Make lateinit diagnostics more clear

compiler/frontend/src/org/jetbrains/kotlin/diagnostics/Errors.java

@@ -328,12 +328,17 @@ public interface Errors {
     DiagnosticFactory0<JetExpression> PROPERTY_INITIALIZER_NO_BACKING_FIELD = DiagnosticFactory0.create(ERROR);
     DiagnosticFactory0<JetExpression> PROPERTY_INITIALIZER_IN_TRAIT = DiagnosticFactory0.create(ERROR);
     DiagnosticFactory0<JetProperty> FINAL_PROPERTY_IN_TRAIT = DiagnosticFactory0.create(ERROR, FINAL_MODIFIER);
-    DiagnosticFactory0<PsiElement> INAPPLICABLE_LATEINIT_MODIFIER = DiagnosticFactory0.create(ERROR);
     DiagnosticFactory0<JetProperty> BACKING_FIELD_IN_TRAIT = DiagnosticFactory0.create(ERROR, DECLARATION_SIGNATURE);
 
     DiagnosticFactory0<JetSimpleNameExpression> BACKING_FIELD_SYNTAX_DEPRECATED = DiagnosticFactory0.create(WARNING);
     DiagnosticFactory0<JetSimpleNameExpression> BACKING_FIELD_USAGE_DEPRECATED = DiagnosticFactory0.create(WARNING);
 
+    DiagnosticFactory0<PsiElement> INAPPLICABLE_LATEINIT_MODIFIER = DiagnosticFactory0.create(ERROR);
+    DiagnosticFactory0<PsiElement> INAPPLICABLE_LATEINIT_MODIFIER_IMMUTABLE = DiagnosticFactory0.create(ERROR);
+    DiagnosticFactory0<PsiElement> INAPPLICABLE_LATEINIT_MODIFIER_ABSTRACT_PROPERTY = DiagnosticFactory0.create(ERROR);
+    DiagnosticFactory0<PsiElement> INAPPLICABLE_LATEINIT_MODIFIER_PRIMARY_CONSTRUCTOR_PARAMETER = DiagnosticFactory0.create(ERROR);
+    DiagnosticFactory0<PsiElement> INAPPLICABLE_LATEINIT_MODIFIER_NULLABLE = DiagnosticFactory0.create(ERROR);
+
     DiagnosticFactory2<JetModifierListOwner, String, ClassDescriptor> ABSTRACT_PROPERTY_IN_NON_ABSTRACT_CLASS = DiagnosticFactory2.create(ERROR, ABSTRACT_MODIFIER);
 
     DiagnosticFactory0<JetPropertyAccessor> VAL_WITH_SETTER = DiagnosticFactory0.create(ERROR);

compiler/frontend/src/org/jetbrains/kotlin/diagnostics/rendering/DefaultErrorMessages.java

@@ -205,8 +205,13 @@ public class DefaultErrorMessages {
         MAP.put(DELEGATED_PROPERTY_IN_TRAIT, "Delegated properties are not allowed in interfaces");
         MAP.put(LOCAL_VARIABLE_WITH_DELEGATE, "Local variables are not allowed to have delegates");
 
+        MAP.put(INAPPLICABLE_LATEINIT_MODIFIER, "''lateinit'' modifier is allowed only on member properties with a backing field");
+        MAP.put(INAPPLICABLE_LATEINIT_MODIFIER_IMMUTABLE, "''lateinit'' modifier is allowed only on mutable properties");
+        MAP.put(INAPPLICABLE_LATEINIT_MODIFIER_ABSTRACT_PROPERTY, "''lateinit'' modifier is not allowed on abstract properties");
+        MAP.put(INAPPLICABLE_LATEINIT_MODIFIER_PRIMARY_CONSTRUCTOR_PARAMETER, "''lateinit'' modifier is not allowed on primary constructor parameters");
+        MAP.put(INAPPLICABLE_LATEINIT_MODIFIER_NULLABLE, "''lateinit'' modifier is not allowed on nullable properties");
+
         MAP.put(GETTER_VISIBILITY_DIFFERS_FROM_PROPERTY_VISIBILITY, "Getter visibility must be the same as property visibility");
-        MAP.put(INAPPLICABLE_LATEINIT_MODIFIER, "''lateinit'' modifier is allowed only on non-null member properties with a backing field");
         MAP.put(BACKING_FIELD_IN_TRAIT, "Property in an interface cannot have a backing field");
         MAP.put(MUST_BE_INITIALIZED, "Property must be initialized");
         MAP.put(MUST_BE_INITIALIZED_OR_BE_ABSTRACT, "Property must be initialized or be abstract");

compiler/frontend/src/org/jetbrains/kotlin/resolve/DeclarationsChecker.java

@@ -329,18 +329,43 @@ public class DeclarationsChecker {
         PsiElement modifier = modifierList.getModifier(JetTokens.LATE_INIT_KEYWORD);
         if (modifier == null) return;
 
