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/*******************************************************************************
 * Copyright (c) 2012, 2024 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *     Jesper S Moller - Contributions for
 *							bug 382701 - [1.8][compiler] Implement semantic analysis of Lambda expressions & Reference expression
 *							bug 382721 - [1.8][compiler] Effectively final variables needs special treatment
 *							Bug 416885 - [1.8][compiler]IncompatibleClassChange error (edit)
 *     Stephan Herrmann - Contribution for
 *							bug 401030 - [1.8][null] Null analysis support for lambda methods.
 *							Bug 392099 - [1.8][compiler][null] Apply null annotation on types for null analysis
 *							Bug 392238 - [1.8][compiler][null] Detect semantically invalid null type annotations
 *							Bug 400874 - [1.8][compiler] Inference infrastructure should evolve to meet JLS8 18.x (Part G of JSR335 spec)
 *							Bug 423504 - [1.8] Implement "18.5.3 Functional Interface Parameterization Inference"
 *							Bug 425142 - [1.8][compiler] NPE in ConstraintTypeFormula.reduceSubType
 *							Bug 425153 - [1.8] Having wildcard allows incompatible types in a lambda expression
 *							Bug 424205 - [1.8] Cannot infer type for diamond type with lambda on method invocation
 *							Bug 425798 - [1.8][compiler] Another NPE in ConstraintTypeFormula.reduceSubType
 *							Bug 425156 - [1.8] Lambda as an argument is flagged with incompatible error
 *							Bug 424403 - [1.8][compiler] Generic method call with method reference argument fails to resolve properly.
 *							Bug 426563 - [1.8] AIOOBE when method with error invoked with lambda expression as argument
 *							Bug 420525 - [1.8] [compiler] Incorrect error "The type Integer does not define sum(Object, Object) that is applicable here"
 *							Bug 427438 - [1.8][compiler] NPE at org.eclipse.jdt.internal.compiler.ast.ConditionalExpression.generateCode(ConditionalExpression.java:280)
 *							Bug 428294 - [1.8][compiler] Type mismatch: cannot convert from List to Collection
 *							Bug 428786 - [1.8][compiler] Inference needs to compute the "ground target type" when reducing a lambda compatibility constraint
 *							Bug 428980 - [1.8][null] simple expression as lambda body doesn't leverage null annotation on argument
 *							Bug 429430 - [1.8] Lambdas and method reference infer wrong exception type with generics (RuntimeException instead of IOException)
 *							Bug 432110 - [1.8][compiler] nested lambda type incorrectly inferred vs javac
 *							Bug 438458 - [1.8][null] clean up handling of null type annotations wrt type variables
 *							Bug 441693 - [1.8][null] Bogus warning for type argument annotated with @NonNull
 *							Bug 452788 - [1.8][compiler] Type not correctly inferred in lambda expression
 *							Bug 453483 - [compiler][null][loop] Improve null analysis for loops
 *							Bug 455723 - Nonnull argument not correctly inferred in loop
 *							Bug 463728 - [1.8][compiler][inference] Ternary operator in lambda derives wrong type
 *     Andy Clement (GoPivotal, Inc) [email protected] - Contributions for
 *                          Bug 405104 - [1.8][compiler][codegen] Implement support for serializeable lambdas
 *******************************************************************************/
package org.eclipse.jdt.internal.compiler.ast;

import static org.eclipse.jdt.internal.compiler.ast.ExpressionContext.INVOCATION_CONTEXT;

import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedHashSet;
import java.util.Map;
import java.util.Set;

import org.eclipse.jdt.core.compiler.CategorizedProblem;
import org.eclipse.jdt.core.compiler.CharOperation;
import org.eclipse.jdt.internal.compiler.ASTVisitor;
import org.eclipse.jdt.internal.compiler.ClassFile;
import org.eclipse.jdt.internal.compiler.CompilationResult;
import org.eclipse.jdt.internal.compiler.IErrorHandlingPolicy;
import org.eclipse.jdt.internal.compiler.classfmt.ClassFileConstants;
import org.eclipse.jdt.internal.compiler.codegen.CodeStream;
import org.eclipse.jdt.internal.compiler.flow.ExceptionHandlingFlowContext;
import org.eclipse.jdt.internal.compiler.flow.ExceptionInferenceFlowContext;
import org.eclipse.jdt.internal.compiler.flow.FlowContext;
import org.eclipse.jdt.internal.compiler.flow.FlowInfo;
import org.eclipse.jdt.internal.compiler.flow.UnconditionalFlowInfo;
import org.eclipse.jdt.internal.compiler.impl.CompilerOptions;
import org.eclipse.jdt.internal.compiler.impl.Constant;
import org.eclipse.jdt.internal.compiler.impl.ReferenceContext;
import org.eclipse.jdt.internal.compiler.lookup.AnnotationBinding;
import org.eclipse.jdt.internal.compiler.lookup.Binding;
import org.eclipse.jdt.internal.compiler.lookup.BlockScope;
import org.eclipse.jdt.internal.compiler.lookup.ClassScope;
import org.eclipse.jdt.internal.compiler.lookup.ExtraCompilerModifiers;
import org.eclipse.jdt.internal.compiler.lookup.InferenceContext18;
import org.eclipse.jdt.internal.compiler.lookup.IntersectionTypeBinding18;
import org.eclipse.jdt.internal.compiler.lookup.LocalTypeBinding;
import org.eclipse.jdt.internal.compiler.lookup.LocalVariableBinding;
import org.eclipse.jdt.internal.compiler.lookup.LookupEnvironment;
import org.eclipse.jdt.internal.compiler.lookup.MethodBinding;
import org.eclipse.jdt.internal.compiler.lookup.MethodScope;
import org.eclipse.jdt.internal.compiler.lookup.ParameterizedGenericMethodBinding;
import org.eclipse.jdt.internal.compiler.lookup.ParameterizedTypeBinding;
import org.eclipse.jdt.internal.compiler.lookup.PolyTypeBinding;
import org.eclipse.jdt.internal.compiler.lookup.ProblemMethodBinding;
import org.eclipse.jdt.internal.compiler.lookup.ProblemReasons;
import org.eclipse.jdt.internal.compiler.lookup.ReferenceBinding;
import org.eclipse.jdt.internal.compiler.lookup.Scope;
import org.eclipse.jdt.internal.compiler.lookup.SourceTypeBinding;
import org.eclipse.jdt.internal.compiler.lookup.Substitution;
import org.eclipse.jdt.internal.compiler.lookup.Substitution.NullSubstitution;
import org.eclipse.jdt.internal.compiler.lookup.SyntheticArgumentBinding;
import org.eclipse.jdt.internal.compiler.lookup.SyntheticMethodBinding;
import org.eclipse.jdt.internal.compiler.lookup.TagBits;
import org.eclipse.jdt.internal.compiler.lookup.TypeBinding;
import org.eclipse.jdt.internal.compiler.lookup.TypeConstants;
import org.eclipse.jdt.internal.compiler.lookup.TypeIds;
import org.eclipse.jdt.internal.compiler.lookup.WildcardBinding;
import org.eclipse.jdt.internal.compiler.lookup.Scope.Substitutor;
import org.eclipse.jdt.internal.compiler.parser.Parser;
import org.eclipse.jdt.internal.compiler.problem.AbortCompilation;
import org.eclipse.jdt.internal.compiler.problem.AbortCompilationUnit;
import org.eclipse.jdt.internal.compiler.problem.AbortMethod;
import org.eclipse.jdt.internal.compiler.problem.AbortType;
import org.eclipse.jdt.internal.compiler.problem.ProblemSeverities;

