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.cfg;
018
019 import com.google.common.collect.Lists;
020 import com.google.common.collect.Maps;
021 import com.google.common.collect.Sets;
022 import com.intellij.psi.PsiElement;
023 import com.intellij.psi.tree.IElementType;
024 import com.intellij.psi.util.PsiTreeUtil;
025 import kotlin.Unit;
026 import kotlin.jvm.functions.Function1;
027 import kotlin.jvm.functions.Function3;
028 import org.jetbrains.annotations.NotNull;
029 import org.jetbrains.annotations.Nullable;
030 import org.jetbrains.kotlin.builtins.KotlinBuiltIns;
031 import org.jetbrains.kotlin.cfg.PseudocodeVariablesData.VariableControlFlowState;
032 import org.jetbrains.kotlin.cfg.PseudocodeVariablesData.VariableUseState;
033 import org.jetbrains.kotlin.cfg.pseudocode.PseudoValue;
034 import org.jetbrains.kotlin.cfg.pseudocode.Pseudocode;
035 import org.jetbrains.kotlin.cfg.pseudocode.PseudocodePackage;
036 import org.jetbrains.kotlin.cfg.pseudocode.PseudocodeUtil;
037 import org.jetbrains.kotlin.cfg.pseudocode.instructions.Instruction;
038 import org.jetbrains.kotlin.cfg.pseudocode.instructions.InstructionVisitor;
039 import org.jetbrains.kotlin.cfg.pseudocode.instructions.JetElementInstruction;
040 import org.jetbrains.kotlin.cfg.pseudocode.instructions.eval.*;
041 import org.jetbrains.kotlin.cfg.pseudocode.instructions.jumps.*;
042 import org.jetbrains.kotlin.cfg.pseudocode.instructions.special.LocalFunctionDeclarationInstruction;
043 import org.jetbrains.kotlin.cfg.pseudocode.instructions.special.MarkInstruction;
044 import org.jetbrains.kotlin.cfg.pseudocode.instructions.special.SubroutineExitInstruction;
045 import org.jetbrains.kotlin.cfg.pseudocode.instructions.special.VariableDeclarationInstruction;
046 import org.jetbrains.kotlin.cfg.pseudocodeTraverser.Edges;
047 import org.jetbrains.kotlin.cfg.pseudocodeTraverser.PseudocodeTraverserPackage;
048 import org.jetbrains.kotlin.cfg.pseudocodeTraverser.TraversalOrder;
049 import org.jetbrains.kotlin.descriptors.*;
050 import org.jetbrains.kotlin.diagnostics.Diagnostic;
051 import org.jetbrains.kotlin.diagnostics.DiagnosticFactory;
052 import org.jetbrains.kotlin.diagnostics.Errors;
053 import org.jetbrains.kotlin.idea.MainFunctionDetector;
054 import org.jetbrains.kotlin.lexer.JetTokens;
055 import org.jetbrains.kotlin.psi.*;
056 import org.jetbrains.kotlin.resolve.*;
057 import org.jetbrains.kotlin.resolve.bindingContextUtil.BindingContextUtilPackage;
058 import org.jetbrains.kotlin.resolve.calls.callUtil.CallUtilPackage;
059 import org.jetbrains.kotlin.resolve.calls.model.ResolvedCall;
060 import org.jetbrains.kotlin.resolve.calls.resolvedCallUtil.ResolvedCallUtilPackage;
061 import org.jetbrains.kotlin.resolve.scopes.receivers.ReceiverValue;
062 import org.jetbrains.kotlin.types.JetType;
063 import org.jetbrains.kotlin.types.expressions.ExpressionTypingUtils;
064
065 import java.util.*;
066
067 import static org.jetbrains.kotlin.cfg.PseudocodeVariablesData.VariableUseState.*;
068 import static org.jetbrains.kotlin.cfg.TailRecursionKind.*;
069 import static org.jetbrains.kotlin.cfg.pseudocodeTraverser.TraversalOrder.FORWARD;
070 import static org.jetbrains.kotlin.diagnostics.Errors.*;
071 import static org.jetbrains.kotlin.resolve.BindingContext.CAPTURED_IN_CLOSURE;
072 import static org.jetbrains.kotlin.resolve.BindingContext.TAIL_RECURSION_CALL;
073 import static org.jetbrains.kotlin.resolve.calls.callUtil.CallUtilPackage.getResolvedCall;
074 import static org.jetbrains.kotlin.types.TypeUtils.NO_EXPECTED_TYPE;
075 import static org.jetbrains.kotlin.types.TypeUtils.noExpectedType;
076
077 public class JetFlowInformationProvider {
078
079 private final JetElement subroutine;
080 private final Pseudocode pseudocode;
081 private final BindingTrace trace;
082 private PseudocodeVariablesData pseudocodeVariablesData;
083
084 private JetFlowInformationProvider(
085 @NotNull JetElement declaration,
086 @NotNull BindingTrace trace,
087 @NotNull Pseudocode pseudocode
088 ) {
089 this.subroutine = declaration;
090 this.trace = trace;
091 this.pseudocode = pseudocode;
092 }
093
094 public JetFlowInformationProvider(
095 @NotNull JetElement declaration,
096 @NotNull BindingTrace trace
097 ) {
098 this(declaration, trace, new JetControlFlowProcessor(trace).generatePseudocode(declaration));
099 }
100
101 public PseudocodeVariablesData getPseudocodeVariablesData() {
102 if (pseudocodeVariablesData == null) {
103 pseudocodeVariablesData = new PseudocodeVariablesData(pseudocode, trace.getBindingContext());
104 }
105 return pseudocodeVariablesData;
106 }
107
108 public void checkForLocalClassOrObjectMode() {
109 // Local classes and objects are analyzed twice: when TopDownAnalyzer processes it and as a part of its container.
110 // Almost all checks can be done when the container is analyzed
111 // except recording initialized variables (this information is needed for DeclarationChecker).
