Copyright (c) 2000, 2018 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
    Stephan Herrmann - Contributions for
							bug 186342 - [compiler][null] Using annotations for null checking
							bug 365519 - editorial cleanup after bug 186342 and bug 365387
							bug 388281 - [compiler][null] inheritance of null annotations as an option
							bug 388795 - [compiler] detection of name clash depends on order of super interfaces
							bug 388739 - [1.8][compiler] consider default methods when detecting whether a class needs to be declared abstract
							bug 390883 - [1.8][compiler] Unable to override default method
							bug 395002 - Self bound generic class doesn't resolve bounds properly for wildcards for certain parametrisation.
							bug 401246 - [1.8][compiler] abstract class method should now trump conflicting default methods
							bug 401796 - [1.8][compiler] don't treat default methods as overriding an independent inherited abstract method
							bug 403867 - [1.8][compiler] Suspect error about duplicate default methods
							bug 391376 - [1.8] check interaction of default methods with bridge methods and generics
							bug 395681 - [compiler] Improve simulation of javac6 behavior from bug 317719 after fixing bug 388795
							bug 409473 - [compiler] JDT cannot compile against JRE 1.8
							Bug 420080 - [1.8] Overridden Default method is reported as duplicated
							Bug 404690 - [1.8][compiler] revisit bridge generation after VM bug is fixed
							Bug 410325 - [1.7][compiler] Generified method override different between javac and eclipse compiler
							Bug 429958 - [1.8][null] evaluate new DefaultLocation attribute of @NonNullByDefault
							Bug 390889 - [1.8][compiler] Evaluate options to support 1.7- projects against 1.8 JRE.
							Bug 440773 - [1.8][null]DefaultLocation.RETURN_TYPE erroneously affects method parameters in @NonNullByDefault
							Bug 435805 - [1.8][compiler][null] Java 8 compiler does not recognize declaration style null annotations
							Bug 446442 - [1.8] merge null annotations from super methods
/*******************************************************************************
 * Copyright (c) 2000, 2018 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
 *     Stephan Herrmann - Contributions for
 *								bug 186342 - [compiler][null] Using annotations for null checking
 *								bug 365519 - editorial cleanup after bug 186342 and bug 365387
 *								bug 388281 - [compiler][null] inheritance of null annotations as an option
 *								bug 388795 - [compiler] detection of name clash depends on order of super interfaces
 *								bug 388739 - [1.8][compiler] consider default methods when detecting whether a class needs to be declared abstract
 *								bug 390883 - [1.8][compiler] Unable to override default method
 *								bug 395002 - Self bound generic class doesn't resolve bounds properly for wildcards for certain parametrisation.
 *								bug 401246 - [1.8][compiler] abstract class method should now trump conflicting default methods
 *								bug 401796 - [1.8][compiler] don't treat default methods as overriding an independent inherited abstract method
 *								bug 403867 - [1.8][compiler] Suspect error about duplicate default methods
 *								bug 391376 - [1.8] check interaction of default methods with bridge methods and generics
 *								bug 395681 - [compiler] Improve simulation of javac6 behavior from bug 317719 after fixing bug 388795
 *								bug 409473 - [compiler] JDT cannot compile against JRE 1.8
 *								Bug 420080 - [1.8] Overridden Default method is reported as duplicated
 *								Bug 404690 - [1.8][compiler] revisit bridge generation after VM bug is fixed
 *								Bug 410325 - [1.7][compiler] Generified method override different between javac and eclipse compiler
 *								Bug 429958 - [1.8][null] evaluate new DefaultLocation attribute of @NonNullByDefault
 *								Bug 390889 - [1.8][compiler] Evaluate options to support 1.7- projects against 1.8 JRE.
 *								Bug 440773 - [1.8][null]DefaultLocation.RETURN_TYPE erroneously affects method parameters in @NonNullByDefault
 *								Bug 435805 - [1.8][compiler][null] Java 8 compiler does not recognize declaration style null annotations
 *								Bug 446442 - [1.8] merge null annotations from super methods
 *******************************************************************************/
package org.eclipse.jdt.internal.compiler.lookup;


import java.util.Arrays;

import org.eclipse.jdt.internal.compiler.ast.ASTNode;
import org.eclipse.jdt.internal.compiler.ast.AbstractMethodDeclaration;
import org.eclipse.jdt.internal.compiler.ast.Argument;
import org.eclipse.jdt.internal.compiler.ast.MethodDeclaration;
import org.eclipse.jdt.internal.compiler.ast.TypeParameter;
import org.eclipse.jdt.internal.compiler.ast.TypeReference;
import org.eclipse.jdt.internal.compiler.classfmt.ClassFileConstants;
import org.eclipse.jdt.internal.compiler.impl.CompilerOptions;
import org.eclipse.jdt.internal.compiler.problem.ProblemSeverities;
import org.eclipse.jdt.internal.compiler.util.HashtableOfObject;
import org.eclipse.jdt.internal.compiler.util.SimpleSet;
import org.eclipse.jdt.internal.compiler.util.Sorting;

class MethodVerifier15 extends MethodVerifier {

MethodVerifier15(LookupEnvironment environment) {
	super(environment);
}
// Given `overridingMethod' which overrides `inheritedMethod' answer whether some subclass method that
// differs in erasure from overridingMethod could override `inheritedMethod'
@Override
protected boolean canOverridingMethodDifferInErasure(MethodBinding overridingMethod, MethodBinding inheritedMethod) {
	if (overridingMethod.areParameterErasuresEqual(inheritedMethod))
		return false;  // no further change in signature is possible due to parameterization.
	if (overridingMethod.declaringClass.isRawType())
		return false;  // no parameterization is happening anyways.
	return true;
}
@Override
boolean canSkipInheritedMethods() {
	if (this.type.superclass() != null)
		if (this.type.superclass().isAbstract() || this.type.superclass().isParameterizedType())
			return false;
	return this.type.superInterfaces() == Binding.NO_SUPERINTERFACES;
}
@Override
boolean canSkipInheritedMethods(MethodBinding one, MethodBinding two) {
	return two == null // already know one is not null
		|| (TypeBinding.equalsEquals(one.declaringClass, two.declaringClass) && !one.declaringClass.isParameterizedType());
}
@Override
void checkConcreteInheritedMethod(MethodBinding concreteMethod, MethodBinding[] abstractMethods) {
	super.checkConcreteInheritedMethod(concreteMethod, abstractMethods);
	boolean analyseNullAnnotations = this.environment.globalOptions.isAnnotationBasedNullAnalysisEnabled;
	// TODO (stephan): unclear if this srcMethod is actually needed
	AbstractMethodDeclaration srcMethod = null;
	if (analyseNullAnnotations && this.type.equals(concreteMethod.declaringClass)) // is currentMethod from the current type?
		srcMethod = concreteMethod.sourceMethod();
	boolean hasReturnNonNullDefault = analyseNullAnnotations && concreteMethod.hasNonNullDefaultForReturnType(srcMethod);
	ParameterNonNullDefaultProvider hasParameterNonNullDefault = analyseNullAnnotations ? concreteMethod.hasNonNullDefaultForParameter(srcMethod): ParameterNonNullDefaultProvider.FALSE_PROVIDER;

	for (int i = 0, l = abstractMethods.length; i < l; i++) {
		MethodBinding abstractMethod = abstractMethods[i];
		if (concreteMethod.isVarargs() != abstractMethod.isVarargs())
			problemReporter().varargsConflict(concreteMethod, abstractMethod, this.type);

