001    /*
002     * Copyright 2010-2015 JetBrains s.r.o.
003     *
004     * Licensed under the Apache License, Version 2.0 (the "License");
005     * you may not use this file except in compliance with the License.
006     * You may obtain a copy of the License at
007     *
008     * http://www.apache.org/licenses/LICENSE-2.0
009     *
010     * Unless required by applicable law or agreed to in writing, software
011     * distributed under the License is distributed on an "AS IS" BASIS,
012     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013     * See the License for the specific language governing permissions and
014     * limitations under the License.
015     */
016    
017    package org.jetbrains.kotlin.resolve.jvm.kotlinSignature;
018    
019    import com.google.common.collect.Lists;
020    import com.google.common.collect.Multimap;
021    import com.google.common.collect.Sets;
022    import com.intellij.util.Function;
023    import com.intellij.util.containers.ContainerUtil;
024    import kotlin.KotlinPackage;
025    import kotlin.jvm.functions.Function1;
026    import org.jetbrains.annotations.NotNull;
027    import org.jetbrains.annotations.Nullable;
028    import org.jetbrains.kotlin.builtins.KotlinBuiltIns;
029    import org.jetbrains.kotlin.descriptors.*;
030    import org.jetbrains.kotlin.descriptors.annotations.Annotations;
031    import org.jetbrains.kotlin.descriptors.impl.TypeParameterDescriptorImpl;
032    import org.jetbrains.kotlin.descriptors.impl.ValueParameterDescriptorImpl;
033    import org.jetbrains.kotlin.incremental.components.NoLookupLocation;
034    import org.jetbrains.kotlin.load.java.components.TypeUsage;
035    import org.jetbrains.kotlin.load.java.descriptors.JavaMethodDescriptor;
036    import org.jetbrains.kotlin.load.java.structure.JavaMethod;
037    import org.jetbrains.kotlin.name.FqNameUnsafe;
038    import org.jetbrains.kotlin.name.Name;
039    import org.jetbrains.kotlin.platform.JavaToKotlinClassMap;
040    import org.jetbrains.kotlin.renderer.DescriptorRenderer;
041    import org.jetbrains.kotlin.resolve.DescriptorUtils;
042    import org.jetbrains.kotlin.resolve.jvm.JavaResolverUtils;
043    import org.jetbrains.kotlin.resolve.jvm.JvmPackage;
044    import org.jetbrains.kotlin.resolve.jvm.jvmSignature.JvmMethodSignature;
045    import org.jetbrains.kotlin.resolve.jvm.jvmSignature.JvmSignaturePackage;
046    import org.jetbrains.kotlin.resolve.jvm.jvmSignature.KotlinToJvmSignatureMapper;
047    import org.jetbrains.kotlin.resolve.scopes.JetScope;
048    import org.jetbrains.kotlin.types.*;
049    
050    import java.util.*;
051    
052    import static org.jetbrains.kotlin.load.java.components.TypeUsage.*;
053    import static org.jetbrains.kotlin.resolve.DescriptorUtils.getFqName;
054    import static org.jetbrains.kotlin.resolve.descriptorUtil.DescriptorUtilPackage.getBuiltIns;
055    import static org.jetbrains.kotlin.types.Variance.INVARIANT;
056    
057    public class SignaturesPropagationData {
058    
059        private static final KotlinToJvmSignatureMapper SIGNATURE_MAPPER = ServiceLoader.load(
060                KotlinToJvmSignatureMapper.class,
061                KotlinToJvmSignatureMapper.class.getClassLoader()
062        ).iterator().next();
063    
064        private final JavaMethodDescriptor autoMethodDescriptor;
065    
066        private final List<TypeParameterDescriptor> modifiedTypeParameters;
067        private final ValueParameters modifiedValueParameters;
068    
069        private final JetType modifiedReturnType;
070        private final List<String> signatureErrors = Lists.newArrayList();
071        private final List<FunctionDescriptor> superFunctions;
072        private final Map<TypeParameterDescriptor, TypeParameterDescriptorImpl> autoTypeParameterToModified;
073        final ClassDescriptor containingClass;
074    
075        public SignaturesPropagationData(
076                @NotNull ClassDescriptor containingClass,
077                @NotNull JetType autoReturnType, // type built by JavaTypeTransformer from Java signature and @NotNull annotations
078                @Nullable JetType receiverType,
079                @NotNull List<ValueParameterDescriptor> autoValueParameters, // descriptors built by parameters resolver
080                @NotNull List<TypeParameterDescriptor> autoTypeParameters, // descriptors built by signature resolver
081                @NotNull JavaMethod method
082        ) {
083            this.containingClass = containingClass;
084    
085            autoMethodDescriptor =
086                    createAutoMethodDescriptor(containingClass, method, autoReturnType, receiverType, autoValueParameters, autoTypeParameters);
087    
088            superFunctions = getSuperFunctionsForMethod(method, autoMethodDescriptor, containingClass);
089    