112 recordInitializedVariables();
113 }
114
115 public void checkDeclaration() {
116
117 recordInitializedVariables();
118
119 checkLocalFunctions();
120
121 markUninitializedVariables();
122
123 markUnusedVariables();
124
125 markStatements();
126
127 markUnusedExpressions();
128
129 markWhenWithoutElse();
130 }
131
132 public void checkFunction(@Nullable JetType expectedReturnType) {
133 UnreachableCode unreachableCode = collectUnreachableCode();
134 reportUnreachableCode(unreachableCode);
135
136 if (subroutine instanceof JetFunctionLiteral) return;
137
138 checkDefiniteReturn(expectedReturnType != null ? expectedReturnType : NO_EXPECTED_TYPE, unreachableCode);
139
140 markTailCalls();
141 }
142
143 private void collectReturnExpressions(@NotNull final Collection<JetElement> returnedExpressions) {
144 final Set<Instruction> instructions = Sets.newHashSet(pseudocode.getInstructions());
145 SubroutineExitInstruction exitInstruction = pseudocode.getExitInstruction();
146 for (Instruction previousInstruction : exitInstruction.getPreviousInstructions()) {
147 previousInstruction.accept(new InstructionVisitor() {
148 @Override
149 public void visitReturnValue(@NotNull ReturnValueInstruction instruction) {
150 if (instructions.contains(instruction)) { //exclude non-local return expressions
151 returnedExpressions.add(instruction.getElement());
152 }
153 }
154
155 @Override
156 public void visitReturnNoValue(@NotNull ReturnNoValueInstruction instruction) {
157 if (instructions.contains(instruction)) {
158 returnedExpressions.add(instruction.getElement());
159 }
160 }
161
162
163 @Override
164 public void visitJump(@NotNull AbstractJumpInstruction instruction) {
165 // Nothing
166 }
167
168 @Override
169 public void visitUnconditionalJump(@NotNull UnconditionalJumpInstruction instruction) {
170 redirectToPrevInstructions(instruction);
171 }
172
173 private void redirectToPrevInstructions(Instruction instruction) {
174 for (Instruction previousInstruction : instruction.getPreviousInstructions()) {
175 previousInstruction.accept(this);
176 }
177 }
178
179 @Override
180 public void visitNondeterministicJump(@NotNull NondeterministicJumpInstruction instruction) {
181 redirectToPrevInstructions(instruction);
182 }
183
184 @Override
185 public void visitMarkInstruction(@NotNull MarkInstruction instruction) {
186 redirectToPrevInstructions(instruction);
187 }
188
189 @Override
190 public void visitInstruction(@NotNull Instruction instruction) {
191 if (instruction instanceof JetElementInstruction) {
192 JetElementInstruction elementInstruction = (JetElementInstruction) instruction;
193 returnedExpressions.add(elementInstruction.getElement());
194 }
195 else {
196 throw new IllegalStateException(instruction + " precedes the exit point");
197 }
198 }
199 });
200 }
201 }
202
203 private void checkLocalFunctions() {
204 for (LocalFunctionDeclarationInstruction localDeclarationInstruction : pseudocode.getLocalDeclarations()) {
205 JetElement element = localDeclarationInstruction.getElement();
206 if (element instanceof JetDeclarationWithBody) {
207 JetDeclarationWithBody localDeclaration = (JetDeclarationWithBody) element;
208
209 CallableDescriptor functionDescriptor =
210 (CallableDescriptor) trace.getBindingContext().get(BindingContext.DECLARATION_TO_DESCRIPTOR, localDeclaration);
211 JetType expectedType = functionDescriptor != null ? functionDescriptor.getReturnType() : null;
212
213 JetFlowInformationProvider providerForLocalDeclaration =
214 new JetFlowInformationProvider(localDeclaration, trace, localDeclarationInstruction.getBody());
215
216 providerForLocalDeclaration.checkFunction(expectedType);
217 }
218 }
219 }
220
221 public void checkDefiniteReturn(final @NotNull JetType expectedReturnType, @NotNull final UnreachableCode unreachableCode) {
222 assert subroutine instanceof JetDeclarationWithBody;
223 JetDeclarationWithBody function = (JetDeclarationWithBody) subroutine;
224
225 if (!function.hasBody()) return;
226
227 List<JetElement> returnedExpressions = Lists.newArrayList();
228 collectReturnExpressions(returnedExpressions);
229
230 final boolean blockBody = function.hasBlockBody();
231
232 final boolean[] noReturnError = new boolean[] { false };
233 for (JetElement returnedExpression : returnedExpressions) {
234 returnedExpression.accept(new JetVisitorVoid() {
235 @Override
236 public void visitReturnExpression(@NotNull JetReturnExpression expression) {
237 if (!blockBody) {
238 trace.report(RETURN_IN_FUNCTION_WITH_EXPRESSION_BODY.on(expression));
239 }
240 }
241
242 @Override
243 public void visitJetElement(@NotNull JetElement element) {
244 if (!(element instanceof JetExpression || element instanceof JetWhenCondition)) return;
245
246 if (blockBody && !noExpectedType(expectedReturnType)
247 && !KotlinBuiltIns.isUnit(expectedReturnType)
248 && !unreachableCode.getElements().contains(element)) {
249 noReturnError[0] = true;
250 }
251 }
252 });
253 }
254 if (noReturnError[0]) {
255 trace.report(NO_RETURN_IN_FUNCTION_WITH_BLOCK_BODY.on(function));
256 }
257 }
258
259 private void reportUnreachableCode(@NotNull UnreachableCode unreachableCode) {
260 for (JetElement element : unreachableCode.getElements()) {
261 trace.report(UNREACHABLE_CODE.on(element, unreachableCode.getUnreachableTextRanges(element)));
262 trace.record(BindingContext.UNREACHABLE_CODE, element, true);
263 }
264 }
265
266 @NotNull
267 private UnreachableCode collectUnreachableCode() {
268 Set<JetElement> reachableElements = Sets.newHashSet();
269 Set<JetElement> unreachableElements = Sets.newHashSet();