@SuppressWarnings({"rawtypes", "unchecked"})
public class LambdaExpression extends FunctionalExpression implements IPolyExpression, ReferenceContext, ProblemSeverities {
	public Argument [] arguments;
	private TypeBinding [] argumentTypes;
	public int arrowPosition;
	public Statement body;
	public boolean hasParentheses;
	public MethodScope scope;
	boolean voidCompatible = true;
	boolean valueCompatible = false;
	boolean returnsValue;
	private final boolean requiresGenericSignature;
	boolean returnsVoid;
	public LambdaExpression original = this;
	private boolean committed = false;
	public SyntheticArgumentBinding[] outerLocalVariables = NO_SYNTHETIC_ARGUMENTS;
	public Map mapSyntheticEnclosingTypes = new HashMap<>();
	public boolean hasOuterClassMemberReference = false;
	private int outerLocalVariablesSlotSize = 0;
	private boolean assistNode = false;
	private ReferenceBinding classType;
	private Set thrownExceptions;
	private static final SyntheticArgumentBinding [] NO_SYNTHETIC_ARGUMENTS = new SyntheticArgumentBinding[0];
	private static final Block NO_BODY = new Block(0);
	private HashMap copiesPerTargetType;
	protected Expression [] resultExpressions = NO_EXPRESSIONS;
	public InferenceContext18 inferenceContext; // when performing tentative resolve keep a back reference to the driving context
	private Map localTypes; // support look-up of a local type from this lambda copy
	public boolean argumentsTypeVar = false;
	int firstLocalLocal; // analysis index of first local variable (if any) post parameter(s) in the lambda; ("local local" as opposed to "outer local")


	public LambdaExpression(CompilationResult compilationResult, boolean assistNode, boolean requiresGenericSignature) {
		super(compilationResult);
		this.assistNode = assistNode;
		this.requiresGenericSignature = requiresGenericSignature;
		setArguments(NO_ARGUMENTS);
		setBody(NO_BODY);
	}

	public LambdaExpression(CompilationResult compilationResult, boolean assistNode) {
		this(compilationResult, assistNode, false);
	}

	public void setArguments(Argument [] arguments) {
		this.arguments = arguments != null ? arguments : ASTNode.NO_ARGUMENTS;
		this.argumentTypes = new TypeBinding[arguments != null ? arguments.length : 0];
	}

	public Argument [] arguments() {
		return this.arguments;
	}

	public TypeBinding[] argumentTypes() {
		return this.argumentTypes;
	}

	public void setBody(Statement body) {
		this.body = body == null ? NO_BODY : body;
	}

	public Statement body() {
		return this.body;
	}

	public Expression[] resultExpressions() {
		return this.resultExpressions;
	}

	public void setArrowPosition(int arrowPosition) {
		this.arrowPosition = arrowPosition;
	}

	public int arrowPosition() {
		return this.arrowPosition;
	}

	protected FunctionalExpression original() {
		return this.original;
	}

	@Override
	public void generateCode(BlockScope currentScope, CodeStream codeStream, boolean valueRequired) {
		if (this.shouldCaptureInstance) {
			this.binding.modifiers &= ~ClassFileConstants.AccStatic;
		} else {
			this.binding.modifiers |= ClassFileConstants.AccStatic;
		}
		SourceTypeBinding sourceType = currentScope.enclosingSourceType();
		boolean firstSpill = !(this.binding instanceof SyntheticMethodBinding);
		this.binding = sourceType.addSyntheticMethod(this);
		int pc = codeStream.position;
		StringBuilder signature = new StringBuilder();
		signature.append('(');
		if (this.shouldCaptureInstance) {
			codeStream.aload_0();
			signature.append(sourceType.signature());
		}
		for (int i = 0, length = this.outerLocalVariables == null ? 0 : this.outerLocalVariables.length; i < length; i++) {
			SyntheticArgumentBinding syntheticArgument = this.outerLocalVariables[i];
			if (this.shouldCaptureInstance && firstSpill) { // finally block handling results in extra spills, avoid side effect.
				syntheticArgument.resolvedPosition++;
			}
			signature.append(syntheticArgument.type.signature());
			Object[] path;
			Binding target;
			if (syntheticArgument.actualOuterLocalVariable != null) {
				LocalVariableBinding capturedOuterLocal = syntheticArgument.actualOuterLocalVariable;
				path = currentScope.getEmulationPath(capturedOuterLocal);
				target = capturedOuterLocal;
			} else {
				path = currentScope.getEmulationPath(
						(ReferenceBinding) syntheticArgument.type,
						false /*not only exact match (that is, allow compatible)*/,
						false);
				target = syntheticArgument.type;
			}
			codeStream.generateOuterAccess(path, this, target, currentScope);
		}
		signature.append(')');
		if (this.expectedType instanceof IntersectionTypeBinding18) {
			signature.append(((IntersectionTypeBinding18)this.expectedType).getSAMType(currentScope).signature());
		} else {
			signature.append(this.expectedType.signature());
		}
		int invokeDynamicNumber = codeStream.classFile.recordBootstrapMethod(this);
		codeStream.invokeDynamic(invokeDynamicNumber, (this.shouldCaptureInstance ? 1 : 0) + this.outerLocalVariablesSlotSize, 1, this.descriptor.selector, signature.toString().toCharArray(),
				this.resolvedType.id, this.resolvedType);
		if (!valueRequired)
			codeStream.pop();
		codeStream.recordPositionsFrom(pc, this.sourceStart);
	}

	@Override
	public boolean kosherDescriptor(Scope currentScope, MethodBinding sam, boolean shouldChatter) {
		if (sam.typeVariables != Binding.NO_TYPE_VARIABLES) {
			if (shouldChatter)
				currentScope.problemReporter().lambdaExpressionCannotImplementGenericMethod(this, sam);
			return false;
		}
		return super.kosherDescriptor(currentScope, sam, shouldChatter);
	}

	public void resolveTypeWithBindings(LocalVariableBinding[] bindings, BlockScope blockScope, boolean skipKosherCheck) {
		blockScope.include(bindings);
		try {
			this.resolveType(blockScope, skipKosherCheck);
		} finally {
			blockScope.exclude(bindings);
		}
	}

	/* This code is arranged so that we can continue with as much analysis as possible while avoiding
	 * mine fields that would result in a slew of spurious messages. This method is a merger of:
	 * @see org.eclipse.jdt.internal.compiler.lookup.MethodScope.createMethod(AbstractMethodDeclaration)
	 * @see org.eclipse.jdt.internal.compiler.lookup.SourceTypeBinding.resolveTypesFor(MethodBinding)
	 * @see org.eclipse.jdt.internal.compiler.ast.AbstractMethodDeclaration.resolve(ClassScope)
	 */
	@Override
	public TypeBinding resolveType(BlockScope blockScope, boolean skipKosherCheck) {

		boolean argumentsTypeElided = argumentsTypeElided();
		int argumentsLength = this.arguments == null ? 0 : this.arguments.length;

		if (this.constant != Constant.NotAConstant) {
			this.constant = Constant.NotAConstant;
			this.enclosingScope = blockScope;
			if (this.original == this)
				this.ordinal = recordFunctionalType(blockScope);

			if (!argumentsTypeElided) {
				for (int i = 0; i < argumentsLength; i++)
					this.argumentTypes[i] = this.arguments[i].type.resolveType(blockScope, true /* check bounds*/);
			}
			if (this.expectedType == null && this.expressionContext == INVOCATION_CONTEXT) {
				return new PolyTypeBinding(this);
			}
		}

		MethodScope methodScope = blockScope.methodScope();
		this.scope = new MethodScope(blockScope, this, methodScope.isStatic, methodScope.lastVisibleFieldID);
		this.scope.isConstructorCall = methodScope.isConstructorCall;

		super.resolveType(blockScope, skipKosherCheck); // compute & capture interface function descriptor.

		final boolean haveDescriptor = this.descriptor != null;

		if (!skipKosherCheck && (!haveDescriptor || this.descriptor.typeVariables != Binding.NO_TYPE_VARIABLES)) // already complained in kosher*
			return this.resolvedType = null;

		this.binding = new MethodBinding(ClassFileConstants.AccPrivate | ClassFileConstants.AccSynthetic | ExtraCompilerModifiers.AccUnresolved,
							CharOperation.concat(TypeConstants.ANONYMOUS_METHOD, Integer.toString(this.ordinal).toCharArray()), // will be fixed up later.
							haveDescriptor ? this.descriptor.returnType : TypeBinding.VOID,
							Binding.NO_PARAMETERS, // for now.
							haveDescriptor ? this.descriptor.thrownExceptions : Binding.NO_EXCEPTIONS,
							blockScope.enclosingSourceType());
		this.binding.typeVariables = Binding.NO_TYPE_VARIABLES;

