Copyright (c) 2000, 2019 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 - Contribution for
							bug 383368 - [compiler][null] syntactic null analysis for field references
							Bug 392238 - [1.8][compiler][null] Detect semantically invalid null type annotations
							Bug 416307 - [1.8][compiler][null] subclass with type parameter substitution confuses null checking
							Bug 392099 - [1.8][compiler][null] Apply null annotation on types for null analysis
							Bug 417295 - [1.8[[null] Massage type annotated null analysis to gel well with deep encoded type bindings.
							Bug 392238 - [1.8][compiler][null] Detect semantically invalid null type annotations
							Bug 435570 - [1.8][null] @NonNullByDefault illegally tries to affect "throws E"
							Bug 466713 - Null Annotations: NullPointerException using  as Type Param
       Andy Clement - Contributions for
                         Bug 383624 - [1.8][compiler] Revive code generation support for type annotations (from Olivier's work)
/*******************************************************************************
 * Copyright (c) 2000, 2019 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 - Contribution for
 *								bug 383368 - [compiler][null] syntactic null analysis for field references
 *								Bug 392238 - [1.8][compiler][null] Detect semantically invalid null type annotations
 *								Bug 416307 - [1.8][compiler][null] subclass with type parameter substitution confuses null checking
 *								Bug 392099 - [1.8][compiler][null] Apply null annotation on types for null analysis
 *								Bug 417295 - [1.8[[null] Massage type annotated null analysis to gel well with deep encoded type bindings.
 *								Bug 392238 - [1.8][compiler][null] Detect semantically invalid null type annotations
 *								Bug 435570 - [1.8][null] @NonNullByDefault illegally tries to affect "throws E"
 *								Bug 466713 - Null Annotations: NullPointerException using <int @Nullable []> as Type Param
 *        Andy Clement - Contributions for
 *                          Bug 383624 - [1.8][compiler] Revive code generation support for type annotations (from Olivier's work)
 *******************************************************************************/
package org.eclipse.jdt.internal.compiler.ast;

import org.eclipse.jdt.internal.compiler.ASTVisitor;
import org.eclipse.jdt.internal.compiler.ast.TypeReference.AnnotationPosition;
import org.eclipse.jdt.internal.compiler.codegen.*;
import org.eclipse.jdt.internal.compiler.flow.*;
import org.eclipse.jdt.internal.compiler.impl.Constant;
import org.eclipse.jdt.internal.compiler.lookup.*;

public class InstanceOfExpression extends OperatorExpression {

	public Expression expression;
	public TypeReference type;

public InstanceOfExpression(Expression expression, TypeReference type) {
	this.expression = expression;
	this.type = type;
	type.bits |= IgnoreRawTypeCheck; // https://bugs.eclipse.org/bugs/show_bug.cgi?id=282141
	this.bits |= INSTANCEOF << OperatorSHIFT;
	this.sourceStart = expression.sourceStart;
	this.sourceEnd = type.sourceEnd;
}

@Override
public FlowInfo analyseCode(BlockScope currentScope, FlowContext flowContext, FlowInfo flowInfo) {
	LocalVariableBinding local = this.expression.localVariableBinding();
	if (local != null && (local.type.tagBits & TagBits.IsBaseType) == 0) {
		flowInfo = this.expression.analyseCode(currentScope, flowContext, flowInfo).
			unconditionalInits();
		FlowInfo initsWhenTrue = flowInfo.copy();
		initsWhenTrue.markAsComparedEqualToNonNull(local);
		flowContext.recordUsingNullReference(currentScope, local,
				this.expression, FlowContext.CAN_ONLY_NULL | FlowContext.IN_INSTANCEOF, flowInfo);
		// no impact upon enclosing try context
		return FlowInfo.conditional(initsWhenTrue, flowInfo.copy());
	}
	if (this.expression instanceof Reference && currentScope.compilerOptions().enableSyntacticNullAnalysisForFields) {
		FieldBinding field = ((Reference)this.expression).lastFieldBinding();
		if (field != null && (field.type.tagBits & TagBits.IsBaseType) == 0) {
			flowContext.recordNullCheckedFieldReference((Reference) this.expression, 1);
		}
	}
	return this.expression.analyseCode(currentScope, flowContext, flowInfo).
			unconditionalInits();
}