270 for (Instruction instruction : pseudocode.getInstructionsIncludingDeadCode()) {
271 if (!(instruction instanceof JetElementInstruction)
272 || instruction instanceof LoadUnitValueInstruction
273 || instruction instanceof MergeInstruction
274 || (instruction instanceof MagicInstruction && ((MagicInstruction) instruction).getSynthetic())) continue;
275
276 JetElement element = ((JetElementInstruction) instruction).getElement();
277
278 if (instruction instanceof JumpInstruction) {
279 boolean isJumpElement = element instanceof JetBreakExpression
280 || element instanceof JetContinueExpression
281 || element instanceof JetReturnExpression
282 || element instanceof JetThrowExpression;
283 if (!isJumpElement) continue;
284 }
285
286 if (instruction.getDead()) {
287 unreachableElements.add(element);
288 }
289 else {
290 reachableElements.add(element);
291 }
292 }
293 return new UnreachableCodeImpl(reachableElements, unreachableElements);
294 }
295
296 ////////////////////////////////////////////////////////////////////////////////
297 // Uninitialized variables analysis
298
299 public void markUninitializedVariables() {
300 final Collection<VariableDescriptor> varWithUninitializedErrorGenerated = Sets.newHashSet();
301 final Collection<VariableDescriptor> varWithValReassignErrorGenerated = Sets.newHashSet();
302 final boolean processClassOrObject = subroutine instanceof JetClassOrObject;
303
304 PseudocodeVariablesData pseudocodeVariablesData = getPseudocodeVariablesData();
305 Map<Instruction, Edges<Map<VariableDescriptor, VariableControlFlowState>>> initializers =
306 pseudocodeVariablesData.getVariableInitializers();
307 final Set<VariableDescriptor> declaredVariables = pseudocodeVariablesData.getDeclaredVariables(pseudocode, true);
308 final LexicalScopeVariableInfo lexicalScopeVariableInfo = pseudocodeVariablesData.getLexicalScopeVariableInfo();
309
310 final Map<Instruction, DiagnosticFactory<?>> reportedDiagnosticMap = Maps.newHashMap();
311
312 PseudocodeTraverserPackage.traverse(
313 pseudocode, FORWARD, initializers,
314 new InstructionDataAnalyzeStrategy<Map<VariableDescriptor, VariableControlFlowState>>() {
315 @Override
316 public void execute(
317 @NotNull Instruction instruction,
318 @Nullable Map<VariableDescriptor, VariableControlFlowState> in,
319 @Nullable Map<VariableDescriptor, VariableControlFlowState> out
320 ) {
321 assert in != null && out != null;
322 VariableInitContext ctxt =
323 new VariableInitContext(instruction, reportedDiagnosticMap, in, out, lexicalScopeVariableInfo);
324 if (ctxt.variableDescriptor == null) return;
325 if (instruction instanceof ReadValueInstruction) {
326 ReadValueInstruction readValueInstruction = (ReadValueInstruction) instruction;
327 JetElement element = readValueInstruction.getElement();
328 boolean error = checkBackingField(ctxt, element);
329 if (!error &&
330 PseudocodeUtil.isThisOrNoDispatchReceiver(readValueInstruction, trace.getBindingContext()) &&
331 declaredVariables.contains(ctxt.variableDescriptor)) {
332 checkIsInitialized(ctxt, element, varWithUninitializedErrorGenerated);
333 }
334 return;
335 }
336 if (!(instruction instanceof WriteValueInstruction)) return;
337 WriteValueInstruction writeValueInstruction = (WriteValueInstruction) instruction;
338 JetElement element = writeValueInstruction.getlValue();
339 boolean error = checkBackingField(ctxt, element);
340 if (!(element instanceof JetExpression)) return;
341 if (!error) {
342 error = checkValReassignment(ctxt, (JetExpression) element, writeValueInstruction,
343 varWithValReassignErrorGenerated);
344 }
345 if (!error && processClassOrObject) {
346 error = checkAssignmentBeforeDeclaration(ctxt, (JetExpression) element);
347 }
348 if (!error && processClassOrObject) {
349 checkInitializationUsingBackingField(ctxt, (JetExpression) element);
350 }
351 }
352 }
353 );
354 }
355
356 public void recordInitializedVariables() {
357 PseudocodeVariablesData pseudocodeVariablesData = getPseudocodeVariablesData();
358 Pseudocode pseudocode = pseudocodeVariablesData.getPseudocode();
359 Map<Instruction, Edges<Map<VariableDescriptor, VariableControlFlowState>>> initializers =
360 pseudocodeVariablesData.getVariableInitializers();
361 recordInitializedVariables(pseudocode, initializers);
362 for (LocalFunctionDeclarationInstruction instruction : pseudocode.getLocalDeclarations()) {
363 recordInitializedVariables(instruction.getBody(), initializers);
364 }
365 }
366
367 private void checkIsInitialized(
368 @NotNull VariableInitContext ctxt,
369 @NotNull JetElement element,
370 @NotNull Collection<VariableDescriptor> varWithUninitializedErrorGenerated
371 ) {
372 if (!(element instanceof JetSimpleNameExpression)) return;
373
374
375 boolean isDefinitelyInitialized = ctxt.exitInitState.definitelyInitialized();
376 VariableDescriptor variableDescriptor = ctxt.variableDescriptor;
377 if (variableDescriptor instanceof PropertyDescriptor) {
378 if (!trace.get(BindingContext.BACKING_FIELD_REQUIRED, (PropertyDescriptor) variableDescriptor)) {
379 isDefinitelyInitialized = true;
380 }
381 }
382 if (!isDefinitelyInitialized && !varWithUninitializedErrorGenerated.contains(variableDescriptor)) {
383 if (!(variableDescriptor instanceof PropertyDescriptor)) {
384 varWithUninitializedErrorGenerated.add(variableDescriptor);
385 }
386 if (variableDescriptor instanceof ValueParameterDescriptor) {
387 report(Errors.UNINITIALIZED_PARAMETER.on((JetSimpleNameExpression) element,
388 (ValueParameterDescriptor) variableDescriptor), ctxt);
389 }
390 else {
