Resolve lateinit variables

Do not report UNINITIALIZED_VARIABLE on lateinit variables
Provide delegating constructors for descriptors for compatibility.

compiler/backend/src/org/jetbrains/kotlin/codegen/binding/CodegenAnnotatingVisitor.java

@@ -396,8 +396,6 @@ class CodegenAnnotatingVisitor extends KtVisitorVoid {
                 Annotations.Companion.getEMPTY(),
                 Name.identifier(variableDescriptor.getName().asString() + "$metadata"),
                 ReflectionTypes.Companion.createKPropertyStarType(DescriptorUtilsKt.getModule(variableDescriptor)),
-                false,
-                false,
                 SourceElement.NO_SOURCE
         );
         bindingTrace.record(LOCAL_VARIABLE_PROPERTY_METADATA, variableDescriptor, metadataVariableDescriptor);

compiler/frontend/src/org/jetbrains/kotlin/cfg/ControlFlowInformationProvider.kt

@@ -354,7 +354,9 @@ class ControlFlowInformationProvider private constructor(
                     }
                 }
                 is VariableDescriptor ->
-                    report(Errors.UNINITIALIZED_VARIABLE.on(element, variableDescriptor), ctxt)
+                    if (!variableDescriptor.isLateInit) {
+                        report(Errors.UNINITIALIZED_VARIABLE.on(element, variableDescriptor), ctxt)
+                    }
             }
         }
     }

compiler/frontend/src/org/jetbrains/kotlin/descriptors/impl/LocalVariableDescriptor.java

@@ -26,6 +26,7 @@ import org.jetbrains.kotlin.types.TypeSubstitutor;
 
 public class LocalVariableDescriptor extends VariableDescriptorWithInitializerImpl implements VariableDescriptorWithAccessors {
     private final boolean isDelegated;
+    private final boolean isLateInit;
     private LocalVariableAccessorDescriptor.Getter getter;
     private LocalVariableAccessorDescriptor.Setter setter;
 
@@ -36,10 +37,34 @@ public class LocalVariableDescriptor extends VariableDescriptorWithInitializerIm
             @Nullable KotlinType type,
             boolean mutable,
             boolean isDelegated,
+            boolean isLateInit,
             @NotNull SourceElement source
     ) {
         super(containingDeclaration, annotations, name, type, mutable, source);
         this.isDelegated = isDelegated;
+        this.isLateInit = isLateInit;
+    }
+
+    public LocalVariableDescriptor(
+            @NotNull DeclarationDescriptor containingDeclaration,
+            @NotNull Annotations annotations,
+            @NotNull Name name,
+            @Nullable KotlinType type,
+            boolean mutable,
+            boolean isDelegated,
+            @NotNull SourceElement source
+    ) {
+        this(containingDeclaration, annotations, name, type, mutable, isDelegated, false, source);
+    }
+
+    public LocalVariableDescriptor(
+            @NotNull DeclarationDescriptor containingDeclaration,
+            @NotNull Annotations annotations,
+            @NotNull Name name,
+            @Nullable KotlinType type,
+            @NotNull SourceElement source
+    ) {
+        this(containingDeclaration, annotations, name, type, false, false, false, source);
     }
 
     @Override
@@ -89,4 +114,9 @@ public class LocalVariableDescriptor extends VariableDescriptorWithInitializerIm
     public boolean isDelegated() {
         return isDelegated;
     }
+
+    @Override
+    public boolean isLateInit() {
+        return isLateInit;
+    }
 }

compiler/frontend/src/org/jetbrains/kotlin/descriptors/impl/SyntheticFieldDescriptor.kt

@@ -29,7 +29,8 @@ class SyntheticFieldDescriptor private constructor(
         accessorDescriptor: PropertyAccessorDescriptor,
         property: KtProperty
 ): LocalVariableDescriptor(accessorDescriptor, Annotations.EMPTY, SyntheticFieldDescriptor.NAME,
-                           propertyDescriptor.type, propertyDescriptor.isVar, false, property.toSourceElement()) {
+                           propertyDescriptor.type, propertyDescriptor.isVar, false, false,
+                           property.toSourceElement()) {
 
     constructor(accessorDescriptor: PropertyAccessorDescriptor,
                 property: KtProperty): this(accessorDescriptor.correspondingProperty, accessorDescriptor, property)

