001    /*
002     * Copyright 2010-2013 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.jet.lang.types.expressions;
018    
019    import com.google.common.collect.Lists;
020    import com.intellij.psi.PsiElement;
021    import com.intellij.psi.tree.IElementType;
022    import com.intellij.psi.tree.TokenSet;
023    import org.jetbrains.annotations.NotNull;
024    import org.jetbrains.annotations.Nullable;
025    import org.jetbrains.jet.JetNodeTypes;
026    import org.jetbrains.jet.lang.PlatformToKotlinClassMap;
027    import org.jetbrains.jet.lang.descriptors.*;
028    import org.jetbrains.jet.lang.descriptors.annotations.AnnotationDescriptor;
029    import org.jetbrains.jet.lang.descriptors.impl.AnonymousFunctionDescriptor;
030    import org.jetbrains.jet.lang.diagnostics.Errors;
031    import org.jetbrains.jet.lang.psi.*;
032    import org.jetbrains.jet.lang.resolve.*;
033    import org.jetbrains.jet.lang.resolve.calls.CallExpressionResolver;
034    import org.jetbrains.jet.lang.resolve.calls.autocasts.DataFlowInfo;
035    import org.jetbrains.jet.lang.resolve.calls.autocasts.DataFlowValue;
036    import org.jetbrains.jet.lang.resolve.calls.autocasts.DataFlowValueFactory;
037    import org.jetbrains.jet.lang.resolve.calls.autocasts.Nullability;
038    import org.jetbrains.jet.lang.resolve.calls.context.CheckValueArgumentsMode;
039    import org.jetbrains.jet.lang.resolve.calls.context.ExpressionPosition;
040    import org.jetbrains.jet.lang.resolve.calls.context.TemporaryTraceAndCache;
041    import org.jetbrains.jet.lang.resolve.calls.model.ResolvedCall;
042    import org.jetbrains.jet.lang.resolve.calls.model.ResolvedCallWithTrace;
043    import org.jetbrains.jet.lang.resolve.calls.model.VariableAsFunctionResolvedCall;
044    import org.jetbrains.jet.lang.resolve.calls.results.OverloadResolutionResults;
045    import org.jetbrains.jet.lang.resolve.calls.results.OverloadResolutionResultsImpl;
046    import org.jetbrains.jet.lang.resolve.calls.results.OverloadResolutionResultsUtil;
047    import org.jetbrains.jet.lang.resolve.calls.util.CallMaker;
048    import org.jetbrains.jet.lang.resolve.constants.*;
049    import org.jetbrains.jet.lang.resolve.constants.StringValue;
050    import org.jetbrains.jet.lang.resolve.name.LabelName;
051    import org.jetbrains.jet.lang.resolve.name.Name;
052    import org.jetbrains.jet.lang.resolve.scopes.JetScope;
053    import org.jetbrains.jet.lang.resolve.scopes.WritableScopeImpl;
054    import org.jetbrains.jet.lang.resolve.scopes.receivers.ExpressionReceiver;
055    import org.jetbrains.jet.lang.resolve.scopes.receivers.ReceiverValue;
056    import org.jetbrains.jet.lang.resolve.scopes.receivers.TransientReceiver;
057    import org.jetbrains.jet.lang.types.*;
058    import org.jetbrains.jet.lang.types.checker.JetTypeChecker;
059    import org.jetbrains.jet.lang.types.lang.KotlinBuiltIns;
060    import org.jetbrains.jet.lexer.JetTokens;
061    import org.jetbrains.jet.utils.ThrowingList;
062    
063    import java.util.Collection;
064    import java.util.Collections;
065    import java.util.List;
066    
067    import static org.jetbrains.jet.lang.descriptors.ReceiverParameterDescriptor.NO_RECEIVER_PARAMETER;
068    import static org.jetbrains.jet.lang.diagnostics.Errors.*;
069    import static org.jetbrains.jet.lang.resolve.BindingContext.*;
070    import static org.jetbrains.jet.lang.resolve.DescriptorUtils.getStaticNestedClassesScope;
071    import static org.jetbrains.jet.lang.resolve.calls.context.ContextDependency.DEPENDENT;
072    import static org.jetbrains.jet.lang.resolve.calls.context.ContextDependency.INDEPENDENT;
073    import static org.jetbrains.jet.lang.resolve.constants.CompileTimeConstantResolver.ErrorValueWithDiagnostic;
074    import static org.jetbrains.jet.lang.resolve.scopes.receivers.ReceiverValue.NO_RECEIVER;
075    import static org.jetbrains.jet.lang.types.TypeUtils.NO_EXPECTED_TYPE;
076    import static org.jetbrains.jet.lang.types.TypeUtils.noExpectedType;
077    import static org.jetbrains.jet.lang.types.expressions.ControlStructureTypingUtils.createCallForSpecialConstruction;
078    import static org.jetbrains.jet.lang.types.expressions.ControlStructureTypingUtils.resolveSpecialConstructionAsCall;
079    import static org.jetbrains.jet.lang.types.expressions.ExpressionTypingUtils.*;
080    import static org.jetbrains.jet.lang.types.expressions.TypeReconstructionUtil.reconstructBareType;
081    import static org.jetbrains.jet.lexer.JetTokens.AS_KEYWORD;
082    import static org.jetbrains.jet.lexer.JetTokens.AS_SAFE;
083    
084    @SuppressWarnings("SuspiciousMethodCalls")
085    public class BasicExpressionTypingVisitor extends ExpressionTypingVisitor {
086    
087        private static final TokenSet BARE_TYPES_ALLOWED = TokenSet.create(AS_KEYWORD, AS_SAFE);
088    
089        private final PlatformToKotlinClassMap platformToKotlinClassMap;
090    
091        protected BasicExpressionTypingVisitor(@NotNull ExpressionTypingInternals facade, @NotNull PlatformToKotlinClassMap platformToKotlinClassMap) {
092            super(facade);
093            this.platformToKotlinClassMap = platformToKotlinClassMap;
094        }
095    
096        @Override
097        public JetTypeInfo visitSimpleNameExpression(@NotNull JetSimpleNameExpression expression, ExpressionTypingContext context) {
098            // TODO : other members
099            // TODO : type substitutions???
