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 - Contribution for
							bug 349326 - [1.7] new warning for missing try-with-resources
							bug 370930 - NonNull annotation not considered for enhanced for loops
							bug 365859 - [compiler][null] distinguish warnings based on flow analysis vs. null annotations
							bug 345305 - [compiler][null] Compiler misidentifies a case of "variable can only be null"
							bug 393719 - [compiler] inconsistent warnings on iteration variables
							Bug 411964 - [1.8][null] leverage null type annotation in foreach statement
							Bug 392099 - [1.8][compiler][null] Apply null annotation on types for null analysis
							Bug 453483 - [compiler][null][loop] Improve null analysis for loops
							Bug 415790 - [compiler][resource]Incorrect potential resource leak warning in for loop with close in try/catch
    Jesper S Moller -  Contribution for
							bug 401853 - Eclipse Java compiler creates invalid bytecode (java.lang.VerifyError)
                              bug 527554 - [18.3] Compiler support for JEP 286 Local-Variable Type
/*******************************************************************************
 * 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 - Contribution for
 *								bug 349326 - [1.7] new warning for missing try-with-resources
 *								bug 370930 - NonNull annotation not considered for enhanced for loops
 *								bug 365859 - [compiler][null] distinguish warnings based on flow analysis vs. null annotations
 *								bug 345305 - [compiler][null] Compiler misidentifies a case of "variable can only be null"
 *								bug 393719 - [compiler] inconsistent warnings on iteration variables
 *								Bug 411964 - [1.8][null] leverage null type annotation in foreach statement
 *								Bug 392099 - [1.8][compiler][null] Apply null annotation on types for null analysis
 *								Bug 453483 - [compiler][null][loop] Improve null analysis for loops
 *								Bug 415790 - [compiler][resource]Incorrect potential resource leak warning in for loop with close in try/catch
 *     Jesper S Moller -  Contribution for
 *								bug 401853 - Eclipse Java compiler creates invalid bytecode (java.lang.VerifyError)
 *                               bug 527554 - [18.3] Compiler support for JEP 286 Local-Variable Type
 *******************************************************************************/
package org.eclipse.jdt.internal.compiler.ast;

import org.eclipse.jdt.internal.compiler.ASTVisitor;
import org.eclipse.jdt.internal.compiler.classfmt.ClassFileConstants;
import org.eclipse.jdt.internal.compiler.codegen.BranchLabel;
import org.eclipse.jdt.internal.compiler.codegen.CodeStream;
import org.eclipse.jdt.internal.compiler.flow.FlowContext;
import org.eclipse.jdt.internal.compiler.flow.FlowInfo;
import org.eclipse.jdt.internal.compiler.flow.LoopingFlowContext;
import org.eclipse.jdt.internal.compiler.flow.UnconditionalFlowInfo;
import org.eclipse.jdt.internal.compiler.impl.Constant;
import org.eclipse.jdt.internal.compiler.lookup.ArrayBinding;
import org.eclipse.jdt.internal.compiler.lookup.Binding;
import org.eclipse.jdt.internal.compiler.lookup.BlockScope;
import org.eclipse.jdt.internal.compiler.lookup.CaptureBinding;
import org.eclipse.jdt.internal.compiler.lookup.LocalVariableBinding;
import org.eclipse.jdt.internal.compiler.lookup.ParameterizedTypeBinding;
import org.eclipse.jdt.internal.compiler.lookup.ReferenceBinding;
import org.eclipse.jdt.internal.compiler.lookup.TagBits;
import org.eclipse.jdt.internal.compiler.lookup.TypeBinding;
import org.eclipse.jdt.internal.compiler.lookup.TypeIds;

public class ForeachStatement extends Statement {

	public LocalDeclaration elementVariable;
	public int elementVariableImplicitWidening = -1;
	public Expression collection;
	public Statement action;

	// set the kind of foreach
	private int kind;
	// possible kinds of iterating behavior
	private static final int ARRAY = 0;
	private static final int RAW_ITERABLE = 1;
	private static final int GENERIC_ITERABLE = 2;

	private TypeBinding iteratorReceiverType;
	private TypeBinding collectionElementType;

	// loop labels
	private BranchLabel breakLabel;
	private BranchLabel continueLabel;

	public BlockScope scope;