		MethodScope enm = this.scope.namedMethodScope();
		MethodBinding enmb = enm == null ? null : enm.referenceMethodBinding();
		if (enmb != null && enmb.isViewedAsDeprecated()) {
			this.binding.modifiers |= ExtraCompilerModifiers.AccDeprecatedImplicitly;
			this.binding.tagBits |= enmb.tagBits & TagBits.AnnotationTerminallyDeprecated;
		}

		boolean argumentsHaveErrors = false;
		if (haveDescriptor) {
			int parametersLength = this.descriptor.parameters.length;
			if (parametersLength != argumentsLength) {
            	this.scope.problemReporter().lambdaSignatureMismatched(this);
            	if (argumentsTypeElided || this.original != this) // no interest in continuing to error check copy.
            		return this.resolvedType = null; // FUBAR, bail out ...
            	else {
            		this.resolvedType = null; // continue to type check.
            		argumentsHaveErrors = true;
            	}
            }
		}

		TypeBinding[] newParameters = new TypeBinding[argumentsLength];

		AnnotationBinding [][] parameterAnnotations = null;
		for (int i = 0; i < argumentsLength; i++) {
			Argument argument = this.arguments[i];
			if (argument.isVarArgs()) {
				if (i == argumentsLength - 1) {
					this.binding.modifiers |= ClassFileConstants.AccVarargs;
				} else {
					this.scope.problemReporter().illegalVarargInLambda(argument);
					argumentsHaveErrors = true;
				}
			}

			TypeBinding argumentType;
			final TypeBinding expectedParameterType = haveDescriptor && i < this.descriptor.parameters.length ? this.descriptor.parameters[i] : null;
			argumentType = argumentsTypeElided ? expectedParameterType : this.argumentTypes[i];
			if (argumentType == null) {
				argumentsHaveErrors = true;
			} else if (argumentType == TypeBinding.VOID) {
				this.scope.problemReporter().argumentTypeCannotBeVoid(this, argument);
				argumentsHaveErrors = true;
			} else {
				if (!argumentType.isValidBinding()) {
					this.binding.tagBits |= TagBits.HasUnresolvedArguments;
				}
				if ((argumentType.tagBits & TagBits.HasMissingType) != 0) {
					this.binding.tagBits |= TagBits.HasMissingType;
				}
			}
		}
		if (!argumentsTypeElided && !argumentsHaveErrors) {
			ReferenceBinding groundType = null;
			ReferenceBinding expectedSAMType = null;
			if (this.expectedType instanceof IntersectionTypeBinding18)
				expectedSAMType = (ReferenceBinding) ((IntersectionTypeBinding18) this.expectedType).getSAMType(blockScope);
			else if (this.expectedType instanceof ReferenceBinding)
				expectedSAMType = (ReferenceBinding) this.expectedType;
			if (expectedSAMType != null)
				groundType = findGroundTargetType(blockScope, this.expectedType, expectedSAMType, argumentsTypeElided);

			if (groundType != null) {
				this.descriptor = groundType.getSingleAbstractMethod(blockScope, true);
				if (!this.descriptor.isValidBinding()) {
					reportSamProblem(blockScope, this.descriptor);
				} else {
					if (groundType != expectedSAMType) { //$IDENTITY-COMPARISON$
						if (!groundType.isCompatibleWith(expectedSAMType, this.scope)) { // the ground has shifted, are we still on firm grounds ?
							blockScope.problemReporter().typeMismatchError(groundType, this.expectedType, this, null); // report deliberately against block scope so as not to blame the lambda.
							return null;
						}
					}
					this.resolvedType = groundType;
				}
			} else {
				this.binding = new ProblemMethodBinding(TypeConstants.ANONYMOUS_METHOD, null, ProblemReasons.NotAWellFormedParameterizedType);
				reportSamProblem(blockScope, this.binding);
				return this.resolvedType = null;
			}
		}
		boolean parametersHaveErrors = false;
		boolean genericSignatureNeeded = this.requiresGenericSignature || blockScope.compilerOptions().generateGenericSignatureForLambdaExpressions;
		TypeBinding[] expectedParameterTypes = new TypeBinding[argumentsLength];
		for (int i = 0; i < argumentsLength; i++) {
			Argument argument = this.arguments[i];
			TypeBinding argumentType;
			final TypeBinding expectedParameterType = haveDescriptor && i < this.descriptor.parameters.length ? this.descriptor.parameters[i] : null;
			argumentType = argumentsTypeElided ? expectedParameterType : this.argumentTypes[i];
			expectedParameterTypes[i] = expectedParameterType;
			if (argumentType != null && argumentType != TypeBinding.VOID) {
				if (haveDescriptor && expectedParameterType != null && argumentType.isValidBinding() && TypeBinding.notEquals(argumentType, expectedParameterType)) {
					if (expectedParameterType.isProperType(true)) {
						if (!isOnlyWildcardMismatch(expectedParameterType, argumentType)) {
							this.scope.problemReporter().lambdaParameterTypeMismatched(argument, argument.type, expectedParameterType);
							parametersHaveErrors = true; // continue to type check, but don't signal success
						}
					}
				}
				if (genericSignatureNeeded) {
					TypeBinding leafType = argumentType.leafComponentType();
					if (leafType instanceof ReferenceBinding && (((ReferenceBinding) leafType).modifiers & ExtraCompilerModifiers.AccGenericSignature) != 0)
						this.binding.modifiers |= ExtraCompilerModifiers.AccGenericSignature;
				}
				newParameters[i] = argument.bind(this.scope, argumentType, false);
				if (argument.annotations != null) {
					this.binding.tagBits |= TagBits.HasParameterAnnotations;
					if (parameterAnnotations == null) {
						parameterAnnotations = new AnnotationBinding[argumentsLength][];
						for (int j = 0; j < i; j++) {
							parameterAnnotations[j] = Binding.NO_ANNOTATIONS;
						}
					}
					parameterAnnotations[i] = argument.binding.getAnnotations();
				} else if (parameterAnnotations != null) {
					parameterAnnotations[i] = Binding.NO_ANNOTATIONS;
				}
			}
		}
		if (this.argumentsTypeVar) {
			for (int i = 0; i < argumentsLength; ++i) {
				this.arguments[i].type.resolvedType = expectedParameterTypes[i];
			}
		}
		// only assign parameters if no problems are found
		if (!argumentsHaveErrors) {
			this.binding.parameters = newParameters;
			if (parameterAnnotations != null)
				this.binding.setParameterAnnotations(parameterAnnotations);
		}

		if (!argumentsTypeElided && !argumentsHaveErrors && this.binding.isVarargs()) {
			if (!this.binding.parameters[this.binding.parameters.length - 1].isReifiable()) {
				this.scope.problemReporter().possibleHeapPollutionFromVararg(this.arguments[this.arguments.length - 1]);
			}
		}

		ReferenceBinding [] exceptions = this.binding.thrownExceptions;
		int exceptionsLength = exceptions.length;
		for (int i = 0; i < exceptionsLength; i++) {
			ReferenceBinding exception = exceptions[i];
			if ((exception.tagBits & TagBits.HasMissingType) != 0) {
				this.binding.tagBits |= TagBits.HasMissingType;
			}
			if (genericSignatureNeeded)
				this.binding.modifiers |= (exception.modifiers & ExtraCompilerModifiers.AccGenericSignature);
		}

		TypeBinding returnType = this.binding.returnType;
		if (returnType != null) {
			if ((returnType.tagBits & TagBits.HasMissingType) != 0) {
				this.binding.tagBits |= TagBits.HasMissingType;
			}
			if (genericSignatureNeeded) {
				TypeBinding leafType = returnType.leafComponentType();
				if (leafType instanceof ReferenceBinding && (((ReferenceBinding) leafType).modifiers & ExtraCompilerModifiers.AccGenericSignature) != 0)
					this.binding.modifiers |= ExtraCompilerModifiers.AccGenericSignature;
			}
		} // TODO (stephan): else? (can that happen?)

