diff --git a/compiler/fir/fir2ir/tests-gen/org/jetbrains/kotlin/test/runners/codegen/FirBlackBoxCodegenTestGenerated.java b/compiler/fir/fir2ir/tests-gen/org/jetbrains/kotlin/test/runners/codegen/FirBlackBoxCodegenTestGenerated.java
index 241b8312f5e..a8f95e18a42 100644
--- a/compiler/fir/fir2ir/tests-gen/org/jetbrains/kotlin/test/runners/codegen/FirBlackBoxCodegenTestGenerated.java
+++ b/compiler/fir/fir2ir/tests-gen/org/jetbrains/kotlin/test/runners/codegen/FirBlackBoxCodegenTestGenerated.java
@@ -23123,6 +23123,12 @@ public class FirBlackBoxCodegenTestGenerated extends AbstractFirBlackBoxCodegenT
                 KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/codegen/box/ir/serializationRegressions"), Pattern.compile("^(.+)\\.kt$"), null, TargetBackend.JVM_IR, true);
             }
 
+            @Test
+            @TestMetadata("anonFakeOverride.kt")
+            public void testAnonFakeOverride() throws Exception {
+                runTest("compiler/testData/codegen/box/ir/serializationRegressions/anonFakeOverride.kt");
+            }
+
             @Test
             @TestMetadata("deepGenericDelegatedProperty.kt")
             public void testDeepGenericDelegatedProperty() throws Exception {
diff --git a/compiler/testData/codegen/box/ir/serializationRegressions/anonFakeOverride.kt b/compiler/testData/codegen/box/ir/serializationRegressions/anonFakeOverride.kt
new file mode 100644
index 00000000000..df2f560ffd4
--- /dev/null
+++ b/compiler/testData/codegen/box/ir/serializationRegressions/anonFakeOverride.kt
@@ -0,0 +1,59 @@
+// KJS_WITH_FULL_RUNTIME
+// WITH_RUNTIME
+
+// extracted case from KT-48912
+
+// MODULE: libxxxxx
+// FILE: l1.kt
+
+package com.soywiz.korag.shader
+
+open class Operand
+
+open class Variable : Operand()
+
+class Program {
+    class Stm(val o: Operand)
+
+    open class Visitor<E>(val default: E) {
+        open fun visit(stm: Stm?) {
+            if (stm?.o is Operand) visit(stm.o)
+        }
+        open fun visit(o: Operand): E {
+            if (o is Uniform) visit(o)
+            return default
+        }
+        open fun visit(operand: Uniform): E = default
+    }
+}
+
+open class Uniform(val result: String): Variable()
+
+open class Shader(val stm: Program.Stm?) {
+
+    // Here for object.visit(Program.Stm?) FO were 2 different mangles
+    // 1.5.31: <anonymous>#static(kotlin.collections.LinkedHashSet<com.soywiz.korag.shader.Uniform>){}visit(com.soywiz.korag.shader.Program.Stm?){}
+    // 1.6.0+: {}uniforms<anonymous>#static(kotlin.collections.LinkedHashSet<com.soywiz.korag.shader.Uniform>){}visit(com.soywiz.korag.shader.Program.Stm?){}
+    // So fix is to make sure those mangles are identical.
+
+    val uniforms = LinkedHashSet<Uniform>().also { out ->
+        object : Program.Visitor<Unit>(Unit) {
+            override fun visit(uniform: Uniform) {
+                out.add(uniform)
+            }
+        }.visit(stm)
+    }.toSet()
+}
+
+// MODULE: main(libxxxxx)
+// FILE: l2.kt
+
+import com.soywiz.korag.shader.*
+
+class D : Shader(Program.Stm((Uniform("OK"))))
+
+fun foo(): Shader = D()
+
+fun box(): String {
+    return foo().uniforms.first().result
+}
\ No newline at end of file
diff --git a/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/BlackBoxCodegenTestGenerated.java b/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/BlackBoxCodegenTestGenerated.java
index c2295a54c89..ac7aaefa460 100644
--- a/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/BlackBoxCodegenTestGenerated.java
+++ b/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/BlackBoxCodegenTestGenerated.java
@@ -22991,6 +22991,12 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
                 KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/codegen/box/ir/serializationRegressions"), Pattern.compile("^(.+)\\.kt$"), null, TargetBackend.JVM, true);
             }
 
+            @Test
+            @TestMetadata("anonFakeOverride.kt")
+            public void testAnonFakeOverride() throws Exception {
+                runTest("compiler/testData/codegen/box/ir/serializationRegressions/anonFakeOverride.kt");
+            }
+
             @Test
             @TestMetadata("deepGenericDelegatedProperty.kt")
             public void testDeepGenericDelegatedProperty() throws Exception {
diff --git a/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/IrBlackBoxCodegenTestGenerated.java b/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/IrBlackBoxCodegenTestGenerated.java
index 32f83d6f880..9eca13452f1 100644
--- a/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/IrBlackBoxCodegenTestGenerated.java
+++ b/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/IrBlackBoxCodegenTestGenerated.java
@@ -23123,6 +23123,12 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
                 KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/codegen/box/ir/serializationRegressions"), Pattern.compile("^(.+)\\.kt$"), null, TargetBackend.JVM_IR, true);
             }
 