391 report(Errors.UNINITIALIZED_VARIABLE.on((JetSimpleNameExpression) element, variableDescriptor), ctxt);
392 }
393 }
394 }
395
396 private boolean checkValReassignment(
397 @NotNull VariableInitContext ctxt,
398 @NotNull JetExpression expression,
399 @NotNull WriteValueInstruction writeValueInstruction,
400 @NotNull Collection<VariableDescriptor> varWithValReassignErrorGenerated
401 ) {
402 VariableDescriptor variableDescriptor = ctxt.variableDescriptor;
403 if (JetPsiUtil.isBackingFieldReference(expression) && variableDescriptor instanceof PropertyDescriptor) {
404 PropertyDescriptor propertyDescriptor = (PropertyDescriptor) variableDescriptor;
405 JetPropertyAccessor accessor = PsiTreeUtil.getParentOfType(expression, JetPropertyAccessor.class);
406 if (accessor != null) {
407 DeclarationDescriptor accessorDescriptor = trace.get(BindingContext.DECLARATION_TO_DESCRIPTOR, accessor);
408 if (propertyDescriptor.getGetter() == accessorDescriptor) {
409 //val can be reassigned through backing field inside its own getter
410 return false;
411 }
412 }
413 }
414
415 boolean mayBeInitializedNotHere = ctxt.enterInitState.mayBeInitialized();
416 boolean hasBackingField = true;
417 if (variableDescriptor instanceof PropertyDescriptor) {
418 hasBackingField = trace.get(BindingContext.BACKING_FIELD_REQUIRED, (PropertyDescriptor) variableDescriptor);
419 }
420 if (variableDescriptor.isVar() && variableDescriptor instanceof PropertyDescriptor) {
421 DeclarationDescriptor descriptor = BindingContextUtils.getEnclosingDescriptor(trace.getBindingContext(), expression);
422 PropertySetterDescriptor setterDescriptor = ((PropertyDescriptor) variableDescriptor).getSetter();
423
424 ResolvedCall<? extends CallableDescriptor> resolvedCall = CallUtilPackage.getResolvedCall(expression, trace.getBindingContext());
425 ReceiverValue receiverValue = ReceiverValue.IRRELEVANT_RECEIVER;
426 if (resolvedCall != null) {
427 receiverValue = ExpressionTypingUtils
428 .normalizeReceiverValueForVisibility(resolvedCall.getDispatchReceiver(), trace.getBindingContext());
429
430 }
431 if (Visibilities.isVisible(receiverValue, variableDescriptor, descriptor) && setterDescriptor != null
432 && !Visibilities.isVisible(receiverValue, setterDescriptor, descriptor)) {
433 report(Errors.INVISIBLE_SETTER.on(expression, variableDescriptor, setterDescriptor.getVisibility(),
434 variableDescriptor.getContainingDeclaration()), ctxt);
435 return true;
436 }
437 }
438 boolean isThisOrNoDispatchReceiver =
439 PseudocodeUtil.isThisOrNoDispatchReceiver(writeValueInstruction, trace.getBindingContext());
440 if ((mayBeInitializedNotHere || !hasBackingField || !isThisOrNoDispatchReceiver) && !variableDescriptor.isVar()) {
441 boolean hasReassignMethodReturningUnit = false;
442 JetSimpleNameExpression operationReference = null;
443 PsiElement parent = expression.getParent();
444 if (parent instanceof JetBinaryExpression) {
445 operationReference = ((JetBinaryExpression) parent).getOperationReference();
446 }
447 else if (parent instanceof JetUnaryExpression) {
448 operationReference = ((JetUnaryExpression) parent).getOperationReference();
449 }
450 if (operationReference != null) {
451 DeclarationDescriptor descriptor = trace.get(BindingContext.REFERENCE_TARGET, operationReference);
452 if (descriptor instanceof FunctionDescriptor) {
453 if (KotlinBuiltIns.isUnit(((FunctionDescriptor) descriptor).getReturnType())) {
454 hasReassignMethodReturningUnit = true;
455 }
456 }
457 if (descriptor == null) {
458 Collection<? extends DeclarationDescriptor> descriptors =
459 trace.get(BindingContext.AMBIGUOUS_REFERENCE_TARGET, operationReference);
460 if (descriptors != null) {
461 for (DeclarationDescriptor referenceDescriptor : descriptors) {
462 if (KotlinBuiltIns.isUnit(((FunctionDescriptor) referenceDescriptor).getReturnType())) {
463 hasReassignMethodReturningUnit = true;
464 }
465 }
466 }
467 }
468 }
469 if (!hasReassignMethodReturningUnit) {
470 if (!isThisOrNoDispatchReceiver || !varWithValReassignErrorGenerated.contains(variableDescriptor)) {
471 report(Errors.VAL_REASSIGNMENT.on(expression, variableDescriptor), ctxt);
472 }
473 if (isThisOrNoDispatchReceiver) {
474 // try to get rid of repeating VAL_REASSIGNMENT diagnostic only for vars with no receiver
475 // or when receiver is this
476 varWithValReassignErrorGenerated.add(variableDescriptor);
477 }
478 return true;
479 }
480 }
481 return false;
482 }
483
484 private boolean checkAssignmentBeforeDeclaration(@NotNull VariableInitContext ctxt, @NotNull JetExpression expression) {
485 if (!ctxt.enterInitState.isDeclared && !ctxt.exitInitState.isDeclared
486 && !ctxt.enterInitState.mayBeInitialized() && ctxt.exitInitState.mayBeInitialized()) {
487 report(Errors.INITIALIZATION_BEFORE_DECLARATION.on(expression, ctxt.variableDescriptor), ctxt);
488 return true;
489 }
490 return false;
491 }
492
493 private boolean checkInitializationUsingBackingField(@NotNull VariableInitContext ctxt, @NotNull JetExpression expression) {
494 VariableDescriptor variableDescriptor = ctxt.variableDescriptor;
495 if (variableDescriptor instanceof PropertyDescriptor
496 && !ctxt.enterInitState.mayBeInitialized() && ctxt.exitInitState.mayBeInitialized()) {
497 if (!variableDescriptor.isVar()) return false;
498 if (!trace.get(BindingContext.BACKING_FIELD_REQUIRED, (PropertyDescriptor) variableDescriptor)) return false;
499 PsiElement property = DescriptorToSourceUtils.descriptorToDeclaration(variableDescriptor);
500 assert property instanceof JetProperty;
