@Contract("_, !null -> !null")
public PsiSubstitutor findNestedSubstitutor(
PsiElement arg, @Nullable PsiSubstitutor defaultSession) {
InferenceSession session =
myNestedSessions.get(PsiTreeUtil.getParentOfType(arg, PsiCall.class));
return session == null ? defaultSession : session.getInferenceSubstitution();
}
private static CompoundInitialState createState(InferenceSession topLevelSession) {
final PsiSubstitutor topInferenceSubstitutor =
replaceVariables(topLevelSession.getInferenceVariables());
final Map<PsiElement, InitialInferenceState> nestedStates =
new LinkedHashMap<PsiElement, InitialInferenceState>();
final InferenceSessionContainer copy =
new InferenceSessionContainer() {
@Override
public PsiSubstitutor findNestedSubstitutor(
PsiElement arg, @Nullable PsiSubstitutor defaultSession) {
// for the case foo(bar(a -> m())): top level inference won't touch lambda "a -> m()"
// for the case foo(a -> bar(b -> m())): top level inference would go till nested lambda
// "b -> m()" and the state from top level could be found here by "bar(b -> m())"
// but proceeding with additional constraints from saved point would produce new
// expression constraints with different inference variables (could be found in
// myNestedSessions)
// which won't be found in the system if we won't reject stored sessions in such cases
final PsiSubstitutor substitutor = super.findNestedSubstitutor(arg, null);
if (substitutor != null) {
return substitutor;
}
final InitialInferenceState state =
nestedStates.get(PsiTreeUtil.getParentOfType(arg, PsiCall.class));
if (state != null) {
return state.getInferenceSubstitutor();
}
return super.findNestedSubstitutor(arg, defaultSession);
}
};
final Map<PsiElement, InferenceSession> nestedSessions =
topLevelSession.getInferenceSessionContainer().myNestedSessions;
for (Map.Entry<PsiElement, InferenceSession> entry : nestedSessions.entrySet()) {
nestedStates.put(
entry.getKey(),
entry
.getValue()
.createInitialState(
copy, topLevelSession.getInferenceVariables(), topInferenceSubstitutor));
}
PsiSubstitutor substitutor = PsiSubstitutor.EMPTY;
for (InferenceVariable variable : topLevelSession.getInferenceVariables()) {
final PsiType instantiation = variable.getInstantiation();
if (instantiation != PsiType.NULL) {
final PsiClass psiClass =
PsiUtil.resolveClassInClassTypeOnly(topInferenceSubstitutor.substitute(variable));
if (psiClass instanceof InferenceVariable) {
substitutor = substitutor.put((PsiTypeParameter) psiClass, instantiation);
}
}
}
return new CompoundInitialState(substitutor, nestedStates);
}
void registerNestedSession(
InferenceSession session, PsiType returnType, PsiExpression returnExpression) {
final PsiSubstitutor callSession =
findNestedSubstitutor(((PsiCallExpression) returnExpression).getArgumentList(), null);
if (callSession == null) {
final InferenceSession inferenceSession =
ExpressionCompatibilityConstraint.reduceExpressionCompatibilityConstraint(
session, returnExpression, returnType);
if (inferenceSession != null && inferenceSession != session) {
registerNestedSession(inferenceSession);
session.propagateVariables(
inferenceSession.getInferenceVariables(),
inferenceSession.getRestoreNameSubstitution());
}
}
}
static PsiSubstitutor infer(
@NotNull PsiTypeParameter[] typeParameters,
@NotNull PsiParameter[] parameters,
@NotNull PsiExpression[] arguments,
@NotNull PsiSubstitutor partialSubstitutor,
@NotNull final PsiElement parent,
@NotNull final ParameterTypeInferencePolicy policy) {
if (parent instanceof PsiCall) {
final PsiExpressionList argumentList = ((PsiCall) parent).getArgumentList();
final MethodCandidateInfo.CurrentCandidateProperties properties =
MethodCandidateInfo.getCurrentMethod(argumentList);
// overload resolution can't depend on outer call => should not traverse to top
if (properties != null
&& !properties.isApplicabilityCheck()
&&
// in order to to avoid caching of candidates's errors on parent (!) , so check for
// overload resolution is left here
// But overload resolution can depend on type of lambda parameter. As it can't depend on
// lambda body,
// traversing down would stop at lambda level and won't take into account overloaded
// method
!MethodCandidateInfo.ourOverloadGuard.currentStack().contains(argumentList)) {
final PsiCall topLevelCall =
PsiResolveHelper.ourGraphGuard.doPreventingRecursion(
parent,
false,
new Computable<PsiCall>() {
@Override
public PsiCall compute() {
if (parent instanceof PsiExpression
&& !PsiPolyExpressionUtil.isPolyExpression((PsiExpression) parent)) {
return null;
}
return LambdaUtil.treeWalkUp(parent);
}
});
if (topLevelCall != null) {
InferenceSession session;
if (MethodCandidateInfo.isOverloadCheck()
|| !PsiDiamondType.ourDiamondGuard.currentStack().isEmpty()
|| LambdaUtil.isLambdaParameterCheck()) {
session = startTopLevelInference(topLevelCall, policy);
} else {
session =
CachedValuesManager.getCachedValue(
topLevelCall,
new CachedValueProvider<InferenceSession>() {
@Nullable
@Override
public Result<InferenceSession> compute() {
return new Result<InferenceSession>(
startTopLevelInference(topLevelCall, policy),
PsiModificationTracker.MODIFICATION_COUNT);
}
});
if (session != null) {
