Forbid lateinit variables of inline class types

Proper support of lateinit inline class values will be added later,
 see #KT-23814

 #KT-25603 Fixed

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

@@ -17,6 +17,7 @@
 package org.jetbrains.kotlin.resolve
 
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns
+import org.jetbrains.kotlin.builtins.UnsignedTypes
 import org.jetbrains.kotlin.descriptors.Modality
 import org.jetbrains.kotlin.descriptors.PropertyDescriptor
 import org.jetbrains.kotlin.descriptors.VariableDescriptor
@@ -45,6 +46,14 @@ object LateinitModifierApplicabilityChecker {
             trace.report(Errors.INAPPLICABLE_LATEINIT_MODIFIER.on(modifier, "is allowed only on mutable $variables"))
         }
 
+        if (type.isInlineClassType()) {
+            if (UnsignedTypes.isUnsignedType(type)) {
+                trace.report(Errors.INAPPLICABLE_LATEINIT_MODIFIER.on(modifier, "is not allowed on $variables of unsigned types"))
+            } else {
+                trace.report(Errors.INAPPLICABLE_LATEINIT_MODIFIER.on(modifier, "is not allowed on $variables of inline class types"))
+            }
+        }
+
         if (type.isMarkedNullable) {
             trace.report(Errors.INAPPLICABLE_LATEINIT_MODIFIER.on(modifier, "is not allowed on $variables of nullable types"))
         } else if (TypeUtils.isNullableType(type)) {

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

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

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

@@ -0,0 +1,12 @@
+package
+
+public lateinit var a: Foo
+public fun foo(): kotlin.Unit
+
+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
+}

compiler/testData/diagnostics/testsWithUnsignedTypes/lateinitUnsignedType.kt

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

compiler/testData/diagnostics/testsWithUnsignedTypes/lateinitUnsignedType.txt

@@ -0,0 +1,4 @@
+package
+
+public lateinit var a: kotlin.UInt
+public fun foo(): kotlin.Unit

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

@@ -10862,6 +10862,11 @@ public class DiagnosticsTestGenerated extends AbstractDiagnosticsTest {
                 runTest("compiler/testData/diagnostics/tests/inlineClasses/inlineClassesInsideAnnotations.kt");
             }
 
+            @TestMetadata("lateinitInlineClasses.kt")
+            public void testLateinitInlineClasses() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/inlineClasses/lateinitInlineClasses.kt");
+            }
+
             @TestMetadata("presenceOfInitializerBlockInsideInlineClass.kt")
             public void testPresenceOfInitializerBlockInsideInlineClass() throws Exception {
                 runTest("compiler/testData/diagnostics/tests/inlineClasses/presenceOfInitializerBlockInsideInlineClass.kt");

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

@@ -44,6 +44,11 @@ public class DiagnosticsWithUnsignedTypesGenerated extends AbstractDiagnosticsWi
         runTest("compiler/testData/diagnostics/testsWithUnsignedTypes/forbiddenEqualsOnUnsignedTypes.kt");
     }
 
+    @TestMetadata("lateinitUnsignedType.kt")
+    public void testLateinitUnsignedType() throws Exception {
+        runTest("compiler/testData/diagnostics/testsWithUnsignedTypes/lateinitUnsignedType.kt");
+    }
+
     @TestMetadata("overloadResolutionOfBasicOperations.kt")
     public void testOverloadResolutionOfBasicOperations() throws Exception {
         runTest("compiler/testData/diagnostics/testsWithUnsignedTypes/overloadResolutionOfBasicOperations.kt");

compiler/tests/org/jetbrains/kotlin/checkers/javac/DiagnosticsUsingJavacTestGenerated.java

@@ -10862,6 +10862,11 @@ public class DiagnosticsUsingJavacTestGenerated extends AbstractDiagnosticsUsing
                 runTest("compiler/testData/diagnostics/tests/inlineClasses/inlineClassesInsideAnnotations.kt");
             }
 
+            @TestMetadata("lateinitInlineClasses.kt")
+            public void testLateinitInlineClasses() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/inlineClasses/lateinitInlineClasses.kt");
+            }
+
             @TestMetadata("presenceOfInitializerBlockInsideInlineClass.kt")
             public void testPresenceOfInitializerBlockInsideInlineClass() throws Exception {
                 runTest("compiler/testData/diagnostics/tests/inlineClasses/presenceOfInitializerBlockInsideInlineClass.kt");