501 if (((PropertyDescriptor) variableDescriptor).getModality() == Modality.FINAL && ((JetProperty) property).getSetter() == null) {
502 return false;
503 }
504 JetExpression variable = expression;
505 if (expression instanceof JetDotQualifiedExpression) {
506 if (((JetDotQualifiedExpression) expression).getReceiverExpression() instanceof JetThisExpression) {
507 variable = ((JetDotQualifiedExpression) expression).getSelectorExpression();
508 }
509 }
510 if (variable instanceof JetSimpleNameExpression) {
511 JetSimpleNameExpression simpleNameExpression = (JetSimpleNameExpression) variable;
512 if (simpleNameExpression.getReferencedNameElementType() != JetTokens.FIELD_IDENTIFIER) {
513 if (((PropertyDescriptor) variableDescriptor).getModality() != Modality.FINAL) {
514 report(Errors.INITIALIZATION_USING_BACKING_FIELD_OPEN_SETTER.on(expression, variableDescriptor), ctxt);
515 }
516 else {
517 report(Errors.INITIALIZATION_USING_BACKING_FIELD_CUSTOM_SETTER.on(expression, variableDescriptor), ctxt);
518 }
519 return true;
520 }
521 }
522 }
523 return false;
524 }
525
526 private boolean checkBackingField(@NotNull VariableContext cxtx, @NotNull JetElement element) {
527 VariableDescriptor variableDescriptor = cxtx.variableDescriptor;
528 boolean[] error = new boolean[1];
529 if (!isCorrectBackingFieldReference(element, cxtx, error, true)) return false;
530 if (error[0]) return true;
531 if (!(variableDescriptor instanceof PropertyDescriptor)) {
532 report(Errors.NOT_PROPERTY_BACKING_FIELD.on(element), cxtx);
533 return true;
534 }
535 PsiElement property = DescriptorToSourceUtils.descriptorToDeclaration(variableDescriptor);
536 boolean insideSelfAccessors = PsiTreeUtil.isAncestor(property, element, false);
537 if (!trace.get(BindingContext.BACKING_FIELD_REQUIRED, (PropertyDescriptor) variableDescriptor) &&
538 // not to generate error in accessors of abstract properties, there is one: declared accessor of abstract property
539 !insideSelfAccessors) {
540
541 if (((PropertyDescriptor) variableDescriptor).getModality() == Modality.ABSTRACT) {
542 report(NO_BACKING_FIELD_ABSTRACT_PROPERTY.on(element), cxtx);
543 }
544 else {
545 report(NO_BACKING_FIELD_CUSTOM_ACCESSORS.on(element), cxtx);
546 }
547 return true;
548 }
549 if (insideSelfAccessors) return false;
550
551 DeclarationDescriptor declarationDescriptor = BindingContextUtils.getEnclosingDescriptor(trace.getBindingContext(), element);
552
553 DeclarationDescriptor containingDeclaration = variableDescriptor.getContainingDeclaration();
554 if ((containingDeclaration instanceof ClassDescriptor)
555 && DescriptorUtils.isAncestor(containingDeclaration, declarationDescriptor, false)) {
556 return false;
557 }
558 report(Errors.INACCESSIBLE_BACKING_FIELD.on(element), cxtx);
559 return true;
560 }
561
562 private boolean isCorrectBackingFieldReference(
563 @Nullable JetElement element,
564 VariableContext ctxt,
565 boolean[] error,
566 boolean reportError
567 ) {
568 error[0] = false;
569 if (JetPsiUtil.isBackingFieldReference(element)) {
570 return true;
571 }
572 if (element instanceof JetDotQualifiedExpression && isCorrectBackingFieldReference(
573 ((JetDotQualifiedExpression) element).getSelectorExpression(), ctxt, error, false)) {
574 if (((JetDotQualifiedExpression) element).getReceiverExpression() instanceof JetThisExpression) {
575 return true;
576 }
577 error[0] = true;
578 if (reportError) {
579 report(Errors.INACCESSIBLE_BACKING_FIELD.on(element), ctxt);
580 }
581 }
582 return false;
583 }
584
585 private void recordInitializedVariables(
586 @NotNull Pseudocode pseudocode,
587 @NotNull Map<Instruction, Edges<Map<VariableDescriptor, VariableControlFlowState>>> initializersMap
588 ) {
589 Edges<Map<VariableDescriptor, VariableControlFlowState>> initializers = initializersMap.get(pseudocode.getExitInstruction());
590 if (initializers == null) return;
591 Set<VariableDescriptor> declaredVariables = getPseudocodeVariablesData().getDeclaredVariables(pseudocode, false);
592 for (VariableDescriptor variable : declaredVariables) {
593 if (variable instanceof PropertyDescriptor) {
594 VariableControlFlowState variableControlFlowState = initializers.getIncoming().get(variable);
595 if (variableControlFlowState != null && variableControlFlowState.definitelyInitialized()) continue;
596 trace.record(BindingContext.IS_UNINITIALIZED, (PropertyDescriptor) variable);
597 }
598 }
599 }
600
601 ////////////////////////////////////////////////////////////////////////////////
602 // "Unused variable" & "unused value" analyses
603
604 public void markUnusedVariables() {
605 final PseudocodeVariablesData pseudocodeVariablesData = getPseudocodeVariablesData();
606 Map<Instruction, Edges<Map<VariableDescriptor, VariableUseState>>> variableStatusData =
607 pseudocodeVariablesData.getVariableUseStatusData();
608 final Map<Instruction, DiagnosticFactory<?>> reportedDiagnosticMap = Maps.newHashMap();
609 InstructionDataAnalyzeStrategy<Map<VariableDescriptor, VariableUseState>> variableStatusAnalyzeStrategy =
610 new InstructionDataAnalyzeStrategy<Map<VariableDescriptor, VariableUseState>>() {
611 @Override
612 public void execute(
613 @NotNull Instruction instruction,
614 @Nullable Map<VariableDescriptor, VariableUseState> in,
615 @Nullable Map<VariableDescriptor, VariableUseState> out
616 ) {
617
618 assert in != null && out != null;
619 VariableContext ctxt = new VariableUseContext(instruction, reportedDiagnosticMap, in, out);
620 Set<VariableDescriptor> declaredVariables =
621 pseudocodeVariablesData.getDeclaredVariables(instruction.getOwner(), false);