100            CallExpressionResolver callExpressionResolver = context.expressionTypingServices.getCallExpressionResolver();
101            JetTypeInfo typeInfo = callExpressionResolver.getSimpleNameExpressionTypeInfo(expression, NO_RECEIVER, null, context);
102            JetType type = DataFlowUtils.checkType(typeInfo.getType(), expression, context);
103            ExpressionTypingUtils.checkCapturingInClosure(expression, context.trace, context.scope);
104            return JetTypeInfo.create(type, typeInfo.getDataFlowInfo()); // TODO : Extensions to this
105        }
106    
107        @Override
108        public JetTypeInfo visitParenthesizedExpression(@NotNull JetParenthesizedExpression expression, ExpressionTypingContext context) {
109            return visitParenthesizedExpression(expression, context, false);
110        }
111    
112        public JetTypeInfo visitParenthesizedExpression(JetParenthesizedExpression expression, ExpressionTypingContext context, boolean isStatement) {
113            JetExpression innerExpression = expression.getExpression();
114            if (innerExpression == null) {
115                return JetTypeInfo.create(null, context.dataFlowInfo);
116            }
117            return facade.getTypeInfo(innerExpression, context.replaceScope(context.scope), isStatement);
118        }
119    
120        private static JetTypeInfo createNumberValueTypeInfo(
121                @NotNull NumberValueTypeConstructor numberValueTypeConstructor,
122                @NotNull Number value,
123                @NotNull DataFlowInfo dataFlowInfo
124        ) {
125            return JetTypeInfo.create(new JetTypeImpl(
126                    Collections.<AnnotationDescriptor>emptyList(), numberValueTypeConstructor,
127                    false, Collections.<TypeProjection>emptyList(),
128                    ErrorUtils.createErrorScope("Scope for number value type (" + value + ")", true)), dataFlowInfo);
129        }
130    
131        @Override
132        public JetTypeInfo visitConstantExpression(@NotNull JetConstantExpression expression, ExpressionTypingContext context) {
133            IElementType elementType = expression.getNode().getElementType();
134            String text = expression.getNode().getText();
135            KotlinBuiltIns builtIns = KotlinBuiltIns.getInstance();
136            CompileTimeConstantResolver compileTimeConstantResolver = context.getCompileTimeConstantResolver();
137    
138            if (noExpectedType(context.expectedType) && context.contextDependency == DEPENDENT) {
139                if (elementType == JetNodeTypes.INTEGER_CONSTANT) {
140                    Long longValue = CompileTimeConstantResolver.parseLongValue(text);
141                    if (longValue != null) {
142                        return createNumberValueTypeInfo(new IntegerValueTypeConstructor((long) longValue), longValue, context.dataFlowInfo);
143                    }
144                }
145                else if (elementType == JetNodeTypes.FLOAT_CONSTANT) {
146                    Double doubleValue = CompileTimeConstantResolver.parseDoubleValue(text);
147                    if (doubleValue != null) {
148                        return createNumberValueTypeInfo(new DoubleValueTypeConstructor(doubleValue), doubleValue, context.dataFlowInfo);
149                    }
150                }
151            }
152    
153            CompileTimeConstant<?> value = compileTimeConstantResolver.getCompileTimeConstant(expression, context.expectedType);
154            if (value instanceof ErrorValue) {
155                assert value instanceof ErrorValueWithDiagnostic;
156                //noinspection CastConflictsWithInstanceof
157                context.trace.report(((ErrorValueWithDiagnostic)value).getDiagnostic());
158                return JetTypeInfo.create(getDefaultType(elementType), context.dataFlowInfo);
159            }
160            context.trace.record(BindingContext.COMPILE_TIME_VALUE, expression, value);
161            return DataFlowUtils.checkType(value.getType(builtIns), expression, context, context.dataFlowInfo);
162        }
163    
164        @Override
165        public JetTypeInfo visitBinaryWithTypeRHSExpression(@NotNull JetBinaryExpressionWithTypeRHS expression, ExpressionTypingContext context) {
166            ExpressionTypingContext contextWithNoExpectedType =
167                    context.replaceExpectedType(NO_EXPECTED_TYPE).replaceContextDependency(INDEPENDENT);
168            JetExpression left = expression.getLeft();
169            JetTypeReference right = expression.getRight();
170            if (right == null) {
171                JetTypeInfo leftTypeInfo = facade.getTypeInfo(left, contextWithNoExpectedType);
172                return JetTypeInfo.create(null, leftTypeInfo.getDataFlowInfo());
173            }
174    
175            IElementType operationType = expression.getOperationReference().getReferencedNameElementType();
176    
177            boolean allowBareTypes = BARE_TYPES_ALLOWED.contains(operationType);
178            TypeResolutionContext typeResolutionContext = new TypeResolutionContext(context.scope, context.trace, true, allowBareTypes);
179            PossiblyBareType possiblyBareTarget = context.expressionTypingServices.getTypeResolver().resolvePossiblyBareType(typeResolutionContext, right);
180    
181            if (isTypeFlexible(left) || operationType == JetTokens.COLON) {
182                // We do not allow bare types on static assertions, because static assertions provide an expected type for their argument,
183                // thus causing a circularity in type dependencies
184                assert !possiblyBareTarget.isBare() : "Bare types should not be allowed for static assertions, because argument inference makes no sense there";
185                JetType targetType = possiblyBareTarget.getActualType();
186    
187                JetTypeInfo typeInfo = facade.getTypeInfo(left, contextWithNoExpectedType.replaceExpectedType(targetType));
188                checkBinaryWithTypeRHS(expression, context, targetType, typeInfo.getType());
189                return DataFlowUtils.checkType(targetType, expression, context, typeInfo.getDataFlowInfo());
190            }
191    
192            JetTypeInfo typeInfo = facade.getTypeInfo(left, contextWithNoExpectedType);
193    
194            DataFlowInfo dataFlowInfo = context.dataFlowInfo;
195            JetType subjectType = typeInfo.getType();
196            JetType targetType = reconstructBareType(right, possiblyBareTarget, subjectType, context.trace);
197    
198            if (subjectType != null) {
199                checkBinaryWithTypeRHS(expression, contextWithNoExpectedType, targetType, subjectType);
200                dataFlowInfo = typeInfo.getDataFlowInfo();
201                if (operationType == AS_KEYWORD) {
202                    DataFlowValue value = DataFlowValueFactory.createDataFlowValue(left, subjectType, context.trace.getBindingContext());
203                    dataFlowInfo = dataFlowInfo.establishSubtyping(value, targetType);
204                }
205            }
206    
207            JetType result = operationType == AS_SAFE ? TypeUtils.makeNullable(targetType) : targetType;
208            return DataFlowUtils.checkType(result, expression, context, dataFlowInfo);
209        }
210    
211        private void checkBinaryWithTypeRHS(
212                @NotNull JetBinaryExpressionWithTypeRHS expression,
213                @NotNull ExpressionTypingContext context,
214                @NotNull JetType targetType,
215                @Nullable JetType actualType
216        ) {
217            if (actualType == null) return;
218            JetSimpleNameExpression operationSign = expression.getOperationReference();
219            IElementType operationType = operationSign.getReferencedNameElementType();
220            if (operationType == JetTokens.COLON) {
221                return;
222            }
223            if (operationType != JetTokens.AS_KEYWORD && operationType != JetTokens.AS_SAFE) {
224                context.trace.report(UNSUPPORTED.on(operationSign, "binary operation with type RHS"));
225                return;
226            }
227            checkForCastImpossibility(expression, actualType, targetType, context);
228        }
229    
230        private void checkForCastImpossibility(
231                JetBinaryExpressionWithTypeRHS expression,
232                JetType actualType,
233                JetType targetType,
234                ExpressionTypingContext context
235        ) {
236            if (actualType == null || noExpectedType(targetType)) return;
237    
238            if (!CastDiagnosticsUtil.isCastPossible(actualType, targetType, platformToKotlinClassMap)) {
239                context.trace.report(CAST_NEVER_SUCCEEDS.on(expression.getOperationReference()));
240            }
241            else {
242                JetTypeChecker typeChecker = JetTypeChecker.INSTANCE;
243                // Upcast?