		// so the parameters are equal and the return type is compatible b/w the currentMethod & the substituted inheritedMethod
		MethodBinding originalInherited = abstractMethod.original();
		if (TypeBinding.notEquals(originalInherited.returnType, concreteMethod.returnType))
			if (!isAcceptableReturnTypeOverride(concreteMethod, abstractMethod))
				problemReporter().unsafeReturnTypeOverride(concreteMethod, originalInherited, this.type);

		// check whether bridge method is already defined above for interface methods
		// skip generation of bridge method for current class & method if an equivalent
		// bridge will be/would have been generated in the context of the super class since
		// the bridge itself will be inherited. See https://bugs.eclipse.org/bugs/show_bug.cgi?id=298362
		if (originalInherited.declaringClass.isInterface()) {
			if ((TypeBinding.equalsEquals(concreteMethod.declaringClass, this.type.superclass) && this.type.superclass.isParameterizedType() && !areMethodsCompatible(concreteMethod, originalInherited))
				|| this.type.superclass.erasure().findSuperTypeOriginatingFrom(originalInherited.declaringClass) == null)
					this.type.addSyntheticBridgeMethod(originalInherited, concreteMethod.original());
		}
		if (analyseNullAnnotations && !concreteMethod.isStatic() && !abstractMethod.isStatic()) {
			checkNullSpecInheritance(concreteMethod, srcMethod, hasReturnNonNullDefault, hasParameterNonNullDefault, true, abstractMethod, abstractMethods, this.type.scope, null);
		}
	}
}
@Override
void checkForBridgeMethod(MethodBinding currentMethod, MethodBinding inheritedMethod, MethodBinding[] allInheritedMethods) {
	if (currentMethod.isVarargs() != inheritedMethod.isVarargs())
		problemReporter(currentMethod).varargsConflict(currentMethod, inheritedMethod, this.type);

	// so the parameters are equal and the return type is compatible b/w the currentMethod & the substituted inheritedMethod
	MethodBinding originalInherited = inheritedMethod.original();
	if (TypeBinding.notEquals(originalInherited.returnType, currentMethod.returnType))
		if (!isAcceptableReturnTypeOverride(currentMethod, inheritedMethod))
			problemReporter(currentMethod).unsafeReturnTypeOverride(currentMethod, originalInherited, this.type);

	MethodBinding bridge = this.type.addSyntheticBridgeMethod(originalInherited, currentMethod.original());
	if (bridge != null) {
		for (int i = 0, l = allInheritedMethods == null ? 0 : allInheritedMethods.length; i < l; i++) {
			if (allInheritedMethods[i] != null && detectInheritedNameClash(originalInherited, allInheritedMethods[i].original()))
				return;
		}
		// See if the new bridge clashes with any of the user methods of the class. For this check
		// we should check for "method descriptor clash" and not just "method signature clash". Really
		// what we are checking is whether there is a contention for the method dispatch table slot.
		// See https://bugs.eclipse.org/bugs/show_bug.cgi?id=293615.
		MethodBinding[] current = (MethodBinding[]) this.currentMethods.get(bridge.selector);
		for (int i = current.length - 1; i >= 0; --i) {
			final MethodBinding thisMethod = current[i];
			if (thisMethod.areParameterErasuresEqual(bridge) && TypeBinding.equalsEquals(thisMethod.returnType.erasure(), bridge.returnType.erasure())) {
				// use inherited method for problem reporting.
				problemReporter(thisMethod).methodNameClash(thisMethod, inheritedMethod.declaringClass.isRawType() ? inheritedMethod : inheritedMethod.original(), ProblemSeverities.Error);
				return;	
			}
		}
	}
}
void checkForNameClash(MethodBinding currentMethod, MethodBinding inheritedMethod) {
	// sent from checkMethods() to compare a current method and an inherited method that are not 'equal'

	// error cases:
	//		abstract class AA<E extends Comparable> { abstract void test(E element); }
	//		class A extends AA<Integer> { public void test(Integer i) {} }
	//		public class B extends A { public void test(Comparable i) {} }
	//		interface I<E extends Comparable> { void test(E element); }
	//		class A implements I<Integer> { public void test(Integer i) {} }
	//		public class B extends A { public void test(Comparable i) {} }

	//		abstract class Y implements EqualityComparable<Integer>, Equivalent<String> {
	//			public boolean equalTo(Integer other) { return true; }
	//		}
	//		interface Equivalent<T> { boolean equalTo(T other); }
	//		interface EqualityComparable<T> { boolean equalTo(T other); }

	//		class Y implements EqualityComparable, Equivalent<String>{
	//			public boolean equalTo(String other) { return true; }
	//			public boolean equalTo(Object other) { return true; }
	//		}
	//		interface Equivalent<T> { boolean equalTo(T other); }
	//		interface EqualityComparable { boolean equalTo(Object other); }

	//		class A<T extends Number> { void m(T t) {} }
	//		class B<S extends Integer> extends A<S> { void m(S t) {}}
	//		class D extends B<Integer> { void m(Number t) {}    void m(Integer t) {} }

	//		inheritedMethods does not include I.test since A has a valid implementation
	//		interface I<E extends Comparable<E>> { void test(E element); }
	//		class A implements I<Integer> { public void test(Integer i) {} }
	//		class B extends A { public void test(Comparable i) {} }

	if (inheritedMethod.isStatic() || currentMethod.isStatic()) {
		MethodBinding original = inheritedMethod.original(); // can be the same as inherited
		if (this.type.scope.compilerOptions().complianceLevel >= ClassFileConstants.JDK1_7 && currentMethod.areParameterErasuresEqual(original)) {
			problemReporter(currentMethod).methodNameClashHidden(currentMethod, inheritedMethod.declaringClass.isRawType() ? inheritedMethod : original);
		}
		return; // no chance of bridge method's clashing
	}

	if (!detectNameClash(currentMethod, inheritedMethod, false)) { // check up the hierarchy for skipped inherited methods
		TypeBinding[] currentParams = currentMethod.parameters;
		TypeBinding[] inheritedParams = inheritedMethod.parameters;
		int length = currentParams.length;
		if (length != inheritedParams.length) return; // no match

		for (int i = 0; i < length; i++)
			if (TypeBinding.notEquals(currentParams[i], inheritedParams[i]))
				if (currentParams[i].isBaseType() != inheritedParams[i].isBaseType() || !inheritedParams[i].isCompatibleWith(currentParams[i]))
					return; // no chance that another inherited method's bridge method can collide