090            autoTypeParameterToModified = JavaResolverUtils.recreateTypeParametersAndReturnMapping(autoTypeParameters, null);
091    
092            modifiedTypeParameters = modifyTypeParametersAccordingToSuperMethods(autoTypeParameters);
093            modifiedReturnType = modifyReturnTypeAccordingToSuperMethods(autoReturnType);
094            modifiedValueParameters = modifyValueParametersAccordingToSuperMethods(receiverType, autoValueParameters);
095        }
096    
097        @NotNull
098        private static JavaMethodDescriptor createAutoMethodDescriptor(
099                @NotNull ClassDescriptor containingClass,
100                @NotNull JavaMethod method, JetType autoReturnType,
101                @Nullable JetType receiverType,
102                @NotNull List<ValueParameterDescriptor> autoValueParameters,
103                @NotNull List<TypeParameterDescriptor> autoTypeParameters
104        ) {
105            JavaMethodDescriptor autoMethodDescriptor = JavaMethodDescriptor.createJavaMethod(
106                    containingClass,
107                    Annotations.EMPTY,
108                    method.getName(),
109                    //TODO: what to do?
110                    SourceElement.NO_SOURCE
111            );
112            autoMethodDescriptor.initialize(
113                    receiverType,
114                    containingClass.getThisAsReceiverParameter(),
115                    autoTypeParameters,
116                    autoValueParameters,
117                    autoReturnType,
118                    Modality.OPEN,
119                    Visibilities.PUBLIC
120            );
121            return autoMethodDescriptor;
122        }
123    
124        public List<TypeParameterDescriptor> getModifiedTypeParameters() {
125            return modifiedTypeParameters;
126        }
127    
128        public JetType getModifiedReceiverType() {
129            return modifiedValueParameters.receiverType;
130        }
131    
132        public List<ValueParameterDescriptor> getModifiedValueParameters() {
133            return modifiedValueParameters.descriptors;
134        }
135    
136        public boolean getModifiedHasStableParameterNames() {
137            return modifiedValueParameters.hasStableParameterNames;
138        }
139    
140        public JetType getModifiedReturnType() {
141            return modifiedReturnType;
142        }
143    
144        public List<String> getSignatureErrors() {
145            return signatureErrors;
146        }
147    
148        public List<FunctionDescriptor> getSuperFunctions() {
149            return superFunctions;
150        }
151    
152        void reportError(String error) {
153            signatureErrors.add(error);
154        }
155    
156        private JetType modifyReturnTypeAccordingToSuperMethods(
157                @NotNull JetType autoType // type built by JavaTypeTransformer
158        ) {
159            if (JvmPackage.getPLATFORM_TYPES()) return autoType;
160    
161            List<TypeAndVariance> typesFromSuperMethods = ContainerUtil.map(superFunctions,
162                                                                            new Function<FunctionDescriptor, TypeAndVariance>() {
163                                                                                @Override
164                                                                                public TypeAndVariance fun(FunctionDescriptor superFunction) {
165                                                                                    return new TypeAndVariance(superFunction.getReturnType(),
166                                                                                                               Variance.OUT_VARIANCE);
167                                                                                }
168                                                                            });
169    
170            return modifyTypeAccordingToSuperMethods(autoType, typesFromSuperMethods, MEMBER_SIGNATURE_COVARIANT);
171        }
172    
173        private List<TypeParameterDescriptor> modifyTypeParametersAccordingToSuperMethods(List<TypeParameterDescriptor> autoTypeParameters) {
174            if (JvmPackage.getPLATFORM_TYPES()) return autoTypeParameters;
175    
176            List<TypeParameterDescriptor> result = Lists.newArrayList();
177    
178            for (TypeParameterDescriptor autoParameter : autoTypeParameters) {
179                int index = autoParameter.getIndex();
180                TypeParameterDescriptorImpl modifiedTypeParameter = autoTypeParameterToModified.get(autoParameter);
181    
182                List<Iterator<JetType>> upperBoundFromSuperFunctionsIterators = Lists.newArrayList();
183                for (FunctionDescriptor superFunction : superFunctions) {
184                    upperBoundFromSuperFunctionsIterators.add(superFunction.getTypeParameters().get(index).getUpperBounds().iterator());
