diff --git a/compiler/frontend.java/src/org/jetbrains/kotlin/jvm/RuntimeAssertions.kt b/compiler/frontend.java/src/org/jetbrains/kotlin/jvm/RuntimeAssertions.kt
index 83ba29f96bc..8dcee1a3756 100644
--- a/compiler/frontend.java/src/org/jetbrains/kotlin/jvm/RuntimeAssertions.kt
+++ b/compiler/frontend.java/src/org/jetbrains/kotlin/jvm/RuntimeAssertions.kt
@@ -27,10 +27,8 @@ import org.jetbrains.kotlin.resolve.calls.context.CallResolutionContext
 import org.jetbrains.kotlin.resolve.calls.context.ResolutionContext
 import org.jetbrains.kotlin.resolve.calls.smartcasts.DataFlowValueFactory
 import org.jetbrains.kotlin.resolve.scopes.receivers.ReceiverValue
-import org.jetbrains.kotlin.types.KotlinType
-import org.jetbrains.kotlin.types.TypeUtils
+import org.jetbrains.kotlin.types.*
 import org.jetbrains.kotlin.types.checker.KotlinTypeChecker
-import org.jetbrains.kotlin.types.upperIfFlexible
 
 public class RuntimeAssertionInfo(public val needNotNullAssertion: Boolean, public val message: String) {
     public interface DataFlowExtras {
@@ -53,7 +51,7 @@ public class RuntimeAssertionInfo(public val needNotNullAssertion: Boolean, publ
                 dataFlowExtras: DataFlowExtras
         ): RuntimeAssertionInfo? {
             fun assertNotNull(): Boolean {
-                if (expectedType.isError() || expressionType.isError()) return false
+                if (expectedType.isError || expressionType.isError) return false
 
                 // T : Any, T! = T..T?
                 // Let T$ will be copy of T! with enhanced nullability.
diff --git a/compiler/testData/codegen/notNullAssertions/assertionForNotNullCaptured.kt b/compiler/testData/codegen/notNullAssertions/assertionForNotNullCaptured.kt
new file mode 100644
index 00000000000..bd2cda22762
--- /dev/null
+++ b/compiler/testData/codegen/notNullAssertions/assertionForNotNullCaptured.kt
@@ -0,0 +1,7 @@
+class A<T> {
+    fun add(element: T) {}
+}
+
+public fun <R : Any> foo(x: MutableCollection<in R>, block: java.util.AbstractList<R>) {
+    x.add(block.get(0))
+}
diff --git a/compiler/testData/codegen/notNullAssertions/noAssertionForNullableCaptured.kt b/compiler/testData/codegen/notNullAssertions/noAssertionForNullableCaptured.kt
new file mode 100644
index 00000000000..5cede7badaa
--- /dev/null
+++ b/compiler/testData/codegen/notNullAssertions/noAssertionForNullableCaptured.kt
@@ -0,0 +1,7 @@
+class A<T> {
+    fun add(element: T) {}
+}
+
+public fun <R> foo(x: MutableCollection<in R>, block: () -> R) {
+    x.add(block())
+}
diff --git a/compiler/tests/org/jetbrains/kotlin/codegen/GenerateNotNullAssertionsTest.java b/compiler/tests/org/jetbrains/kotlin/codegen/GenerateNotNullAssertionsTest.java
index 77f244bbe4f..d41499d74f4 100644
--- a/compiler/tests/org/jetbrains/kotlin/codegen/GenerateNotNullAssertionsTest.java
+++ b/compiler/tests/org/jetbrains/kotlin/codegen/GenerateNotNullAssertionsTest.java
@@ -157,6 +157,22 @@ public class GenerateNotNullAssertionsTest extends CodegenTestCase {
         assertNoIntrinsicsMethodIsCalledInMyClasses(true);
     }
 
+    public void testNoAssertionForNullableCaptured() {
+        setUpEnvironment(false, true);
+
+        loadFile("notNullAssertions/noAssertionForNullableCaptured.kt");
+
+        assertNoIntrinsicsMethodIsCalledInMyClasses(true);
+    }
+
+    public void testAssertionForNotNullCaptured() {
+        setUpEnvironment(false, true);
+
+        loadFile("notNullAssertions/assertionForNotNullCaptured.kt");
+
+        assertTrue(generateToText().contains("checkExpressionValueIsNotNull"));
+    }
+
     public void testNoAssertionForNullableGenericMethodCall() {
         setUpEnvironment(false, true);