Improve support of 'lateinit' modifier

- Allow 'lateinit' for inline classes which underlying type
is suitable for 'lateinit'

- K2: report all problems related to 'lateinit' modifier

^KT-55052: Fixed

compiler/testData/diagnostics/tests/declarationChecks/localVariablesWithTypeParameters_1_3.fir.kt

@@ -8,7 +8,7 @@ fun test() {
     val <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS_WARNING!><T : <!UNRESOLVED_REFERENCE!>__UNRESOLVED__<!>><!> a1 = ""
     val <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS_WARNING!><T : <!FINAL_UPPER_BOUND!>String<!>><!> a2 = 0
     <!WRONG_MODIFIER_TARGET!>const<!> val <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS_WARNING!><T><!> a3 = 0
-    <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> val <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS_WARNING!><T><!> a4 = 0
+    <!INAPPLICABLE_LATEINIT_MODIFIER, INAPPLICABLE_LATEINIT_MODIFIER, INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> val <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS_WARNING!><T><!> a4 = 0
     val <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS_WARNING!><T><!> a5 by Delegate<Int>()
     val <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS_WARNING!><T><!> a6 by Delegate<<!UNRESOLVED_REFERENCE!>T<!>>()
 }

compiler/testData/diagnostics/tests/declarationChecks/localVariablesWithTypeParameters_1_4.fir.kt

@@ -8,7 +8,7 @@ fun test() {
     val <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS!><T : <!UNRESOLVED_REFERENCE!>__UNRESOLVED__<!>><!> a1 = ""
     val <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS!><T : <!FINAL_UPPER_BOUND!>String<!>><!> a2 = 0
     <!WRONG_MODIFIER_TARGET!>const<!> val <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS!><T><!> a3 = 0
-    <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> val <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS!><T><!> a4 = 0
+    <!INAPPLICABLE_LATEINIT_MODIFIER, INAPPLICABLE_LATEINIT_MODIFIER, INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> val <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS!><T><!> a4 = 0
     val <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS!><T><!> a5 by Delegate<Int>()
     val <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS!><T><!> a6 by Delegate<<!UNRESOLVED_REFERENCE!>T<!>>()
 }

compiler/testData/diagnostics/tests/inlineClasses/lateinitInlineClasses.fir.kt

@@ -1,10 +0,0 @@
-// !LANGUAGE: +InlineClasses, -JvmInlineValueClasses
-// !DIAGNOSTICS: -UNUSED_VARIABLE
-
-inline class Foo(val x: Int)
-
-lateinit var a: Foo
-
-fun foo() {
-    lateinit var b: Foo
-}

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

@@ -1,5 +1,6 @@
 // !LANGUAGE: +InlineClasses, -JvmInlineValueClasses
 // !DIAGNOSTICS: -UNUSED_VARIABLE
+// FIR_IDENTICAL
 
 inline class Foo(val x: Int)
 

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

@@ -0,0 +1,86 @@
+// WITH_STDLIB
+// SKIP_TXT
+// !LANGUAGE: +InlineLateinit
+// FIR_IDENTICAL
+
+@JvmInline
+value class IC1(val x: Int)
+
+@JvmInline
+value class IC2(val x: IC1)
+
+@JvmInline
+value class IC3(val x: String)
+
+@JvmInline
+value class IC4(val x: String?)
+
+@JvmInline
+value class IC5(val x: IC4)
+
+@JvmInline
+value class IC6<T>(val x: T)
+
+@JvmInline
+value class IC7<T : Any>(val x: T)
+
+@JvmInline
+value class IC8(val x: <!VALUE_CLASS_CANNOT_BE_RECURSIVE!>IC9<!>)
+
+@JvmInline
+value class IC9(val x: <!VALUE_CLASS_CANNOT_BE_RECURSIVE!>IC8<!>)
+
+@JvmInline
+value class IC10(val x: IC6<String>)
+
+@JvmInline
+value class IC11(val x : IC4?)
+
+<!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var a: IC1
+<!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var b: IC2
+lateinit var c: IC3
+<!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var d: IC4
+<!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var e: IC6<String>
+<!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var f: IC6<*>
+<!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var g: IC5
+lateinit var h: IC7<Double>
+lateinit var i: IC7<*>
+lateinit var j: IC8
+<!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var k : IC10
+<!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var o : IC3?
+<!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var m : UInt
+<!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var n : IC11
+
+class B {
+    <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var a: IC1
+    <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var b: IC2
+    lateinit var c: IC3
+    <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var d: IC4
+    <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var e: IC6<String>
+    <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var f: IC6<*>
+    <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var g: IC5
+    lateinit var h: IC7<Double>
+    lateinit var i: IC7<*>
+    lateinit var j: IC8
+    <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var k : IC10
+    <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var o : IC3?
+    <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var m : UInt
+    <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var n : IC11
+}
+
+fun foo() {
+    <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var a: IC1
+    <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var b: IC2
+    lateinit var c: IC3
+    <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var d: IC4
+    <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var e: IC6<String>
+    <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var f: IC6<*>
+    <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var g: IC5
+    lateinit var h: IC7<Double>
+    lateinit var i: IC7<*>
+    lateinit var j: IC8
+    <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var k : IC10
+    <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var o : IC3?
+    <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var m : UInt
+    <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var n : IC11
+}

compiler/testData/diagnostics/tests/lateinit/modifierApplicability_lv12.fir.kt

@@ -30,7 +30,7 @@ public abstract class A<T: Any, V: String?>(lateinit var p2: String) {
     <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var e5 = "A"
 
     // With initializer, primitive
-    <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var e6 = 3
+    <!INAPPLICABLE_LATEINIT_MODIFIER, INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var e6 = 3
 
     <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var e7 by CustomDelegate()
 

compiler/testData/diagnostics/tests/unsignedTypes/lateinitUnsignedType.fir.kt

@@ -1,9 +0,0 @@
-// !DIAGNOSTICS: -UNUSED_VARIABLE
-
-lateinit var a: UInt
-
-fun foo() {
-    lateinit var b: UByte
-    lateinit var c: UShort
-    lateinit var d: ULong
-}

compiler/testData/diagnostics/tests/unsignedTypes/lateinitUnsignedType.kt

@@ -1,4 +1,5 @@
 // !DIAGNOSTICS: -UNUSED_VARIABLE
+// FIR_IDENTICAL
 
 <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var a: UInt
 

compiler/testData/diagnostics/tests/valueClasses/lateinitValueClasses.fir.kt

@@ -1,17 +0,0 @@
-// !SKIP_JAVAC
-// !LANGUAGE: +InlineClasses
-// ALLOW_KOTLIN_PACKAGE
-// !DIAGNOSTICS: -UNUSED_VARIABLE
-
-package kotlin.jvm
-
-annotation class JvmInline
-
-@JvmInline
-value class Foo(val x: Int)
-
-lateinit var a: Foo
-
-fun foo() {
-    lateinit var b: Foo
-}

compiler/testData/diagnostics/tests/valueClasses/lateinitValueClasses.kt

@@ -2,6 +2,7 @@
 // !LANGUAGE: +InlineClasses
 // ALLOW_KOTLIN_PACKAGE
 // !DIAGNOSTICS: -UNUSED_VARIABLE
+// FIR_IDENTICAL
 
 package kotlin.jvm