185                }
186    
187                for (JetType autoUpperBound : autoParameter.getUpperBounds()) {
188                    List<TypeAndVariance> upperBoundsFromSuperFunctions = Lists.newArrayList();
189    
190                    for (Iterator<JetType> iterator : upperBoundFromSuperFunctionsIterators) {
191                        assert iterator.hasNext();
192                        upperBoundsFromSuperFunctions.add(new TypeAndVariance(iterator.next(), INVARIANT));
193                    }
194    
195                    JetType modifiedUpperBound = modifyTypeAccordingToSuperMethods(autoUpperBound, upperBoundsFromSuperFunctions, UPPER_BOUND);
196                    modifiedTypeParameter.addUpperBound(modifiedUpperBound);
197                }
198    
199                for (Iterator<JetType> iterator : upperBoundFromSuperFunctionsIterators) {
200                    assert !iterator.hasNext();
201                }
202    
203                modifiedTypeParameter.setInitialized();
204                result.add(modifiedTypeParameter);
205            }
206    
207            return result;
208        }
209    
210        private ValueParameters modifyValueParametersAccordingToSuperMethods(
211                @Nullable JetType receiverType,
212                @NotNull List<ValueParameterDescriptor> parameters // descriptors built by parameters resolver
213        ) {
214            assert receiverType == null : "Parameters before propagation have receiver type," +
215                                          " but propagation should be disabled for functions compiled from Kotlin in class: " +
216                                          DescriptorUtils.getFqName(containingClass);
217    
218            JetType resultReceiverType = null;
219            List<ValueParameterDescriptor> resultParameters = new ArrayList<ValueParameterDescriptor>(parameters.size());
220    
221            boolean shouldBeExtension = checkIfShouldBeExtension();
222    
223            for (final ValueParameterDescriptor originalParam : parameters) {
224                final int originalIndex = originalParam.getIndex();
225                List<TypeAndName> typesFromSuperMethods = ContainerUtil.map(superFunctions,
226                        new Function<FunctionDescriptor, TypeAndName>() {
227                            @Override
228                            public TypeAndName fun(FunctionDescriptor superFunction) {
229                                ReceiverParameterDescriptor receiver = superFunction.getExtensionReceiverParameter();
230                                int index = receiver != null ? originalIndex - 1 : originalIndex;
231                                if (index == -1) {
232                                    assert receiver != null : "can't happen: index is -1, while function is not extension";
233                                    return new TypeAndName(receiver.getType(), originalParam.getName());
234                                }
235                                ValueParameterDescriptor parameter = superFunction.getValueParameters().get(index);
236                                return new TypeAndName(parameter.getType(), parameter.getName());
237                            }
238                        });
239    
240                VarargCheckResult varargCheckResult = checkVarargInSuperFunctions(originalParam);
241    
242                JetType altType = modifyTypeAccordingToSuperMethods(varargCheckResult.parameterType,
243                                                                    convertToTypeVarianceList(typesFromSuperMethods),
244                                                                    MEMBER_SIGNATURE_CONTRAVARIANT);
245    
246                if (shouldBeExtension && originalIndex == 0) {
247                    resultReceiverType = altType;
248                }
249                else {
250                    Name stableName = null;
251                    for (int i = 0; i < superFunctions.size(); i++) {
252                        if (superFunctions.get(i).hasStableParameterNames()) {
253                            // When there's more than one stable name in super functions, we pick the first one. This behaviour is similar to
254                            // the compiler front-end, except that it reports a warning in such cases
255                            // TODO: report a warning somewhere if there's more than one stable name in super functions
256                            stableName = typesFromSuperMethods.get(i).name;
257                            break;
258                        }
259                    }
260    
261                    resultParameters.add(new ValueParameterDescriptorImpl(
262                            originalParam.getContainingDeclaration(),
263                            null,
264                            shouldBeExtension ? originalIndex - 1 : originalIndex,
