Fix ClassCastException on equality comparison on inline class objects

^KT-54603: Fixed

compiler/fir/fir2ir/tests-gen/org/jetbrains/kotlin/test/runners/codegen/FirBlackBoxCodegenTestGenerated.java

@@ -22265,6 +22265,12 @@ public class FirBlackBoxCodegenTestGenerated extends AbstractFirBlackBoxCodegenT
             runTest("compiler/testData/codegen/box/inlineClasses/kt54455.kt", TransformersFunctions.getReplaceOptionalJvmInlineAnnotationWithReal());
         }
 
+        @Test
+        @TestMetadata("kt54603.kt")
+        public void testKt54603() throws Exception {
+            runTest("compiler/testData/codegen/box/inlineClasses/kt54603.kt", TransformersFunctions.getReplaceOptionalJvmInlineAnnotationWithReal());
+        }
+
         @Test
         @TestMetadata("mangledDefaultParameterFunction.kt")
         public void testMangledDefaultParameterFunction() throws Exception {

compiler/ir/backend.jvm/lower/src/org/jetbrains/kotlin/backend/jvm/lower/JvmInlineClassLowering.kt

@@ -497,9 +497,10 @@ private class JvmInlineClassLowering(context: JvmBackendContext) : JvmValueClass
 
                     fun irBox(expr: IrExpression) = irCall(boxFunction).apply { putValueArgument(0, expr) }
 
+                    val underlyingType = getInlineClassUnderlyingType(valueClass)
                     irCall(untypedEquals).apply {
-                        dispatchReceiver = irBox(irGet(left))
-                        putValueArgument(0, irBox(irGet(right)))
+                        dispatchReceiver = irBox(coerceInlineClasses(irGet(left), left.type, underlyingType))
+                        putValueArgument(0, irBox(coerceInlineClasses(irGet(right), right.type, underlyingType)))
                     }
                 } else {
                     irEquals(coerceInlineClasses(irGet(left), left.type, type), coerceInlineClasses(irGet(right), right.type, type))

compiler/testData/codegen/box/inlineClasses/kt54603.kt

@@ -0,0 +1,68 @@
+// WITH_STDLIB
+// WORKS_WHEN_VALUE_CLASS
+// LANGUAGE: +ValueClasses, +CustomEqualsInInlineClasses
+// TARGET_BACKEND: JVM_IR
+
+class A(x: Int)
+
+OPTIONAL_JVM_INLINE_ANNOTATION
+value class B(val a: A) {
+    override fun equals(other: Any?) = true
+}
+
+OPTIONAL_JVM_INLINE_ANNOTATION
+value class C<T>(val t: T) {
+    override fun equals(other: Any?) = true
+}
+
+OPTIONAL_JVM_INLINE_ANNOTATION
+value class D<T : Int>(val t: T) {
+    override fun equals(other: Any?) = true
+}
+
+OPTIONAL_JVM_INLINE_ANNOTATION
+value class E(val d: Double) {
+    override fun equals(other: Any?) = true
+}
+
+OPTIONAL_JVM_INLINE_ANNOTATION
+value class F(val e: E) {
+    override fun equals(other: Any?) = true
+}
+
+OPTIONAL_JVM_INLINE_ANNOTATION
+value class G(val e: Int?) {
+    override fun equals(other: Any?) = true
+}
+
+OPTIONAL_JVM_INLINE_ANNOTATION
+value class H(val e: Any?) {
+    override fun equals(other: Any?) = true
+}
+
+OPTIONAL_JVM_INLINE_ANNOTATION
+value class I(val e: E?) {
+    override fun equals(other: Any?) = true
+}
+
+fun box(): String {
+    if (B(A(0)) != B(A(5))) return "Fail 1"
+    if (C(0) != C("a")) return "Fail 2"
+    if (D(0) != D(2)) return "Fail 3"
+    if (E(0.0) != E(0.5)) return "Fail 4"
+    if (F(E(0.0)) != F(E(0.5))) return "Fail 5"
+
+    if (G(0) != G(2)) return "Fail 6.1"
+    if (G(0) != G(null)) return "Fail 6.2"
+    if (G(null) != G(0)) return "Fail 6.3"
+
+    if (H("aba") != H("caba")) return "Fail 7.1"
+    if (H("aba") != H(null)) return "Fail 7.2"
+    if (H(null) != H("caba")) return "Fail 7.3"
+
+    if (I(E(0.0)) != I(E(0.5))) return "Fail 8.1"
+    if (I(E(0.0)) != I(null)) return "Fail 8.2"
+    if (I(null) != I(E(0.5))) return "Fail 8.3"
+
+    return "OK"
+}

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

@@ -22265,6 +22265,12 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
             runTest("compiler/testData/codegen/box/inlineClasses/kt54455.kt", TransformersFunctions.getReplaceOptionalJvmInlineAnnotationWithReal());
         }
 
+        @Test
+        @TestMetadata("kt54603.kt")
+        public void testKt54603() throws Exception {
+            runTest("compiler/testData/codegen/box/inlineClasses/kt54603.kt", TransformersFunctions.getReplaceOptionalJvmInlineAnnotationWithReal());
+        }
+
         @Test
         @TestMetadata("mangledDefaultParameterFunction.kt")
         public void testMangledDefaultParameterFunction() throws Exception {