diff --git a/compiler/frontend/src/org/jetbrains/kotlin/resolve/OverrideResolver.kt b/compiler/frontend/src/org/jetbrains/kotlin/resolve/OverrideResolver.kt
index 10168b7c88c..15445dfaa38 100644
--- a/compiler/frontend/src/org/jetbrains/kotlin/resolve/OverrideResolver.kt
+++ b/compiler/frontend/src/org/jetbrains/kotlin/resolve/OverrideResolver.kt
@@ -586,7 +586,9 @@ class OverrideResolver(
             if (kind != FAKE_OVERRIDE && kind != DELEGATION) return
 
             val directOverridden = descriptor.overriddenDescriptors
-            assert(!directOverridden.isEmpty()) { kind.toString() + " " + descriptor.name.asString() + " must override something" }
+
+            // directOverridden may be empty if user tries to delegate implementation of abstract class instead of interface
+            if (directOverridden.isEmpty()) return
 
             // collects map from the directly overridden descriptor to the set of declarations:
             // -- if directly overridden is not fake, the set consists of one element: this directly overridden
diff --git a/compiler/testData/diagnostics/tests/delegation/kt40510.fir.kt b/compiler/testData/diagnostics/tests/delegation/kt40510.fir.kt
new file mode 100644
index 00000000000..75d72840e0c
--- /dev/null
+++ b/compiler/testData/diagnostics/tests/delegation/kt40510.fir.kt
@@ -0,0 +1,14 @@
+// ISSUE: KT-40510
+
+// FILE: foo/A.java
+package foo;
+
+public abstract class A {
+    // package-private
+    abstract void foo();
+}
+
+// FILE: main.kt
+import foo.A
+
+class DelegatedA(val a: A) : A by a
diff --git a/compiler/testData/diagnostics/tests/delegation/kt40510.kt b/compiler/testData/diagnostics/tests/delegation/kt40510.kt
new file mode 100644
index 00000000000..ca1dcd07848
--- /dev/null
+++ b/compiler/testData/diagnostics/tests/delegation/kt40510.kt
@@ -0,0 +1,14 @@
+// ISSUE: KT-40510
+
+// FILE: foo/A.java
+package foo;
+
+public abstract class A {
+    // package-private
+    abstract void foo();
+}
+
+// FILE: main.kt
+import foo.A
+
+class DelegatedA(val a: A) : <!DELEGATION_NOT_TO_INTERFACE!>A<!> by a
diff --git a/compiler/testData/diagnostics/tests/delegation/kt40510.txt b/compiler/testData/diagnostics/tests/delegation/kt40510.txt
new file mode 100644
index 00000000000..94aed60a082
--- /dev/null
+++ b/compiler/testData/diagnostics/tests/delegation/kt40510.txt
@@ -0,0 +1,22 @@
+package
+
+public final class DelegatedA : foo.A {
+    public constructor DelegatedA(/*0*/ a: foo.A)
+    public final val a: foo.A
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open /*delegation*/ fun foo(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+package foo {
+
+    public abstract class A {
+        public constructor A()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public/*package*/ abstract fun foo(): kotlin.Unit
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}
+
diff --git a/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/DiagnosticTestGenerated.java b/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/DiagnosticTestGenerated.java
index 6e09f40619a..fbb0cacf8f4 100644
--- a/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/DiagnosticTestGenerated.java
+++ b/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/DiagnosticTestGenerated.java
@@ -7389,6 +7389,12 @@ public class DiagnosticTestGenerated extends AbstractDiagnosticTest {
                 runTest("compiler/testData/diagnostics/tests/delegation/Delegation_ScopeInitializationOrder.kt");
             }
 
+            @Test
+            @TestMetadata("kt40510.kt")
+            public void testKt40510() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/delegation/kt40510.kt");
+            }
+
             @Test
             @TestMetadata("kt8154.kt")
             public void testKt8154() throws Exception {
diff --git a/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendDiagnosticsTestGenerated.java b/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendDiagnosticsTestGenerated.java
index 2df1ed4ac7a..5e40236383c 100644
--- a/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendDiagnosticsTestGenerated.java
+++ b/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendDiagnosticsTestGenerated.java
@@ -7383,6 +7383,12 @@ public class FirOldFrontendDiagnosticsTestGenerated extends AbstractFirDiagnosti
                 runTest("compiler/testData/diagnostics/tests/delegation/Delegation_ScopeInitializationOrder.kt");
             }
 
+            @Test
+            @TestMetadata("kt40510.kt")
+            public void testKt40510() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/delegation/kt40510.kt");
+            }
+
             @Test
             @TestMetadata("kt8154.kt")
             public void testKt8154() throws Exception {