		ReferenceBinding[] interfacesToVisit = null;
		int nextPosition = 0;
		ReferenceBinding superType = inheritedMethod.declaringClass;
		ReferenceBinding[] itsInterfaces = superType.superInterfaces();
		if (itsInterfaces != Binding.NO_SUPERINTERFACES) {
			nextPosition = itsInterfaces.length;
			interfacesToVisit = itsInterfaces;
		}
		superType = superType.superclass(); // now start with its superclass
		while (superType != null && superType.isValidBinding()) {
			MethodBinding[] methods = superType.getMethods(currentMethod.selector);
			for (int m = 0, n = methods.length; m < n; m++) {
				MethodBinding substitute = computeSubstituteMethod(methods[m], currentMethod);
				if (substitute != null && !isSubstituteParameterSubsignature(currentMethod, substitute) && detectNameClash(currentMethod, substitute, true))
					return;
			}
			if ((itsInterfaces = superType.superInterfaces()) != Binding.NO_SUPERINTERFACES) {
				if (interfacesToVisit == null) {
					interfacesToVisit = itsInterfaces;
					nextPosition = interfacesToVisit.length;
				} else {
					int itsLength = itsInterfaces.length;
					if (nextPosition + itsLength >= interfacesToVisit.length)
						System.arraycopy(interfacesToVisit, 0, interfacesToVisit = new ReferenceBinding[nextPosition + itsLength + 5], 0, nextPosition);
					nextInterface : for (int a = 0; a < itsLength; a++) {
						ReferenceBinding next = itsInterfaces[a];
						for (int b = 0; b < nextPosition; b++)
							if (TypeBinding.equalsEquals(next, interfacesToVisit[b])) continue nextInterface;
						interfacesToVisit[nextPosition++] = next;
					}
				}
			}
			superType = superType.superclass();
		}

		for (int i = 0; i < nextPosition; i++) {
			superType = interfacesToVisit[i];
			if (superType.isValidBinding()) {
				MethodBinding[] methods = superType.getMethods(currentMethod.selector);
				for (int m = 0, n = methods.length; m < n; m++){
					MethodBinding substitute = computeSubstituteMethod(methods[m], currentMethod);
					if (substitute != null && !isSubstituteParameterSubsignature(currentMethod, substitute) && detectNameClash(currentMethod, substitute, true))
						return;
				}
				if ((itsInterfaces = superType.superInterfaces()) != Binding.NO_SUPERINTERFACES) {
					int itsLength = itsInterfaces.length;
					if (nextPosition + itsLength >= interfacesToVisit.length)
						System.arraycopy(interfacesToVisit, 0, interfacesToVisit = new ReferenceBinding[nextPosition + itsLength + 5], 0, nextPosition);
					nextInterface : for (int a = 0; a < itsLength; a++) {
						ReferenceBinding next = itsInterfaces[a];
						for (int b = 0; b < nextPosition; b++)
							if (TypeBinding.equalsEquals(next, interfacesToVisit[b])) continue nextInterface;
						interfacesToVisit[nextPosition++] = next;
					}
				}
			}
		}
	}
}
void checkInheritedMethods(MethodBinding inheritedMethod, MethodBinding otherInheritedMethod) {

	// the 2 inherited methods clash because of a parameterized type overrides a raw type
	//		interface I { void foo(A a); }
	//		class Y { void foo(A<String> a) {} }
	//		abstract class X extends Y implements I { }
	//		class A<T> {}
	// in this case the 2 inherited methods clash because of type variables
	//		interface I { <T, S> void foo(T t); }
	//		class Y { <T> void foo(T t) {} }
	//		abstract class X extends Y implements I {}

	if (inheritedMethod.isStatic()) return;
	if (this.environment.globalOptions.complianceLevel < ClassFileConstants.JDK1_7 && inheritedMethod.declaringClass.isInterface())
		return;  // JDK7 checks for name clashes in interface inheritance, while JDK6 and below don't. See https://bugs.eclipse.org/bugs/show_bug.cgi?id=354229

	detectInheritedNameClash(inheritedMethod.original(), otherInheritedMethod.original());
}
// 8.4.8.4
@Override
void checkInheritedMethods(MethodBinding[] methods, int length, boolean[] isOverridden, boolean[] isInherited) {
	boolean continueInvestigation = true;
	MethodBinding concreteMethod = null;
	MethodBinding abstractSuperClassMethod = null;
	boolean playingTrump = false; // invariant: playingTrump => (concreteMethod == null)
	for (int i = 0; i < length; i++) {
		if (!methods[i].declaringClass.isInterface()
				&& TypeBinding.notEquals(methods[i].declaringClass, this.type)
				&& methods[i].isAbstract())
		{
			abstractSuperClassMethod = methods[i];
			break;
		}
	}
	for (int i = 0; i < length; i++) {
		// methods not inherited as of 8.4.8 cannot create a name clash,
		// but could still cause errors against return types etc. (below)
		if (isInherited[i] && !methods[i].isAbstract()) {
			// 8.4.8.4 defines an exception for default methods if
			// (a) there exists an abstract method declared in a superclass of C and inherited by C
			// (b) that is override-equivalent with the two methods.
			if (methods[i].isDefaultMethod()
					&& abstractSuperClassMethod != null							// condition (a)
					&& areParametersEqual(abstractSuperClassMethod, methods[i]) // condition (b)...
					&& concreteMethod == null) {
				// skip, class method trumps this default method (concreteMethod remains null)
				playingTrump = true;
			} else {
				playingTrump = false;
				if (concreteMethod != null) {
					// re-checking compatibility is needed for https://bugs.eclipse.org/346029
					if (isOverridden[i] && areMethodsCompatible(concreteMethod, methods[i])) {
						continue;
					}
					// https://bugs.eclipse.org/195802 with https://bugs.eclipse.org/410325
					// If a replace method (from findReplacedMethod()) is the rawified version of another
					// don't count this as duplicates:
					//   (Not asking ParameterizedGenericMethodBinding.isRawMethod(),
					//    because that is true only for methods of a RawTypeBinding,
					//    but here we look for rawness regarding the method's type variables).
					if (TypeBinding.equalsEquals(concreteMethod.declaringClass, methods[i].declaringClass) 
							&& concreteMethod.typeVariables.length != methods[i].typeVariables.length) 
					{
						if (concreteMethod.typeVariables == Binding.NO_TYPE_VARIABLES
								&& concreteMethod.original() == methods[i])
							continue;
						if (methods[i].typeVariables == Binding.NO_TYPE_VARIABLES
								&& methods[i].original() == concreteMethod)
							continue;
					}

					problemReporter().duplicateInheritedMethods(this.type, concreteMethod, methods[i],
											this.environment.globalOptions.sourceLevel >= ClassFileConstants.JDK1_8);
					continueInvestigation = false;
				}
				concreteMethod = methods[i];
			}
		}
	}
	if (continueInvestigation) {
		if (playingTrump) {
			// multiple abstract & default methods are OK on this branch, but then the class must be declared abstract:
			if (!this.type.isAbstract()) {
				problemReporter().abstractMethodMustBeImplemented(this.type, abstractSuperClassMethod);
				return;
			}
		} else {
			if (concreteMethod != null && concreteMethod.isDefaultMethod()) {
				if (this.environment.globalOptions.complianceLevel >= ClassFileConstants.JDK1_8) {
					if (!checkInheritedDefaultMethods(methods, isOverridden, length))
						return;
				}
			}
		}
		super.checkInheritedMethods(methods, length, isOverridden, isInherited);
	}
}
boolean checkInheritedDefaultMethods(MethodBinding[] methods, boolean[] isOverridden, int length) {
	// JLS8  9.4.1.3 (interface) and  8.4.8.4 (class):
	// default method clashes with other inherited method which is override-equivalent 
	if (length < 2) return true;
	boolean ok = true;
	findDefaultMethod: for (int i=0; i<length; i++) {
		if (methods[i].isDefaultMethod() && !isOverridden[i]) {
			findEquivalent: for (int j=0; j<length; j++) {
				if (j == i || isOverridden[j]) continue findEquivalent;
				if (isMethodSubsignature(methods[i], methods[j])) {
					if (!doesMethodOverride(methods[i], methods[j]) && !doesMethodOverride(methods[j], methods[i])) { 
						problemReporter().inheritedDefaultMethodConflictsWithOtherInherited(this.type, methods[i], methods[j]);
						ok = false;
						continue findDefaultMethod;
					}
				}
			}
		}
	}
	return ok;
}
@Override
boolean checkInheritedReturnTypes(MethodBinding method, MethodBinding otherMethod) {
	if (areReturnTypesCompatible(method, otherMethod)) return true;