244                if (typeChecker.isSubtypeOf(actualType, targetType)) {
245                    if (!typeChecker.isSubtypeOf(targetType, actualType)) {
246                        // proper upcast: String as Any
247                        context.trace.report(USELESS_CAST_STATIC_ASSERT_IS_FINE.on(expression.getOperationReference()));
248                    }
249                    else {
250                        // cast to itself: String as String
251                        context.trace.report(USELESS_CAST.on(expression.getOperationReference()));
252                    }
253                }
254                else if (CastDiagnosticsUtil.isCastErased(actualType, targetType, typeChecker)) {
255                    context.trace.report(Errors.UNCHECKED_CAST.on(expression, actualType, targetType));
256                }
257            }
258        }
259    
260        @Override
261        public JetTypeInfo visitThisExpression(@NotNull JetThisExpression expression, ExpressionTypingContext context) {
262            JetType result = null;
263            LabelResolver.LabeledReceiverResolutionResult resolutionResult = resolveToReceiver(expression, context, false);
264    
265            switch (resolutionResult.getCode()) {
266                case LABEL_RESOLUTION_ERROR:
267                    // Do nothing, the error is already reported
268                    break;
269                case NO_THIS:
270                    context.trace.report(NO_THIS.on(expression));
271                    break;
272                case SUCCESS:
273                    result = resolutionResult.getReceiverParameterDescriptor().getType();
274                    context.trace.record(BindingContext.EXPRESSION_TYPE, expression.getInstanceReference(), result);
275                    break;
276            }
277            return DataFlowUtils.checkType(result, expression, context, context.dataFlowInfo);
278        }
279    
280        @Override
281        public JetTypeInfo visitSuperExpression(@NotNull JetSuperExpression expression, ExpressionTypingContext context) {
282            LabelResolver.LabeledReceiverResolutionResult resolutionResult = resolveToReceiver(expression, context, true);
283    
284            if (context.expressionPosition == ExpressionPosition.FREE) {
285                context.trace.report(SUPER_IS_NOT_AN_EXPRESSION.on(expression, expression.getText()));
286                return errorInSuper(expression, context);
287            }
288            switch (resolutionResult.getCode()) {
289                case LABEL_RESOLUTION_ERROR:
290                    // The error is already reported
291                    return errorInSuper(expression, context);
292                case NO_THIS:
293                    context.trace.report(SUPER_NOT_AVAILABLE.on(expression));
294                    return errorInSuper(expression, context);
295                case SUCCESS:
296                    JetType result = checkPossiblyQualifiedSuper(expression, context, resolutionResult.getReceiverParameterDescriptor());
297                    if (result != null) {
298                        context.trace.record(BindingContext.EXPRESSION_TYPE, expression.getInstanceReference(), result);
299                    }
300                    return DataFlowUtils.checkType(result, expression, context, context.dataFlowInfo);
301            }
302            throw new IllegalStateException("Unknown code: " + resolutionResult.getCode());
303        }
304    
305        private static JetTypeInfo errorInSuper(JetSuperExpression expression, ExpressionTypingContext context) {
306            JetTypeReference superTypeQualifier = expression.getSuperTypeQualifier();
307            if (superTypeQualifier != null) {
308                context.expressionTypingServices.getTypeResolver().resolveType(context.scope, superTypeQualifier, context.trace, true);
309            }
310            return JetTypeInfo.create(null, context.dataFlowInfo);
311        }
312    
313        private static JetType checkPossiblyQualifiedSuper(
314                JetSuperExpression expression,
315                ExpressionTypingContext context,
316                ReceiverParameterDescriptor thisReceiver
317        ) {
318            JetType result = null;
319            JetType thisType = thisReceiver.getType();
320            Collection<JetType> supertypes = thisType.getConstructor().getSupertypes();
321            TypeSubstitutor substitutor = TypeSubstitutor.create(thisType);
322    
323            JetTypeReference superTypeQualifier = expression.getSuperTypeQualifier();
324            if (superTypeQualifier != null) {
325                JetTypeElement typeElement = superTypeQualifier.getTypeElement();
326    
327                DeclarationDescriptor classifierCandidate = null;
328                JetType supertype = null;
329                PsiElement redundantTypeArguments = null;
330                if (typeElement instanceof JetUserType) {
331                    JetUserType userType = (JetUserType) typeElement;
332                    // This may be just a superclass name even if the superclass is generic
333                    if (userType.getTypeArguments().isEmpty()) {
334                        classifierCandidate = context.expressionTypingServices.getTypeResolver().resolveClass(context.scope, userType, context.trace);
335                    }
336                    else {
337                        supertype = context.expressionTypingServices.getTypeResolver().resolveType(context.scope, superTypeQualifier, context.trace, true);
338                        redundantTypeArguments = userType.getTypeArgumentList();
339                    }
340                }
341                else {
342                    supertype = context.expressionTypingServices.getTypeResolver().resolveType(context.scope, superTypeQualifier, context.trace, true);
343                }
344    
345                if (supertype != null) {
346                    if (supertypes.contains(supertype)) {
347                        result = supertype;
348                    }
349                }
350                else if (classifierCandidate instanceof ClassDescriptor) {
351                    ClassDescriptor superclass = (ClassDescriptor) classifierCandidate;
352    
353                    for (JetType declaredSupertype : supertypes) {
354                        if (declaredSupertype.getConstructor().equals(superclass.getTypeConstructor())) {
355                            result = substitutor.safeSubstitute(declaredSupertype, Variance.INVARIANT);
356                            break;
357                        }
358                    }
359                }
360    
361                boolean validClassifier = classifierCandidate != null && !ErrorUtils.isError(classifierCandidate);
362                boolean validType = supertype != null && !supertype.isError();
363                if (result == null && (validClassifier || validType)) {
364                    context.trace.report(NOT_A_SUPERTYPE.on(superTypeQualifier));
365                }
366                else if (redundantTypeArguments != null) {
367                    context.trace.report(TYPE_ARGUMENTS_REDUNDANT_IN_SUPER_QUALIFIER.on(redundantTypeArguments));
368                }
369            }
370            else {
371                if (supertypes.size() > 1) {
372                    context.trace.report(AMBIGUOUS_SUPER.on(expression));
373                }
374                else {
375                    // supertypes may be empty when all the supertypes are error types (are not resolved, for example)
376                    JetType type = supertypes.isEmpty()
377                                   ? KotlinBuiltIns.getInstance().getAnyType()
378                                   : supertypes.iterator().next();
379                    result = substitutor.substitute(type, Variance.INVARIANT);
380                }
381            }
382            if (result != null) {
383                if (DescriptorUtils.isTrait(thisType.getConstructor().getDeclarationDescriptor())) {
384                    if (DescriptorUtils.isClass(result.getConstructor().getDeclarationDescriptor())) {
385                        context.trace.report(SUPERCLASS_NOT_ACCESSIBLE_FROM_TRAIT.on(expression));
386                    }
387                }
388                context.trace.record(BindingContext.EXPRESSION_TYPE, expression.getInstanceReference(), result);
389                context.trace.record(BindingContext.REFERENCE_TARGET, expression.getInstanceReference(), result.getConstructor().getDeclarationDescriptor());
390                if (superTypeQualifier != null) {
391                    context.trace.record(BindingContext.TYPE_RESOLUTION_SCOPE, superTypeQualifier, context.scope);
392                }
393            }
394            return result;
395        }
396    
397        @NotNull // No class receivers
398        private static LabelResolver.LabeledReceiverResolutionResult resolveToReceiver(
399                JetLabelQualifiedInstanceExpression expression,
400                ExpressionTypingContext context,
401                boolean onlyClassReceivers
402        ) {
403            String labelName = expression.getLabelName();
404            if (labelName != null) {
405                LabelResolver.LabeledReceiverResolutionResult resolutionResult = context.labelResolver.resolveThisLabel(
406                        expression.getInstanceReference(), expression.getTargetLabel(), context, new LabelName(labelName));
407                if (onlyClassReceivers && resolutionResult.success()) {
408                    if (!isDeclaredInClass(resolutionResult.getReceiverParameterDescriptor())) {
409                        return LabelResolver.LabeledReceiverResolutionResult.labelResolutionSuccess(NO_RECEIVER_PARAMETER);
410                    }
411                }
412                return resolutionResult;
413            }
414            else {
415                ReceiverParameterDescriptor result = NO_RECEIVER_PARAMETER;
416                List<ReceiverParameterDescriptor> receivers = context.scope.getImplicitReceiversHierarchy();
417                if (onlyClassReceivers) {
418                    for (ReceiverParameterDescriptor receiver : receivers) {
419                        if (isDeclaredInClass(receiver)) {
420                            result = receiver;
421                            break;
422                        }
423                    }
424                }
425                else if (!receivers.isEmpty()) {
426                    result = receivers.get(0);