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

@@ -675,8 +675,6 @@ public class DescriptorResolver {
                 annotationResolver.resolveAnnotationsWithArguments(scope, parameter.getModifierList(), trace),
                 KtPsiUtil.safeName(parameter.getName()),
                 approximatedType,
-                false,
-                false,
                 KotlinSourceElementKt.toSourceElement(parameter)
         );
         trace.record(BindingContext.VALUE_PARAMETER, parameter, variableDescriptor);

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

@@ -22,6 +22,7 @@ import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.descriptors.annotations.Annotations
 import org.jetbrains.kotlin.descriptors.impl.*
 import org.jetbrains.kotlin.diagnostics.Errors.*
+import org.jetbrains.kotlin.lexer.KtTokens
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.psi.KtProperty
 import org.jetbrains.kotlin.psi.KtPsiUtil
@@ -195,6 +196,7 @@ class LocalVariableResolver(
             trace: BindingTrace
     ): LocalVariableDescriptor {
         val hasDelegate = variable is KtProperty && variable.hasDelegate()
+        val hasLateinit = variable.hasModifier(KtTokens.LATEINIT_KEYWORD)
         val variableDescriptor = LocalVariableDescriptor(
                 scope.ownerDescriptor,
                 annotationResolver.resolveAnnotationsWithArguments(scope, variable.modifierList, trace),
@@ -207,6 +209,7 @@ class LocalVariableResolver(
                 type,
                 variable.isVar,
                 hasDelegate,
+                hasLateinit,
                 variable.toSourceElement()
         )
         trace.record(BindingContext.VARIABLE, variable, variableDescriptor)

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

@@ -275,6 +275,8 @@ class TypeResolver(
 
                     override fun isVar() = false
 
+                    override fun isLateInit() = false
+
                     override fun getCompileTimeInitializer() = null
 
                     override fun <R : Any?, D : Any?> accept(visitor: DeclarationDescriptorVisitor<R, D>, data: D): R {

compiler/frontend/src/org/jetbrains/kotlin/types/expressions/DoubleColonExpressionResolver.kt

@@ -592,8 +592,8 @@ class DoubleColonExpressionResolver(
 
     internal fun bindPropertyReference(expression: KtCallableReferenceExpression, referenceType: KotlinType, context: ResolutionContext<*>) {
         val localVariable = LocalVariableDescriptor(
-                context.scope.ownerDescriptor, Annotations.EMPTY, Name.special("<anonymous>"), referenceType, /* mutable = */ false,
+                context.scope.ownerDescriptor, Annotations.EMPTY, Name.special("<anonymous>"), referenceType,
-                /* isDelegated = */ false, expression.toSourceElement()
+                expression.toSourceElement()
         )
 
         context.trace.record(BindingContext.VARIABLE, expression, localVariable)

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/descriptors/SharedVariablesManager.kt

@@ -111,7 +111,7 @@ class JvmSharedVariablesManager(val builtIns: KotlinBuiltIns) : SharedVariablesM
             LocalVariableDescriptor(
                     variableDescriptor.containingDeclaration, variableDescriptor.annotations, variableDescriptor.name,
                     getSharedVariableType(variableDescriptor.type),
-                    false, false, variableDescriptor.source
+                    false, false, variableDescriptor.isLateInit, variableDescriptor.source
             )
 
     override fun defineSharedValue(sharedVariableDescriptor: VariableDescriptor, originalDeclaration: IrVariable): IrStatement {

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/descriptors/IrDelegateDescriptor.kt

