                 return substitutedType.buildSimpleType {
                     kotlinType = null
                     hasQuestionMark = type.hasQuestionMark or substitutedType.isMarkedNullable()
diff --git a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/transformers/irToJs/IrElementToJsExpressionTransformer.kt b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/transformers/irToJs/IrElementToJsExpressionTransformer.kt
index 5930565b5bd..0d531ab0fcf 100644
--- a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/transformers/irToJs/IrElementToJsExpressionTransformer.kt
+++ b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/transformers/irToJs/IrElementToJsExpressionTransformer.kt
@@ -282,6 +282,8 @@ class IrElementToJsExpressionTransformer : BaseIrElementToJsNodeTransformer<JsEx
                 JsInvocation(
                     // Create scope for temporary variable holding dispatch receiver
                     // It is used both during method reference and passing `this` value to `apply` function.
+                    JsNameRef(
+                    "call",
                     JsFunction(
                         context.currentScope,
                         JsBlock(
@@ -297,7 +299,8 @@ class IrElementToJsExpressionTransformer : BaseIrElementToJsNodeTransformer<JsEx
                             )
                         ),
                         "VarargIIFE"
-                    )
+                    )),
+                    JsThisRef()
                 )
             } else {
                 JsInvocation(
diff --git a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/transformers/irToJs/jsAstUtils.kt b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/transformers/irToJs/jsAstUtils.kt
index 514fb5de126..1cc4e8815fc 100644
--- a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/transformers/irToJs/jsAstUtils.kt
+++ b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/transformers/irToJs/jsAstUtils.kt
@@ -78,7 +78,7 @@ fun translateCallArguments(expression: IrMemberAccessExpression, context: JsGene
         val argument = expression.getValueArgument(index)
         val result = argument?.accept(transformer, context)
         if (result == null) {
-            assert(expression is IrFunctionAccessExpression && expression.symbol.owner.isEffectivelyExternal())
+            require(expression is IrFunctionAccessExpression && expression.symbol.owner.isEffectivelyExternal())
             JsPrefixOperation(JsUnaryOperator.VOID, JsIntLiteral(1))
         } else
             result
diff --git a/compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/JvmLower.kt b/compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/JvmLower.kt
index dadafffc4d1..d372f199ea6 100644
--- a/compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/JvmLower.kt
+++ b/compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/JvmLower.kt
@@ -48,7 +48,7 @@ private val arrayConstructorPhase = makeIrFilePhase(
 )
 
 private val expectDeclarationsRemovingPhase = makeIrFilePhase(
-    ::ExpectDeclarationsRemoving,
+    ::ExpectDeclarationsRemoveLowering,
     name = "ExpectDeclarationsRemoving",
     description = "Remove expect declaration from module fragment"
 )
diff --git a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/ExpectDeclarationsRemoving.kt b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/util/ExpectDeclarationRemover.kt
similarity index 86%
rename from compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/ExpectDeclarationsRemoving.kt
rename to compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/util/ExpectDeclarationRemover.kt
index d7cd5d6109e..1c05b6318f4 100644
--- a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/ExpectDeclarationsRemoving.kt
+++ b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/util/ExpectDeclarationRemover.kt
@@ -1,12 +1,10 @@
 /*
- * Copyright 2010-2018 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Copyright 2010-2019 JetBrains s.r.o. and Kotlin Programming Language contributors.
  * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
  */
 
-package org.jetbrains.kotlin.backend.common.lower
+package org.jetbrains.kotlin.ir.util
 
-import org.jetbrains.kotlin.backend.common.BackendContext
-import org.jetbrains.kotlin.backend.common.FileLoweringPass
 import org.jetbrains.kotlin.descriptors.MemberDescriptor
 import org.jetbrains.kotlin.ir.IrElement
 import org.jetbrains.kotlin.ir.declarations.*
@@ -15,8 +13,6 @@ import org.jetbrains.kotlin.ir.expressions.IrGetValue
 import org.jetbrains.kotlin.ir.expressions.impl.IrGetValueImpl
 import org.jetbrains.kotlin.ir.symbols.IrValueParameterSymbol
 import org.jetbrains.kotlin.ir.symbols.IrValueSymbol
-import org.jetbrains.kotlin.ir.util.patchDeclarationParents
-import org.jetbrains.kotlin.ir.util.referenceFunction
 import org.jetbrains.kotlin.ir.visitors.IrElementTransformerVoid
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitorVoid
 import org.jetbrains.kotlin.ir.visitors.acceptChildrenVoid
@@ -25,18 +21,19 @@ import org.jetbrains.kotlin.resolve.checkers.ExpectedActualDeclarationChecker
 import org.jetbrains.kotlin.resolve.descriptorUtil.module
 import org.jetbrains.kotlin.resolve.multiplatform.ExpectedActualResolver
 