427                }
428                if (result != NO_RECEIVER_PARAMETER) {
429                    context.trace.record(REFERENCE_TARGET, expression.getInstanceReference(), result.getContainingDeclaration());
430                }
431                return LabelResolver.LabeledReceiverResolutionResult.labelResolutionSuccess(result);
432            }
433        }
434    
435        private static boolean isDeclaredInClass(ReceiverParameterDescriptor receiver) {
436            return receiver.getContainingDeclaration() instanceof ClassDescriptor;
437        }
438    
439        @Override
440        public JetTypeInfo visitBlockExpression(@NotNull JetBlockExpression expression, ExpressionTypingContext context) {
441            return visitBlockExpression(expression, context, false);
442        }
443    
444        public static JetTypeInfo visitBlockExpression(JetBlockExpression expression, ExpressionTypingContext context, boolean isStatement) {
445            return context.expressionTypingServices.getBlockReturnedType(
446                    expression, isStatement ? CoercionStrategy.COERCION_TO_UNIT : CoercionStrategy.NO_COERCION, context);
447        }
448    
449        @Override
450        public JetTypeInfo visitCallableReferenceExpression(@NotNull JetCallableReferenceExpression expression, ExpressionTypingContext context) {
451            JetTypeReference typeReference = expression.getTypeReference();
452    
453            JetType receiverType =
454                    typeReference == null
455                    ? null
456                    : context.expressionTypingServices.getTypeResolver().resolveType(context.scope, typeReference, context.trace, false);
457    
458            JetSimpleNameExpression callableReference = expression.getCallableReference();
459            if (callableReference.getReferencedName().isEmpty()) {
460                context.trace.report(UNRESOLVED_REFERENCE.on(callableReference, callableReference));
461                JetType errorType = ErrorUtils.createErrorType("Empty callable reference");
462                return DataFlowUtils.checkType(errorType, expression, context, context.dataFlowInfo);
463            }
464    
465            JetType result = getCallableReferenceType(expression, receiverType, context);
466            return DataFlowUtils.checkType(result, expression, context, context.dataFlowInfo);
467        }
468    
469        @Nullable
470        private static JetType getCallableReferenceType(
471                @NotNull JetCallableReferenceExpression expression,
472                @Nullable JetType lhsType,
473                @NotNull ExpressionTypingContext context
474        ) {
475            JetSimpleNameExpression reference = expression.getCallableReference();
476    
477            boolean[] result = new boolean[1];
478            FunctionDescriptor descriptor = resolveCallableReferenceTarget(lhsType, context, expression, result);
479    
480            if (!result[0]) {
481                context.trace.report(UNRESOLVED_REFERENCE.on(reference, reference));
482            }
483            if (descriptor == null) return null;
484    
485            ReceiverParameterDescriptor receiverParameter = descriptor.getReceiverParameter();
486            ReceiverParameterDescriptor expectedThisObject = descriptor.getExpectedThisObject();
487            if (receiverParameter != null && expectedThisObject != null) {
488                context.trace.report(EXTENSION_IN_CLASS_REFERENCE_NOT_ALLOWED.on(reference, descriptor));
489                return null;
490            }
491    
492            JetType receiverType = null;
493            if (receiverParameter != null) {
494                receiverType = receiverParameter.getType();
495            }
496            else if (expectedThisObject != null) {
497                receiverType = expectedThisObject.getType();
498            }
499    
500            //noinspection ConstantConditions
501            JetType type = KotlinBuiltIns.getInstance().getKFunctionType(
502                    Collections.<AnnotationDescriptor>emptyList(),
503                    receiverType,
504                    DescriptorUtils.getValueParametersTypes(descriptor.getValueParameters()),
505                    descriptor.getReturnType(),
506                    receiverParameter != null
507            );
508    
509            AnonymousFunctionDescriptor functionDescriptor = new AnonymousFunctionDescriptor(
510                    context.scope.getContainingDeclaration(),
511                    Collections.<AnnotationDescriptor>emptyList(),
512                    CallableMemberDescriptor.Kind.DECLARATION);
513    
514            FunctionDescriptorUtil.initializeFromFunctionType(functionDescriptor, type, null, Modality.FINAL, Visibilities.PUBLIC);
515    
516            context.trace.record(FUNCTION, expression, functionDescriptor);
517    
518            return type;
519        }
520    
521        @Nullable
522        private static FunctionDescriptor resolveCallableReferenceTarget(
523                @Nullable JetType lhsType,
524                @NotNull ExpressionTypingContext context,
525                @NotNull JetCallableReferenceExpression expression,
526                @NotNull boolean[] result
527        ) {
528            JetSimpleNameExpression reference = expression.getCallableReference();
529    
530            if (lhsType == null) {
531                return resolveCallableNotCheckingArguments(reference, NO_RECEIVER, context, result);
532            }
533    
534            ClassifierDescriptor classifier = lhsType.getConstructor().getDeclarationDescriptor();
535            if (!(classifier instanceof ClassDescriptor)) {
536                context.trace.report(CALLABLE_REFERENCE_LHS_NOT_A_CLASS.on(expression));
537                return null;
538            }
539    
540            ReceiverValue receiver = new TransientReceiver(lhsType);
541            TemporaryTraceAndCache temporaryWithReceiver = TemporaryTraceAndCache.create(
542                    context, "trace to resolve callable reference with receiver", reference);
543            FunctionDescriptor descriptor = resolveCallableNotCheckingArguments(
544                    reference, receiver, context.replaceTraceAndCache(temporaryWithReceiver), result);
545            if (result[0]) {
546                temporaryWithReceiver.commit();
547                return descriptor;
548            }
549    
550            JetScope staticScope = getStaticNestedClassesScope((ClassDescriptor) classifier);
551            TemporaryTraceAndCache temporaryForStatic = TemporaryTraceAndCache.create(
552                    context, "trace to resolve callable reference in static scope", reference);
553            FunctionDescriptor possibleStaticNestedClassConstructor = resolveCallableNotCheckingArguments(reference, NO_RECEIVER,
554                    context.replaceTraceAndCache(temporaryForStatic).replaceScope(staticScope), result);
555            if (result[0]) {
556                temporaryForStatic.commit();
557                return possibleStaticNestedClassConstructor;
558            }
559    
560            return null;
561        }
562    
563        @Nullable
564        private static FunctionDescriptor resolveCallableNotCheckingArguments(
565                @NotNull JetSimpleNameExpression reference,
566                @NotNull ReceiverValue receiver,
567                @NotNull ExpressionTypingContext context,
568                @NotNull boolean[] result
569        ) {
570            Call call = CallMaker.makeCall(reference, receiver, null, reference, ThrowingList.<ValueArgument>instance());
571    
572            TemporaryBindingTrace trace = TemporaryBindingTrace.create(context.trace, "trace to resolve as function", reference);
573    
574            ExpressionTypingContext contextForResolve = context.replaceBindingTrace(trace).replaceExpectedType(NO_EXPECTED_TYPE);
575            ResolvedCallWithTrace<FunctionDescriptor> function = contextForResolve.expressionTypingServices.getCallExpressionResolver()
576                    .getResolvedCallForFunction(call, reference, contextForResolve, CheckValueArgumentsMode.DISABLED, result);
577            if (!result[0]) return null;
578    
579            if (function instanceof VariableAsFunctionResolvedCall) {
580                // TODO: KProperty
581                context.trace.report(UNSUPPORTED.on(reference, "References to variables aren't supported yet"));
582                context.trace.report(UNRESOLVED_REFERENCE.on(reference, reference));
583                return null;
584            }
585    
586            trace.commit();
587            return function != null ? function.getResultingDescriptor() : null;
588        }
589    
590        @Override
591        public JetTypeInfo visitQualifiedExpression(@NotNull JetQualifiedExpression expression, ExpressionTypingContext context) {
592            CallExpressionResolver callExpressionResolver = context.expressionTypingServices.getCallExpressionResolver();
593            return callExpressionResolver.getQualifiedExpressionTypeInfo(expression, context);
594        }
595    
596        @Override
597        public JetTypeInfo visitCallExpression(@NotNull JetCallExpression expression, ExpressionTypingContext context) {
598            CallExpressionResolver callExpressionResolver = context.expressionTypingServices.getCallExpressionResolver();
599            return callExpressionResolver.getCallExpressionTypeInfo(expression, NO_RECEIVER, null, context);
600        }
601    
602        @Override
603        public JetTypeInfo visitUnaryExpression(@NotNull JetUnaryExpression expression, ExpressionTypingContext context) {
604            return visitUnaryExpression(expression, context, false);
605        }
606    
607        public JetTypeInfo visitUnaryExpression(JetUnaryExpression expression, ExpressionTypingContext context, boolean isStatement) {
608            JetExpression baseExpression = expression.getBaseExpression();
609            if (baseExpression == null) return JetTypeInfo.create(null, context.dataFlowInfo);
610    
611            JetSimpleNameExpression operationSign = expression.getOperationReference();
612    
613            IElementType operationType = operationSign.getReferencedNameElementType();
614            // If it's a labeled expression
615            if (JetTokens.LABELS.contains(operationType)) {
616                return visitLabeledExpression(expression, context, isStatement);
617            }
618    
619            // Special case for expr!!