	// secret variables for codegen
	public LocalVariableBinding indexVariable;
	public LocalVariableBinding collectionVariable;	// to store the collection expression value
	public LocalVariableBinding maxVariable;
	// secret variable names
	private static final char[] SecretIteratorVariableName = " iterator".toCharArray(); //$NON-NLS-1$
	private static final char[] SecretIndexVariableName = " index".toCharArray(); //$NON-NLS-1$
	private static final char[] SecretCollectionVariableName = " collection".toCharArray(); //$NON-NLS-1$
	private static final char[] SecretMaxVariableName = " max".toCharArray(); //$NON-NLS-1$

	int postCollectionInitStateIndex = -1;
	int mergedInitStateIndex = -1;

	public ForeachStatement(
		LocalDeclaration elementVariable,
		int start) {

		this.elementVariable = elementVariable;
		this.sourceStart = start;
		this.kind = -1;
	}

	@Override
	public FlowInfo analyseCode(BlockScope currentScope, FlowContext flowContext, FlowInfo flowInfo) {
		// initialize break and continue labels
		this.breakLabel = new BranchLabel();
		this.continueLabel = new BranchLabel();
		int initialComplaintLevel = (flowInfo.reachMode() & FlowInfo.UNREACHABLE) != 0 ? Statement.COMPLAINED_FAKE_REACHABLE : Statement.NOT_COMPLAINED;

		// process the element variable and collection
		flowInfo = this.elementVariable.analyseCode(this.scope, flowContext, flowInfo);
		FlowInfo condInfo = this.collection.analyseCode(this.scope, flowContext, flowInfo.copy());
		this.collection.checkNPE(currentScope, flowContext, condInfo.copy(), 1);
		LocalVariableBinding elementVarBinding = this.elementVariable.binding;

		// element variable will be assigned when iterating
		condInfo.markAsDefinitelyAssigned(elementVarBinding);

		this.postCollectionInitStateIndex = currentScope.methodScope().recordInitializationStates(condInfo);


		// process the action
		LoopingFlowContext loopingContext =
			new LoopingFlowContext(flowContext, flowInfo, this, this.breakLabel,
				this.continueLabel, this.scope, true);
		UnconditionalFlowInfo actionInfo =
			condInfo.nullInfoLessUnconditionalCopy();
		actionInfo.markAsDefinitelyUnknown(elementVarBinding);
		if (currentScope.compilerOptions().isAnnotationBasedNullAnalysisEnabled) {
			int elementNullStatus = NullAnnotationMatching.nullStatusFromExpressionType(this.collectionElementType);
			int nullStatus = NullAnnotationMatching.checkAssignment(currentScope, flowContext, elementVarBinding, null, // have no useful flowinfo for element var
																		elementNullStatus, this.collection, this.collectionElementType);
			if ((elementVarBinding.type.tagBits & TagBits.IsBaseType) == 0) {
				actionInfo.markNullStatus(elementVarBinding, nullStatus);
			}
		}
		FlowInfo exitBranch;
		if (!(this.action == null || (this.action.isEmptyBlock()
				&& currentScope.compilerOptions().complianceLevel <= ClassFileConstants.JDK1_3))) {

			if (this.action.complainIfUnreachable(actionInfo, this.scope, initialComplaintLevel, true) < Statement.COMPLAINED_UNREACHABLE) {
				actionInfo = this.action.analyseCode(this.scope, loopingContext, actionInfo).unconditionalCopy();
				if (this.action instanceof Block) {
					FakedTrackingVariable.markForeachElementVar(this.elementVariable);
					// action.analyseCode() missed the following check due to identical scopes of ForeachStatement and Block:
					this.scope.checkUnclosedCloseables(actionInfo, loopingContext, null, null);
				}
			}

			// code generation can be optimized when no need to continue in the loop
			exitBranch = flowInfo.unconditionalCopy().
					addInitializationsFrom(condInfo.initsWhenFalse());
			// TODO (maxime) no need to test when false: can optimize (same for action being unreachable above)
			if ((actionInfo.tagBits & loopingContext.initsOnContinue.tagBits &
					FlowInfo.UNREACHABLE_OR_DEAD) != 0) {
				this.continueLabel = null;
			} else {
				actionInfo = actionInfo.mergedWith(loopingContext.initsOnContinue);
				loopingContext.complainOnDeferredFinalChecks(this.scope, actionInfo);
				exitBranch.addPotentialInitializationsFrom(actionInfo);
			}
		} else {
			exitBranch = condInfo.initsWhenFalse();
			if (this.action instanceof Block && !this.action.isEmptyBlock()) {
				this.scope.checkUnclosedCloseables(actionInfo, loopingContext, null, null);
			}
		}