265                            originalParam.getAnnotations(),
266                            stableName != null ? stableName : originalParam.getName(),
267                            altType,
268                            originalParam.declaresDefaultValue(),
269                            varargCheckResult.isVararg ? getBuiltIns(originalParam).getArrayElementType(altType) : null,
270                            SourceElement.NO_SOURCE
271                    ));
272                }
273            }
274    
275            boolean hasStableParameterNames = KotlinPackage.any(superFunctions, new Function1<FunctionDescriptor, Boolean>() {
276                @Override
277                public Boolean invoke(FunctionDescriptor descriptor) {
278                    return descriptor.hasStableParameterNames();
279                }
280            });
281    
282            return new ValueParameters(resultReceiverType, resultParameters, hasStableParameterNames);
283        }
284    
285        @NotNull
286        private static List<TypeAndVariance> convertToTypeVarianceList(@NotNull List<TypeAndName> list) {
287            return KotlinPackage.map(list, new Function1<TypeAndName, TypeAndVariance>() {
288                @Override
289                public TypeAndVariance invoke(TypeAndName tvn) {
290                    return new TypeAndVariance(tvn.type, INVARIANT);
291                }
292            });
293        }
294    
295        private static List<FunctionDescriptor> getSuperFunctionsForMethod(
296                @NotNull JavaMethod method,
297                @NotNull JavaMethodDescriptor autoMethodDescriptor,
298                @NotNull ClassDescriptor containingClass
299        ) {
300            List<FunctionDescriptor> superFunctions = Lists.newArrayList();
301    
302            // TODO: Add propagation for other kotlin descriptors (KT-3621)
303            Name name = method.getName();
304            JvmMethodSignature autoSignature = SIGNATURE_MAPPER.mapToJvmMethodSignature(autoMethodDescriptor);
305            for (JetType supertype : containingClass.getTypeConstructor().getSupertypes()) {
306                Collection<FunctionDescriptor> superFunctionCandidates = supertype.getMemberScope().getFunctions(name, NoLookupLocation.WHEN_GET_SUPER_MEMBERS);
307                for (FunctionDescriptor candidate : superFunctionCandidates) {
308                    JvmMethodSignature candidateSignature = SIGNATURE_MAPPER.mapToJvmMethodSignature(candidate);
309                    if (JvmSignaturePackage.erasedSignaturesEqualIgnoringReturnTypes(autoSignature, candidateSignature)) {
310                        superFunctions.add(candidate);
311                    }
312                }
313            }
314    
315            // sorting for diagnostic stability
316            Collections.sort(superFunctions, new Comparator<FunctionDescriptor>() {
317                @Override
318                public int compare(@NotNull FunctionDescriptor fun1, @NotNull FunctionDescriptor fun2) {
319                    FqNameUnsafe fqName1 = getFqName(fun1.getContainingDeclaration());
320                    FqNameUnsafe fqName2 = getFqName(fun2.getContainingDeclaration());
321                    return fqName1.asString().compareTo(fqName2.asString());
322                }
323            });
324            return superFunctions;
325        }
326    
327        private boolean checkIfShouldBeExtension() {
328            boolean someSupersExtension = false;
329            boolean someSupersNotExtension = false;
330    
331            for (FunctionDescriptor superFunction : superFunctions) {
332                if (superFunction.getExtensionReceiverParameter() != null)  {
333                    someSupersExtension = true;
334                }
335                else {
336                    someSupersNotExtension = true;
337                }
338            }
339    
340            if (someSupersExtension) {
341                if (someSupersNotExtension) {
342                    reportError("Incompatible super methods: some are extension functions, some are not");
343                }
344                else {
345                    return true;
346                }
347            }
348            return false;
349        }
350    
351        @NotNull
352        private VarargCheckResult checkVarargInSuperFunctions(@NotNull ValueParameterDescriptor originalParam) {
353            boolean someSupersVararg = false;
354            boolean someSupersNotVararg = false;
355            for (FunctionDescriptor superFunction : superFunctions) {
356                int originalIndex = originalParam.getIndex();
357                int index = superFunction.getExtensionReceiverParameter() != null ? originalIndex - 1 : originalIndex;
358                if (index != -1 && superFunction.getValueParameters().get(index).getVarargElementType() != null) {