+            @Test
+            @TestMetadata("anonFakeOverride.kt")
+            public void testAnonFakeOverride() throws Exception {
+                runTest("compiler/testData/codegen/box/ir/serializationRegressions/anonFakeOverride.kt");
+            }
+
             @Test
             @TestMetadata("deepGenericDelegatedProperty.kt")
             public void testDeepGenericDelegatedProperty() throws Exception {
diff --git a/compiler/tests-gen/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java b/compiler/tests-gen/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java
index 00dd430c3ee..1f52b7f22ca 100644
--- a/compiler/tests-gen/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java
+++ b/compiler/tests-gen/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java
@@ -19288,6 +19288,11 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
                 KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/codegen/box/ir/serializationRegressions"), Pattern.compile("^(.+)\\.kt$"), null, TargetBackend.JVM, true);
             }
 
+            @TestMetadata("anonFakeOverride.kt")
+            public void testAnonFakeOverride() throws Exception {
+                runTest("compiler/testData/codegen/box/ir/serializationRegressions/anonFakeOverride.kt");
+            }
+
             @TestMetadata("deepGenericDelegatedProperty.kt")
             public void testDeepGenericDelegatedProperty() throws Exception {
                 runTest("compiler/testData/codegen/box/ir/serializationRegressions/deepGenericDelegatedProperty.kt");
diff --git a/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/es6/semantics/IrJsCodegenBoxES6TestGenerated.java b/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/es6/semantics/IrJsCodegenBoxES6TestGenerated.java
index acba8a68fdd..e76072953ef 100644
--- a/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/es6/semantics/IrJsCodegenBoxES6TestGenerated.java
+++ b/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/es6/semantics/IrJsCodegenBoxES6TestGenerated.java
@@ -16382,6 +16382,11 @@ public class IrJsCodegenBoxES6TestGenerated extends AbstractIrJsCodegenBoxES6Tes
                 KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/codegen/box/ir/serializationRegressions"), Pattern.compile("^(.+)\\.kt$"), null, TargetBackend.JS_IR_ES6, true);
             }
 
+            @TestMetadata("anonFakeOverride.kt")
+            public void testAnonFakeOverride() throws Exception {
+                runTest("compiler/testData/codegen/box/ir/serializationRegressions/anonFakeOverride.kt");
+            }
+
             @TestMetadata("deepGenericDelegatedProperty.kt")
             public void testDeepGenericDelegatedProperty() throws Exception {
                 runTest("compiler/testData/codegen/box/ir/serializationRegressions/deepGenericDelegatedProperty.kt");
diff --git a/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/ir/semantics/IrJsCodegenBoxTestGenerated.java b/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/ir/semantics/IrJsCodegenBoxTestGenerated.java
index 7ec06fc4438..e46ca31f1c3 100644
--- a/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/ir/semantics/IrJsCodegenBoxTestGenerated.java
+++ b/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/ir/semantics/IrJsCodegenBoxTestGenerated.java
@@ -15788,6 +15788,11 @@ public class IrJsCodegenBoxTestGenerated extends AbstractIrJsCodegenBoxTest {
                 KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/codegen/box/ir/serializationRegressions"), Pattern.compile("^(.+)\\.kt$"), null, TargetBackend.JS_IR, true);
             }
 
+            @TestMetadata("anonFakeOverride.kt")
+            public void testAnonFakeOverride() throws Exception {
+                runTest("compiler/testData/codegen/box/ir/serializationRegressions/anonFakeOverride.kt");
+            }
+
             @TestMetadata("deepGenericDelegatedProperty.kt")
             public void testDeepGenericDelegatedProperty() throws Exception {
                 runTest("compiler/testData/codegen/box/ir/serializationRegressions/deepGenericDelegatedProperty.kt");
diff --git a/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/semantics/JsCodegenBoxTestGenerated.java b/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/semantics/JsCodegenBoxTestGenerated.java
index e4d476dcc39..a73f7e203c3 100644
--- a/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/semantics/JsCodegenBoxTestGenerated.java
+++ b/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/semantics/JsCodegenBoxTestGenerated.java
@@ -15818,6 +15818,11 @@ public class JsCodegenBoxTestGenerated extends AbstractJsCodegenBoxTest {
                 KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/codegen/box/ir/serializationRegressions"), Pattern.compile("^(.+)\\.kt$"), null, TargetBackend.JS, true);
             }
 
+            @TestMetadata("anonFakeOverride.kt")
+            public void testAnonFakeOverride() throws Exception {
+                runTest("compiler/testData/codegen/box/ir/serializationRegressions/anonFakeOverride.kt");
+            }
+
             @TestMetadata("deepGenericDelegatedProperty.kt")
             public void testDeepGenericDelegatedProperty() throws Exception {
                 runTest("compiler/testData/codegen/box/ir/serializationRegressions/deepGenericDelegatedProperty.kt");
diff --git a/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/wasm/semantics/IrCodegenBoxWasmTestGenerated.java b/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/wasm/semantics/IrCodegenBoxWasmTestGenerated.java
index 0e966bca5eb..5fed1cb9a52 100644
--- a/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/wasm/semantics/IrCodegenBoxWasmTestGenerated.java
+++ b/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/wasm/semantics/IrCodegenBoxWasmTestGenerated.java
@@ -12567,6 +12567,11 @@ public class IrCodegenBoxWasmTestGenerated extends AbstractIrCodegenBoxWasmTest
                 KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/codegen/box/ir/serializationRegressions"), Pattern.compile("^([^_](.+))\\.kt$"), null, TargetBackend.WASM, true);
             }
 
+            @TestMetadata("anonFakeOverride.kt")
+            public void testAnonFakeOverride() throws Exception {
+                runTest("compiler/testData/codegen/box/ir/serializationRegressions/anonFakeOverride.kt");
+            }
+
             @TestMetadata("deepGenericDelegatedProperty.kt")
             public void testDeepGenericDelegatedProperty() throws Exception {
                 runTest("compiler/testData/codegen/box/ir/serializationRegressions/deepGenericDelegatedProperty.kt");