		if (haveDescriptor && !argumentsHaveErrors && blockScope.compilerOptions().isAnnotationBasedNullAnalysisEnabled) {
			if (!argumentsTypeElided) {
				AbstractMethodDeclaration.createArgumentBindings(this.arguments, this.binding, this.scope); // includes validation
				// no application of null-ness default, hence also no warning regarding redundant null annotation
				mergeParameterNullAnnotations(blockScope);
			}
			this.binding.tagBits |= (this.descriptor.tagBits & TagBits.AnnotationNullMASK);
		}

		this.binding.modifiers &= ~ExtraCompilerModifiers.AccUnresolved;

		this.firstLocalLocal = this.scope.outerMostMethodScope().analysisIndex;
		if (this.body instanceof Expression && ((Expression) this.body).isTrulyExpression()) {
			Expression expression = (Expression) this.body;
			new ReturnStatement(expression, expression.sourceStart, expression.sourceEnd, true).resolve(this.scope); // :-) ;-)
			if (expression.resolvedType == TypeBinding.VOID && !expression.statementExpression())
				this.scope.problemReporter().invalidExpressionAsStatement(expression);
		} else {
			this.body.resolve(this.scope);
			/* At this point, shape analysis is complete for ((see returnsExpression(...))
		       - a lambda with an expression body,
			   - a lambda with a block body in which we saw a return statement naked or otherwise.
		    */
			if (!this.returnsVoid && !this.returnsValue)
				this.valueCompatible = this.body.doesNotCompleteNormally();
		}
		if ((this.binding.tagBits & TagBits.HasMissingType) != 0) {
			this.scope.problemReporter().missingTypeInLambda(this, this.binding);
		}
		if (this.shouldCaptureInstance && this.scope.isConstructorCall) {
			this.scope.problemReporter().fieldsOrThisBeforeConstructorInvocation(this);
		}
		// beyond this point ensure that all local type bindings are their final binding:
		updateLocalTypes();
		if (this.original == this) {
			this.committed = true; // the original has been resolved
		}
		return (argumentsHaveErrors || parametersHaveErrors) ? null : this.resolvedType;
	}

	// check if the given types are parameterized types and if their type arguments
	// differ only in a wildcard
	// ? and ? extends Object
	private boolean isOnlyWildcardMismatch(TypeBinding expected, TypeBinding argument) {
		boolean onlyWildcardMismatch = false;
		if (expected.isParameterizedType() && argument.isParameterizedType()) {
			TypeBinding[] expectedArgs = ((ParameterizedTypeBinding)expected).typeArguments();
			TypeBinding[] args = ((ParameterizedTypeBinding)argument).typeArguments();
			if (args.length != expectedArgs.length)
				return false;
			for (int j = 0; j < args.length; j++) {
				if (TypeBinding.notEquals(expectedArgs[j], args[j])) {
					if (expectedArgs[j].isWildcard() && args[j].isUnboundWildcard()) {
						WildcardBinding wc = (WildcardBinding)expectedArgs[j];
						TypeBinding bound = wc.allBounds();
						if (bound != null && wc.boundKind == Wildcard.EXTENDS && bound.id == TypeIds.T_JavaLangObject)
							onlyWildcardMismatch = true;
					} else {
						onlyWildcardMismatch = false;
						break;
					}
				}
			}
		}
		return onlyWildcardMismatch;
	}
	private ReferenceBinding findGroundTargetType(BlockScope blockScope, TypeBinding targetType, TypeBinding expectedSAMType, boolean argumentTypesElided) {

		if (expectedSAMType instanceof IntersectionTypeBinding18)
			expectedSAMType = ((IntersectionTypeBinding18) expectedSAMType).getSAMType(blockScope);

		if (expectedSAMType instanceof ReferenceBinding && expectedSAMType.isValidBinding()) {
			ParameterizedTypeBinding withWildCards = InferenceContext18.parameterizedWithWildcard(expectedSAMType);
			if (withWildCards != null) {
				if (!argumentTypesElided) {
					InferenceContext18 freshInferenceContext = new InferenceContext18(blockScope);
					try {
						return freshInferenceContext.inferFunctionalInterfaceParameterization(this, blockScope, withWildCards);
					} finally {
						freshInferenceContext.cleanUp();
					}
				} else {
					return withWildCards.getNonWildcardParameterization(blockScope);
				}
			}
			if (targetType instanceof ReferenceBinding)
				return (ReferenceBinding) targetType;
		}
		return null;
	}

	@Override
	public boolean argumentsTypeElided() {
		return (this.arguments.length > 0 && this.arguments[0].hasElidedType()) || this.argumentsTypeVar;
	}

	private void analyzeExceptions() {
		ExceptionHandlingFlowContext ehfc;
		CompilerOptions compilerOptions = this.scope.compilerOptions();
		boolean oldAnalyseResources = compilerOptions.analyseResourceLeaks;
		compilerOptions.analyseResourceLeaks = false;
		try {
			this.body.analyseCode(this.scope,
									 ehfc = new ExceptionInferenceFlowContext(null, this, Binding.NO_EXCEPTIONS, null, this.scope, FlowInfo.DEAD_END),
									 UnconditionalFlowInfo.fakeInitializedFlowInfo(this.firstLocalLocal, this.scope.referenceType().maxFieldCount));
			this.thrownExceptions = ehfc.extendedExceptions == null ? Collections.emptySet() : new HashSet(ehfc.extendedExceptions);
		} catch (Exception e) {
			// drop silently.
		} finally {
			compilerOptions.analyseResourceLeaks = oldAnalyseResources;
		}
	}
	@Override
	public FlowInfo analyseCode(BlockScope currentScope, FlowContext flowContext, final FlowInfo flowInfo) {

		if (this.ignoreFurtherInvestigation)
			return flowInfo;

		FlowInfo lambdaInfo = flowInfo.copy(); // what happens in vegas, stays in vegas ...
		ExceptionHandlingFlowContext methodContext =
				new ExceptionHandlingFlowContext(
						flowContext,
						this,
						this.binding.thrownExceptions,
						flowContext.getInitializationContext(),
						this.scope,
						FlowInfo.DEAD_END);

		// nullity, owning and mark as assigned
		MethodBinding methodWithParameterDeclaration = argumentsTypeElided() ? this.descriptor : this.binding;
		AbstractMethodDeclaration.analyseArguments(currentScope.environment(), lambdaInfo, flowContext, this.arguments, methodWithParameterDeclaration);

		if (this.arguments != null) {
			for (Argument argument : this.arguments) {
				this.bits |= (argument.bits & ASTNode.HasTypeAnnotations);
			}
		}

		lambdaInfo = this.body.analyseCode(this.scope, methodContext, lambdaInfo);

		// check for missing returning path for block body's ...
		if (this.body instanceof Block) {
			TypeBinding returnTypeBinding = expectedResultType();
			if ((returnTypeBinding == TypeBinding.VOID)) {
				if ((lambdaInfo.tagBits & FlowInfo.UNREACHABLE_OR_DEAD) == 0 || ((Block) this.body).statements == null) {
					this.bits |= ASTNode.NeedFreeReturn;
				}
			} else {
				if (lambdaInfo != FlowInfo.DEAD_END) {
					this.scope.problemReporter().shouldReturn(returnTypeBinding, this);
				}
			}
		} else if (this.body instanceof Expression expression ){
			if (lambdaInfo.reachMode() == FlowInfo.REACHABLE) {
				CompilerOptions compilerOptions = currentScope.compilerOptions();
				if (compilerOptions.isAnnotationBasedNullAnalysisEnabled) {
					checkAgainstNullAnnotation(flowContext, expression, flowInfo, expression.nullStatus(lambdaInfo, flowContext));
				}
				if (compilerOptions.analyseResourceLeaks) {
					long owningTagBits = this.descriptor.tagBits & TagBits.AnnotationOwningMASK;
					ReturnStatement.anylizeCloseableReturnExpression(expression, currentScope, owningTagBits, flowContext, flowInfo);
				}
			}
		}
		return flowInfo;
	}