359                    someSupersVararg = true;
360                }
361                else {
362                    someSupersNotVararg = true;
363                }
364            }
365    
366            JetType originalVarargElementType = originalParam.getVarargElementType();
367            JetType originalType = originalParam.getType();
368    
369            if (someSupersVararg && someSupersNotVararg) {
370                reportError("Incompatible super methods: some have vararg parameter, some have not");
371                return new VarargCheckResult(originalType, originalVarargElementType != null);
372            }
373    
374            if (someSupersVararg && originalVarargElementType == null) {
375                // convert to vararg
376    
377                assert isArrayType(originalType);
378                return new VarargCheckResult(TypeUtils.makeNotNullable(originalType), true);
379            }
380            else if (someSupersNotVararg && originalVarargElementType != null) {
381                // convert to non-vararg
382    
383                assert isArrayType(originalType);
384                return new VarargCheckResult(TypeUtils.makeNullable(originalType), false);
385            }
386            return new VarargCheckResult(originalType, originalVarargElementType != null);
387        }
388    
389        @NotNull
390        private JetType modifyTypeAccordingToSuperMethods(
391                @NotNull JetType autoType,
392                @NotNull List<TypeAndVariance> typesFromSuper,
393                @NotNull TypeUsage howThisTypeIsUsed
394        ) {
395            if (autoType.isError()) return autoType;
396    
397            if (JvmPackage.getPLATFORM_TYPES()) return autoType;
398    
399            boolean resultNullable = typeMustBeNullable(autoType, typesFromSuper, howThisTypeIsUsed);
400            ClassifierDescriptor resultClassifier = modifyTypeClassifier(autoType, typesFromSuper);
401            List<TypeProjection> resultArguments = getTypeArgsOfType(autoType, resultClassifier, typesFromSuper);
402            JetScope resultScope;
403            if (resultClassifier instanceof ClassDescriptor) {
404                resultScope = ((ClassDescriptor) resultClassifier).getMemberScope(resultArguments);
405            }
406            else {
407                resultScope = autoType.getMemberScope();
408            }
409    
410            JetType type = JetTypeImpl.create(autoType.getAnnotations(),
411                                               resultClassifier.getTypeConstructor(),
412                                               resultNullable,
413                                               resultArguments,
414                                               resultScope);
415    
416            PropagationHeuristics.checkArrayInReturnType(this, type, typesFromSuper);
417            return type;
418        }
419    
420        @NotNull
421        private List<TypeProjection> getTypeArgsOfType(
422                @NotNull JetType autoType,
423                @NotNull ClassifierDescriptor classifier,
424                @NotNull List<TypeAndVariance> typesFromSuper
425        ) {
426            if (typesFromSuper.isEmpty()) return autoType.getArguments();
427    
428            List<TypeProjection> autoArguments = autoType.getArguments();
429    
430            if (!(classifier instanceof ClassDescriptor)) {
431                assert autoArguments.isEmpty() :
432                        "Unexpected type arguments when type constructor is not ClassDescriptor, type = " + autoType +
433                        ", classifier = " + classifier + ", classifier class = " + classifier.getClass();
434                return autoArguments;
435            }
436    
437            List<List<TypeProjectionAndVariance>> typeArgumentsFromSuper = calculateTypeArgumentsFromSuper((ClassDescriptor) classifier,
438                                                                                                           typesFromSuper);
439    
440            // Modify type arguments using info from typesFromSuper
441            List<TypeProjection> resultArguments = Lists.newArrayList();
442            for (TypeParameterDescriptor parameter : classifier.getTypeConstructor().getParameters()) {
443                TypeProjection argument = autoArguments.get(parameter.getIndex());
444    
445                JetType argumentType = argument.getType();
446                List<TypeProjectionAndVariance> projectionsFromSuper = typeArgumentsFromSuper.get(parameter.getIndex());
447                List<TypeAndVariance> argTypesFromSuper = getTypes(projectionsFromSuper);
448    
449                JetType type = modifyTypeAccordingToSuperMethods(argumentType, argTypesFromSuper, TYPE_ARGUMENT);
450                Variance projectionKind = calculateArgumentProjectionKindFromSuper(argument, projectionsFromSuper);