620            if (operationType == JetTokens.EXCLEXCL) {
621                return visitExclExclExpression(expression, context);
622            }
623    
624            // Type check the base expression
625            JetTypeInfo typeInfo = facade.getTypeInfo(
626                    baseExpression, context.replaceExpectedType(NO_EXPECTED_TYPE).replaceContextDependency(INDEPENDENT));
627            JetType type = typeInfo.getType();
628            if (type == null) {
629                return typeInfo;
630            }
631            DataFlowInfo dataFlowInfo = typeInfo.getDataFlowInfo();
632    
633            // Conventions for unary operations
634            Name name = OperatorConventions.UNARY_OPERATION_NAMES.get(operationType);
635            if (name == null) {
636                context.trace.report(UNSUPPORTED.on(operationSign, "visitUnaryExpression"));
637                return JetTypeInfo.create(null, dataFlowInfo);
638            }
639    
640            // a[i]++/-- takes special treatment because it is actually let j = i, arr = a in arr.set(j, a.get(j).inc())
641            if ((operationType == JetTokens.PLUSPLUS || operationType == JetTokens.MINUSMINUS) && baseExpression instanceof JetArrayAccessExpression) {
642                JetExpression stubExpression = ExpressionTypingUtils.createFakeExpressionOfType(baseExpression.getProject(), context.trace, "$e", type);
643                resolveArrayAccessSetMethod((JetArrayAccessExpression) baseExpression,
644                                            stubExpression,
645                                            context.replaceExpectedType(NO_EXPECTED_TYPE).replaceBindingTrace(
646                                                    TemporaryBindingTrace.create(context.trace, "trace to resolve array access set method for unary expression", expression)),
647                                            context.trace);
648            }
649    
650            ExpressionReceiver receiver = new ExpressionReceiver(baseExpression, type);
651    
652            // Resolve the operation reference
653            OverloadResolutionResults<FunctionDescriptor> resolutionResults = context.resolveCallWithGivenName(
654                    CallMaker.makeCall(receiver, expression),
655                    expression.getOperationReference(),
656                    name);
657    
658            if (!resolutionResults.isSuccess()) {
659                return JetTypeInfo.create(null, dataFlowInfo);
660            }
661    
662            // Computing the return type
663            JetType returnType = resolutionResults.getResultingDescriptor().getReturnType();
664            JetType result;
665            if (operationType == JetTokens.PLUSPLUS || operationType == JetTokens.MINUSMINUS) {
666                assert returnType != null : "returnType is null for " + resolutionResults.getResultingDescriptor();
667                if (JetTypeChecker.INSTANCE.isSubtypeOf(returnType, KotlinBuiltIns.getInstance().getUnitType())) {
668                    result = ErrorUtils.createErrorType(KotlinBuiltIns.getInstance().getUnit().getName().asString());
669                    context.trace.report(INC_DEC_SHOULD_NOT_RETURN_UNIT.on(operationSign));
670                }
671                else {
672                    JetType receiverType = receiver.getType();
673                    if (!JetTypeChecker.INSTANCE.isSubtypeOf(returnType, receiverType)) {
674                        context.trace.report(RESULT_TYPE_MISMATCH.on(operationSign, name.asString(), receiverType, returnType));
675                    }
676                    else {
677                        context.trace.record(BindingContext.VARIABLE_REASSIGNMENT, expression);
678    
679                        checkLValue(context.trace, baseExpression);
680                    }
681                    // TODO : Maybe returnType?
682                    result = receiverType;
683                }
684            }
685            else {
686                result = returnType;
687            }
688            return DataFlowUtils.checkType(result, expression, context, dataFlowInfo);
689        }
690    
691        private JetTypeInfo visitExclExclExpression(@NotNull JetUnaryExpression expression, @NotNull ExpressionTypingContext context) {
692            JetExpression baseExpression = expression.getBaseExpression();
693            assert baseExpression != null;
694            JetSimpleNameExpression operationSign = expression.getOperationReference();
695            assert operationSign.getReferencedNameElementType() == JetTokens.EXCLEXCL;
696    
697            Call call = createCallForSpecialConstruction(expression, Collections.singletonList(baseExpression));
698            resolveSpecialConstructionAsCall(
699                    call, "ExclExcl", Collections.singletonList("baseExpr"), Collections.singletonList(true), context, null);
700            JetTypeInfo baseTypeInfo = BindingContextUtils.getRecordedTypeInfo(baseExpression, context.trace.getBindingContext());
701            assert baseTypeInfo != null : "Base expression was not processed: " + expression;
702            JetType baseType = baseTypeInfo.getType();
703            if (baseType == null) {
704                return baseTypeInfo;
705            }
706            DataFlowInfo dataFlowInfo = baseTypeInfo.getDataFlowInfo();
707            if (isKnownToBeNotNull(baseExpression, context) && !baseType.isError()) {
708                context.trace.report(UNNECESSARY_NOT_NULL_ASSERTION.on(operationSign, baseType));
709            }
710            else {
711                DataFlowValue value = DataFlowValueFactory.createDataFlowValue(baseExpression, baseType, context.trace.getBindingContext());
712                dataFlowInfo = dataFlowInfo.disequate(value, DataFlowValue.NULL);
713            }
714            return JetTypeInfo.create(TypeUtils.makeNotNullable(baseType), dataFlowInfo);
715        }
716    
717        private JetTypeInfo visitLabeledExpression(@NotNull JetUnaryExpression expression, @NotNull ExpressionTypingContext context,
718                boolean isStatement) {
719            JetExpression baseExpression = expression.getBaseExpression();
720            assert baseExpression != null;
721            JetSimpleNameExpression operationSign = expression.getOperationReference();
722            assert JetTokens.LABELS.contains(operationSign.getReferencedNameElementType());
723    
724            String referencedName = operationSign.getReferencedName();
725            context.labelResolver.enterLabeledElement(new LabelName(referencedName.substring(1)), baseExpression);
726            // TODO : Some processing for the label?
727            JetTypeInfo typeInfo = facade.getTypeInfo(baseExpression, context, isStatement);
728            context.labelResolver.exitLabeledElement(baseExpression);
729            return typeInfo;
730        }
731    
732        private static boolean isKnownToBeNotNull(JetExpression expression, ExpressionTypingContext context) {
733            JetType type = context.trace.get(EXPRESSION_TYPE, expression);
734            assert type != null : "This method is only supposed to be called when the type is not null";
735            return isKnownToBeNotNull(expression, type, context);
736        }
737    
738        private static boolean isKnownToBeNotNull(JetExpression expression, JetType jetType, ExpressionTypingContext context) {
739            DataFlowValue dataFlowValue = DataFlowValueFactory.createDataFlowValue(expression, jetType, context.trace.getBindingContext());
740            return !context.dataFlowInfo.getNullability(dataFlowValue).canBeNull();
741        }
742    
743        public static void checkLValue(@NotNull BindingTrace trace, @NotNull JetExpression expression) {
744            checkLValue(trace, expression, false);
745        }
746    
747        private static void checkLValue(@NotNull BindingTrace trace, @NotNull JetExpression expressionWithParenthesis, boolean canBeThis) {
748            JetExpression expression = JetPsiUtil.deparenthesize(expressionWithParenthesis);
749            if (expression instanceof JetArrayAccessExpression) {
750                JetExpression arrayExpression = ((JetArrayAccessExpression) expression).getArrayExpression();
751                if (arrayExpression != null) {
752                    checkLValue(trace, arrayExpression, true);
753                }
754                return;
755            }
756            if (canBeThis && expression instanceof JetThisExpression) return;
757            VariableDescriptor variable = BindingContextUtils.extractVariableDescriptorIfAny(trace.getBindingContext(), expression, true);
758            if (variable == null) {
759                trace.report(VARIABLE_EXPECTED.on(expression != null ? expression : expressionWithParenthesis));
760            }
761        }
762    
763        @Override
764        public JetTypeInfo visitBinaryExpression(@NotNull JetBinaryExpression expression, ExpressionTypingContext contextWithExpectedType) {
765            ExpressionTypingContext context = isBinaryExpressionDependentOnExpectedType(expression)
766                    ? contextWithExpectedType
767                    : contextWithExpectedType.replaceContextDependency(INDEPENDENT).replaceExpectedType(NO_EXPECTED_TYPE);
768    
769            JetSimpleNameExpression operationSign = expression.getOperationReference();