	/* We used to have some checks here to see if we would have already blamed the super type and if so avoid blaming
	   the current type again. I have gotten rid of them as they in fact short circuit error reporting in cases where
	   they should not. This means that occasionally we would report the error twice - the diagnostics is valid however,
	   albeit arguably redundant. See https://bugs.eclipse.org/bugs/show_bug.cgi?id=334313. For an example of a test
	   where we do this extra reporting see org.eclipse.jdt.core.tests.compiler.regression.MethodVerifyTest.test159()
	 */
	// check to see if this is just a warning, if so report it & skip to next method
	if (isUnsafeReturnTypeOverride(method, otherMethod)) {
		if (!method.declaringClass.implementsInterface(otherMethod.declaringClass, false))
			problemReporter(method).unsafeReturnTypeOverride(method, otherMethod, this.type);
		return true;
	}

	return false;
}
@Override
void checkAgainstInheritedMethods(MethodBinding currentMethod, MethodBinding[] methods, int length, MethodBinding[] allInheritedMethods)
{
	super.checkAgainstInheritedMethods(currentMethod, methods, length, allInheritedMethods);
	CompilerOptions options = this.environment.globalOptions;
	if (options.isAnnotationBasedNullAnalysisEnabled 
			&& (currentMethod.tagBits & TagBits.IsNullnessKnown) == 0)
	{
		// if annotations are inherited these have been checked during STB.resolveTypesFor() (for methods explicit in this.type)
		AbstractMethodDeclaration srcMethod = null;
		if (this.type.equals(currentMethod.declaringClass)) // is currentMethod from the current type?
			srcMethod = currentMethod.sourceMethod();
		boolean hasReturnNonNullDefault = currentMethod.hasNonNullDefaultForReturnType(srcMethod);
		ParameterNonNullDefaultProvider hasParameterNonNullDefault = currentMethod.hasNonNullDefaultForParameter(srcMethod);
		for (int i = length; --i >= 0;)
			if (!currentMethod.isStatic() && !methods[i].isStatic())
				checkNullSpecInheritance(currentMethod, srcMethod, hasReturnNonNullDefault, hasParameterNonNullDefault, true, methods[i], methods, this.type.scope, null);
	}
}

@Override
void checkNullSpecInheritance(MethodBinding currentMethod, AbstractMethodDeclaration srcMethod, 
		boolean hasReturnNonNullDefault, ParameterNonNullDefaultProvider hasParameterNonNullDefault, boolean complain, MethodBinding inheritedMethod, MethodBinding[] allInherited, Scope scope, InheritedNonNullnessInfo[] inheritedNonNullnessInfos)
{
	complain &= !currentMethod.isConstructor();
	if (!hasReturnNonNullDefault && !hasParameterNonNullDefault.hasAnyNonNullDefault() && !complain && !this.environment.globalOptions.inheritNullAnnotations) {
		// nothing to be done, take the shortcut
		currentMethod.tagBits |= TagBits.IsNullnessKnown;
		return;
	}
	// in this context currentMethod can be inherited, too. Recurse if needed.
	if (TypeBinding.notEquals(currentMethod.declaringClass, this.type) 
			&& (currentMethod.tagBits & TagBits.IsNullnessKnown) == 0) 
	{
		this.buddyImplicitNullAnnotationsVerifier.checkImplicitNullAnnotations(currentMethod, srcMethod, complain, scope);
	}
	super.checkNullSpecInheritance(currentMethod, srcMethod, hasReturnNonNullDefault, hasParameterNonNullDefault, complain, inheritedMethod, allInherited, scope, inheritedNonNullnessInfos);
}

void reportRawReferences() {
	CompilerOptions compilerOptions = this.type.scope.compilerOptions();
	if (compilerOptions.sourceLevel < ClassFileConstants.JDK1_5 // shouldn't whine at all
			|| compilerOptions.reportUnavoidableGenericTypeProblems) { // must have already whined 
		return;
	}
	/* Code below is only for a method that does not override/implement a super type method. If it were to,
	   it would have been handled in checkAgainstInheritedMethods.
	*/
	Object [] methodArray = this.currentMethods.valueTable;
	for (int s = methodArray.length; --s >= 0;) {
		if (methodArray[s] == null) continue;
		MethodBinding[] current = (MethodBinding[]) methodArray[s];
		for (int i = 0, length = current.length; i < length; i++) {
			MethodBinding currentMethod = current[i];
			if ((currentMethod.modifiers & (ExtraCompilerModifiers.AccImplementing | ExtraCompilerModifiers.AccOverriding)) == 0) {
				AbstractMethodDeclaration methodDecl = currentMethod.sourceMethod();
				if (methodDecl == null) return;
				TypeBinding [] parameterTypes = currentMethod.parameters;
				Argument[] arguments = methodDecl.arguments;
				for (int j = 0, size = currentMethod.parameters.length; j < size; j++) {
					TypeBinding parameterType = parameterTypes[j];
					Argument arg = arguments[j];
					if (parameterType.leafComponentType().isRawType()
						&& compilerOptions.getSeverity(CompilerOptions.RawTypeReference) != ProblemSeverities.Ignore
			      		&& (arg.type.bits & ASTNode.IgnoreRawTypeCheck) == 0) {
						methodDecl.scope.problemReporter().rawTypeReference(arg.type, parameterType);
			    	}
				}
				if (!methodDecl.isConstructor() && methodDecl instanceof MethodDeclaration) {
					TypeReference returnType = ((MethodDeclaration) methodDecl).returnType;
					TypeBinding methodType = currentMethod.returnType;
					if (returnType != null) {
						if (methodType.leafComponentType().isRawType()
								&& compilerOptions.getSeverity(CompilerOptions.RawTypeReference) != ProblemSeverities.Ignore
								&& (returnType.bits & ASTNode.IgnoreRawTypeCheck) == 0) {
							methodDecl.scope.problemReporter().rawTypeReference(returnType, methodType);
						}
					}
				}
			}
		}
	}
}
@Override
public void reportRawReferences(MethodBinding currentMethod, MethodBinding inheritedMethod) {
	CompilerOptions compilerOptions = this.type.scope.compilerOptions();
	if (compilerOptions.sourceLevel < ClassFileConstants.JDK1_5 // shouldn't whine at all
			|| compilerOptions.reportUnavoidableGenericTypeProblems) { // must have already whined 
		return;
	}
	AbstractMethodDeclaration methodDecl = currentMethod.sourceMethod();
	if (methodDecl == null) return;
	TypeBinding [] parameterTypes = currentMethod.parameters;
	TypeBinding [] inheritedParameterTypes = inheritedMethod.parameters;
	Argument[] arguments = methodDecl.arguments;
	for (int j = 0, size = currentMethod.parameters.length; j < size; j++) {
		TypeBinding parameterType = parameterTypes[j];
		TypeBinding inheritedParameterType = inheritedParameterTypes[j];
		Argument arg = arguments[j];
		if (parameterType.leafComponentType().isRawType()) {
			if (inheritedParameterType.leafComponentType().isRawType()) {
				arg.binding.tagBits |= TagBits.ForcedToBeRawType;
			} else {
				if (compilerOptions.getSeverity(CompilerOptions.RawTypeReference) != ProblemSeverities.Ignore
						&& (arg.type.bits & ASTNode.IgnoreRawTypeCheck) == 0) {
					methodDecl.scope.problemReporter().rawTypeReference(arg.type, parameterType);
				}
			}
    	}
    }
	TypeReference returnType = null;
	if (!methodDecl.isConstructor() && methodDecl instanceof MethodDeclaration && (returnType = ((MethodDeclaration) methodDecl).returnType) != null) {
		final TypeBinding inheritedMethodType = inheritedMethod.returnType;
		final TypeBinding methodType = currentMethod.returnType;
		if (methodType.leafComponentType().isRawType()) {
			if (inheritedMethodType.leafComponentType().isRawType()) {
				// 
			} else {
				if ((returnType.bits & ASTNode.IgnoreRawTypeCheck) == 0
						&& compilerOptions.getSeverity(CompilerOptions.RawTypeReference) != ProblemSeverities.Ignore) {
					methodDecl.scope.problemReporter().rawTypeReference(returnType, methodType);
				}
			}
		}
	}
 }