451    
452                resultArguments.add(new TypeProjectionImpl(projectionKind, type));
453            }
454            return resultArguments;
455        }
456    
457        private Variance calculateArgumentProjectionKindFromSuper(
458                @NotNull TypeProjection argument,
459                @NotNull List<TypeProjectionAndVariance> projectionsFromSuper
460        ) {
461            if (projectionsFromSuper.isEmpty()) return argument.getProjectionKind();
462    
463            Set<Variance> projectionKindsInSuper = Sets.newLinkedHashSet();
464            for (TypeProjectionAndVariance projectionAndVariance : projectionsFromSuper) {
465                projectionKindsInSuper.add(projectionAndVariance.typeProjection.getProjectionKind());
466            }
467    
468            Variance defaultProjectionKind = argument.getProjectionKind();
469            if (projectionKindsInSuper.size() == 0) {
470                return defaultProjectionKind;
471            }
472            else if (projectionKindsInSuper.size() == 1) {
473                Variance projectionKindInSuper = projectionKindsInSuper.iterator().next();
474                if (defaultProjectionKind == INVARIANT || defaultProjectionKind == projectionKindInSuper) {
475                    return projectionKindInSuper;
476                }
477                else {
478                    reportError("Incompatible projection kinds in type arguments of super methods' return types: "
479                                + projectionsFromSuper + ", defined in current: " + argument);
480                    return defaultProjectionKind;
481                }
482            }
483            else {
484                reportError("Incompatible projection kinds in type arguments of super methods' return types: " + projectionsFromSuper);
485                return defaultProjectionKind;
486            }
487        }
488    
489        @NotNull
490        private static List<TypeAndVariance> getTypes(@NotNull List<TypeProjectionAndVariance> projections) {
491            List<TypeAndVariance> types = Lists.newArrayList();
492            for (TypeProjectionAndVariance projection : projections) {
493                types.add(new TypeAndVariance(projection.typeProjection.getType(),
494                                              merge(projection.varianceOfPosition, projection.typeProjection.getProjectionKind())));
495            }
496            return types;
497        }
498    
499        private static Variance merge(Variance positionOfOuter, Variance projectionKind) {
500            // Inv<Inv<out X>>, X is in invariant position
501            if (positionOfOuter == INVARIANT) return INVARIANT;
502            // Out<X>, X is in out-position
503            if (projectionKind == INVARIANT) return positionOfOuter;
504            // Out<Out<X>>, X is in out-position
505            // In<In<X>>, X is in out-position
506            // Out<In<X>>, X is in in-position
507            // In<Out<X>>, X is in in-position
508            return positionOfOuter.superpose(projectionKind);
509        }
510    
511        // Returns list with type arguments info from supertypes
512        // Example:
513        //     - Foo<A, B> is a subtype of Bar<A, List<B>>, Baz<Boolean, A>
514        //     - input: klass = Foo, typesFromSuper = [Bar<String, List<Int>>, Baz<Boolean, CharSequence>]
515        //     - output[0] = [String, CharSequence], output[1] = []
516        private static List<List<TypeProjectionAndVariance>> calculateTypeArgumentsFromSuper(
517                @NotNull ClassDescriptor klass,
518                @NotNull Collection<TypeAndVariance> typesFromSuper
519        ) {
520            // For each superclass of klass and its parameters, hold their mapping to klass' parameters
521            // #0 of Bar ->  A
522            // #1 of Bar ->  List<B>
523            // #0 of Baz ->  Boolean
524            // #1 of Baz ->  A
525            // #0 of Foo ->  A (mapped to itself)
526            // #1 of Foo ->  B (mapped to itself)
527            Multimap<TypeConstructor, TypeProjection> substitution = SubstitutionUtils.buildDeepSubstitutionMultimap(
528                    TypeUtils.makeUnsubstitutedType(klass, ErrorUtils.createErrorScope("Do not access this scope", true)));
529    
530            // for each parameter of klass, hold arguments in corresponding supertypes
531            List<List<TypeProjectionAndVariance>> parameterToArgumentsFromSuper = Lists.newArrayList();
532            for (TypeParameterDescriptor ignored : klass.getTypeConstructor().getParameters()) {
533                parameterToArgumentsFromSuper.add(new ArrayList<TypeProjectionAndVariance>());
534            }
535    
536            // Enumerate all types from super and all its parameters
537            for (TypeAndVariance typeFromSuper : typesFromSuper) {