	// cf. AbstractMethodDeclaration.validateNullAnnotations()
	// pre: !argumentTypeElided()
	void validateNullAnnotations() {
		// null annotations on parameters?
		if (this.binding != null) {
			int length = this.binding.parameters.length;
			for (int i=0; i> ASTNode.ParenthesizedSHIFT;
		String suffix = ""; //$NON-NLS-1$
		for(int i = 0; i < parenthesesCount; i++) {
			output.append('(');
			suffix += ')';
		}
		output.append('(');
		if (this.arguments != null) {
			for (int i = 0; i < this.arguments.length; i++) {
				if (i > 0) output.append(", "); //$NON-NLS-1$
				this.arguments[i].print(0, output);
			}
		}
		output.append(") -> " ); //$NON-NLS-1$
		if (makeShort) {
			output.append("{}"); //$NON-NLS-1$
		} else {
			if (this.body != null)
				this.body.print(this.body instanceof Block ? tab : 0, output);
			else
				output.append("<@incubator>"); //$NON-NLS-1$
		}
		return output.append(suffix);
	}

	public TypeBinding expectedResultType() {
		return this.descriptor != null && this.descriptor.isValidBinding() ? this.descriptor.returnType : null;
	}

	@Override
	public void traverse(ASTVisitor visitor, BlockScope blockScope) {

			if (visitor.visit(this, blockScope)) {
				if (this.arguments != null) {
					int argumentsLength = this.arguments.length;
					for (int i = 0; i < argumentsLength; i++)
						this.arguments[i].traverse(visitor, this.scope);
				}

				if (this.body != null) {
					this.body.traverse(visitor, this.scope);
				}
			}
			visitor.endVisit(this, blockScope);
	}

	public MethodScope getScope() {
		return this.scope;
	}

	private void analyzeShape() { // Simple minded analysis for code assist & potential compatibility.
		class ShapeComputer extends ASTVisitor {
			@Override
			public boolean visit(TypeDeclaration type, BlockScope skope) {
				return false;
			}
			@Override
			public boolean visit(TypeDeclaration type, ClassScope skope) {
				return false;
			}
			@Override
			public boolean visit(LambdaExpression type, BlockScope skope) {
				return false;
			}
		    @Override
			public boolean visit(ReturnStatement returnStatement, BlockScope skope) {
		    	if (returnStatement.expression != null) {
		    		LambdaExpression.this.valueCompatible = true;
		    		LambdaExpression.this.voidCompatible = false;
		    		LambdaExpression.this.returnsValue = true;
		    	} else {
		    		LambdaExpression.this.voidCompatible = true;
		    		LambdaExpression.this.valueCompatible = false;
		    		LambdaExpression.this.returnsVoid = true;
		    	}
		    	return false;
		    }
		}
		if (this.body instanceof Expression && ((Expression) this.body).isTrulyExpression()) {
			// When completion is still in progress, it is not possible to ask if the expression constitutes a statement expression. See https://bugs.eclipse.org/bugs/show_bug.cgi?id=435219
			this.voidCompatible = this.assistNode ? true : ((Expression) this.body).statementExpression();
			this.valueCompatible = true; // expression could be of type void - we can't determine that as we are working with unresolved expressions, for potential compatibility it is OK.
		} else {
			// For code assist, we need to be a bit tolerant/fuzzy here: the code is being written "just now", if we are too pedantic, selection/completion will break;
			if (this.assistNode) {
				this.voidCompatible = true;
				this.valueCompatible = true;
			}
			this.body.traverse(new ShapeComputer(), null);
			if (!this.returnsValue && !this.returnsVoid)
				this.valueCompatible = this.body.doesNotCompleteNormally();
		}
	}

	@Override
	public boolean isPotentiallyCompatibleWith(TypeBinding targetType, Scope skope) {
		/* We get here only when the lambda is NOT pertinent to applicability and that too only for type elided lambdas. */

		/* 15.12.2.1: A lambda expression (§15.27) is potentially compatible with a functional interface type (§9.8) if all of the following are true:
		       – The arity of the target type's function type is the same as the arity of the lambda expression.
		       – If the target type's function type has a void return, then the lambda body is either a statement expression (§14.8) or a void-compatible block (§15.27.2).
		       – If the target type's function type has a (non-void) return type, then the lambda body is either an expression or a value-compatible block (§15.27.2).
		*/
		if (!super.isPertinentToApplicability(targetType, null))
			return true;

		final MethodBinding sam = targetType.getSingleAbstractMethod(skope, true);
		if (sam == null || !sam.isValidBinding())
			return false;

		if (sam.parameters.length != this.arguments.length)
			return false;

		analyzeShape();
		if (sam.returnType.id == TypeIds.T_void) {
			if (!this.voidCompatible)
				return false;
		} else {
			if (!this.valueCompatible)
				return false;
		}
		return true;
	}

	private enum CompatibilityResult { COMPATIBLE, INCOMPATIBLE, REPORTED }

	public boolean reportShapeError(TypeBinding targetType, Scope skope) {
		return internalIsCompatibleWith(targetType, skope, true) == CompatibilityResult.REPORTED;
	}

	@Override
	public boolean isCompatibleWith(TypeBinding targetType, final Scope skope) {
		return internalIsCompatibleWith(targetType, skope, false) == CompatibilityResult.COMPATIBLE;
	}
	CompatibilityResult internalIsCompatibleWith(TypeBinding targetType, Scope skope, boolean reportShapeProblem) {

		if (!super.isPertinentToApplicability(targetType, null))
			return CompatibilityResult.COMPATIBLE;

		LambdaExpression copy = null;
		try {
			copy = cachedResolvedCopy(targetType, argumentsTypeElided(), false, null, skope); // if argument types are elided, we don't care for result expressions against *this* target, any valid target is OK.
		} catch (CopyFailureException cfe) {
			if (this.assistNode)
				return CompatibilityResult.COMPATIBLE; // can't type check result expressions, just say yes.
			return isPertinentToApplicability(targetType, null) ? CompatibilityResult.INCOMPATIBLE : CompatibilityResult.COMPATIBLE; // don't expect to hit this ever.
		}
		if (copy == null)
			return CompatibilityResult.INCOMPATIBLE;

		// copy here is potentially compatible with the target type and has its shape fully computed: i.e value/void compatibility is determined and result expressions have been gathered.
		targetType = findGroundTargetType(this.enclosingScope, targetType, targetType, argumentsTypeElided());
		MethodBinding sam = targetType.getSingleAbstractMethod(this.enclosingScope, true);
		if (sam == null || sam.problemId() == ProblemReasons.NoSuchSingleAbstractMethod) {
			return CompatibilityResult.INCOMPATIBLE;
		}
		if (sam.returnType.id == TypeIds.T_void) {
			if (!copy.voidCompatible) {
				return CompatibilityResult.INCOMPATIBLE;
			}
		} else {
			if (!copy.valueCompatible) {
				if (reportShapeProblem) {
					skope.problemReporter().missingValueFromLambda(this, sam.returnType);
					return CompatibilityResult.REPORTED;
				}
				return CompatibilityResult.INCOMPATIBLE;
			}
		}
		if (reportShapeProblem)
			return CompatibilityResult.COMPATIBLE; // enough seen

		if (!isPertinentToApplicability(targetType, null))
			return CompatibilityResult.COMPATIBLE;

		// catch up on one check deferred via skipKosherCheck=true (only if pertinent for applicability)
		if (!kosherDescriptor(this.enclosingScope, sam, false))
			return CompatibilityResult.INCOMPATIBLE;

		Expression [] returnExpressions = copy.resultExpressions;
		for (Expression returnExpression : returnExpressions) {
			if (sam.returnType.isProperType(true) // inference variables can reach here during nested inference
					&& this.enclosingScope.parameterCompatibilityLevel(returnExpression.resolvedType, sam.returnType) == Scope.NOT_COMPATIBLE) {
				if (!returnExpression.isConstantValueOfTypeAssignableToType(returnExpression.resolvedType, sam.returnType))
					if (sam.returnType.id != TypeIds.T_void || this.body instanceof Block)
						return CompatibilityResult.INCOMPATIBLE;
			}
		}
		return CompatibilityResult.COMPATIBLE;
	}

	static class CopyFailureException extends RuntimeException {
		private static final long serialVersionUID = 1L;
	}

	private LambdaExpression cachedResolvedCopy(TypeBinding targetType, boolean anyTargetOk, boolean requireExceptionAnalysis, InferenceContext18 context, Scope outerScope) {
		if (this.committed && outerScope instanceof BlockScope) {
			this.enclosingScope = (BlockScope) outerScope;
			// trust the result of any previous shape analysis:
			if (this.copiesPerTargetType != null && !this.copiesPerTargetType.isEmpty()) {
				LambdaExpression firstCopy = this.copiesPerTargetType.values().iterator().next();
				if (firstCopy != null) {
					this.valueCompatible = firstCopy.valueCompatible;
					this.voidCompatible = firstCopy.voidCompatible;
				}
			}
			return this;
		}

		targetType = findGroundTargetType(this.enclosingScope, targetType, targetType, argumentsTypeElided());
		if (targetType == null)
			return null;