@Override
void checkMethods() {
	boolean mustImplementAbstractMethods = mustImplementAbstractMethods();
	boolean skipInheritedMethods = mustImplementAbstractMethods && canSkipInheritedMethods(); // have a single concrete superclass so only check overridden methods
	boolean isOrEnclosedByPrivateType = this.type.isOrEnclosedByPrivateType();
	char[][] methodSelectors = this.inheritedMethods.keyTable;
	nextSelector : for (int s = methodSelectors.length; --s >= 0;) {
		if (methodSelectors[s] == null) continue nextSelector;
		MethodBinding[] current = (MethodBinding[]) this.currentMethods.get(methodSelectors[s]);
		MethodBinding[] inherited = (MethodBinding[]) this.inheritedMethods.valueTable[s];
		// ensure that if we have a concrete method this shows up at position [0]:
		inherited = Sorting.concreteFirst(inherited, inherited.length);
		
		// https://bugs.eclipse.org/bugs/show_bug.cgi?id=296660, if current type is exposed,
		// inherited methods of super classes are too. current != null case handled below.
		if (current == null && !isOrEnclosedByPrivateType) {
			int length = inherited.length;
			for (int i = 0; i < length; i++){
				inherited[i].original().modifiers |= ExtraCompilerModifiers.AccLocallyUsed;
			}
		}
		if (current == null && this.type.isPublic()) {
			int length = inherited.length;
			for (int i = 0; i < length; i++) {
				MethodBinding inheritedMethod = inherited[i];
				if (inheritedMethod.isPublic() && (!inheritedMethod.declaringClass.isInterface() && !inheritedMethod.declaringClass.isPublic()))
					this.type.addSyntheticBridgeMethod(inheritedMethod.original());
			}
		}

		if (current == null && skipInheritedMethods)
			continue nextSelector;

		if (inherited.length == 1 && current == null) { // handle the common case
			if (mustImplementAbstractMethods && inherited[0].isAbstract())
				checkAbstractMethod(inherited[0]);
			continue nextSelector;
		}

		int index = -1;
		int inheritedLength = inherited.length;
		MethodBinding[] matchingInherited = new MethodBinding[inheritedLength];
		MethodBinding[] foundMatch = new MethodBinding[inheritedLength]; // null is no match, otherwise value is matching currentMethod

		// skip tracks inherited methods which can be safely ignored for one of these reasons:
		// - methods that have matched other inherited methods
		// 		either because they match the same currentMethod or match each other
		// - methods that are overridden by a current method
		boolean[] skip = new boolean[inheritedLength];
		boolean[] isOverridden = new boolean[inheritedLength];
		boolean[] isInherited = new boolean[inheritedLength];
		Arrays.fill(isInherited, true);
		if (current != null) {
			for (int i = 0, length1 = current.length; i < length1; i++) {
				MethodBinding currentMethod = current[i];
				MethodBinding[] nonMatchingInherited = null;
				for (int j = 0; j < inheritedLength; j++) {
					MethodBinding inheritedMethod = computeSubstituteMethod(inherited[j], currentMethod);
					if (inheritedMethod != null) {
						if (foundMatch[j] == null && isSubstituteParameterSubsignature(currentMethod, inheritedMethod)) {
							// already checked compatibility, do visibility etc. also indicate overriding? If so ignore inheritedMethod further downstream
							isOverridden[j] = skip[j] = couldMethodOverride(currentMethod, inheritedMethod);
							matchingInherited[++index] = inheritedMethod;
							foundMatch[j] = currentMethod;
						} else {
							// best place to check each currentMethod against each non-matching inheritedMethod
							checkForNameClash(currentMethod, inheritedMethod);
							if (inheritedLength > 1) {
								if (nonMatchingInherited == null)
									nonMatchingInherited = new MethodBinding[inheritedLength];
								nonMatchingInherited[j] = inheritedMethod;
							}
						}
					}
				}
				if (index >= 0) {
					// see addtional comments in https://bugs.eclipse.org/bugs/show_bug.cgi?id=122881
					// if (index > 0 && currentMethod.declaringClass.isInterface()) // only check when inherited methods are from interfaces
					//	checkInheritedReturnTypes(matchingInherited, index + 1);
					checkAgainstInheritedMethods(currentMethod, matchingInherited, index + 1, nonMatchingInherited); // pass in the length of matching
					while (index >= 0) matchingInherited[index--] = null; // clear the contents of the matching methods
				}
			}
		}
		// first round: collect information into skip and isOverridden by comparing all pairs:
		// (and perform some side effects : bridge methods & use flags)
		for (int i = 0; i < inheritedLength; i++) {
			MethodBinding matchMethod = foundMatch[i];
			