		// we need the variable to iterate the collection even if the
		// element variable is not used
		final boolean hasEmptyAction = this.action == null
		|| this.action.isEmptyBlock()
		|| ((this.action.bits & IsUsefulEmptyStatement) != 0);

		switch(this.kind) {
			case ARRAY :
				if (!hasEmptyAction
						|| elementVarBinding.resolvedPosition != -1) {
					this.collectionVariable.useFlag = LocalVariableBinding.USED;
					if (this.continueLabel != null) {
						this.indexVariable.useFlag = LocalVariableBinding.USED;
						this.maxVariable.useFlag = LocalVariableBinding.USED;
					}
				}
				break;
			case RAW_ITERABLE :
			case GENERIC_ITERABLE :
				this.indexVariable.useFlag = LocalVariableBinding.USED;
				break;
		}
		//end of loop
		loopingContext.complainOnDeferredNullChecks(currentScope, actionInfo);
		if (loopingContext.hasEscapingExceptions()) { // https://bugs.eclipse.org/bugs/show_bug.cgi?id=321926
			FlowInfo loopbackFlowInfo = flowInfo.copy();
			if (this.continueLabel != null) {  // we do get to the bottom
				// loopback | (loopback + action):
				loopbackFlowInfo = loopbackFlowInfo.mergedWith(loopbackFlowInfo.unconditionalCopy().addNullInfoFrom(actionInfo).unconditionalInits());
			}
			loopingContext.simulateThrowAfterLoopBack(loopbackFlowInfo);
		}

		FlowInfo mergedInfo = FlowInfo.mergedOptimizedBranches(
				(loopingContext.initsOnBreak.tagBits &
						FlowInfo.UNREACHABLE) != 0 ?
								loopingContext.initsOnBreak :
									flowInfo.addInitializationsFrom(loopingContext.initsOnBreak), // recover upstream null info
									false,
									exitBranch,
									false,
									true /*for(;;){}while(true); unreachable(); */);
		mergedInfo.resetAssignmentInfo(this.elementVariable.binding);
		this.mergedInitStateIndex = currentScope.methodScope().recordInitializationStates(mergedInfo);
		return mergedInfo;
	}

	
For statement code generation
Params:
currentScope – org.eclipse.jdt.internal.compiler.lookup.BlockScope
codeStream – org.eclipse.jdt.internal.compiler.codegen.CodeStream/**
	 * For statement code generation
	 *
	 * @param currentScope org.eclipse.jdt.internal.compiler.lookup.BlockScope
	 * @param codeStream org.eclipse.jdt.internal.compiler.codegen.CodeStream
	 */
	@Override
	public void generateCode(BlockScope currentScope, CodeStream codeStream) {

		if ((this.bits & IsReachable) == 0) {
			return;
		}
		int pc = codeStream.position;
		final boolean hasEmptyAction = this.action == null
			|| this.action.isEmptyBlock()
			|| ((this.action.bits & IsUsefulEmptyStatement) != 0);

		if (hasEmptyAction
				&& this.elementVariable.binding.resolvedPosition == -1
				&& this.kind == ARRAY) {
			this.collection.generateCode(this.scope, codeStream, false);
			codeStream.exitUserScope(this.scope);
			if (this.mergedInitStateIndex != -1) {
				codeStream.removeNotDefinitelyAssignedVariables(currentScope, this.mergedInitStateIndex);
				codeStream.addDefinitelyAssignedVariables(currentScope, this.mergedInitStateIndex);
			}
			codeStream.recordPositionsFrom(pc, this.sourceStart);
			return;
		}

		// generate the initializations
		switch(this.kind) {
			case ARRAY :
				this.collection.generateCode(this.scope, codeStream, true);
				codeStream.store(this.collectionVariable, true);
				codeStream.addVariable(this.collectionVariable);
				if (this.continueLabel != null) {
					// int length = (collectionVariable = [collection]).length;
					codeStream.arraylength();
					codeStream.store(this.maxVariable, false);
					codeStream.addVariable(this.maxVariable);
					codeStream.iconst_0();
					codeStream.store(this.indexVariable, false);
					codeStream.addVariable(this.indexVariable);
				} else {
					// leave collectionVariable on execution stack (will be consumed when swapping condition further down)
				}
				break;
			case RAW_ITERABLE :
			case GENERIC_ITERABLE :
				this.collection.generateCode(this.scope, codeStream, true);
				// declaringClass.iterator();
				codeStream.invokeIterableIterator(this.iteratorReceiverType);
				codeStream.store(this.indexVariable, false);
				codeStream.addVariable(this.indexVariable);
				break;
		}
		// label management
		BranchLabel actionLabel = new BranchLabel(codeStream);
		actionLabel.tagBits |= BranchLabel.USED;
		BranchLabel conditionLabel = new BranchLabel(codeStream);
		conditionLabel.tagBits |= BranchLabel.USED;
		this.breakLabel.initialize(codeStream);
		if (this.continueLabel == null) {
			// generate the condition (swapped for optimizing)
			conditionLabel.place();
			int conditionPC = codeStream.position;
			switch(this.kind) {
				case ARRAY :
					// inline the arraylength call
					// collectionVariable is already on execution stack
					codeStream.arraylength();
					codeStream.ifeq(this.breakLabel);
					break;
				case RAW_ITERABLE :
				case GENERIC_ITERABLE :
					codeStream.load(this.indexVariable);
					codeStream.invokeJavaUtilIteratorHasNext();
					codeStream.ifeq(this.breakLabel);
					break;
			}
			codeStream.recordPositionsFrom(conditionPC, this.elementVariable.sourceStart);
		} else {
			this.continueLabel.initialize(codeStream);
			this.continueLabel.tagBits |= BranchLabel.USED;
			// jump over the actionBlock
			codeStream.goto_(conditionLabel);
		}