		MethodBinding sam = targetType.getSingleAbstractMethod(this.enclosingScope, true);
		if (sam == null || !sam.isValidBinding())
			return null;

		if (sam.parameters.length != this.arguments.length)
			return null;

		LambdaExpression copy = null;
		if (this.copiesPerTargetType != null) {
			copy = this.copiesPerTargetType.get(targetType);
			if (copy == null) {
				if (anyTargetOk && this.copiesPerTargetType.values().size() > 0)
					copy = this.copiesPerTargetType.values().iterator().next();
			}
		}
		IErrorHandlingPolicy oldPolicy = this.enclosingScope.problemReporter().switchErrorHandlingPolicy(silentErrorHandlingPolicy);
		try {
			if (copy == null) {
				copy = copy();
				if (copy == null)
					throw new CopyFailureException();
				if (InferenceContext18.DEBUG) {
					System.out.println("Copy lambda "+this+" for target "+targetType.debugName()); //$NON-NLS-1$ //$NON-NLS-2$
				}

				copy.setExpressionContext(this.expressionContext);
				copy.setExpectedType(targetType);
				copy.inferenceContext = context;
				TypeBinding type = copy.resolveType(this.enclosingScope, true);
				if (type == null || !type.isValidBinding())
					return null;

				targetType = copy.expectedType; // possibly updated local types
				if (this.copiesPerTargetType == null)
					this.copiesPerTargetType = new HashMap<>();
				this.copiesPerTargetType.put(targetType, copy);
			}
			if (!requireExceptionAnalysis)
				return copy;
			if (copy.thrownExceptions == null)
				copy.analyzeExceptions();
			return copy;
		} finally {
			this.enclosingScope.problemReporter().switchErrorHandlingPolicy(oldPolicy);
		}
	}

	/**
	 * Get a resolved copy of this lambda for use by type inference, as to avoid spilling any premature
	 * type results into the original lambda.
	 *
	 * @param targetType the target functional type against which inference is attempted, must be a non-null valid functional type
	 * @return a resolved copy of 'this' or null if significant errors where encountered
	 */
	@Override
	public LambdaExpression resolveExpressionExpecting(TypeBinding targetType, Scope skope, InferenceContext18 context) {
		LambdaExpression copy = null;
		try {
			copy = cachedResolvedCopy(targetType, false, true, context, null /* to be safe we signal: not yet committed */);
		} catch (CopyFailureException cfe) {
			return null;
		}
		return copy;
	}

	@Override
	public boolean sIsMoreSpecific(TypeBinding s, TypeBinding t, Scope skope) {

		// 15.12.2.5

		if (super.sIsMoreSpecific(s, t, skope))
			return true;

		if (argumentsTypeElided() || t.findSuperTypeOriginatingFrom(s) != null)
			return false;
		TypeBinding sPrime = s; // uncaptured
		s = s.capture(this.enclosingScope, this.sourceStart, this.sourceEnd);
		MethodBinding sSam = s.getSingleAbstractMethod(this.enclosingScope, true);
		if (sSam == null || !sSam.isValidBinding())
			return false;
		MethodBinding tSam = t.getSingleAbstractMethod(this.enclosingScope, true);
		if (tSam == null || !tSam.isValidBinding())
			return true; // See ORT8.test450415a for a case that slips through isCompatibleWith.
		MethodBinding adapted = tSam.computeSubstitutedMethod(sSam, skope.environment());
		if (adapted == null) // not same type params
			return false;
		MethodBinding sSamPrime = sPrime.getSingleAbstractMethod(this.enclosingScope, true);
		TypeBinding[] ps = adapted.parameters; // parameters of S adapted to type parameters of T
		// parameters of S (without capture), adapted to type params of T
		MethodBinding prime = tSam.computeSubstitutedMethod(sSamPrime, skope.environment());
		TypeBinding[] pPrimes = prime.parameters;
		TypeBinding[] qs = tSam.parameters;
		for (int i = 0; i < ps.length; i++) {
			if (!qs[i].isCompatibleWith(ps[i]) || TypeBinding.notEquals(qs[i], pPrimes[i]))
				return false;
		}
		TypeBinding r1 = adapted.returnType; // return type of S adapted to type parameters of T
		TypeBinding r2 = tSam.returnType;

		if (r2.id == TypeIds.T_void)
			return true;

		if (r1.id == TypeIds.T_void)
			return false;

		// r1 <: r2
		if (r1.isCompatibleWith(r2, skope))
			return true;

		LambdaExpression copy;
		try {
			copy = cachedResolvedCopy(s, true /* any resolved copy is good */, false, null, null /*not yet committed*/); // we expect a cached copy - otherwise control won't reach here.
		} catch (CopyFailureException cfe) {
			if (this.assistNode)
				return false;
			throw cfe;
		}
		Expression [] returnExpressions = copy.resultExpressions;
		int returnExpressionsLength = returnExpressions == null ? 0 : returnExpressions.length;
		if (returnExpressionsLength > 0) {
			int i;
			// r1 is a primitive type, r2 is a reference type, and each result expression is a standalone expression (15.2) of a primitive type
			if (r1.isBaseType() && !r2.isBaseType()) {
				for (i = 0; i < returnExpressionsLength; i++) {
					if (returnExpressions[i].isPolyExpression() || !returnExpressions[i].resolvedType.isBaseType())
						break;
				}
				if (i == returnExpressionsLength)
					return true;
			}
			if (!r1.isBaseType() && r2.isBaseType()) {
				for (i = 0; i < returnExpressionsLength; i++) {
					if (returnExpressions[i].resolvedType.isBaseType())
						break;
				}
				if (i == returnExpressionsLength)
					return true;
			}
			if (r1.isFunctionalInterface(this.enclosingScope) && r2.isFunctionalInterface(this.enclosingScope)) {
				for (i = 0; i < returnExpressionsLength; i++) {
					Expression resultExpression = returnExpressions[i];
					if (!resultExpression.sIsMoreSpecific(r1, r2, skope))
						break;
				}
				if (i == returnExpressionsLength)
					return true;
			}
		}
		return false;
	}

	/**
	 * @return a virgin copy of `this' by reparsing the stashed textual form.
	 */
	LambdaExpression copy() {
		final Parser parser = new Parser(this.enclosingScope.problemReporter(), false);
		char [] source = new char [this.sourceEnd+1];
		System.arraycopy(this.text, 0, source, this.sourceStart, this.sourceEnd - this.sourceStart + 1);
		LambdaExpression copy =  (LambdaExpression) parser.parseLambdaExpression(source,this.sourceStart, this.sourceEnd - this.sourceStart + 1,
										this.enclosingScope.referenceCompilationUnit(), false /* record line separators */);

		if (copy != null) { // ==> syntax errors == null
			if (copy.sourceStart != this.sourceStart || copy.sourceEnd != this.sourceEnd)
				return null; // something wrong
			copy.original = this;
			copy.assistNode = this.assistNode;
			copy.enclosingScope = this.enclosingScope;
			copy.text = this.text; // discard redundant textual copy
		}
		return copy;
	}

	public void returnsExpression(Expression expression, TypeBinding resultType) {
		if (this.original == this) // Not in overload resolution context. result expressions not relevant.
			return;
		if (this.body instanceof Expression && ((Expression) this.body).isTrulyExpression()) {
			this.valueCompatible = resultType != null && resultType.id == TypeIds.T_void ? false : true;
			this.voidCompatible = this.assistNode ? true : ((Expression) this.body).statementExpression(); // while code is still being written and completed, we can't ask if it is a statement
			this.resultExpressions = new Expression[] { expression };
			return;
		}
		if (expression != null) {
			this.returnsValue = true;
			this.voidCompatible = false;
			this.valueCompatible = !this.returnsVoid;
			Expression [] returnExpressions = this.resultExpressions;
			int resultsLength = returnExpressions.length;
			System.arraycopy(returnExpressions, 0, returnExpressions = new Expression[resultsLength + 1], 0, resultsLength);
			returnExpressions[resultsLength] = expression;
			this.resultExpressions = returnExpressions;
		} else {
			this.returnsVoid = true;
			this.valueCompatible = false;
			this.voidCompatible = !this.returnsValue;
		}
	}