+        if (!propertyDescriptor.isVar()) {
+            trace.report(INAPPLICABLE_LATEINIT_MODIFIER_IMMUTABLE.on(modifier));
+            return;
+        }
+
+        boolean returnTypeIsNullable = true;
+        boolean returnTypeIsPrimitive = true;
+
+        JetType returnType = propertyDescriptor.getReturnType();
+        if (returnType != null) {
+            returnTypeIsNullable = TypeUtils.isNullableType(returnType);
+            returnTypeIsPrimitive = KotlinBuiltIns.isPrimitiveType(returnType);
+        }
+
+        if (returnTypeIsNullable) {
+            trace.report(INAPPLICABLE_LATEINIT_MODIFIER_NULLABLE.on(modifier));
+            return;
+        }
+
+        if (propertyDescriptor.getModality() == Modality.ABSTRACT) {
+            trace.report(INAPPLICABLE_LATEINIT_MODIFIER_ABSTRACT_PROPERTY.on(modifier));
+            return;
+        }
+
+        if (property instanceof JetParameter) {
+            trace.report(INAPPLICABLE_LATEINIT_MODIFIER_PRIMARY_CONSTRUCTOR_PARAMETER.on(modifier));
+            return;
+        }
+
         boolean hasBackingField =
                 Boolean.TRUE.equals(trace.getBindingContext().get(BindingContext.BACKING_FIELD_REQUIRED, propertyDescriptor));
 
         boolean hasDelegateOrInitializer = false;
-        boolean hasCorrespondingValueParameter = false;
 
         if (property instanceof JetProperty) {
             hasDelegateOrInitializer = ((JetProperty) property).hasDelegateExpressionOrInitializer();
         }
-        else if (property instanceof JetParameter) {
-            hasCorrespondingValueParameter = true;
-        }
 
         PropertyGetterDescriptor getter = propertyDescriptor.getGetter();
         PropertySetterDescriptor setter = propertyDescriptor.getSetter();
@@ -353,17 +378,8 @@ public class DeclarationsChecker {
             customGetterOrSetter |= setter.hasBody();
         }
 
-        boolean returnTypeIsNullable = true;
+        if (!hasBackingField || hasDelegateOrInitializer || customGetterOrSetter
-        boolean returnTypeIsPrimitive = true;
+                || returnTypeIsPrimitive || propertyDescriptor.getExtensionReceiverParameter() != null) {
-
-        JetType returnType = propertyDescriptor.getReturnType();
-        if (returnType != null) {
-            returnTypeIsNullable = TypeUtils.isNullableType(returnType);
-            returnTypeIsPrimitive = KotlinBuiltIns.isPrimitiveType(returnType);
-        }
-
-        if (!hasBackingField || hasCorrespondingValueParameter || hasDelegateOrInitializer || customGetterOrSetter
-                || returnTypeIsNullable || returnTypeIsPrimitive || propertyDescriptor.getExtensionReceiverParameter() != null) {
             trace.report(INAPPLICABLE_LATEINIT_MODIFIER.on(modifier));
         }
     }

compiler/testData/codegen/box/properties/lateinit/simple.kt

@@ -1,12 +0,0 @@
-class A {
-    public lateinit val str: String
-
-    init {
-        str = "OK"
-    }
-}
-
-fun box(): String {
-    val a = A()
-    return a.str
-}

compiler/testData/codegen/box/properties/lateinit/simpleField.kt

@@ -1,16 +0,0 @@
-class A {
-    private lateinit val str: String
-
-    init {
-        str = "OK"
-    }
-
-    public fun getMyStr(): String {
-        return str
-    }
-}
-
-fun box(): String {
-    val a = A()
-    return a.getMyStr()
-}

compiler/testData/diagnostics/tests/LateInit.kt

@@ -2,13 +2,13 @@ class CustomDelegate {
     public fun get(thisRef: Any?, prop: PropertyMetadata): String = prop.name
 }
 
-public abstract class A<T: Any, V: String?>(<!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> val p2: String) {
+public abstract class A<T: Any, V: String?>(<!INAPPLICABLE_LATEINIT_MODIFIER_PRIMARY_CONSTRUCTOR_PARAMETER!>lateinit<!> var p2: String) {
 
-    public lateinit val a: String
+    public <!INAPPLICABLE_LATEINIT_MODIFIER_IMMUTABLE!>lateinit<!> val a: String
-    lateinit val b: T
+    <!INAPPLICABLE_LATEINIT_MODIFIER_IMMUTABLE!>lateinit<!> val b: T
     private lateinit var c: CharSequence
 
-    lateinit val d: String
+    <!INAPPLICABLE_LATEINIT_MODIFIER_IMMUTABLE!>lateinit<!> val d: String
         get
 
     public lateinit var e: String
@@ -16,42 +16,42 @@ public abstract class A<T: Any, V: String?>(<!INAPPLICABLE_LATEINIT_MODIFIER!>la
         private set
 
     fun a() {
-        <!WRONG_MODIFIER_TARGET!>lateinit<!> val <!UNUSED_VARIABLE!>a<!>: String
+        <!WRONG_MODIFIER_TARGET!>lateinit<!> var <!UNUSED_VARIABLE!>a<!>: String
     }
 