538                for (TypeParameterDescriptor parameter : typeFromSuper.type.getConstructor().getParameters()) {
539                    TypeProjection argument = typeFromSuper.type.getArguments().get(parameter.getIndex());
540    
541                    // for given example, this block is executed four times:
542                    // 1. typeFromSuper = Bar<String, List<Int>>,      parameter = "#0 of Bar",  argument = String
543                    // 2. typeFromSuper = Bar<String, List<Int>>,      parameter = "#1 of Bar",  argument = List<Int>
544                    // 3. typeFromSuper = Baz<Boolean, CharSequence>,  parameter = "#0 of Baz",  argument = Boolean
545                    // 4. typeFromSuper = Baz<Boolean, CharSequence>,  parameter = "#1 of Baz",  argument = CharSequence
546    
547                    // if it is mapped to klass' parameter, then store it into map
548                    for (TypeProjection projection : substitution.get(parameter.getTypeConstructor())) {
549                        // 1. projection = A
550                        // 2. projection = List<B>
551                        // 3. projection = Boolean
552                        // 4. projection = A
553                        ClassifierDescriptor classifier = projection.getType().getConstructor().getDeclarationDescriptor();
554    
555                        // this condition is true for 1 and 4, false for 2 and 3
556                        if (classifier instanceof TypeParameterDescriptor && classifier.getContainingDeclaration() == klass) {
557                            int parameterIndex = ((TypeParameterDescriptor) classifier).getIndex();
558                            Variance effectiveVariance = parameter.getVariance().superpose(typeFromSuper.varianceOfPosition);
559                            parameterToArgumentsFromSuper.get(parameterIndex).add(new TypeProjectionAndVariance(argument, effectiveVariance));
560                        }
561                    }
562                }
563            }
564            return parameterToArgumentsFromSuper;
565        }
566    
567        private boolean typeMustBeNullable(
568                @NotNull JetType autoType,
569                @NotNull List<TypeAndVariance> typesFromSuper,
570                @NotNull TypeUsage howThisTypeIsUsed
571        ) {
572            boolean someSupersNotCovariantNullable = false;
573            boolean someSupersCovariantNullable = false;
574            boolean someSupersNotNull = false;
575            for (TypeAndVariance typeFromSuper : typesFromSuper) {
576                if (!TypeUtils.isNullableType(typeFromSuper.type)) {
577                    someSupersNotNull = true;
578                }
579                else {
580                    if (typeFromSuper.varianceOfPosition == Variance.OUT_VARIANCE) {
581                        someSupersCovariantNullable = true;
582                    }
583                    else {
584                        someSupersNotCovariantNullable = true;
585                    }
586                }
587            }
588    
589            if (someSupersNotNull && someSupersNotCovariantNullable) {
590                reportError("Incompatible types in superclasses: " + typesFromSuper);
591                return TypeUtils.isNullableType(autoType);
592            }
593            else if (someSupersNotNull) {
594                return false;
595            }
596            else if (someSupersNotCovariantNullable || someSupersCovariantNullable) {
597                boolean annotatedAsNotNull = howThisTypeIsUsed != TYPE_ARGUMENT && !TypeUtils.isNullableType(autoType);
598    
599                if (annotatedAsNotNull && someSupersNotCovariantNullable) {
600                    DescriptorRenderer renderer = DescriptorRenderer.SHORT_NAMES_IN_TYPES;
601                    reportError("In superclass type is nullable: " + typesFromSuper + ", in subclass it is not: " + renderer.renderType(autoType));
602                    return true;
603                }
604    
605                return !annotatedAsNotNull;
606            }
607            return TypeUtils.isNullableType(autoType);
608        }
609    
610        @NotNull
611        private ClassifierDescriptor modifyTypeClassifier(
612                @NotNull JetType autoType,
613                @NotNull List<TypeAndVariance> typesFromSuper
614        ) {
615            ClassifierDescriptor classifier = autoType.getConstructor().getDeclarationDescriptor();
616            if (!(classifier instanceof ClassDescriptor)) {
617                assert classifier != null : "no declaration descriptor for type " + autoType + ", auto method descriptor: " + autoMethodDescriptor;
618    
619                if (classifier instanceof TypeParameterDescriptor && autoTypeParameterToModified.containsKey(classifier)) {
620                    return autoTypeParameterToModified.get(classifier);
621                }