// reject cached top level session if it was based on wrong candidate: check nested
// session if candidate (it's type parameters) are the same
// such situations are avoided when overload resolution is performed
// (MethodCandidateInfo.isOverloadCheck above)
// but situations when client code iterates through
// PsiResolveHelper.getReferencedMethodCandidates or similar are impossible to guess
final Map<PsiElement, InferenceSession> sessions =
session.getInferenceSessionContainer().myNestedSessions;
final InferenceSession childSession = sessions.get(parent);
if (childSession != null) {
for (PsiTypeParameter parameter : typeParameters) {
if (!childSession
.getInferenceSubstitution()
.getSubstitutionMap()
.containsKey(parameter)) {
session = startTopLevelInference(topLevelCall, policy);
break;
}
}
}
}
}
if (session != null) {
final PsiSubstitutor childSubstitutor =
inferNested(
typeParameters,
parameters,
arguments,
partialSubstitutor,
(PsiCall) parent,
policy,
properties,
session);
if (childSubstitutor != null) return childSubstitutor;
} else if (topLevelCall instanceof PsiMethodCallExpression) {
return new InferenceSession(
typeParameters, partialSubstitutor, parent.getManager(), parent, policy)
.prepareSubstitution();
}
}
}
}
final InferenceSession inferenceSession =
new InferenceSession(
typeParameters, partialSubstitutor, parent.getManager(), parent, policy);
inferenceSession.initExpressionConstraints(parameters, arguments, parent);
return inferenceSession.infer(parameters, arguments, parent);
}
public void registerNestedSession(InferenceSession session) {
myNestedSessions.put(session.getContext(), session);
myNestedSessions.putAll(session.getInferenceSessionContainer().myNestedSessions);
}
private static PsiSubstitutor inferNested(
final PsiTypeParameter[] typeParameters,
@NotNull final PsiParameter[] parameters,
@NotNull final PsiExpression[] arguments,
final PsiSubstitutor partialSubstitutor,
@NotNull final PsiCall parent,
@NotNull final ParameterTypeInferencePolicy policy,
final MethodCandidateInfo.CurrentCandidateProperties properties,
final InferenceSession parentSession) {
final CompoundInitialState compoundInitialState = createState(parentSession);
InitialInferenceState initialInferenceState = compoundInitialState.getInitialState(parent);
if (initialInferenceState != null) {
final InferenceSession childSession = new InferenceSession(initialInferenceState);
final List<String> errorMessages = parentSession.getIncompatibleErrorMessages();
if (errorMessages != null) {
return childSession.prepareSubstitution();
}
return childSession.collectAdditionalAndInfer(
parameters, arguments, properties, compoundInitialState.getInitialSubstitutor());
}
// we do not investigate lambda return expressions when lambda's return type is already inferred
// (proper)
// this way all calls from lambda's return expressions won't appear in nested sessions
else {
PsiElement gParent = PsiUtil.skipParenthesizedExprUp(parent.getParent());
// find the nearest parent which appears in the map and start inference with a provided target
// type for a nested lambda
while (true) {
if (gParent instanceof PsiReturnStatement) { // process code block lambda
final PsiElement returnContainer = gParent.getParent();
if (returnContainer instanceof PsiCodeBlock) {
gParent = returnContainer.getParent();
}
}
if (gParent instanceof PsiLambdaExpression) {
final PsiCall call = PsiTreeUtil.getParentOfType(gParent, PsiCall.class);
if (call != null) {
initialInferenceState = compoundInitialState.getInitialState(call);
if (initialInferenceState != null) {
final int idx = LambdaUtil.getLambdaIdx(call.getArgumentList(), gParent);
final PsiMethod method = call.resolveMethod();
if (method != null && idx > -1) {
final PsiType parameterType =
PsiTypesUtil.getParameterType(
method.getParameterList().getParameters(), idx, true);
final PsiType parameterTypeInTermsOfSession =
initialInferenceState.getInferenceSubstitutor().substitute(parameterType);
final PsiType lambdaTargetType =
compoundInitialState
.getInitialSubstitutor()
.substitute(parameterTypeInTermsOfSession);
return LambdaUtil.performWithLambdaTargetType(
(PsiLambdaExpression) gParent,
lambdaTargetType,
new Producer<PsiSubstitutor>() {
@Nullable
@Override
public PsiSubstitutor produce() {
if (call.equals(PsiTreeUtil.getParentOfType(parent, PsiCall.class, true))) {
// parent was mentioned in the top inference session
// just proceed with the target type
final InferenceSession inferenceSession =
new InferenceSession(
typeParameters,
partialSubstitutor,
parent.getManager(),
parent,
policy);
inferenceSession.initExpressionConstraints(parameters, arguments, parent);
return inferenceSession.infer(parameters, arguments, parent);
}
// one of the grand parents were found in the top inference session
// start from it as it is the top level call
final InferenceSession sessionInsideLambda =
startTopLevelInference(call, policy);
return inferNested(
typeParameters,
parameters,
arguments,
partialSubstitutor,
parent,
policy,
properties,
sessionInsideLambda);
}
});
}
} else {
gParent = PsiUtil.skipParenthesizedExprUp(call.getParent());
continue;
}
}
}
break;
}
}
return null;
}