-/**
- * This pass removes all declarations with `isExpect == true`.
- */
-class ExpectDeclarationsRemoving(val context: BackendContext) : FileLoweringPass {
+// `doRemove` means should expect-declaration be removed from IR
+class ExpectDeclarationRemover(val symbolTable: ReferenceSymbolTable, private val doRemove: Boolean) : IrElementVisitorVoid {
+    override fun visitElement(element: IrElement) {
+        element.acceptChildrenVoid(this)
+    }
 
-    override fun lower(irFile: IrFile) {
+    override fun visitFile(declaration: IrFile) {
         // All declarations with `isExpect == true` are nested into a top-level declaration with `isExpect == true`.
-        irFile.declarations.removeAll {
+        declaration.declarations.removeAll {
             val descriptor = it.descriptor
             if (descriptor is MemberDescriptor && descriptor.isExpect) {
                 copyDefaultArgumentsFromExpectToActual(it)
-                true
+                doRemove
             } else {
                 false
             }
@@ -83,10 +80,10 @@ class ExpectDeclarationsRemoving(val context: BackendContext) : FileLoweringPass
     }
 
     private fun IrFunction.findActualForExpected(): IrFunction =
-        context.ir.symbols.externalSymbolTable.referenceFunction(descriptor.findActualForExpect()).owner
+        symbolTable.referenceFunction(descriptor.findActualForExpect()).owner
 
     private fun IrClass.findActualForExpected(): IrClass =
-        context.ir.symbols.externalSymbolTable.referenceClass(descriptor.findActualForExpect()).owner
+        symbolTable.referenceClass(descriptor.findActualForExpect()).owner
 
     private inline fun <reified T : MemberDescriptor> T.findActualForExpect() = with(ExpectedActualResolver) {
         val descriptor = this@findActualForExpect
diff --git a/compiler/ir/serialization.js/src/org/jetbrains/kotlin/ir/backend/js/klib.kt b/compiler/ir/serialization.js/src/org/jetbrains/kotlin/ir/backend/js/klib.kt
index e5ea8404e13..d83c0c44723 100644
--- a/compiler/ir/serialization.js/src/org/jetbrains/kotlin/ir/backend/js/klib.kt
+++ b/compiler/ir/serialization.js/src/org/jetbrains/kotlin/ir/backend/js/klib.kt
@@ -29,7 +29,9 @@ import org.jetbrains.kotlin.ir.backend.js.lower.serialization.metadata.createJsK
 import org.jetbrains.kotlin.ir.backend.js.lower.serialization.metadata.*
 import org.jetbrains.kotlin.ir.declarations.IrModuleFragment
 import org.jetbrains.kotlin.ir.descriptors.IrBuiltIns
+import org.jetbrains.kotlin.ir.util.ExpectDeclarationRemover
 import org.jetbrains.kotlin.ir.util.SymbolTable
+import org.jetbrains.kotlin.ir.visitors.acceptVoid
 import org.jetbrains.kotlin.js.analyze.TopDownAnalyzerFacadeForJS
 import org.jetbrains.kotlin.js.analyzer.JsAnalysisResult
 import org.jetbrains.kotlin.name.Name
@@ -83,6 +85,9 @@ fun generateKLib(
     val moduleFragment = psi2IrContext.generateModuleFragment(files)
 