			if (matchMethod == null && current != null && this.type.isPublic()) { // current == null case handled already.
				MethodBinding inheritedMethod = inherited[i];
				if (inheritedMethod.isPublic() && (!inheritedMethod.declaringClass.isInterface() && !inheritedMethod.declaringClass.isPublic())) {
					this.type.addSyntheticBridgeMethod(inheritedMethod.original());
				}
			}
			// https://bugs.eclipse.org/bugs/show_bug.cgi?id=296660, if current type is exposed,
			// inherited methods of super classes are too. current == null case handled already.
			if (!isOrEnclosedByPrivateType && matchMethod == null && current != null) {
				inherited[i].original().modifiers |= ExtraCompilerModifiers.AccLocallyUsed;	
			}
			MethodBinding inheritedMethod = inherited[i];
			for (int j = i + 1; j < inheritedLength; j++) {
				MethodBinding otherInheritedMethod = inherited[j];
				if (matchMethod == foundMatch[j] && matchMethod != null)
					continue; // both inherited methods matched the same currentMethod
				if (canSkipInheritedMethods(inheritedMethod, otherInheritedMethod))
					continue;
				// Skip the otherInheritedMethod if it is completely replaced by inheritedMethod
				// This elimination used to happen rather eagerly in computeInheritedMethods step
				// itself earlier. (https://bugs.eclipse.org/bugs/show_bug.cgi?id=302358)
				if (TypeBinding.notEquals(inheritedMethod.declaringClass, otherInheritedMethod.declaringClass)) {
					// these method calls produce their effect as side-effects into skip and isOverridden:
					if (isSkippableOrOverridden(inheritedMethod, otherInheritedMethod, skip, isOverridden, isInherited, j))
						continue;
					if (isSkippableOrOverridden(otherInheritedMethod, inheritedMethod, skip, isOverridden, isInherited, i))
						continue;
				}
			}
		}
		// second round: collect and check matchingInherited, directly check methods with no replacing etc.
		for (int i = 0; i < inheritedLength; i++) {
			MethodBinding matchMethod = foundMatch[i];
			if (skip[i]) continue;
			MethodBinding inheritedMethod = inherited[i];
			if (matchMethod == null)
				matchingInherited[++index] = inheritedMethod;
			for (int j = i + 1; j < inheritedLength; j++) {
				if (foundMatch[j] == null) {
					MethodBinding otherInheritedMethod = inherited[j];
					if (matchMethod == foundMatch[j] && matchMethod != null)
						continue; // both inherited methods matched the same currentMethod
					if (canSkipInheritedMethods(inheritedMethod, otherInheritedMethod))
						continue;

					MethodBinding replaceMatch;
					if ((replaceMatch = findReplacedMethod(inheritedMethod, otherInheritedMethod)) != null) {
						matchingInherited[++index] = replaceMatch;
						skip[j] = true;
					} else if ((replaceMatch = findReplacedMethod(otherInheritedMethod, inheritedMethod)) != null) {
						matchingInherited[++index] = replaceMatch;
						skip[j] = true;						
					} else if (matchMethod == null) {
						// none replaced by the other, check these methods against each other now:
						checkInheritedMethods(inheritedMethod, otherInheritedMethod);
					}
				}
			}
			if (index == -1) continue;

			if (index > 0) {
				int length = index + 1;
				boolean[] matchingIsOverridden;
				boolean[] matchingIsInherited;
				if (length != inheritedLength) { // transfer inherited & overridden status to align with subset of methods.
					matchingIsOverridden = new boolean[length];
					matchingIsInherited = new boolean[length];
					for (int j = 0; j < length; j++) {
						for (int k = 0; k < inheritedLength; k++) {
							if (matchingInherited[j] == inherited[k]) {
								matchingIsOverridden[j] = isOverridden[k];
								matchingIsInherited[j] = isInherited[k];
								break;
							}
						}
					}
				} else {
					matchingIsOverridden = isOverridden;
					matchingIsInherited = isInherited;
				}
				
				checkInheritedMethods(matchingInherited, length, matchingIsOverridden, matchingIsInherited); // pass in the length of matching
			}
			else if (mustImplementAbstractMethods && matchingInherited[0].isAbstract() && matchMethod == null)
				checkAbstractMethod(matchingInherited[0]);
			while (index >= 0) matchingInherited[index--] = null; // clear the previous contents of the matching methods
		}
	}
}
/* mark as skippable
 * - any interface method implemented by a class method
 * - an x method (x in {class, interface}), for which another x method with a subsignature was found
 * mark as isOverridden
 * - any skippable method as defined above iff it is actually overridden by the specific method (disregarding visibility etc.)
 * Note, that 'idx' corresponds to the position of 'general' in the arrays 'skip' and 'isOverridden'
 * TODO(stephan) currently (as of Bug 410325), the boarder between skip and isOverridden is blurred,
 *                should reassess after more experience with this patch.
 */
boolean isSkippableOrOverridden(MethodBinding specific, MethodBinding general, boolean[] skip, boolean[] isOverridden, boolean[] isInherited, int idx) {
	boolean specificIsInterface = specific.declaringClass.isInterface();
	boolean generalIsInterface = general.declaringClass.isInterface();
	if (!specificIsInterface && generalIsInterface) {
		if (!specific.isAbstract() && isParameterSubsignature(specific, general)) {
			// 8.4.8: abstract and default methods are not inherited if a concrete method with a subsignature is defined or inherited in C
			isInherited[idx] = false;
			return true;
		} else if (isInterfaceMethodImplemented(general, specific, general.declaringClass)) {
			skip[idx] = true;
			isOverridden[idx] = true;
			return true;
		}
	} else if (specificIsInterface == generalIsInterface) { 
		if (specific.declaringClass.isCompatibleWith(general.declaringClass) && isMethodSubsignature(specific, general)) {
			skip[idx] = true;
			isOverridden[idx] = true;
			return true;
		}
	}
	return false;
}
/* 'general' is considered as replaced by 'specific' if
 * - 'specific' is "at least as concrete as" 'general'
 * - 'specific' has a signature that is a subsignature of the substituted signature of 'general' (as seen from specific's declaring class)  
 * - default methods should also be considered replaced by class methods that meet the signature that is a subsignature criteria.
 */
MethodBinding findReplacedMethod(MethodBinding specific, MethodBinding general) {
	MethodBinding generalSubstitute = computeSubstituteMethod(general, specific);
	if (generalSubstitute != null 
			&& (!specific.isAbstract() || general.isAbstract() || (general.isDefaultMethod() && specific.declaringClass.isClass()))	// if (abstract(specific) => abstract(general)) check if 'specific' overrides 'general' 
			&& isSubstituteParameterSubsignature(specific, generalSubstitute)) 
	{
		return generalSubstitute;
	} 
	return null;
}
void checkTypeVariableMethods(TypeParameter typeParameter) {
	char[][] methodSelectors = this.inheritedMethods.keyTable;
	nextSelector : for (int s = methodSelectors.length; --s >= 0;) {
		if (methodSelectors[s] == null) continue nextSelector;
		MethodBinding[] inherited = (MethodBinding[]) this.inheritedMethods.valueTable[s];
		if (inherited.length == 1) continue nextSelector;