622 VariableDescriptor variableDescriptor = PseudocodeUtil.extractVariableDescriptorIfAny(
623 instruction, false, trace.getBindingContext());
624 if (variableDescriptor == null || !declaredVariables.contains(variableDescriptor)
625 || !ExpressionTypingUtils.isLocal(variableDescriptor.getContainingDeclaration(), variableDescriptor)) {
626 return;
627 }
628 PseudocodeVariablesData.VariableUseState variableUseState = in.get(variableDescriptor);
629 if (instruction instanceof WriteValueInstruction) {
630 if (trace.get(CAPTURED_IN_CLOSURE, variableDescriptor) != null) return;
631 JetElement element = ((WriteValueInstruction) instruction).getElement();
632 if (variableUseState != READ) {
633 if (element instanceof JetBinaryExpression &&
634 ((JetBinaryExpression) element).getOperationToken() == JetTokens.EQ) {
635 JetExpression right = ((JetBinaryExpression) element).getRight();
636 if (right != null) {
637 report(Errors.UNUSED_VALUE.on((JetBinaryExpression) element, right, variableDescriptor), ctxt);
638 }
639 }
640 else if (element instanceof JetPostfixExpression) {
641 IElementType operationToken =
642 ((JetPostfixExpression) element).getOperationReference().getReferencedNameElementType();
643 if (operationToken == JetTokens.PLUSPLUS || operationToken == JetTokens.MINUSMINUS) {
644 report(Errors.UNUSED_CHANGED_VALUE.on(element, element), ctxt);
645 }
646 }
647 }
648 }
649 else if (instruction instanceof VariableDeclarationInstruction) {
650 JetDeclaration element = ((VariableDeclarationInstruction) instruction).getVariableDeclarationElement();
651 if (!(element instanceof JetNamedDeclaration)) return;
652 PsiElement nameIdentifier = ((JetNamedDeclaration) element).getNameIdentifier();
653 if (nameIdentifier == null) return;
654 if (!VariableUseState.isUsed(variableUseState)) {
655 if (JetPsiUtil.isVariableNotParameterDeclaration(element)) {
656 report(Errors.UNUSED_VARIABLE.on((JetNamedDeclaration) element, variableDescriptor), ctxt);
657 }
658 else if (element instanceof JetParameter) {
659 PsiElement owner = element.getParent().getParent();
660 if (owner instanceof JetPrimaryConstructor) {
661 if (!((JetParameter) element).hasValOrVar()) {
662 JetClassOrObject containingClass = ((JetPrimaryConstructor) owner).getContainingClassOrObject();
663 DeclarationDescriptor containingClassDescriptor = trace.get(
664 BindingContext.DECLARATION_TO_DESCRIPTOR, containingClass
665 );
666 if (!DescriptorUtils.isAnnotationClass(containingClassDescriptor)) {
667 report(Errors.UNUSED_PARAMETER.on((JetParameter) element, variableDescriptor), ctxt);
668 }
669 }
670 }
671 else if (owner instanceof JetFunction) {
672 MainFunctionDetector mainFunctionDetector = new MainFunctionDetector(trace.getBindingContext());
673 boolean isMain = (owner instanceof JetNamedFunction) && mainFunctionDetector.isMain((JetNamedFunction) owner);
674 if (owner instanceof JetFunctionLiteral) return;
675 DeclarationDescriptor descriptor = trace.get(BindingContext.DECLARATION_TO_DESCRIPTOR, owner);
676 assert descriptor instanceof FunctionDescriptor : owner.getText();
677 FunctionDescriptor functionDescriptor = (FunctionDescriptor) descriptor;
678 String functionName = functionDescriptor.getName().asString();
679 if (isMain
680 || functionDescriptor.getModality().isOverridable()
681 || !functionDescriptor.getOverriddenDescriptors().isEmpty()
682 || "get".equals(functionName) || "set".equals(functionName) || "propertyDelegated".equals(functionName)
683 ) {
684 return;
685 }
686 report(Errors.UNUSED_PARAMETER.on((JetParameter) element, variableDescriptor), ctxt);
687 }
688 }
689 }
690 else if (variableUseState == ONLY_WRITTEN_NEVER_READ && JetPsiUtil.isVariableNotParameterDeclaration(element)) {
691 report(Errors.ASSIGNED_BUT_NEVER_ACCESSED_VARIABLE.on((JetNamedDeclaration) element, variableDescriptor), ctxt);
692 }
693 else if (variableUseState == WRITTEN_AFTER_READ && element instanceof JetVariableDeclaration) {
694 if (element instanceof JetProperty) {
695 JetExpression initializer = ((JetProperty) element).getInitializer();
696 if (initializer != null) {
697 report(Errors.VARIABLE_WITH_REDUNDANT_INITIALIZER.on(initializer, variableDescriptor), ctxt);
698 }
699 }
700 else if (element instanceof JetMultiDeclarationEntry) {
701 report(VARIABLE_WITH_REDUNDANT_INITIALIZER.on(element, variableDescriptor), ctxt);
702 }
703 }
704 }
705 }
706 };
707 PseudocodeTraverserPackage.traverse(pseudocode, TraversalOrder.BACKWARD, variableStatusData, variableStatusAnalyzeStrategy);
708 }
709
710 ////////////////////////////////////////////////////////////////////////////////
711 // "Unused expressions" in block
712
713 public void markUnusedExpressions() {
714 final Map<Instruction, DiagnosticFactory<?>> reportedDiagnosticMap = Maps.newHashMap();
715 PseudocodeTraverserPackage.traverse(
716 pseudocode, FORWARD, new JetFlowInformationProvider.FunctionVoid1<Instruction>() {
717 @Override
718 public void execute(@NotNull Instruction instruction) {
719 if (!(instruction instanceof JetElementInstruction)) return;
720
721 JetElement element = ((JetElementInstruction)instruction).getElement();
722 if (!(element instanceof JetExpression)) return;
723
724 if (BindingContextUtilPackage.isUsedAsStatement((JetExpression) element, trace.getBindingContext())
725 && PseudocodePackage.getSideEffectFree(instruction)) {
726 VariableContext ctxt = new VariableContext(instruction, reportedDiagnosticMap);
727 report(
728 element instanceof JetFunctionLiteralExpression
729 ? Errors.UNUSED_FUNCTION_LITERAL.on((JetFunctionLiteralExpression) element)