Code generation for instanceOfExpression
Params:
currentScope – org.eclipse.jdt.internal.compiler.lookup.BlockScope
codeStream – org.eclipse.jdt.internal.compiler.codegen.CodeStream
valueRequired – boolean/**
 * Code generation for instanceOfExpression
 *
 * @param currentScope org.eclipse.jdt.internal.compiler.lookup.BlockScope
 * @param codeStream org.eclipse.jdt.internal.compiler.codegen.CodeStream
 * @param valueRequired boolean
*/
@Override
public void generateCode(BlockScope currentScope, CodeStream codeStream, boolean valueRequired) {
	int pc = codeStream.position;
	this.expression.generateCode(currentScope, codeStream, true);
	codeStream.instance_of(this.type, this.type.resolvedType);
	if (valueRequired) {
		codeStream.generateImplicitConversion(this.implicitConversion);
	} else {
		codeStream.pop();
	}
	codeStream.recordPositionsFrom(pc, this.sourceStart);
}

@Override
public StringBuffer printExpressionNoParenthesis(int indent, StringBuffer output) {
	this.expression.printExpression(indent, output).append(" instanceof "); //$NON-NLS-1$
	return this.type.print(0, output);
}

@Override
public TypeBinding resolveType(BlockScope scope) {
	this.constant = Constant.NotAConstant;
	TypeBinding checkedType = this.type.resolveType(scope, true /* check bounds*/);
	if (this.expression instanceof CastExpression) {
		((CastExpression) this.expression).setInstanceofType(checkedType); // for cast expression we need to know instanceof type to not tag unnecessary when needed
	}
	TypeBinding expressionType = this.expression.resolveType(scope);
	if (expressionType != null && checkedType != null && this.type.hasNullTypeAnnotation(AnnotationPosition.ANY)) {
		// don't complain if the entire operation is redundant anyway
		if (!expressionType.isCompatibleWith(checkedType) || NullAnnotationMatching.analyse(checkedType, expressionType, -1).isAnyMismatch())
			scope.problemReporter().nullAnnotationUnsupportedLocation(this.type);
	}
	if (expressionType == null || checkedType == null)
		return null;

	if (!checkedType.isReifiable()) {
		scope.problemReporter().illegalInstanceOfGenericType(checkedType, this);
	} else if (checkedType.isValidBinding()) {
		// if not a valid binding, an error has already been reported for unresolved type
		if ((expressionType != TypeBinding.NULL && expressionType.isBaseType()) // disallow autoboxing
				|| !checkCastTypesCompatibility(scope, checkedType, expressionType, null)) {
			scope.problemReporter().notCompatibleTypesError(this, expressionType, checkedType);
		}
	}
	return this.resolvedType = TypeBinding.BOOLEAN;
}

See Also:
tagAsUnnecessaryCast.tagAsUnnecessaryCast(Scope, TypeBinding)/**
 * @see org.eclipse.jdt.internal.compiler.ast.Expression#tagAsUnnecessaryCast(Scope,TypeBinding)
 */
@Override
public void tagAsUnnecessaryCast(Scope scope, TypeBinding castType) {
	// null is not instanceof Type, recognize direct scenario
	if (this.expression.resolvedType != TypeBinding.NULL)
		scope.problemReporter().unnecessaryInstanceof(this, castType);
}

@Override
public void traverse(ASTVisitor visitor, BlockScope scope) {
	if (visitor.visit(this, scope)) {
		this.expression.traverse(visitor, scope);
		this.type.traverse(visitor, scope);
	}
	visitor.endVisit(this, scope);
}
}