		int index = -1;
		MethodBinding[] matchingInherited = new MethodBinding[inherited.length];
		for (int i = 0, length = inherited.length; i < length; i++) {
			while (index >= 0) matchingInherited[index--] = null; // clear the previous contents of the matching methods
			MethodBinding inheritedMethod = inherited[i];
			if (inheritedMethod != null) {
				matchingInherited[++index] = inheritedMethod;
				for (int j = i + 1; j < length; j++) {
					MethodBinding otherInheritedMethod = inherited[j];
					if (canSkipInheritedMethods(inheritedMethod, otherInheritedMethod))
						continue;
					otherInheritedMethod = computeSubstituteMethod(otherInheritedMethod, inheritedMethod);
					if (otherInheritedMethod != null && isSubstituteParameterSubsignature(inheritedMethod, otherInheritedMethod)) {
						matchingInherited[++index] = otherInheritedMethod;
						inherited[j] = null; // do not want to find it again
					}
				}
			}
			if (index > 0) {
				MethodBinding first = matchingInherited[0];
				int count = index + 1;
				while (--count > 0) {
					MethodBinding match = matchingInherited[count];
					// https://bugs.eclipse.org/bugs/show_bug.cgi?id=314556
					MethodBinding interfaceMethod = null, implementation = null;
					if (first.declaringClass.isInterface()) {
						interfaceMethod = first;
					} else if (first.declaringClass.isClass()) {
						implementation = first;
					}
					if (match.declaringClass.isInterface()) {
						interfaceMethod = match;
					} else if (match.declaringClass.isClass()) {
						implementation = match;
					}
					if (interfaceMethod != null && implementation != null && !implementation.isAbstract() && !isAsVisible(implementation, interfaceMethod))
						problemReporter().inheritedMethodReducesVisibility(typeParameter, implementation, new MethodBinding [] {interfaceMethod});
					
					if (areReturnTypesCompatible(first, match)) continue;
					// unrelated interfaces - check to see if return types are compatible
					if (first.declaringClass.isInterface() && match.declaringClass.isInterface() && areReturnTypesCompatible(match, first))
						continue;
					break;
				}
				if (count > 0) {  // All inherited methods do NOT have the same vmSignature
					problemReporter().inheritedMethodsHaveIncompatibleReturnTypes(typeParameter, matchingInherited, index + 1);
					continue nextSelector;
				}
			}
		}
	}
}
boolean detectInheritedNameClash(MethodBinding inherited, MethodBinding otherInherited) {
	if (!inherited.areParameterErasuresEqual(otherInherited))
		return false;
	// https://bugs.eclipse.org/bugs/show_bug.cgi?id=322001
	// https://bugs.eclipse.org/bugs/show_bug.cgi?id=323693
	// When reporting a name clash between two inherited methods, we should not look for a
	// signature clash, but instead should be looking for method descriptor clash. 
	if (TypeBinding.notEquals(inherited.returnType.erasure(), otherInherited.returnType.erasure()))
		return false;
	// skip it if otherInherited is defined by a subtype of inherited's declaringClass or vice versa.
	// avoid being order sensitive and check with the roles reversed also.
	if (TypeBinding.notEquals(inherited.declaringClass.erasure(), otherInherited.declaringClass.erasure())) {
		if (inherited.declaringClass.findSuperTypeOriginatingFrom(otherInherited.declaringClass) != null)
			return false;
		if (otherInherited.declaringClass.findSuperTypeOriginatingFrom(inherited.declaringClass) != null)
			return false;
	}

	problemReporter().inheritedMethodsHaveNameClash(this.type, inherited, otherInherited);
	return true;
}
boolean detectNameClash(MethodBinding current, MethodBinding inherited, boolean treatAsSynthetic) {
	MethodBinding methodToCheck = inherited;
	MethodBinding original = methodToCheck.original(); // can be the same as inherited
	if (!current.areParameterErasuresEqual(original))
		return false;
	int severity = ProblemSeverities.Error;
	if (this.environment.globalOptions.complianceLevel == ClassFileConstants.JDK1_6) {
		// for 1.6 return types also need to be checked
		// https://bugs.eclipse.org/bugs/show_bug.cgi?id=317719
		if (TypeBinding.notEquals(current.returnType.erasure(), original.returnType.erasure()))
			severity = ProblemSeverities.Warning;
	}
	if (!treatAsSynthetic) {
		// For a user method, see if current class overrides the inherited method. If it does,
		// then any grievance we may have ought to be against the current class's method and
		// NOT against any super implementations. https://bugs.eclipse.org/bugs/show_bug.cgi?id=293615
		
		// https://bugs.eclipse.org/bugs/show_bug.cgi?id=315978 : we now defer this rather expensive
		// check to just before reporting (the incorrect) name clash. In the event there is no name
		// clash to report to begin with (the common case), no penalty needs to be paid.  
		MethodBinding[] currentNamesakes = (MethodBinding[]) this.currentMethods.get(inherited.selector);
		if (currentNamesakes.length > 1) { // we know it ought to at least one and that current is NOT the override
			for (int i = 0, length = currentNamesakes.length; i < length; i++) {
				MethodBinding currentMethod = currentNamesakes[i];
				if (currentMethod != current && doesMethodOverride(currentMethod, inherited)) {
					methodToCheck = currentMethod;
					break;
				}
			}
		}
	}
	original = methodToCheck.original(); // can be the same as inherited
	if (!current.areParameterErasuresEqual(original))
		return false;
	original = inherited.original();  // For error reporting use, inherited.original()
	problemReporter(current).methodNameClash(current, inherited.declaringClass.isRawType() ? inherited : original, severity);
	if (severity == ProblemSeverities.Warning) return false;
	return true;
}
boolean doTypeVariablesClash(MethodBinding one, MethodBinding substituteTwo) {
	// one has type variables and substituteTwo did not pass bounds check in computeSubstituteMethod()
	return one.typeVariables != Binding.NO_TYPE_VARIABLES && !(substituteTwo instanceof ParameterizedGenericMethodBinding);
}
@Override
SimpleSet findSuperinterfaceCollisions(ReferenceBinding superclass, ReferenceBinding[] superInterfaces) {
	ReferenceBinding[] interfacesToVisit = null;
	int nextPosition = 0;
	ReferenceBinding[] itsInterfaces = superInterfaces;
	if (itsInterfaces != Binding.NO_SUPERINTERFACES) {
		nextPosition = itsInterfaces.length;
		interfacesToVisit = itsInterfaces;
	}

	boolean isInconsistent = this.type.isHierarchyInconsistent();
	ReferenceBinding superType = superclass;
	while (superType != null && superType.isValidBinding()) {
		isInconsistent |= superType.isHierarchyInconsistent();
		if ((itsInterfaces = superType.superInterfaces()) != Binding.NO_SUPERINTERFACES) {
			if (interfacesToVisit == null) {
				interfacesToVisit = itsInterfaces;
				nextPosition = interfacesToVisit.length;
			} else {
				int itsLength = itsInterfaces.length;
				if (nextPosition + itsLength >= interfacesToVisit.length)
					System.arraycopy(interfacesToVisit, 0, interfacesToVisit = new ReferenceBinding[nextPosition + itsLength + 5], 0, nextPosition);
				nextInterface : for (int a = 0; a < itsLength; a++) {
					ReferenceBinding next = itsInterfaces[a];
					for (int b = 0; b < nextPosition; b++)
						if (TypeBinding.equalsEquals(next, interfacesToVisit[b])) continue nextInterface;
					interfacesToVisit[nextPosition++] = next;
				}
			}
		}
		superType = superType.superclass();
	}