		// generate the loop action
		actionLabel.place();

		// generate the loop action
		switch(this.kind) {
			case ARRAY :
				if (this.elementVariable.binding.resolvedPosition != -1) {
					codeStream.load(this.collectionVariable);
					if (this.continueLabel == null) {
						codeStream.iconst_0(); // no continue, thus simply hardcode offset 0
					} else {
						codeStream.load(this.indexVariable);
					}
					codeStream.arrayAt(this.collectionElementType.id);
					if (this.elementVariableImplicitWidening != -1) {
						codeStream.generateImplicitConversion(this.elementVariableImplicitWidening);
					}
					codeStream.store(this.elementVariable.binding, false);
					codeStream.addVisibleLocalVariable(this.elementVariable.binding);
					if (this.postCollectionInitStateIndex != -1) {
						codeStream.addDefinitelyAssignedVariables(
							currentScope,
							this.postCollectionInitStateIndex);
					}
				}
				break;
			case RAW_ITERABLE :
			case GENERIC_ITERABLE :
				codeStream.load(this.indexVariable);
				codeStream.invokeJavaUtilIteratorNext();
				if (this.elementVariable.binding.type.id != T_JavaLangObject) {
					if (this.elementVariableImplicitWidening != -1) {
						codeStream.checkcast(this.collectionElementType);
						codeStream.generateImplicitConversion(this.elementVariableImplicitWidening);
					} else {
						codeStream.checkcast(this.elementVariable.binding.type);
					}
				}
				if (this.elementVariable.binding.resolvedPosition == -1) {
					switch (this.elementVariable.binding.type.id) {
						case TypeIds.T_long :
						case TypeIds.T_double :
							codeStream.pop2();
							break;
						default:
							codeStream.pop();
							break;
					}
				} else {
					codeStream.store(this.elementVariable.binding, false);
					codeStream.addVisibleLocalVariable(this.elementVariable.binding);
					if (this.postCollectionInitStateIndex != -1) {
						codeStream.addDefinitelyAssignedVariables(
							currentScope,
							this.postCollectionInitStateIndex);
					}
				}
				break;
		}

		if (!hasEmptyAction) {
			this.action.generateCode(this.scope, codeStream);
		}
		codeStream.removeVariable(this.elementVariable.binding);
		if (this.postCollectionInitStateIndex != -1) {
			codeStream.removeNotDefinitelyAssignedVariables(currentScope, this.postCollectionInitStateIndex);
		}
		// continuation point
		if (this.continueLabel != null) {
			this.continueLabel.place();
			int continuationPC = codeStream.position;
			// generate the increments for next iteration
			switch(this.kind) {
				case ARRAY :
					if (!hasEmptyAction || this.elementVariable.binding.resolvedPosition >= 0) {
						codeStream.iinc(this.indexVariable.resolvedPosition, 1);
					}
					// generate the condition
					conditionLabel.place();
					codeStream.load(this.indexVariable);
					codeStream.load(this.maxVariable);
					codeStream.if_icmplt(actionLabel);
					break;
				case RAW_ITERABLE :
				case GENERIC_ITERABLE :
					// generate the condition
					conditionLabel.place();
					codeStream.load(this.indexVariable);
					codeStream.invokeJavaUtilIteratorHasNext();
					codeStream.ifne(actionLabel);
					break;
			}
			codeStream.recordPositionsFrom(continuationPC, this.elementVariable.sourceStart);
		}
		switch(this.kind) {
			case ARRAY :
				codeStream.removeVariable(this.indexVariable);
				codeStream.removeVariable(this.maxVariable);
				codeStream.removeVariable(this.collectionVariable);
				break;
			case RAW_ITERABLE :
			case GENERIC_ITERABLE :
				// generate the condition
				codeStream.removeVariable(this.indexVariable);
				break;
		}
		codeStream.exitUserScope(this.scope);
		if (this.mergedInitStateIndex != -1) {
			codeStream.removeNotDefinitelyAssignedVariables(currentScope, this.mergedInitStateIndex);
			codeStream.addDefinitelyAssignedVariables(currentScope, this.mergedInitStateIndex);
		}
		this.breakLabel.place();
		codeStream.recordPositionsFrom(pc, this.sourceStart);
	}