730 : Errors.UNUSED_EXPRESSION.on(element),
731 ctxt
732 );
733 }
734 }
735 }
736 );
737 }
738
739 ////////////////////////////////////////////////////////////////////////////////
740 // Statements
741
742 public void markStatements() {
743 PseudocodeTraverserPackage.traverse(
744 pseudocode, FORWARD, new JetFlowInformationProvider.FunctionVoid1<Instruction>() {
745 @Override
746 public void execute(@NotNull Instruction instruction) {
747 PseudoValue value = instruction instanceof InstructionWithValue
748 ? ((InstructionWithValue) instruction).getOutputValue()
749 : null;
750 Pseudocode pseudocode = instruction.getOwner();
751 boolean isUsedAsExpression = !pseudocode.getUsages(value).isEmpty();
752 for (JetElement element : pseudocode.getValueElements(value)) {
753 trace.record(BindingContext.USED_AS_EXPRESSION, element, isUsedAsExpression);
754 }
755 }
756 }
757 );
758 }
759
760 public void markWhenWithoutElse() {
761 PseudocodeTraverserPackage.traverse(
762 pseudocode, FORWARD, new JetFlowInformationProvider.FunctionVoid1<Instruction>() {
763 @Override
764 public void execute(@NotNull Instruction instruction) {
765 PseudoValue value = instruction instanceof InstructionWithValue
766 ? ((InstructionWithValue) instruction).getOutputValue()
767 : null;
768 for (JetElement element : instruction.getOwner().getValueElements(value)) {
769 if (!(element instanceof JetWhenExpression)) continue;
770 JetWhenExpression whenExpression = (JetWhenExpression) element;
771 if (whenExpression.getElseExpression() != null) continue;
772
773 if (WhenChecker.mustHaveElse(whenExpression, trace)) {
774 trace.report(NO_ELSE_IN_WHEN.on(whenExpression));
775 }
776 else if (whenExpression.getSubjectExpression() != null) {
777 ClassDescriptor enumClassDescriptor = WhenChecker.getClassDescriptorOfTypeIfEnum(
778 trace.getType(whenExpression.getSubjectExpression()));
779 if (enumClassDescriptor != null
780 && !WhenChecker.isWhenOnEnumExhaustive(whenExpression, trace, enumClassDescriptor)) {
781 trace.report(NON_EXHAUSTIVE_WHEN.on(whenExpression));
782 }
783 }
784 }
785 }
786 }
787 );
788 }
789
790 ////////////////////////////////////////////////////////////////////////////////
791 // Tail calls
792
793 public void markTailCalls() {
794 final DeclarationDescriptor subroutineDescriptor = trace.get(BindingContext.DECLARATION_TO_DESCRIPTOR, subroutine);
795 if (!(subroutineDescriptor instanceof FunctionDescriptor)) return;
796 if (!KotlinBuiltIns.isTailRecursive(subroutineDescriptor)) return;
797
798 // finally blocks are copied which leads to multiple diagnostics reported on one instruction
799 class KindAndCall {
800 TailRecursionKind kind;
801 ResolvedCall<?> call;
802
803 KindAndCall(TailRecursionKind kind, ResolvedCall<?> call) {
804 this.kind = kind;
805 this.call = call;
806 }
807 }
808 final Map<JetElement, KindAndCall> calls = new HashMap<JetElement, KindAndCall>();
809 PseudocodeTraverserPackage.traverse(
810 pseudocode,
811 FORWARD,
812 new FunctionVoid1<Instruction>() {
813 public void execute(@NotNull Instruction instruction) {
814 if (!(instruction instanceof CallInstruction)) return;
815 CallInstruction callInstruction = (CallInstruction) instruction;
816
817 ResolvedCall<?> resolvedCall = getResolvedCall(callInstruction.getElement(), trace.getBindingContext());
818 if (resolvedCall == null) return;
819
820 // is this a recursive call?
821 CallableDescriptor functionDescriptor = resolvedCall.getResultingDescriptor();
822 if (!functionDescriptor.getOriginal().equals(subroutineDescriptor)) return;
823
824 JetElement element = callInstruction.getElement();
825 //noinspection unchecked
826 JetExpression parent = PsiTreeUtil.getParentOfType(
827 element,
828 JetTryExpression.class, JetFunction.class, JetClassInitializer.class
829 );
830
831 if (parent instanceof JetTryExpression) {
832 // We do not support tail calls Collections.singletonMap() try-catch-finally, for simplicity of the mental model
833 // very few cases there would be real tail-calls, and it's often not so easy for the user to see why
834 calls.put(element, new KindAndCall(IN_TRY, resolvedCall));
835 return;
836 }
837
838 boolean isTail = PseudocodeTraverserPackage.traverseFollowingInstructions(
839 callInstruction,
840 new HashSet<Instruction>(),
841 FORWARD,
842 new TailRecursionDetector(subroutine, callInstruction)
843 );
844
845 // A tail call is not allowed to change dispatch receiver
846 // class C {
847 // fun foo(other: C) {
848 // other.foo(this) // not a tail call
849 // }
850 // }
851 boolean sameDispatchReceiver =
852 ResolvedCallUtilPackage.hasThisOrNoDispatchReceiver(resolvedCall, trace.getBindingContext());
853
854 TailRecursionKind kind = isTail && sameDispatchReceiver ? TAIL_CALL : NON_TAIL;
855
856 KindAndCall kindAndCall = calls.get(element);
857 calls.put(element,
858 new KindAndCall(
859 combineKinds(kind, kindAndCall == null ? null : kindAndCall.kind),
860 resolvedCall
861 )
862 );
863 }
864 }
865 );
866 boolean hasTailCalls = false;
867 for (Map.Entry<JetElement, KindAndCall> entry : calls.entrySet()) {
868 JetElement element = entry.getKey();
869 KindAndCall kindAndCall = entry.getValue();
870 switch (kindAndCall.kind) {
871 case TAIL_CALL:
872 trace.record(TAIL_RECURSION_CALL, kindAndCall.call, TailRecursionKind.TAIL_CALL);
873 hasTailCalls = true;
874 break;
875 case IN_TRY:
876 trace.report(Errors.TAIL_RECURSION_IN_TRY_IS_NOT_SUPPORTED.on(element));
877 break;
878 case NON_TAIL:
879 trace.report(Errors.NON_TAIL_RECURSIVE_CALL.on(element));
880 break;
881 }
882 }
883
