Prohibit identity equals on inline class types

compiler/testData/diagnostics/tests/inlineClasses/identityComparisonWithInlineClasses.kt

@@ -0,0 +1,15 @@
+// !LANGUAGE: +InlineClasses
+// !DIAGNOSTICS: -UNUSED_VARIABLE
+
+inline class Foo(val x: Int)
+inline class Bar(val y: String)
+
+fun test(f1: Foo, f2: Foo, b1: Bar, fn1: Foo?, fn2: Foo?) {
+    val a1 = <!FORBIDDEN_IDENTITY_EQUALS!>f1 === f2<!> || <!FORBIDDEN_IDENTITY_EQUALS!>f1 !== f2<!>
+    val a2 = <!FORBIDDEN_IDENTITY_EQUALS!>f1 === f1<!>
+    val a3 = <!EQUALITY_NOT_APPLICABLE!>f1 === b1<!> || <!EQUALITY_NOT_APPLICABLE!>f1 !== b1<!>
+
+    val c1 = <!FORBIDDEN_IDENTITY_EQUALS!>fn1 === fn2<!> || <!FORBIDDEN_IDENTITY_EQUALS!>fn1 !== fn2<!>
+    val c2 = f1 === fn1 || f1 !== fn1
+    val c3 = <!EQUALITY_NOT_APPLICABLE!>b1 === fn1<!> || <!EQUALITY_NOT_APPLICABLE!>b1 !== fn1<!>
+}

compiler/testData/diagnostics/tests/inlineClasses/identityComparisonWithInlineClasses.txt

@@ -0,0 +1,19 @@
+package
+
+public fun test(/*0*/ f1: Foo, /*1*/ f2: Foo, /*2*/ b1: Bar, /*3*/ fn1: Foo?, /*4*/ fn2: Foo?): kotlin.Unit
+
+public final inline class Bar {
+    public constructor Bar(/*0*/ y: kotlin.String)
+    public final val y: kotlin.String
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public final inline class Foo {
+    public constructor Foo(/*0*/ x: kotlin.Int)
+    public final val x: kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}