     val moduleName = configuration[CommonConfigurationKeys.MODULE_NAME]!!
+
+    moduleFragment.acceptVoid(ExpectDeclarationRemover(psi2IrContext.symbolTable, false))
+
     serializeModuleIntoKlib(
         moduleName,
         configuration.metadataVersion,
diff --git a/compiler/testData/codegen/box/multiplatform/defaultArguments/inheritedFromExpectedFunction.kt b/compiler/testData/codegen/box/multiplatform/defaultArguments/inheritedFromExpectedFunction.kt
new file mode 100644
index 00000000000..d7db513626f
--- /dev/null
+++ b/compiler/testData/codegen/box/multiplatform/defaultArguments/inheritedFromExpectedFunction.kt
@@ -0,0 +1,17 @@
+// !LANGUAGE: +MultiPlatformProjects
+// WITH_RUNTIME
+// MODULE: lib
+// FILE: common.kt
+
+expect fun foo(a: String, b: String = "O"): String
+
+// FILE: platform.kt
+
+actual fun foo(a: String, b: String) = a + b
+
+// MODULE: main(lib)
+// FILE: main.kt
+
+fun box(): String {
+    return foo("") + foo("K", "")
+}
\ No newline at end of file
diff --git a/compiler/tests/org/jetbrains/kotlin/codegen/BlackBoxCodegenTestGenerated.java b/compiler/tests/org/jetbrains/kotlin/codegen/BlackBoxCodegenTestGenerated.java
index 197483e3ecf..c45e66fe0c0 100644
--- a/compiler/tests/org/jetbrains/kotlin/codegen/BlackBoxCodegenTestGenerated.java
+++ b/compiler/tests/org/jetbrains/kotlin/codegen/BlackBoxCodegenTestGenerated.java
@@ -16150,6 +16150,11 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
                 runTest("compiler/testData/codegen/box/multiplatform/defaultArguments/inheritedFromExpectedClass.kt");
             }
 
+            @TestMetadata("inheritedFromExpectedFunction.kt")
+            public void testInheritedFromExpectedFunction() throws Exception {
+                runTest("compiler/testData/codegen/box/multiplatform/defaultArguments/inheritedFromExpectedFunction.kt");
+            }
+
             @TestMetadata("inheritedFromExpectedInterface.kt")
             public void testInheritedFromExpectedInterface() throws Exception {
                 runTest("compiler/testData/codegen/box/multiplatform/defaultArguments/inheritedFromExpectedInterface.kt");
diff --git a/compiler/tests/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java b/compiler/tests/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java
index ab5ee9baf1f..932c6d93c34 100644
--- a/compiler/tests/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java
+++ b/compiler/tests/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java
@@ -16155,6 +16155,11 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
                 runTest("compiler/testData/codegen/box/multiplatform/defaultArguments/inheritedFromExpectedClass.kt");
             }
 
+            @TestMetadata("inheritedFromExpectedFunction.kt")
+            public void testInheritedFromExpectedFunction() throws Exception {
+                runTest("compiler/testData/codegen/box/multiplatform/defaultArguments/inheritedFromExpectedFunction.kt");
+            }
+
             @TestMetadata("inheritedFromExpectedInterface.kt")
             public void testInheritedFromExpectedInterface() throws Exception {
                 runTest("compiler/testData/codegen/box/multiplatform/defaultArguments/inheritedFromExpectedInterface.kt");
diff --git a/compiler/tests/org/jetbrains/kotlin/codegen/ir/IrBlackBoxCodegenTestGenerated.java b/compiler/tests/org/jetbrains/kotlin/codegen/ir/IrBlackBoxCodegenTestGenerated.java
index 0ffe278b308..e45fa004454 100644
--- a/compiler/tests/org/jetbrains/kotlin/codegen/ir/IrBlackBoxCodegenTestGenerated.java
+++ b/compiler/tests/org/jetbrains/kotlin/codegen/ir/IrBlackBoxCodegenTestGenerated.java
@@ -16155,6 +16155,11 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
                 runTest("compiler/testData/codegen/box/multiplatform/defaultArguments/inheritedFromExpectedClass.kt");
             }
 