884 if (!hasTailCalls) {
885 trace.report(Errors.NO_TAIL_CALLS_FOUND.on((JetNamedFunction) subroutine));
886 }
887 }
888
889 private static TailRecursionKind combineKinds(TailRecursionKind kind, @Nullable TailRecursionKind existingKind) {
890 TailRecursionKind resultingKind;
891 if (existingKind == null || existingKind == kind) {
892 resultingKind = kind;
893 }
894 else {
895 if (check(kind, existingKind, IN_TRY, TAIL_CALL)) {
896 resultingKind = IN_TRY;
897 }
898 else if (check(kind, existingKind, IN_TRY, NON_TAIL)) {
899 resultingKind = IN_TRY;
900 }
901 else {
902 // TAIL_CALL, NON_TAIL
903 resultingKind = NON_TAIL;
904 }
905 }
906 return resultingKind;
907 }
908
909 private static boolean check(Object a, Object b, Object x, Object y) {
910 return (a == x && b == y) || (a == y && b == x);
911 }
912
913 ////////////////////////////////////////////////////////////////////////////////
914 // Utility classes and methods
915
916 /**
917 * The method provides reporting of the same diagnostic only once for copied instructions
918 * (depends on whether it should be reported for all or only for one of the copies)
919 */
920 private void report(
921 @NotNull Diagnostic diagnostic,
922 @NotNull VariableContext ctxt
923 ) {
924 Instruction instruction = ctxt.instruction;
925 if (instruction.getCopies().isEmpty()) {
926 trace.report(diagnostic);
927 return;
928 }
929 Map<Instruction, DiagnosticFactory<?>> previouslyReported = ctxt.reportedDiagnosticMap;
930 previouslyReported.put(instruction, diagnostic.getFactory());
931
932 boolean alreadyReported = false;
933 boolean sameErrorForAllCopies = true;
934 for (Instruction copy : instruction.getCopies()) {
935 DiagnosticFactory<?> previouslyReportedErrorFactory = previouslyReported.get(copy);
936 if (previouslyReportedErrorFactory != null) {
937 alreadyReported = true;
938 }
939
940 if (previouslyReportedErrorFactory != diagnostic.getFactory()) {
941 sameErrorForAllCopies = false;
942 }
943 }
944
945 if (mustBeReportedOnAllCopies(diagnostic.getFactory())) {
946 if (sameErrorForAllCopies) {
947 trace.report(diagnostic);
948 }
949 }
950 else {
951 //only one reporting required
952 if (!alreadyReported) {
953 trace.report(diagnostic);
954 }
955 }
956 }
957
958 private static boolean mustBeReportedOnAllCopies(@NotNull DiagnosticFactory<?> diagnosticFactory) {
959 return diagnosticFactory == UNUSED_VARIABLE
960 || diagnosticFactory == UNUSED_PARAMETER
961 || diagnosticFactory == UNUSED_CHANGED_VALUE;
962 }
963
964
965 private class VariableContext {
966 final Map<Instruction, DiagnosticFactory<?>> reportedDiagnosticMap;
967 final Instruction instruction;
968 final VariableDescriptor variableDescriptor;
969
970 private VariableContext(
971 @NotNull Instruction instruction,
972 @NotNull Map<Instruction, DiagnosticFactory<?>> map
973 ) {
974 this.instruction = instruction;
975 reportedDiagnosticMap = map;
976 variableDescriptor = PseudocodeUtil.extractVariableDescriptorIfAny(instruction, true, trace.getBindingContext());
977 }
978 }
979
980 private class VariableInitContext extends VariableContext {
981 final VariableControlFlowState enterInitState;
982 final VariableControlFlowState exitInitState;
983
984 private VariableInitContext(
985 @NotNull Instruction instruction,
986 @NotNull Map<Instruction, DiagnosticFactory<?>> map,
987 @NotNull Map<VariableDescriptor, VariableControlFlowState> in,
988 @NotNull Map<VariableDescriptor, VariableControlFlowState> out,
989 @NotNull LexicalScopeVariableInfo lexicalScopeVariableInfo
990 ) {
991 super(instruction, map);
992 enterInitState = initialize(variableDescriptor, lexicalScopeVariableInfo, in);
993 exitInitState = initialize(variableDescriptor, lexicalScopeVariableInfo, out);
994 }
995
996 private VariableControlFlowState initialize(
997 VariableDescriptor variableDescriptor,
998 LexicalScopeVariableInfo lexicalScopeVariableInfo,
999 Map<VariableDescriptor, VariableControlFlowState> map
1000 ) {
1001 if (variableDescriptor == null) return null;
1002 VariableControlFlowState state = map.get(variableDescriptor);
1003 if (state != null) return state;
1004 return PseudocodeVariablesData.getDefaultValueForInitializers(variableDescriptor, instruction, lexicalScopeVariableInfo);
1005 }
1006 }
1007
1008 private class VariableUseContext extends VariableContext {
1009 final VariableUseState enterUseState;
1010 final VariableUseState exitUseState;
1011
1012
1013 private VariableUseContext(
1014 @NotNull Instruction instruction,
1015 @NotNull Map<Instruction, DiagnosticFactory<?>> map,
1016 @NotNull Map<VariableDescriptor, VariableUseState> in,
1017 @NotNull Map<VariableDescriptor, VariableUseState> out
1018 ) {
1019 super(instruction, map);
1020 enterUseState = variableDescriptor != null ? in.get(variableDescriptor) : null;
1021 exitUseState = variableDescriptor != null ? out.get(variableDescriptor) : null;
1022 }
1023 }
1024
1025 //TODO after KT-4621 rewrite to Kotlin
1026 public abstract static class InstructionDataAnalyzeStrategy<D> implements Function3<Instruction, D, D, Unit> {
1027 @Override
1028 public Unit invoke(Instruction instruction, D enterData, D exitData) {
1029 execute(instruction, enterData, exitData);
1030 return Unit.INSTANCE$;
1031 }
1032
1033 public abstract void execute(Instruction instruction, D enterData, D exitData);
1034 }
1035
1036 public abstract static class FunctionVoid1<P> implements Function1<P, Unit> {
1037 @Override
1038 public Unit invoke(P p) {
1039 execute(p);
1040 return Unit.INSTANCE$;
1041 }
1042
1043 public abstract void execute(P p);
1044 }
1045 }