	@Override
	public CompilationResult compilationResult() {
		return this.compilationResult;
	}

	@Override
	public void abort(int abortLevel, CategorizedProblem problem) {

		switch (abortLevel) {
			case AbortCompilation :
				throw new AbortCompilation(this.compilationResult, problem);
			case AbortCompilationUnit :
				throw new AbortCompilationUnit(this.compilationResult, problem);
			case AbortType :
				throw new AbortType(this.compilationResult, problem);
			default :
				throw new AbortMethod(this.compilationResult, problem);
		}
	}

	@Override
	public CompilationUnitDeclaration getCompilationUnitDeclaration() {
		return this.enclosingScope == null ? null : this.enclosingScope.compilationUnitScope().referenceContext;
	}

	@Override
	public boolean hasErrors() {
		return this.ignoreFurtherInvestigation;
	}

	@Override
	public void tagAsHavingErrors() {
		this.ignoreFurtherInvestigation = true;
		Scope parent = this.enclosingScope.parent;
		while (parent != null) {
			switch(parent.kind) {
				case Scope.CLASS_SCOPE:
				case Scope.METHOD_SCOPE:
					ReferenceContext parentAST = parent.referenceContext();
					if (parentAST != this) {
						parentAST.tagAsHavingErrors();
						return;
					}
					//$FALL-THROUGH$
				default:
					parent = parent.parent;
					break;
			}
		}
	}

	public Set getThrownExceptions() {
		if (this.thrownExceptions == null)
			return Collections.emptySet();
		return this.thrownExceptions;
	}

	public void generateCode(ClassScope classScope, ClassFile classFile) {
		int problemResetPC = 0;
		classFile.codeStream.wideMode = false;
		boolean restart = false;
		do {
			try {
				problemResetPC = classFile.contentsOffset;
				this.generateCode(classFile);
				restart = false;
			} catch (AbortMethod e) {
				// Restart code generation if possible ...
				if (e.compilationResult == CodeStream.RESTART_IN_WIDE_MODE) {
					// a branch target required a goto_w, restart code generation in wide mode.
					classFile.contentsOffset = problemResetPC;
					classFile.methodCount--;
					classFile.codeStream.resetInWideMode(); // request wide mode
					restart = true;
				} else if (e.compilationResult == CodeStream.RESTART_CODE_GEN_FOR_UNUSED_LOCALS_MODE) {
					classFile.contentsOffset = problemResetPC;
					classFile.methodCount--;
					classFile.codeStream.resetForCodeGenUnusedLocals();
					restart = true;
				} else {
					throw new AbortType(this.compilationResult, e.problem);
				}
			}
		} while (restart);
	}

	public void generateCode(ClassFile classFile) {
		classFile.generateMethodInfoHeader(this.binding);
		int methodAttributeOffset = classFile.contentsOffset;
		int attributeNumber = classFile.generateMethodInfoAttributes(this.binding);
		int codeAttributeOffset = classFile.contentsOffset;
		classFile.generateCodeAttributeHeader();
		CodeStream codeStream = classFile.codeStream;
		codeStream.reset(this, classFile);
		// initialize local positions
		this.scope.computeLocalVariablePositions(this.outerLocalVariablesSlotSize + (this.binding.isStatic() ? 0 : 1), codeStream);
		if (this.outerLocalVariables != null) {
			for (SyntheticArgumentBinding outerLocalVariable : this.outerLocalVariables) {
				LocalVariableBinding argBinding;
				codeStream.addVisibleLocalVariable(argBinding = outerLocalVariable);
				codeStream.record(argBinding);
				argBinding.recordInitializationStartPC(0);
			}
		}
		// arguments initialization for local variable debug attributes
		if (this.arguments != null) {
			for (Argument argument : this.arguments) {
				LocalVariableBinding argBinding;
				codeStream.addVisibleLocalVariable(argBinding = argument.binding);
				argBinding.recordInitializationStartPC(0);
			}
		}
		codeStream.pushPatternAccessTrapScope(this.scope);
		if (this.body instanceof Block) {
			boolean prev = codeStream.stmtInPreConContext;
			codeStream.stmtInPreConContext = this.inPreConstructorContext;
			this.body.generateCode(this.scope, codeStream);
			codeStream.stmtInPreConContext = prev;
			if ((this.bits & ASTNode.NeedFreeReturn) != 0) {
				codeStream.return_();
			}
		} else {
			Expression expression = (Expression) this.body;
			expression.generateCode(this.scope, codeStream, true);
			if (this.binding.returnType == TypeBinding.VOID) {
				codeStream.return_();
			} else {
				codeStream.generateReturnBytecode(expression);
			}
		}
		// See https://github.com/eclipse-jdt/eclipse.jdt.core/issues/1796#issuecomment-1933458054
		codeStream.exitUserScope(this.scope, lvb -> !lvb.isParameter());
		codeStream.handleRecordAccessorExceptions(this.scope);
		// local variable attributes
		codeStream.exitUserScope(this.scope);
		codeStream.recordPositionsFrom(0, this.sourceEnd); // WAS declarationSourceEnd.
		try {
			classFile.completeCodeAttribute(codeAttributeOffset, this.scope);
		} catch(NegativeArraySizeException e) {
			throw new AbortMethod(this.scope.referenceCompilationUnit().compilationResult, null);
		}
		attributeNumber++;

		classFile.completeMethodInfo(this.binding, methodAttributeOffset, attributeNumber);
	}

	public void addSyntheticArgument(LocalVariableBinding actualOuterLocalVariable) {

		if (this.original != this || this.binding == null)
			return; // Do not bother tracking outer locals for clones created during overload resolution.

		SyntheticArgumentBinding syntheticLocal = null;
		int newSlot = this.outerLocalVariables.length;
		for (int i = 0; i < newSlot; i++) {
			if (this.outerLocalVariables[i].actualOuterLocalVariable == actualOuterLocalVariable)
				return;
		}
		System.arraycopy(this.outerLocalVariables, 0, this.outerLocalVariables = new SyntheticArgumentBinding[newSlot + 1], 0, newSlot);
		this.outerLocalVariables[newSlot] = syntheticLocal = new SyntheticArgumentBinding(actualOuterLocalVariable);
		syntheticLocal.resolvedPosition = this.outerLocalVariablesSlotSize; // may need adjusting later if we need to generate an instance method for the lambda.
		syntheticLocal.declaringScope = this.scope;
		int parameterCount = this.binding.parameters.length;
		TypeBinding [] newParameters = new TypeBinding[parameterCount + 1];
		newParameters[newSlot] = actualOuterLocalVariable.type;
		for (int i = 0, j = 0; i < parameterCount; i++, j++) {
			if (i == newSlot) j++;
			newParameters[j] = this.binding.parameters[i];
		}
		this.binding.parameters = newParameters;
		switch (syntheticLocal.type.id) {
			case TypeIds.T_long :
			case TypeIds.T_double :
				this.outerLocalVariablesSlotSize  += 2;
				break;
			default :
				this.outerLocalVariablesSlotSize++;
				break;
		}
	}

	public SyntheticArgumentBinding addSyntheticArgument(ReferenceBinding enclosingType) {

		if (this.original != this || this.binding == null)
			return null; // Do not bother tracking outer locals for clones created during overload resolution.