770            JetExpression left = expression.getLeft();
771            JetExpression right = expression.getRight();
772            IElementType operationType = operationSign.getReferencedNameElementType();
773    
774            JetTypeInfo result;
775    
776            //Expressions that can depend on expected type
777            if (operationType == JetTokens.IDENTIFIER) {
778                Name referencedName = operationSign.getReferencedNameAsName();
779                result = getTypeInfoForBinaryCall(referencedName, context, expression);
780            }
781            else if (OperatorConventions.BINARY_OPERATION_NAMES.containsKey(operationType)) {
782                Name referencedName = OperatorConventions.BINARY_OPERATION_NAMES.get(operationType);
783                result = getTypeInfoForBinaryCall(referencedName, context, expression);
784            }
785            else if (operationType == JetTokens.ELVIS) {
786                //base expression of elvis operator is checked for 'type mismatch', so the whole expression shouldn't be checked
787                return visitElvisExpression(expression, context);
788            }
789    
790            //Expressions that don't depend on expected type
791            else if (operationType == JetTokens.EQ) {
792                result = visitAssignment(expression, context);
793            }
794            else if (OperatorConventions.ASSIGNMENT_OPERATIONS.containsKey(operationType)) {
795                result = visitAssignmentOperation(expression, context);
796            }
797            else if (OperatorConventions.COMPARISON_OPERATIONS.contains(operationType)) {
798                result = visitComparison(expression, context, operationSign);
799            }
800            else if (OperatorConventions.EQUALS_OPERATIONS.contains(operationType)) {
801                result = visitEquality(expression, context, operationSign, left, right);
802            }
803            else if (operationType == JetTokens.EQEQEQ || operationType == JetTokens.EXCLEQEQEQ) {
804                ensureNonemptyIntersectionOfOperandTypes(expression, context);
805                // TODO : Check comparison pointlessness
806                result = JetTypeInfo.create(KotlinBuiltIns.getInstance().getBooleanType(), context.dataFlowInfo);
807            }
808            else if (OperatorConventions.IN_OPERATIONS.contains(operationType)) {
809                result = checkInExpression(expression, operationSign, left, right, context);
810            }
811            else if (OperatorConventions.BOOLEAN_OPERATIONS.containsKey(operationType)) {
812                result = visitBooleanOperationExpression(operationType, left, right, context);
813            }
814            else {
815                context.trace.report(UNSUPPORTED.on(operationSign, "Unknown operation"));
816                result = JetTypeInfo.create(null, context.dataFlowInfo);
817            }
818            return DataFlowUtils.checkType(result, expression, contextWithExpectedType);
819        }
820    
821        private JetTypeInfo visitEquality(
822                JetBinaryExpression expression,
823                ExpressionTypingContext context,
824                JetSimpleNameExpression operationSign,
825                JetExpression left,
826                JetExpression right
827        ) {
828            JetTypeInfo result;DataFlowInfo dataFlowInfo = context.dataFlowInfo;
829            if (right != null && left != null) {
830                ExpressionReceiver receiver = ExpressionTypingUtils.safeGetExpressionReceiver(facade, left, context);
831    
832                JetTypeInfo leftTypeInfo = getTypeInfoOrNullType(left, context, facade);
833    
834                dataFlowInfo = leftTypeInfo.getDataFlowInfo();
835                ExpressionTypingContext contextWithDataFlow = context.replaceDataFlowInfo(dataFlowInfo);
836    
837                OverloadResolutionResults<FunctionDescriptor> resolutionResults = resolveFakeCall(
838                        contextWithDataFlow, receiver, OperatorConventions.EQUALS, KotlinBuiltIns.getInstance().getNullableAnyType());
839    
840                dataFlowInfo = facade.getTypeInfo(right, contextWithDataFlow).getDataFlowInfo();
841    
842                if (resolutionResults.isSuccess()) {
843                    FunctionDescriptor equals = resolutionResults.getResultingCall().getResultingDescriptor();
844                    context.trace.record(REFERENCE_TARGET, operationSign, equals);
845                    context.trace.record(RESOLVED_CALL, operationSign, resolutionResults.getResultingCall());
846                    if (ensureBooleanResult(operationSign, OperatorConventions.EQUALS, equals.getReturnType(), context)) {
847                        ensureNonemptyIntersectionOfOperandTypes(expression, context);
848                    }
849                }
850                else {
851                    if (resolutionResults.isAmbiguity()) {
852                        context.trace.report(OVERLOAD_RESOLUTION_AMBIGUITY.on(operationSign, resolutionResults.getResultingCalls()));
853                    }
854                    else {
855                        context.trace.report(EQUALS_MISSING.on(operationSign));
856                    }
857                }
858            }
859            result = JetTypeInfo.create(KotlinBuiltIns.getInstance().getBooleanType(), dataFlowInfo);
860            return result;
861        }
862    
863        @NotNull
864        private JetTypeInfo visitComparison(
865                @NotNull JetBinaryExpression expression,
866                @NotNull ExpressionTypingContext context,
867                @NotNull JetSimpleNameExpression operationSign
868        ) {
869            JetTypeInfo typeInfo = getTypeInfoForBinaryCall(OperatorConventions.COMPARE_TO, context, expression);
870            DataFlowInfo dataFlowInfo = typeInfo.getDataFlowInfo();
871            JetType compareToReturnType = typeInfo.getType();
872            JetType type = null;
873            if (compareToReturnType != null && !compareToReturnType.isError()) {
874                TypeConstructor constructor = compareToReturnType.getConstructor();
875                KotlinBuiltIns builtIns = KotlinBuiltIns.getInstance();
876                TypeConstructor intTypeConstructor = builtIns.getInt().getTypeConstructor();
877                if (constructor.equals(intTypeConstructor)) {
878                    type = builtIns.getBooleanType();
879                }
880                else {
881                    context.trace.report(COMPARE_TO_TYPE_MISMATCH.on(operationSign, compareToReturnType));
882                }
883            }
884            return JetTypeInfo.create(type, dataFlowInfo);
885        }
886    
887        @NotNull
888        private JetTypeInfo visitBooleanOperationExpression(
889                @Nullable IElementType operationType,
890                @Nullable JetExpression left,
891                @Nullable JetExpression right,
892                @NotNull ExpressionTypingContext context
893        ) {
894            JetType booleanType = KotlinBuiltIns.getInstance().getBooleanType();
895            JetTypeInfo leftTypeInfo = getTypeInfoOrNullType(left, context, facade);
896    
897            JetType leftType = leftTypeInfo.getType();
898            DataFlowInfo dataFlowInfo = leftTypeInfo.getDataFlowInfo();
899    
900            WritableScopeImpl leftScope = newWritableScopeImpl(context, "Left scope of && or ||");
901            // TODO: This gets computed twice: here and in extractDataFlowInfoFromCondition() for the whole condition
902            boolean isAnd = operationType == JetTokens.ANDAND;
903            DataFlowInfo flowInfoLeft = DataFlowUtils.extractDataFlowInfoFromCondition(left, isAnd, context).and(dataFlowInfo);
904            WritableScopeImpl rightScope = isAnd ? leftScope : newWritableScopeImpl(context, "Right scope of && or ||");
905    
906            ExpressionTypingContext contextForRightExpr = context.replaceDataFlowInfo(flowInfoLeft).replaceScope(rightScope);
907            JetType rightType = right != null ? facade.getTypeInfo(right, contextForRightExpr).getType() : null;
908            if (left != null && leftType != null && !isBoolean(leftType)) {
909                context.trace.report(TYPE_MISMATCH.on(left, booleanType, leftType));
910            }
911            if (rightType != null && !isBoolean(rightType)) {
912                context.trace.report(TYPE_MISMATCH.on(right, booleanType, rightType));
913            }
914            return JetTypeInfo.create(booleanType, dataFlowInfo);
915        }
916    
917        @NotNull
918        private JetTypeInfo visitElvisExpression(
919                @NotNull JetBinaryExpression expression,
920                @NotNull ExpressionTypingContext contextWithExpectedType
921        ) {
922            ExpressionTypingContext context = contextWithExpectedType.replaceExpectedType(NO_EXPECTED_TYPE);
923            JetExpression left = expression.getLeft();
924            JetExpression right = expression.getRight();
925    
926            if (left == null || right == null) {
927                getTypeInfoOrNullType(left, context, facade);
928                return JetTypeInfo.create(null, context.dataFlowInfo);
929            }
930    