622                return classifier;
623            }
624            ClassDescriptor klass = (ClassDescriptor) classifier;
625    
626            boolean someSupersMutable = false;
627            boolean someSupersCovariantReadOnly = false;
628            boolean someSupersNotCovariantReadOnly = false;
629            for (TypeAndVariance typeFromSuper : typesFromSuper) {
630                ClassifierDescriptor classifierFromSuper = typeFromSuper.type.getConstructor().getDeclarationDescriptor();
631                if (classifierFromSuper instanceof ClassDescriptor) {
632                    ClassDescriptor classFromSuper = (ClassDescriptor) classifierFromSuper;
633    
634                    if (JavaToKotlinClassMap.INSTANCE.isMutable(classFromSuper)) {
635                        someSupersMutable = true;
636                    }
637                    else if (JavaToKotlinClassMap.INSTANCE.isReadOnly(classFromSuper)) {
638                        if (typeFromSuper.varianceOfPosition == Variance.OUT_VARIANCE) {
639                            someSupersCovariantReadOnly = true;
640                        }
641                        else {
642                            someSupersNotCovariantReadOnly = true;
643                        }
644                    }
645                }
646            }
647    
648            if (someSupersMutable && someSupersNotCovariantReadOnly) {
649                reportError("Incompatible types in superclasses: " + typesFromSuper);
650                return classifier;
651            }
652            else if (someSupersMutable) {
653                if (JavaToKotlinClassMap.INSTANCE.isReadOnly(klass)) {
654                    return JavaToKotlinClassMap.INSTANCE.convertReadOnlyToMutable(klass);
655                }
656            }
657            else if (someSupersNotCovariantReadOnly || someSupersCovariantReadOnly) {
658                if (JavaToKotlinClassMap.INSTANCE.isMutable(klass)) {
659                    return JavaToKotlinClassMap.INSTANCE.convertMutableToReadOnly(klass);
660                }
661            }
662    
663            ClassifierDescriptor fixed = PropagationHeuristics.tryToFixOverridingTWithRawType(this, typesFromSuper);
664            return fixed != null ? fixed : classifier;
665        }
666    
667        private static boolean isArrayType(@NotNull JetType type) {
668            return KotlinBuiltIns.isArray(type) || KotlinBuiltIns.isPrimitiveArray(type);
669        }
670    
671        private static class VarargCheckResult {
672            public final JetType parameterType;
673            public final boolean isVararg;
674    
675            public VarargCheckResult(JetType parameterType, boolean isVararg) {
676                this.parameterType = parameterType;
677                this.isVararg = isVararg;
678            }
679        }
680    
681        private static class TypeProjectionAndVariance {
682            public final TypeProjection typeProjection;
683            public final Variance varianceOfPosition;
684    
685            public TypeProjectionAndVariance(TypeProjection typeProjection, Variance varianceOfPosition) {
686                this.typeProjection = typeProjection;
687                this.varianceOfPosition = varianceOfPosition;
688            }
689    
690            public String toString() {
691                return typeProjection.toString();
692            }
693        }
694    
695        static class TypeAndVariance {
696            public final JetType type;
697            public final Variance varianceOfPosition;
698    
699            public TypeAndVariance(JetType type, Variance varianceOfPosition) {
700                this.type = type;
701                this.varianceOfPosition = varianceOfPosition;
702            }
703    
704            public String toString() {
705                return type.toString();
706            }
707        }
708    
709        private static class TypeAndName {
710            public final JetType type;
711            public final Name name;
712    
713            public TypeAndName(JetType type, Name name) {
714                this.type = type;
715                this.name = name;
716            }
717        }
718    
719        private static class ValueParameters {
720            private final JetType receiverType;
721            private final List<ValueParameterDescriptor> descriptors;
722            private final boolean hasStableParameterNames;
723    
724            public ValueParameters(
725                    @Nullable JetType receiverType,
726                    @NotNull List<ValueParameterDescriptor> descriptors,
727                    boolean hasStableParameterNames
728            ) {
729                this.receiverType = receiverType;
730                this.descriptors = descriptors;
731                this.hasStableParameterNames = hasStableParameterNames;
732            }
733        }
734    }