-    <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> val e1: V
+    <!INAPPLICABLE_LATEINIT_MODIFIER_NULLABLE!>lateinit<!> var e1: V
-    <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> val e2: String?
+    <!INAPPLICABLE_LATEINIT_MODIFIER_NULLABLE!>lateinit<!> var e2: String?
-    <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> val e3: Int
+    <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var e3: Int
-    <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> val e4: Int?
+    <!INAPPLICABLE_LATEINIT_MODIFIER_NULLABLE!>lateinit<!> var e4: Int?
     <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var e5 = "A"
     <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var e6 = 3
 
-    <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> val e7 by CustomDelegate()
+    <!INAPPLICABLE_LATEINIT_MODIFIER_IMMUTABLE!>lateinit<!> val e7 by CustomDelegate()
 
-    <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> val e8: String
+    <!INAPPLICABLE_LATEINIT_MODIFIER_IMMUTABLE!>lateinit<!> val e8: String
         get() = "A"
 
     <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var e9: String
         set(v) { field = v }
 
-    abstract <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> val e10: String
+    abstract <!INAPPLICABLE_LATEINIT_MODIFIER_ABSTRACT_PROPERTY!>lateinit<!> var e10: String
 
-    <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> val String.e11: String
+    <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var String.e11: String
 
     <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> var String.e12: String
 }
 
-<!WRONG_MODIFIER_TARGET!>lateinit<!> val topLevel: String
+<!INAPPLICABLE_LATEINIT_MODIFIER_IMMUTABLE, WRONG_MODIFIER_TARGET!>lateinit<!> val topLevel: String
 <!WRONG_MODIFIER_TARGET!>lateinit<!> var topLevelMutable: String
 
 public interface Intf {
-    <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> val str: String
+    <!INAPPLICABLE_LATEINIT_MODIFIER_ABSTRACT_PROPERTY!>lateinit<!> var str: String
 }
 
 public abstract class AbstractClass {
-    abstract val str: String
+    abstract var str: String
 }
 
 public class AbstractClassImpl : AbstractClass() {
-    override lateinit val str: String
+    override lateinit var str: String
 }

compiler/testData/diagnostics/tests/LateInit.txt

@@ -10,18 +10,18 @@ public abstract class A</*0*/ T : kotlin.Any, /*1*/ V : kotlin.String?> {
     private final lateinit var c: kotlin.CharSequence
     public final lateinit val d: kotlin.String
     public final lateinit var e: kotlin.String
-    public final lateinit val e1: V
+    public final lateinit var e1: V
-    public abstract lateinit val e10: kotlin.String
+    public abstract lateinit var e10: kotlin.String
-    public final lateinit val e2: kotlin.String?
+    public final lateinit var e2: kotlin.String?
-    public final lateinit val e3: kotlin.Int
+    public final lateinit var e3: kotlin.Int
-    public final lateinit val e4: kotlin.Int?
+    public final lateinit var e4: kotlin.Int?
     public final lateinit var e5: kotlin.String
     public final lateinit var e6: kotlin.Int
     public final lateinit val e7: kotlin.String
     public final lateinit val e8: kotlin.String
     public final lateinit var e9: kotlin.String
-    public final val p2: kotlin.String
+    public final var p2: kotlin.String
-    public final lateinit val kotlin.String.e11: kotlin.String
+    public final lateinit var kotlin.String.e11: kotlin.String
     public final lateinit var kotlin.String.e12: kotlin.String
     public final fun a(): kotlin.Unit
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
@@ -31,7 +31,7 @@ public abstract class A</*0*/ T : kotlin.Any, /*1*/ V : kotlin.String?> {
 
 public abstract class AbstractClass {
     public constructor AbstractClass()
-    public abstract val str: kotlin.String
+    public abstract var str: 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
@@ -39,7 +39,7 @@ public abstract class AbstractClass {
 
 public final class AbstractClassImpl : AbstractClass {
     public constructor AbstractClassImpl()
-    public open override /*1*/ lateinit val str: kotlin.String
+    public open override /*1*/ lateinit var str: 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
@@ -54,7 +54,7 @@ public final class CustomDelegate {
 }
 
 public interface Intf {
-    public abstract lateinit val str: kotlin.String
+    public abstract lateinit var str: 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

compiler/tests/org/jetbrains/kotlin/codegen/generated/BlackBoxCodegenTestGenerated.java

@@ -6603,18 +6603,6 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
                 doTest(fileName);
             }
 
-            @TestMetadata("simple.kt")
-            public void testSimple() throws Exception {
-                String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/box/properties/lateinit/simple.kt");
-                doTest(fileName);
-            }
-
-            @TestMetadata("simpleField.kt")
-            public void testSimpleField() throws Exception {
-                String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/box/properties/lateinit/simpleField.kt");
-                doTest(fileName);
-            }
-
             @TestMetadata("simpleVar.kt")
             public void testSimpleVar() throws Exception {
                 String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/box/properties/lateinit/simpleVar.kt");