931            Call call = createCallForSpecialConstruction(expression, Lists.newArrayList(left, right));
932            ResolvedCall<FunctionDescriptor> resolvedCall = resolveSpecialConstructionAsCall(
933                    call, "Elvis", Lists.newArrayList("left", "right"), Lists.newArrayList(true, false), contextWithExpectedType, null);
934            JetTypeInfo leftTypeInfo = BindingContextUtils.getRecordedTypeInfo(left, context.trace.getBindingContext());
935            assert leftTypeInfo != null : "Left expression was not processed: " + expression;
936            JetType leftType = leftTypeInfo.getType();
937            if (leftType != null && isKnownToBeNotNull(left, leftType, context)) {
938                context.trace.report(USELESS_ELVIS.on(left, leftType));
939            }
940            JetTypeInfo rightTypeInfo = BindingContextUtils.getRecordedTypeInfo(right, context.trace.getBindingContext());
941            assert rightTypeInfo != null : "Right expression was not processed: " + expression;
942            JetType rightType = rightTypeInfo.getType();
943    
944            DataFlowInfo dataFlowInfo = resolvedCall.getDataFlowInfoForArguments().getResultInfo();
945            JetType type = resolvedCall.getResultingDescriptor().getReturnType();
946            if (type == null || rightType == null) return JetTypeInfo.create(null, dataFlowInfo);
947    
948            return JetTypeInfo.create(TypeUtils.makeNullableAsSpecified(type, rightType.isNullable()), dataFlowInfo);
949        }
950    
951        @NotNull
952        public JetTypeInfo checkInExpression(
953                @NotNull JetElement callElement,
954                @NotNull JetSimpleNameExpression operationSign,
955                @Nullable JetExpression left,
956                @Nullable JetExpression right,
957                @NotNull ExpressionTypingContext context
958        ) {
959            ExpressionTypingContext contextWithNoExpectedType = context.replaceExpectedType(NO_EXPECTED_TYPE);
960            if (right == null) {
961                if (left != null) facade.getTypeInfo(left, contextWithNoExpectedType);
962                return JetTypeInfo.create(null, context.dataFlowInfo);
963            }
964    
965            DataFlowInfo dataFlowInfo = facade.getTypeInfo(right, contextWithNoExpectedType).getDataFlowInfo();
966    
967            ExpressionReceiver receiver = safeGetExpressionReceiver(facade, right, contextWithNoExpectedType);
968            ExpressionTypingContext contextWithDataFlow = context.replaceDataFlowInfo(dataFlowInfo);
969    
970            OverloadResolutionResults<FunctionDescriptor> resolutionResult = contextWithDataFlow.resolveCallWithGivenName(
971                    CallMaker.makeCallWithExpressions(callElement, receiver, null, operationSign, Collections.singletonList(left)),
972                    operationSign,
973                    OperatorConventions.CONTAINS);
974            JetType containsType = OverloadResolutionResultsUtil.getResultingType(resolutionResult, context.contextDependency);
975            ensureBooleanResult(operationSign, OperatorConventions.CONTAINS, containsType, context);
976    
977            if (left != null) {
978                dataFlowInfo = facade.getTypeInfo(left, contextWithDataFlow).getDataFlowInfo().and(dataFlowInfo);
979            }
980    
981            return JetTypeInfo.create(resolutionResult.isSuccess() ? KotlinBuiltIns.getInstance().getBooleanType() : null, dataFlowInfo);
982        }
983    
984        private void ensureNonemptyIntersectionOfOperandTypes(JetBinaryExpression expression, ExpressionTypingContext context) {
985            JetExpression left = expression.getLeft();
986            if (left == null) return;
987    
988            JetExpression right = expression.getRight();
989    
990            // TODO : duplicated effort for == and !=
991            JetType leftType = facade.getTypeInfo(left, context).getType();
992            if (leftType != null && right != null) {
993                JetType rightType = facade.getTypeInfo(right, context).getType();
994    
995                if (rightType != null) {
996                    if (TypeUtils.isIntersectionEmpty(leftType, rightType)) {
997                        context.trace.report(EQUALITY_NOT_APPLICABLE.on(expression, expression.getOperationReference(), leftType, rightType));
998                    }
999                    checkSenselessComparisonWithNull(expression, left, right, context);
1000                }
1001            }
1002        }
1003    
1004        private void checkSenselessComparisonWithNull(@NotNull JetBinaryExpression expression, @NotNull JetExpression left, @NotNull JetExpression right, @NotNull ExpressionTypingContext context) {
1005            JetExpression expr;
1006            if (JetPsiUtil.isNullConstant(left)) {
1007                expr = right;
1008            }
1009            else if (JetPsiUtil.isNullConstant(right)) {
1010                expr = left;
1011            }
1012            else return;
1013    
1014            JetSimpleNameExpression operationSign = expression.getOperationReference();
1015            JetType type = facade.getTypeInfo(expr, context).getType();
1016            if (type == null || type.isError()) return;
1017    
1018            DataFlowValue value = DataFlowValueFactory.createDataFlowValue(expr, type, context.trace.getBindingContext());
1019            Nullability nullability = context.dataFlowInfo.getNullability(value);
1020    
1021            boolean expressionIsAlways;
1022            boolean equality = operationSign.getReferencedNameElementType() == JetTokens.EQEQ || operationSign.getReferencedNameElementType() == JetTokens.EQEQEQ;
1023    
1024            if (nullability == Nullability.NULL) {
1025                expressionIsAlways = equality;
1026            }
1027            else if (nullability == Nullability.NOT_NULL) {
1028                expressionIsAlways = !equality;
1029            }
1030            else return;
1031    
1032            context.trace.report(SENSELESS_COMPARISON.on(expression, expression, expressionIsAlways));
1033        }
1034    
1035        @NotNull
1036        private JetTypeInfo visitAssignmentOperation(JetBinaryExpression expression, ExpressionTypingContext context) {
1037            return assignmentIsNotAnExpressionError(expression, context);
1038        }
1039    
1040        @NotNull
1041        private JetTypeInfo visitAssignment(JetBinaryExpression expression, ExpressionTypingContext context) {
1042            return assignmentIsNotAnExpressionError(expression, context);
1043        }
1044    
1045        @NotNull
1046        private JetTypeInfo assignmentIsNotAnExpressionError(JetBinaryExpression expression, ExpressionTypingContext context) {
1047            facade.checkStatementType(expression, context);
1048            context.trace.report(ASSIGNMENT_IN_EXPRESSION_CONTEXT.on(expression));
1049            return JetTypeInfo.create(null, context.dataFlowInfo);
1050        }
1051    
1052        @Override
1053        public JetTypeInfo visitArrayAccessExpression(@NotNull JetArrayAccessExpression expression, ExpressionTypingContext context) {
1054            JetTypeInfo typeInfo = resolveArrayAccessGetMethod(expression, context);
1055            return DataFlowUtils.checkType(typeInfo, expression, context);
1056        }
1057    
1058        @NotNull
1059        public JetTypeInfo getTypeInfoForBinaryCall(
1060                @NotNull Name name,
1061                @NotNull ExpressionTypingContext context,
1062                @NotNull JetBinaryExpression binaryExpression
1063        ) {
1064            JetExpression left = binaryExpression.getLeft();
1065            DataFlowInfo dataFlowInfo = context.dataFlowInfo;
1066            if (left != null) {
1067                //left here is a receiver, so it doesn't depend on expected type
1068                dataFlowInfo = facade.getTypeInfo(
1069                        left, context.replaceContextDependency(INDEPENDENT).replaceExpectedType(NO_EXPECTED_TYPE)).getDataFlowInfo();
1070            }
1071            ExpressionTypingContext contextWithDataFlow = context.replaceDataFlowInfo(dataFlowInfo);
1072    
1073            OverloadResolutionResults<FunctionDescriptor> resolutionResults;
1074            if (left != null) {
1075                ExpressionReceiver receiver = safeGetExpressionReceiver(facade, left, context);
1076                resolutionResults = getResolutionResultsForBinaryCall(context.scope, name, contextWithDataFlow, binaryExpression, receiver);
1077            }
1078            else {
1079                resolutionResults = OverloadResolutionResultsImpl.nameNotFound();
1080            }
1081    
1082            JetExpression right = binaryExpression.getRight();
1083            if (right != null) {
1084                dataFlowInfo = facade.getTypeInfo(right, contextWithDataFlow).getDataFlowInfo();
1085            }
1086    
1087            return JetTypeInfo.create(OverloadResolutionResultsUtil.getResultingType(resolutionResults, context.contextDependency), dataFlowInfo);
1088        }
1089    
1090        @NotNull
1091        static
1092            /*package*/ OverloadResolutionResults<FunctionDescriptor> getResolutionResultsForBinaryCall(
1093                JetScope scope,
1094                Name name,
1095                ExpressionTypingContext context,
1096                JetBinaryExpression binaryExpression,