		SyntheticArgumentBinding syntheticLocal = null;
		int newSlot = this.outerLocalVariables.length;
		System.arraycopy(this.outerLocalVariables, 0, this.outerLocalVariables = new SyntheticArgumentBinding[newSlot + 1], 0, newSlot);
		this.outerLocalVariables[newSlot] = syntheticLocal = new SyntheticArgumentBinding(enclosingType);
		syntheticLocal.resolvedPosition = this.outerLocalVariablesSlotSize; // may need adjusting later if we need to generate an instance method for the lambda.
		syntheticLocal.declaringScope = this.scope;
		int parameterCount = this.binding.parameters.length;
		TypeBinding [] newParameters = new TypeBinding[parameterCount + 1];
		newParameters[newSlot] = enclosingType;
		for (int i = 0, j = 0; i < parameterCount; i++, j++) {
			if (i == newSlot) j++;
			newParameters[j] = this.binding.parameters[i];
		}
		this.binding.parameters = newParameters;
		switch (syntheticLocal.type.id) {
			case TypeIds.T_long :
			case TypeIds.T_double :
				this.outerLocalVariablesSlotSize  += 2;
				break;
			default :
				this.outerLocalVariablesSlotSize++;
				break;
		}
		return syntheticLocal;
	}
	public SyntheticArgumentBinding getSyntheticArgument(LocalVariableBinding actualOuterLocalVariable) {
		for (int i = 0, length = this.outerLocalVariables == null ? 0 : this.outerLocalVariables.length; i < length; i++)
			if (this.outerLocalVariables[i].actualOuterLocalVariable == actualOuterLocalVariable)
				return this.outerLocalVariables[i];
		return null;
	}

	// Return the actual method binding devoid of synthetics.
	@Override
	public MethodBinding getMethodBinding() {
		if (this.actualMethodBinding == null) {
			if (this.binding != null) {
				// Get rid of the synthetic arguments added via addSyntheticArgument()
				TypeBinding[] newParams = null;
				if (this.binding instanceof SyntheticMethodBinding && this.outerLocalVariables.length > 0) {
					newParams = new TypeBinding[this.binding.parameters.length - this.outerLocalVariables.length];
					System.arraycopy(this.binding.parameters, this.outerLocalVariables.length, newParams, 0, newParams.length);
				} else {
					newParams = this.binding.parameters;
				}
				this.actualMethodBinding = new MethodBinding(this.binding.modifiers, this.binding.selector,
						this.binding.returnType, newParams, this.binding.thrownExceptions, this.binding.declaringClass);
				this.actualMethodBinding.tagBits = this.binding.tagBits;
			} else {
				this.actualMethodBinding = new ProblemMethodBinding(CharOperation.NO_CHAR, null, ProblemReasons.NoSuchSingleAbstractMethod);
			}
		}
		return this.actualMethodBinding;
	}

	@Override
	public int diagnosticsSourceEnd() {
		return this.body instanceof Block ? this.arrowPosition : this.sourceEnd;
	}

	public TypeBinding[] getMarkerInterfaces() {
		if (this.expectedType instanceof IntersectionTypeBinding18) {
			Set markerBindings = new LinkedHashSet();
			IntersectionTypeBinding18 intersectionType = (IntersectionTypeBinding18)this.expectedType;
			TypeBinding[] intersectionTypes = intersectionType.intersectingTypes;
			TypeBinding samType = intersectionType.getSAMType(this.enclosingScope);
			for (TypeBinding typeBinding : intersectionTypes) {
				if (!typeBinding.isInterface()							// only interfaces
					|| TypeBinding.equalsEquals(samType, typeBinding)	// except for the samType itself
					|| typeBinding.id == TypeIds.T_JavaIoSerializable)	// but Serializable is captured as a bitflag
				{
					continue;
				}
				markerBindings.add(typeBinding);
			}
			if (markerBindings.size() > 0) {
				return (TypeBinding[])markerBindings.toArray(new TypeBinding[markerBindings.size()]);
			}
		}
		return null;
	}

	public ReferenceBinding getTypeBinding() {

		if (this.classType != null || this.resolvedType == null)
			return null;

		class LambdaTypeBinding extends ReferenceBinding {
			@Override
			public MethodBinding[] methods() {
				return new MethodBinding [] { getMethodBinding() };
			}
			@Override
			public char[] sourceName() {
				return TypeConstants.LAMBDA_TYPE;
			}
			@Override
			public ReferenceBinding superclass() {
				return LambdaExpression.this.scope.getJavaLangObject();
			}
			@Override
			public ReferenceBinding[] superInterfaces() {
				return new ReferenceBinding[] { (ReferenceBinding) LambdaExpression.this.resolvedType };
			}
			@Override
			public char[] computeUniqueKey() {
				return LambdaExpression.this.descriptor.declaringClass.computeUniqueKey();
			}
			@Override
			public String toString() {
				StringBuilder output = new StringBuilder("()->{} implements "); //$NON-NLS-1$
				output.append(LambdaExpression.this.descriptor.declaringClass.sourceName());
				output.append('.');
				output.append(LambdaExpression.this.descriptor.toString());
				return output.toString();
			}
		}
		return this.classType = new LambdaTypeBinding();
	}

	public void addLocalType(LocalTypeBinding localTypeBinding) {
		if (this.localTypes == null)
			this.localTypes = new HashMap<>();
		this.localTypes.put(localTypeBinding.sourceStart, localTypeBinding);
	}

	/**
	 * During inference, several copies of a lambda may be created.
	 * If a lambda body contains a local type declaration, one binding may be created
	 * within each of the lambda copies. Once inference finished, we need to map all
	 * such local type bindings to the instance from the correct lambda copy.
	 * 

	 * When a local type binding occurs as a field of another type binding (e.g.,
	 * type argument), the local type will be replaced in-place, assuming that the
	 * previous binding should never escape the context of resolving this lambda.
	 * 

	 */
	static class LocalTypeSubstitutor extends Substitutor {
		Map localTypes2;

		public LocalTypeSubstitutor(Map localTypes, MethodBinding methodBinding) {
			this.localTypes2 = localTypes;
			if (methodBinding != null && methodBinding.isStatic())
				this.staticContext = methodBinding.declaringClass;
		}

		@Override
		public TypeBinding substitute(Substitution substitution, TypeBinding originalType) {
			if (originalType.isLocalType()) {
				LocalTypeBinding orgLocal = (LocalTypeBinding) originalType.original();
				MethodScope lambdaScope2 = orgLocal.scope.enclosingLambdaScope();
				if (lambdaScope2 != null) {
					// local type within a lambda may need replacement:
					TypeBinding substType = this.localTypes2.get(orgLocal.sourceStart);
					if (substType != null && substType != orgLocal) { //$IDENTITY-COMPARISON$
						orgLocal.transferConstantPoolNameTo(substType);
						return substType;
					}
				}
				return originalType;
			}
			return super.substitute(substitution, originalType);
		}
	}

	boolean updateLocalTypes() {
		if (this.descriptor == null || this.localTypes == null)
			return false;
		LocalTypeSubstitutor substor = new LocalTypeSubstitutor(this.localTypes, null/*lambda method is never static*/);
		NullSubstitution subst = new NullSubstitution(this.scope.environment());
		updateLocalTypesInMethod(this.binding, substor, subst);
		updateLocalTypesInMethod(this.descriptor, substor, subst);
		this.resolvedType = substor.substitute(subst, this.resolvedType);
		this.expectedType = substor.substitute(subst, this.expectedType);
		return true;
	}

	/**
	 * Perform substitution with a {@link LocalTypeSubstitutor} on all types mentioned in the given method binding.
	 */
	boolean updateLocalTypesInMethod(MethodBinding method) {
		if (this.localTypes == null)
			return false;
		updateLocalTypesInMethod(method, new LocalTypeSubstitutor(this.localTypes, method), new NullSubstitution(this.scope.environment()));
		return true;
	}

	public static void updateLocalTypesInMethod(MethodBinding method, Substitutor substor, Substitution subst) {
		method.declaringClass = (ReferenceBinding) substor.substitute(subst, method.declaringClass);
		method.returnType = substor.substitute(subst, method.returnType);
		for (int i = 0; i < method.parameters.length; i++) {
			method.parameters[i] = substor.substitute(subst, method.parameters[i]);
		}
		if (method instanceof ParameterizedGenericMethodBinding) {
			ParameterizedGenericMethodBinding pgmb = (ParameterizedGenericMethodBinding) method;
			for (int i = 0; i < pgmb.typeArguments.length; i++) {
				pgmb.typeArguments[i] = substor.substitute(subst, pgmb.typeArguments[i]);
			}
		}
	}
}
    

    

    

            

    

            



    
    






    
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