+            @TestMetadata("inheritedFromExpectedFunction.kt")
+            public void testInheritedFromExpectedFunction() throws Exception {
+                runTest("compiler/testData/codegen/box/multiplatform/defaultArguments/inheritedFromExpectedFunction.kt");
+            }
+
             @TestMetadata("inheritedFromExpectedInterface.kt")
             public void testInheritedFromExpectedInterface() throws Exception {
                 runTest("compiler/testData/codegen/box/multiplatform/defaultArguments/inheritedFromExpectedInterface.kt");
diff --git a/js/js.tests/test/org/jetbrains/kotlin/js/test/ir/semantics/IrJsCodegenBoxTestGenerated.java b/js/js.tests/test/org/jetbrains/kotlin/js/test/ir/semantics/IrJsCodegenBoxTestGenerated.java
index c3acfa0ffc5..bee60886e29 100644
--- a/js/js.tests/test/org/jetbrains/kotlin/js/test/ir/semantics/IrJsCodegenBoxTestGenerated.java
+++ b/js/js.tests/test/org/jetbrains/kotlin/js/test/ir/semantics/IrJsCodegenBoxTestGenerated.java
@@ -12365,6 +12365,11 @@ public class IrJsCodegenBoxTestGenerated extends AbstractIrJsCodegenBoxTest {
                 runTest("compiler/testData/codegen/box/multiplatform/defaultArguments/inheritedFromExpectedClass.kt");
             }
 
+            @TestMetadata("inheritedFromExpectedFunction.kt")
+            public void testInheritedFromExpectedFunction() throws Exception {
+                runTest("compiler/testData/codegen/box/multiplatform/defaultArguments/inheritedFromExpectedFunction.kt");
+            }
+
             @TestMetadata("inheritedFromExpectedInterface.kt")
             public void testInheritedFromExpectedInterface() throws Exception {
                 runTest("compiler/testData/codegen/box/multiplatform/defaultArguments/inheritedFromExpectedInterface.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 6da5baffb00..0354b391b11 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
@@ -13520,6 +13520,11 @@ public class JsCodegenBoxTestGenerated extends AbstractJsCodegenBoxTest {
                 runTest("compiler/testData/codegen/box/multiplatform/defaultArguments/inheritedFromExpectedClass.kt");
             }
 
+            @TestMetadata("inheritedFromExpectedFunction.kt")
+            public void testInheritedFromExpectedFunction() throws Exception {
+                runTest("compiler/testData/codegen/box/multiplatform/defaultArguments/inheritedFromExpectedFunction.kt");
+            }
+
             @TestMetadata("inheritedFromExpectedInterface.kt")
             public void testInheritedFromExpectedInterface() throws Exception {
                 runTest("compiler/testData/codegen/box/multiplatform/defaultArguments/inheritedFromExpectedInterface.kt");
diff --git a/js/js.translator/testData/box/jsModule/externalClass.js b/js/js.translator/testData/box/jsModule/externalClass.js
index 676c34773db..438a3bc597e 100644
--- a/js/js.translator/testData/box/jsModule/externalClass.js
+++ b/js/js.translator/testData/box/jsModule/externalClass.js
@@ -6,5 +6,9 @@ define("lib", [], function() {
         return this.x + y;
     };
 
+    A.prototype.bar = function() {
+        return "(" + Array.prototype.join.call(arguments, "") + ")";
+    };
+
     return A;
 });
\ No newline at end of file
diff --git a/js/js.translator/testData/box/jsModule/externalClass.kt b/js/js.translator/testData/box/jsModule/externalClass.kt
index 1c7af34da2f..a45d2cc2dc7 100644
--- a/js/js.translator/testData/box/jsModule/externalClass.kt
+++ b/js/js.translator/testData/box/jsModule/externalClass.kt
@@ -7,12 +7,24 @@ external class A(x: Int = definedExternally) {
     val x: Int
 
     fun foo(y: Int): Int = definedExternally
+
+    fun bar(vararg arg: String): String = definedExternally
 }
 
+class C {
+    val e = arrayOf("e")
+    val f = arrayOf("f")
+    val a = A(1)
+
+    fun qux() = a.bar(*e, *f)
+}
+
+
 fun box(): String {
     val a = A(23)
     assertEquals(23, a.x)
     assertEquals(65, a.foo(42))
+    assertEquals(C().qux(), "(ef)")
 
     return "OK"
 }
\ No newline at end of file