Improve support of custom equals in inline classes

- Ensure that typed equals parameter's type is a star projection of
  corresponding inline class

- Make possible to declare typed equals that returns 'Nothing'

- Forbid type parameters in typed equals operator declaration

^KT-54909 fixed
^KT-54910 fixed

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

@@ -19,7 +19,7 @@ interface I {
 
 OPTIONAL_JVM_INLINE_ANNOTATION
 value class IC2(val value: Int) : I {
-    override fun equals(param: IC2): Boolean {
+    override operator fun equals(param: IC2): Boolean {
         return abs(value - param.value) < 2
     }
 }
@@ -34,6 +34,26 @@ value class IC4(val value: Int) {
     override fun equals(other: Any?) = TODO()
 }
 
+OPTIONAL_JVM_INLINE_ANNOTATION
+value class IC5(val value: Int) {
+    operator fun equals(other: IC5): Nothing = TODO()
+}
+
+OPTIONAL_JVM_INLINE_ANNOTATION
+value class IC6(val value: Int) {
+    override fun equals(other: Any?): Nothing = TODO()
+}
+
+inline fun <reified T> assertThrows(block: () -> Unit): Boolean {
+    try {
+        block.invoke()
+    } catch (t: Throwable) {
+        return t is T
+    }
+    return false
+}
+
+
 fun box() = when {
     IC1(1.0) != IC1(1.05) -> "Fail 1.1"
     (IC1(1.0) as Any) != IC1(1.05) -> "Fail 1.2"
@@ -68,5 +88,9 @@ fun box() = when {
     IC1(1.0) == Any() -> "Fail 7.1"
     (IC1(1.0) as Any) == Any() -> "Fail 7.2"
 
+    !assertThrows<NotImplementedError> { IC5(0) == IC5(1) } -> "Fail 8.1"
+    !assertThrows<NotImplementedError> { IC6(0) == IC6(1) } -> "Fail 8.2"
+
+
     else -> "OK"
 }