	for (int i = 0; i < nextPosition; i++) {
		superType = interfacesToVisit[i];
		if (superType.isValidBinding()) {
			isInconsistent |= superType.isHierarchyInconsistent();
			if ((itsInterfaces = superType.superInterfaces()) != Binding.NO_SUPERINTERFACES) {
				int itsLength = itsInterfaces.length;
				if (nextPosition + itsLength >= interfacesToVisit.length)
					System.arraycopy(interfacesToVisit, 0, interfacesToVisit = new ReferenceBinding[nextPosition + itsLength + 5], 0, nextPosition);
				nextInterface : for (int a = 0; a < itsLength; a++) {
					ReferenceBinding next = itsInterfaces[a];
					for (int b = 0; b < nextPosition; b++)
						if (TypeBinding.equalsEquals(next, interfacesToVisit[b])) continue nextInterface;
					interfacesToVisit[nextPosition++] = next;
				}
			}
		}
	}

	if (!isInconsistent) return null; // hierarchy is consistent so no collisions are possible
	SimpleSet copy = null;
	for (int i = 0; i < nextPosition; i++) {
		ReferenceBinding current = interfacesToVisit[i];
		if (current.isValidBinding()) {
			TypeBinding erasure = current.erasure();
			for (int j = i + 1; j < nextPosition; j++) {
				ReferenceBinding next = interfacesToVisit[j];
				if (next.isValidBinding() && TypeBinding.equalsEquals(next.erasure(), erasure)) {
					if (copy == null)
						copy = new SimpleSet(nextPosition);
					copy.add(interfacesToVisit[i]);
					copy.add(interfacesToVisit[j]);
				}
			}
		}
	}
	return copy;
}
boolean isAcceptableReturnTypeOverride(MethodBinding currentMethod, MethodBinding inheritedMethod) {
	// called when currentMethod's return type is compatible with inheritedMethod's return type

	if (inheritedMethod.declaringClass.isRawType())
		return true; // since the inheritedMethod comes from a raw type, the return type is always acceptable

	MethodBinding originalInherited = inheritedMethod.original();
	TypeBinding originalInheritedReturnType = originalInherited.returnType.leafComponentType();
	if (originalInheritedReturnType.isParameterizedTypeWithActualArguments())
		return !currentMethod.returnType.leafComponentType().isRawType(); // raw types issue a warning if inherited is parameterized

	TypeBinding currentReturnType = currentMethod.returnType.leafComponentType();
	switch (currentReturnType.kind()) {
	   	case Binding.TYPE_PARAMETER :
	   		if (TypeBinding.equalsEquals(currentReturnType, inheritedMethod.returnType.leafComponentType()))
	   			return true;
	   		//$FALL-THROUGH$
		default :
			if (originalInheritedReturnType.isTypeVariable())
				if (((TypeVariableBinding) originalInheritedReturnType).declaringElement == originalInherited)
					return false;
			return true;
	}
}
// caveat: returns false if a method is implemented, but with a return type that is incompatible with that of the interface method
@Override
boolean isInterfaceMethodImplemented(MethodBinding inheritedMethod, MethodBinding existingMethod, ReferenceBinding superType) {
	if (inheritedMethod.original() != inheritedMethod && existingMethod.declaringClass.isInterface())
		return false; // must hold onto ParameterizedMethod to see if a bridge method is necessary

	inheritedMethod = computeSubstituteMethod(inheritedMethod, existingMethod);
	if (inheritedMethod == null	|| !doesMethodOverride(existingMethod, inheritedMethod))
		return false;
	return TypeBinding.equalsEquals(inheritedMethod.returnType, existingMethod.returnType)
			|| (TypeBinding.notEquals(this.type, existingMethod.declaringClass) // ... not if inheriting the bridge situation from a superclass
				&& !existingMethod.declaringClass.isInterface()
				&& areReturnTypesCompatible(existingMethod, inheritedMethod)); // may have to report incompatible return type
}
@Override
public boolean isMethodSubsignature(MethodBinding method, MethodBinding inheritedMethod) {
	if (!org.eclipse.jdt.core.compiler.CharOperation.equals(method.selector, inheritedMethod.selector))
		return false;

	// need to switch back to the original if the method is from a ParameterizedType
	if (method.declaringClass.isParameterizedType())
		method = method.original();

	MethodBinding inheritedOriginal = method.findOriginalInheritedMethod(inheritedMethod);
	return isParameterSubsignature(method, inheritedOriginal == null ? inheritedMethod : inheritedOriginal);
}
boolean isUnsafeReturnTypeOverride(MethodBinding currentMethod, MethodBinding inheritedMethod) {
	// called when currentMethod's return type is NOT compatible with inheritedMethod's return type

	// JLS 3 §8.4.5: more are accepted, with an unchecked conversion
	if (TypeBinding.equalsEquals(currentMethod.returnType, inheritedMethod.returnType.erasure())) {
		TypeBinding[] currentParams = currentMethod.parameters;
		TypeBinding[] inheritedParams = inheritedMethod.parameters;
		for (int i = 0, l = currentParams.length; i < l; i++)
			if (!areTypesEqual(currentParams[i], inheritedParams[i]))
				return true;
	}
	if (currentMethod.typeVariables == Binding.NO_TYPE_VARIABLES
		&& inheritedMethod.original().typeVariables != Binding.NO_TYPE_VARIABLES
		&& currentMethod.returnType.erasure().findSuperTypeOriginatingFrom(inheritedMethod.returnType.erasure()) != null) {
			return true;
	}
	return false;
}
@Override
boolean reportIncompatibleReturnTypeError(MethodBinding currentMethod, MethodBinding inheritedMethod) {
	if (isUnsafeReturnTypeOverride(currentMethod, inheritedMethod)) {
		problemReporter(currentMethod).unsafeReturnTypeOverride(currentMethod, inheritedMethod, this.type);
		return false;
	}
	return super.reportIncompatibleReturnTypeError(currentMethod, inheritedMethod);
}
@Override
void verify() {
	if (this.type.isAnnotationType())
		this.type.detectAnnotationCycle();

	super.verify();
	
	reportRawReferences();

	for (int i = this.type.typeVariables.length; --i >= 0;) {
		TypeVariableBinding var = this.type.typeVariables[i];
		// must verify bounds if the variable has more than 1
		if (var.superInterfaces == Binding.NO_SUPERINTERFACES) continue;
		if (var.superInterfaces.length == 1 && var.superclass.id == TypeIds.T_JavaLangObject) continue;

		this.currentMethods = new HashtableOfObject(0);
		ReferenceBinding superclass = var.superclass();
		if (superclass.kind() == Binding.TYPE_PARAMETER)
			superclass = (ReferenceBinding) superclass.erasure();
		ReferenceBinding[] itsInterfaces = var.superInterfaces();
		ReferenceBinding[] superInterfaces = new ReferenceBinding[itsInterfaces.length];
		for (int j = itsInterfaces.length; --j >= 0;) {
			superInterfaces[j] = itsInterfaces[j].kind() == Binding.TYPE_PARAMETER
				? (ReferenceBinding) itsInterfaces[j].erasure()
				: itsInterfaces[j];
		}
		computeInheritedMethods(superclass, superInterfaces);
		checkTypeVariableMethods(this.type.scope.referenceContext.typeParameters[i]);
	}
}
}