Support lateinit modifier on top-level properties

Allow lateinit modifier on top-level properties.
Modifiers 'lateinit' and 'header' are incompatible.

compiler/frontend/src/org/jetbrains/kotlin/resolve/ModifiersChecker.kt

@@ -74,7 +74,7 @@ object ModifierCheckerCore {
             REIFIED_KEYWORD   to EnumSet.of(TYPE_PARAMETER),
             VARARG_KEYWORD    to EnumSet.of(VALUE_PARAMETER, PROPERTY_PARAMETER),
             COMPANION_KEYWORD to EnumSet.of(OBJECT),
-            LATEINIT_KEYWORD  to EnumSet.of(MEMBER_PROPERTY, LOCAL_VARIABLE),
+            LATEINIT_KEYWORD  to EnumSet.of(MEMBER_PROPERTY, TOP_LEVEL_PROPERTY, LOCAL_VARIABLE),
             DATA_KEYWORD      to EnumSet.of(CLASS_ONLY, LOCAL_CLASS),
             INLINE_KEYWORD    to EnumSet.of(FUNCTION, PROPERTY, PROPERTY_GETTER, PROPERTY_SETTER),
             NOINLINE_KEYWORD  to EnumSet.of(VALUE_PARAMETER),
@@ -166,6 +166,9 @@ object ModifierCheckerCore {
         // (see the KEEP https://github.com/Kotlin/KEEP/blob/master/proposals/sealed-class-inheritance.md)
         result += incompatibilityRegister(SEALED_KEYWORD, INNER_KEYWORD)
 
+        // lateinit is incompatible with header
+        result += incompatibilityRegister(LATEINIT_KEYWORD, HEADER_KEYWORD)
+
         return result
     }
 

compiler/testData/diagnostics/tests/lateinit/modifierApplicability.kt

@@ -46,8 +46,8 @@ public abstract class A<T: Any, V: String?>(<!INAPPLICABLE_LATEINIT_MODIFIER!>la
     <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var String.e12: String
 }
 
-<!INAPPLICABLE_LATEINIT_MODIFIER, WRONG_MODIFIER_TARGET!>lateinit<!> val topLevel: String
-<!WRONG_MODIFIER_TARGET!>lateinit<!> var topLevelMutable: String
+<!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> val topLevel: String
+lateinit var topLevelMutable: String
 
 public interface Intf {
     <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var str: String

compiler/testData/diagnostics/tests/multiplatform/topLevelProperty/differentKindsOfProperties.kt

@@ -28,7 +28,7 @@ header var customAccessorVar: String
 
 header <!CONST_VAL_WITHOUT_INITIALIZER!>const<!> val constVal: Int
 
-header <!WRONG_MODIFIER_TARGET!>lateinit<!> var lateinitVar: String
+<!INCOMPATIBLE_MODIFIERS!>header<!> <!INCOMPATIBLE_MODIFIERS!>lateinit<!> var lateinitVar: String
 
 <!WRONG_MODIFIER_TARGET!>header<!> val delegated: String by Delegate
 object Delegate { operator fun getValue(x: Any?, y: Any?): String = "" }

compiler/testData/diagnostics/tests/properties/lateinitOnTopLevel.kt

@@ -0,0 +1,12 @@
+object Delegate {
+    operator fun getValue(instance: Any?, property: Any) : String = ""
+    operator fun setValue(instance: Any?, property: Any, value: String) {}
+}
+
+lateinit var testOk: String
+
+<!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> val testErr0: Any
+<!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var testErr1: Int
+<!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var testErr2: Any?
+<!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var testErr3: String = ""
+<!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var testErr4 by Delegate

compiler/testData/diagnostics/tests/properties/lateinitOnTopLevel.txt

@@ -0,0 +1,17 @@
+package
+
+public lateinit val testErr0: kotlin.Any
+public lateinit var testErr1: kotlin.Int
+public lateinit var testErr2: kotlin.Any?
+public lateinit var testErr3: kotlin.String
+public lateinit var testErr4: kotlin.String
+public lateinit var testOk: kotlin.String
+
+public object Delegate {
+    private constructor Delegate()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public final operator fun getValue(/*0*/ instance: kotlin.Any?, /*1*/ property: kotlin.Any): kotlin.String
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public final operator fun setValue(/*0*/ instance: kotlin.Any?, /*1*/ property: kotlin.Any, /*2*/ value: kotlin.String): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

compiler/tests/org/jetbrains/kotlin/checkers/DiagnosticsTestGenerated.java

@@ -16174,6 +16174,12 @@ public class DiagnosticsTestGenerated extends AbstractDiagnosticsTest {
                 doTest(fileName);
             }
 
+            @TestMetadata("lateinitOnTopLevel.kt")
+            public void testLateinitOnTopLevel() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/properties/lateinitOnTopLevel.kt");
+                doTest(fileName);
+            }
+
             @TestMetadata("compiler/testData/diagnostics/tests/properties/inferenceFromGetters")
             @TestDataPath("$PROJECT_ROOT")
             @RunWith(JUnit3RunnerWithInners.class)