1097                ExpressionReceiver receiver
1098        ) {
1099    //        ExpressionReceiver receiver = safeGetExpressionReceiver(facade, binaryExpression.getLeft(), context.replaceScope(scope));
1100            return context.replaceScope(scope).resolveCallWithGivenName(
1101                    CallMaker.makeCall(receiver, binaryExpression),
1102                    binaryExpression.getOperationReference(),
1103                    name
1104            );
1105        }
1106    
1107        @Override
1108        public JetTypeInfo visitDeclaration(@NotNull JetDeclaration dcl, ExpressionTypingContext context) {
1109            context.trace.report(DECLARATION_IN_ILLEGAL_CONTEXT.on(dcl));
1110            return JetTypeInfo.create(null, context.dataFlowInfo);
1111        }
1112    
1113        @Override
1114        public JetTypeInfo visitRootNamespaceExpression(@NotNull JetRootNamespaceExpression expression, ExpressionTypingContext context) {
1115            if (context.expressionPosition == ExpressionPosition.LHS_OF_DOT) {
1116                return DataFlowUtils.checkType(JetModuleUtil.getRootNamespaceType(expression), expression, context, context.dataFlowInfo);
1117            }
1118            context.trace.report(NAMESPACE_IS_NOT_AN_EXPRESSION.on(expression));
1119            return JetTypeInfo.create(null, context.dataFlowInfo);
1120        }
1121    
1122    
1123        @Override
1124        public JetTypeInfo visitStringTemplateExpression(@NotNull JetStringTemplateExpression expression, ExpressionTypingContext contextWithExpectedType) {
1125            final ExpressionTypingContext context = contextWithExpectedType.replaceExpectedType(NO_EXPECTED_TYPE).replaceContextDependency(INDEPENDENT);
1126            final StringBuilder builder = new StringBuilder();
1127            final boolean[] isCompileTimeValue = new boolean[] { true };
1128            final DataFlowInfo[] dataFlowInfo = new DataFlowInfo[] { context.dataFlowInfo };
1129    
1130            for (JetStringTemplateEntry entry : expression.getEntries()) {
1131                entry.accept(new JetVisitorVoid() {
1132    
1133                    @Override
1134                    public void visitStringTemplateEntryWithExpression(JetStringTemplateEntryWithExpression entry) {
1135                        JetExpression entryExpression = entry.getExpression();
1136                        if (entryExpression != null) {
1137                            JetTypeInfo typeInfo = facade.getTypeInfo(entryExpression, context.replaceDataFlowInfo(dataFlowInfo[0]));
1138                            dataFlowInfo[0] = typeInfo.getDataFlowInfo();
1139                        }
1140                        isCompileTimeValue[0] = false;
1141                    }
1142    
1143                    @Override
1144                    public void visitLiteralStringTemplateEntry(JetLiteralStringTemplateEntry entry) {
1145                        builder.append(entry.getText());
1146                    }
1147    
1148                    @Override
1149                    public void visitEscapeStringTemplateEntry(JetEscapeStringTemplateEntry entry) {
1150                        CompileTimeConstant<?> character = CompileTimeConstantResolver.escapedStringToCharValue(entry.getText(), entry);
1151                        if (character instanceof ErrorValue) {
1152                            assert character instanceof ErrorValueWithDiagnostic;
1153                            //noinspection CastConflictsWithInstanceof
1154                            context.trace.report(((ErrorValueWithDiagnostic) character).getDiagnostic());
1155                            isCompileTimeValue[0] = false;
1156                        }
1157                        else {
1158                            builder.append(((CharValue) character).getValue());
1159                        }
1160                    }
1161                });
1162            }
1163            if (isCompileTimeValue[0]) {
1164                context.trace.record(BindingContext.COMPILE_TIME_VALUE, expression, new StringValue(builder.toString()));
1165            }
1166            return DataFlowUtils.checkType(KotlinBuiltIns.getInstance().getStringType(), expression, contextWithExpectedType, dataFlowInfo[0]);
1167        }
1168    
1169        @Override
1170        public JetTypeInfo visitAnnotatedExpression(@NotNull JetAnnotatedExpression expression, ExpressionTypingContext context) {
1171            return visitAnnotatedExpression(expression, context, false);
1172        }
1173    
1174        public JetTypeInfo visitAnnotatedExpression(JetAnnotatedExpression expression, ExpressionTypingContext context, boolean isStatement) {
1175            context.expressionTypingServices.getAnnotationResolver().resolveAnnotationsWithArguments(
1176                    context.scope, expression.getAnnotationEntries(), context.trace);
1177    
1178            JetExpression baseExpression = expression.getBaseExpression();
1179            if (baseExpression == null) {
1180                return JetTypeInfo.create(null, context.dataFlowInfo);
1181            }
1182            return facade.getTypeInfo(baseExpression, context, isStatement);
1183        }
1184    
1185        @Override
1186        public JetTypeInfo visitJetElement(@NotNull JetElement element, ExpressionTypingContext context) {
1187            context.trace.report(UNSUPPORTED.on(element, getClass().getCanonicalName()));
1188            return JetTypeInfo.create(null, context.dataFlowInfo);
1189        }
1190    
1191        @NotNull
1192            /*package*/ JetTypeInfo resolveArrayAccessSetMethod(@NotNull JetArrayAccessExpression arrayAccessExpression, @NotNull JetExpression rightHandSide, @NotNull ExpressionTypingContext context, @NotNull BindingTrace traceForResolveResult) {
1193            return resolveArrayAccessSpecialMethod(arrayAccessExpression, rightHandSide, context, traceForResolveResult, false);
1194        }
1195    
1196        @NotNull
1197            /*package*/ JetTypeInfo resolveArrayAccessGetMethod(@NotNull JetArrayAccessExpression arrayAccessExpression, @NotNull ExpressionTypingContext context) {
1198            return resolveArrayAccessSpecialMethod(arrayAccessExpression, null, context, context.trace, true);
1199        }
1200    
1201        @NotNull
1202        private JetTypeInfo resolveArrayAccessSpecialMethod(@NotNull JetArrayAccessExpression arrayAccessExpression,
1203                                                        @Nullable JetExpression rightHandSide, //only for 'set' method
1204                                                        @NotNull ExpressionTypingContext oldContext,
1205                                                        @NotNull BindingTrace traceForResolveResult,
1206                                                        boolean isGet) {
1207            JetExpression arrayExpression = arrayAccessExpression.getArrayExpression();
1208            if (arrayExpression == null) return JetTypeInfo.create(null, oldContext.dataFlowInfo);
1209    
1210            JetTypeInfo arrayTypeInfo = facade.getTypeInfo(arrayExpression, oldContext.replaceExpectedType(NO_EXPECTED_TYPE)
1211                    .replaceContextDependency(INDEPENDENT));
1212            JetType arrayType = arrayTypeInfo.getType();
1213            if (arrayType == null) return arrayTypeInfo;
1214    
1215            DataFlowInfo dataFlowInfo = arrayTypeInfo.getDataFlowInfo();
1216            ExpressionTypingContext context = oldContext.replaceDataFlowInfo(dataFlowInfo);
1217            ExpressionReceiver receiver = new ExpressionReceiver(arrayExpression, arrayType);
1218            if (!isGet) assert rightHandSide != null;
1219    
1220            OverloadResolutionResults<FunctionDescriptor> functionResults = context.resolveCallWithGivenName(
1221                    isGet
1222                    ? CallMaker.makeArrayGetCall(receiver, arrayAccessExpression, Call.CallType.ARRAY_GET_METHOD)
1223                    : CallMaker.makeArraySetCall(receiver, arrayAccessExpression, rightHandSide, Call.CallType.ARRAY_SET_METHOD),
1224                    arrayAccessExpression,
1225                    Name.identifier(isGet ? "get" : "set"));
1226    
1227            List<JetExpression> indices = arrayAccessExpression.getIndexExpressions();
1228            // The accumulated data flow info of all index expressions is saved on the last index
1229            if (!indices.isEmpty()) {
1230                dataFlowInfo = facade.getTypeInfo(indices.get(indices.size() - 1), context).getDataFlowInfo();
1231            }
1232    
1233            if (!isGet) {
1234                dataFlowInfo = facade.getTypeInfo(rightHandSide, context.replaceDataFlowInfo(dataFlowInfo)).getDataFlowInfo();
1235            }
1236    
1237            if (!functionResults.isSingleResult()) {
1238                traceForResolveResult.report(isGet ? NO_GET_METHOD.on(arrayAccessExpression) : NO_SET_METHOD.on(arrayAccessExpression));
1239                return JetTypeInfo.create(null, dataFlowInfo);
1240            }
1241            traceForResolveResult.record(isGet ? INDEXED_LVALUE_GET : INDEXED_LVALUE_SET, arrayAccessExpression, functionResults.getResultingCall());
1242            return JetTypeInfo.create(functionResults.getResultingDescriptor().getReturnType(), dataFlowInfo);
1243        }
1244    }