@@ -136,6 +136,7 @@ class IrLocalDelegatedPropertyDelegateDescriptorImpl(
 
     override fun getCompileTimeInitializer(): ConstantValue<*>? = null
     override fun isVar(): Boolean = false
+    override fun isLateInit(): Boolean = false
     override fun substitute(substitutor: TypeSubstitutor): VariableDescriptor? = throw UnsupportedOperationException()
     override fun getVisibility(): Visibility = Visibilities.LOCAL
 

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/descriptors/IrTemporaryVariableDescriptor.kt

@@ -44,6 +44,8 @@ class IrTemporaryVariableDescriptorImpl(
 
     override fun isVar(): Boolean = isMutable
 
+    override fun isLateInit(): Boolean = false
+
     override fun <R, D> accept(visitor: DeclarationDescriptorVisitor<R, D>, data: D): R =
             visitor.visitVariableDescriptor(this, data)
 }

compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/util/FakeCallableDescriptorForObject.kt

@@ -67,6 +67,8 @@ open class FakeCallableDescriptorForObject(
 
     override fun isConst(): Boolean = false
 
+    override fun isLateInit(): Boolean = false
+
     override fun equals(other: Any?) = other is FakeCallableDescriptorForObject && classDescriptor == other.classDescriptor
 
     override fun hashCode() = classDescriptor.hashCode()

compiler/testData/diagnostics/tests/properties/localLateinit/uninitialized.kt

@@ -0,0 +1,22 @@
+fun test1() {
+    lateinit var s: String
+    s.length
+}
+
+fun test2() {
+    lateinit var s: String
+    run {
+        s = ""
+    }
+    s.length
+}
+
+fun almostAlwaysTrue(): Boolean = true
+
+fun test3() {
+    lateinit var s: String
+    if (almostAlwaysTrue()) {
+        s = ""
+    }
+    s.length
+}

compiler/testData/diagnostics/tests/properties/localLateinit/uninitialized.txt

@@ -0,0 +1,6 @@
+package
+
+public fun almostAlwaysTrue(): kotlin.Boolean
+public fun test1(): kotlin.Unit
+public fun test2(): kotlin.Unit
+public fun test3(): kotlin.Unit

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

@@ -16268,6 +16268,12 @@ public class DiagnosticsTestGenerated extends AbstractDiagnosticsTest {
                     String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/properties/localLateinit/localLateinit.kt");
                     doTest(fileName);
                 }
+
+                @TestMetadata("uninitialized.kt")
+                public void testUninitialized() throws Exception {
+                    String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/properties/localLateinit/uninitialized.kt");
+                    doTest(fileName);
+                }
             }
         }
 

core/descriptors/src/org/jetbrains/kotlin/descriptors/PropertyDescriptor.java

@@ -57,8 +57,6 @@ public interface PropertyDescriptor extends VariableDescriptorWithAccessors, Cal
     @Override
     PropertyDescriptor substitute(@NotNull TypeSubstitutor substitutor);
 
-    boolean isLateInit();
-
     @NotNull
     @Override
     CopyBuilder<? extends PropertyDescriptor> newCopyBuilder();

core/descriptors/src/org/jetbrains/kotlin/descriptors/ValueParameterDescriptor.kt

@@ -54,4 +54,6 @@ interface ValueParameterDescriptor : VariableDescriptor, ParameterDescriptor {
     val isCrossinline: Boolean
 
     val isNoinline: Boolean
+
+    override fun isLateInit(): Boolean = false
 }

core/descriptors/src/org/jetbrains/kotlin/descriptors/VariableDescriptor.java

@@ -36,4 +36,6 @@ public interface VariableDescriptor extends ValueDescriptor {
      * It completely does not means that if isConst then `getCompileTimeInitializer` is not null
      */
     boolean isConst();
+
+    boolean isLateInit();
 }

js/js.translator/src/org/jetbrains/kotlin/js/translate/context/TranslationContext.java

@@ -121,8 +121,6 @@ public class TranslationContext {
                         Annotations.Companion.getEMPTY(),
                         Name.identifier("continuation"),
                         continuationDescriptor.getDefaultType(),
-                        /* mutable = */ false,
-                        /* delegated = */ false,
                         SourceElement.NO_SOURCE);
             }
         }