FE: add tests to reproduce KT-56720

analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/DiagnosisCompilerTestFE10TestdataTestGenerated.java

@@ -23952,6 +23952,18 @@ public class DiagnosisCompilerTestFE10TestdataTestGenerated extends AbstractDiag
                 runTest("compiler/testData/diagnostics/tests/override/kt8990.kt");
             }
 
+            @Test
+            @TestMetadata("manyImplFromOneJavaInterfaceWithDelegation.kt")
+            public void testManyImplFromOneJavaInterfaceWithDelegation() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/override/manyImplFromOneJavaInterfaceWithDelegation.kt");
+            }
+
+            @Test
+            @TestMetadata("manyImplFromOneKotlinInterfaceWithDelegation.kt")
+            public void testManyImplFromOneKotlinInterfaceWithDelegation() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/override/manyImplFromOneKotlinInterfaceWithDelegation.kt");
+            }
+
             @Test
             @TestMetadata("MissingDelegate.kt")
             public void testMissingDelegate() throws Exception {

compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirLightTreeOldFrontendDiagnosticsTestGenerated.java

@@ -23952,6 +23952,18 @@ public class FirLightTreeOldFrontendDiagnosticsTestGenerated extends AbstractFir
                 runTest("compiler/testData/diagnostics/tests/override/kt8990.kt");
             }
 
+            @Test
+            @TestMetadata("manyImplFromOneJavaInterfaceWithDelegation.kt")
+            public void testManyImplFromOneJavaInterfaceWithDelegation() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/override/manyImplFromOneJavaInterfaceWithDelegation.kt");
+            }
+
+            @Test
+            @TestMetadata("manyImplFromOneKotlinInterfaceWithDelegation.kt")
+            public void testManyImplFromOneKotlinInterfaceWithDelegation() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/override/manyImplFromOneKotlinInterfaceWithDelegation.kt");
+            }
+
             @Test
             @TestMetadata("MissingDelegate.kt")
             public void testMissingDelegate() throws Exception {

compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirPsiOldFrontendDiagnosticsTestGenerated.java

@@ -23958,6 +23958,18 @@ public class FirPsiOldFrontendDiagnosticsTestGenerated extends AbstractFirPsiDia
                 runTest("compiler/testData/diagnostics/tests/override/kt8990.kt");
             }
 
+            @Test
+            @TestMetadata("manyImplFromOneJavaInterfaceWithDelegation.kt")
+            public void testManyImplFromOneJavaInterfaceWithDelegation() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/override/manyImplFromOneJavaInterfaceWithDelegation.kt");
+            }
+
+            @Test
+            @TestMetadata("manyImplFromOneKotlinInterfaceWithDelegation.kt")
+            public void testManyImplFromOneKotlinInterfaceWithDelegation() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/override/manyImplFromOneKotlinInterfaceWithDelegation.kt");
+            }
+
             @Test
             @TestMetadata("MissingDelegate.kt")
             public void testMissingDelegate() throws Exception {

compiler/testData/diagnostics/tests/override/manyImplFromOneJavaInterfaceWithDelegation.fir.kt

@@ -0,0 +1,19 @@
+// FILE: A.java
+
+public interface A {
+    default void foo() {}
+}
+
+// FILE: B.java
+
+public interface B extends A
+
+// FILE: C.java
+
+public interface C extends A
+
+// FILE: test.kt
+
+class Adapter : B, C
+
+<!MANY_IMPL_MEMBER_NOT_IMPLEMENTED!>class D<!>(val adapter: Adapter) : B by adapter, C by adapter

compiler/testData/diagnostics/tests/override/manyImplFromOneJavaInterfaceWithDelegation.kt

@@ -0,0 +1,19 @@
+// FILE: A.java
+
+public interface A {
+    default void foo() {}
+}
+
+// FILE: B.java
+
+public interface B extends A
+
+// FILE: C.java
+
+public interface C extends A
+
+// FILE: test.kt
+
+class Adapter : B, C
+
+class D(val adapter: Adapter) : B by adapter, C by adapter

compiler/testData/diagnostics/tests/override/manyImplFromOneKotlinInterfaceWithDelegation.kt

@@ -0,0 +1,20 @@
+// FIR_IDENTICAL
+// FILE: A.kt
+
+interface A {
+    fun foo() {}
+}
+
+// FILE: B.kt
+
+interface B : A
+
+// FILE: C.kt
+
+interface C : A
+
+// FILE: test.kt
+
+class Adapter : B, C
+
+<!MANY_IMPL_MEMBER_NOT_IMPLEMENTED!>class D<!>(val adapter: Adapter) : B by adapter, C by adapter

compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/DiagnosticTestGenerated.java

@@ -23958,6 +23958,18 @@ public class DiagnosticTestGenerated extends AbstractDiagnosticTest {
                 runTest("compiler/testData/diagnostics/tests/override/kt8990.kt");
             }
 
+            @Test
+            @TestMetadata("manyImplFromOneJavaInterfaceWithDelegation.kt")
+            public void testManyImplFromOneJavaInterfaceWithDelegation() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/override/manyImplFromOneJavaInterfaceWithDelegation.kt");
+            }
+
+            @Test
+            @TestMetadata("manyImplFromOneKotlinInterfaceWithDelegation.kt")
+            public void testManyImplFromOneKotlinInterfaceWithDelegation() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/override/manyImplFromOneKotlinInterfaceWithDelegation.kt");
+            }
+
             @Test
             @TestMetadata("MissingDelegate.kt")
             public void testMissingDelegate() throws Exception {

compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/IrBlackBoxCodegenWithIrInlinerTestGenerated.java

@@ -18445,6 +18445,12 @@ public class IrBlackBoxCodegenWithIrInlinerTestGenerated extends AbstractIrBlack
             runTest("compiler/testData/codegen/box/fir/LookupTags.kt");
         }
 
+        @Test
+        @TestMetadata("manyImplFromOneJavaInterfaceWithDelegation.kt")
+        public void testManyImplFromOneJavaInterfaceWithDelegation() throws Exception {
+            runTest("compiler/testData/codegen/box/fir/manyImplFromOneJavaInterfaceWithDelegation.kt");
+        }
+
         @Test
         @TestMetadata("NameHighlighter.kt")
         public void testNameHighlighter() throws Exception {