	@Override
	public StringBuffer printStatement(int indent, StringBuffer output) {

		printIndent(indent, output).append("for ("); //$NON-NLS-1$
		this.elementVariable.printAsExpression(0, output);
		output.append(" : ");//$NON-NLS-1$
		if (this.collection != null) {
			this.collection.print(0, output).append(") "); //$NON-NLS-1$
		} else {
			output.append(')');
		}
		//block
		if (this.action == null) {
			output.append(';');
		} else {
			output.append('\n');
			this.action.printStatement(indent + 1, output);
		}
		return output;
	}

	public static TypeBinding getCollectionElementType(BlockScope scope, TypeBinding collectionType) {
		if (collectionType == null) return null;
		
		boolean isTargetJsr14 = scope.compilerOptions().targetJDK == ClassFileConstants.JDK1_4;
		if (collectionType.isCapture()) {
			TypeBinding upperBound = ((CaptureBinding)collectionType).firstBound;
			if (upperBound != null && upperBound.isArrayType())
				collectionType = upperBound; // partially anticipating the fix for https://bugs.openjdk.java.net/browse/JDK-8013843
		}
		if (collectionType.isArrayType()) { // for(E e : E[])
			return ((ArrayBinding) collectionType).elementsType();
		} else if (collectionType instanceof ReferenceBinding) {
			ReferenceBinding iterableType = ((ReferenceBinding)collectionType).findSuperTypeOriginatingFrom(T_JavaLangIterable, false /*Iterable is not a class*/);
			if (iterableType == null && isTargetJsr14) {
				iterableType = ((ReferenceBinding)collectionType).findSuperTypeOriginatingFrom(T_JavaUtilCollection, false /*Iterable is not a class*/);
			}
			if (iterableType == null) return null;

			TypeBinding[] arguments = null;
			switch (iterableType.kind()) {
				case Binding.RAW_TYPE : // for(Object o : Iterable)
					return scope.getJavaLangObject();

				case Binding.GENERIC_TYPE : // for (T t : Iterable<T>) - in case used inside Iterable itself
					arguments = iterableType.typeVariables();
					break;

				case Binding.PARAMETERIZED_TYPE : // for(E e : Iterable<E>)
					arguments = ((ParameterizedTypeBinding)iterableType).arguments;
					break;

				default:
					return null;
			}
			// generic or parameterized case
			if (arguments.length != 1) return null; // per construction can only be one
			return arguments[0];
		}
		return null;
	}
	@Override
	public void resolve(BlockScope upperScope) {
		// use the scope that will hold the init declarations
		this.scope = new BlockScope(upperScope);
		this.scope.blockStatement = this;
		this.elementVariable.resolve(this.scope); // collection expression can see itemVariable
		TypeBinding elementType = this.elementVariable.type.resolvedType;
		TypeBinding collectionType = this.collection == null ? null : this.collection.resolveType(upperScope);

		// Patch the resolved type
		if (this.elementVariable.isTypeNameVar(upperScope)) {
			if (this.elementVariable.type.dimensions() > 0 || this.elementVariable.type.extraDimensions() > 0) {
				upperScope.problemReporter().varLocalCannotBeArray(this.elementVariable);
			}
			if (TypeBinding.equalsEquals(TypeBinding.NULL, collectionType)) {
				upperScope.problemReporter().varLocalInitializedToNull(this.elementVariable);
				elementType = collectionType;
			} else if (TypeBinding.equalsEquals(TypeBinding.VOID, collectionType)) {
				upperScope.problemReporter().varLocalInitializedToVoid(this.elementVariable);
				elementType = collectionType;
			}
			if ((elementType = getCollectionElementType(this.scope, collectionType)) == null) {
				elementType = collectionType;
			} else {
				elementType = this.elementVariable.patchType(elementType);
			}
			// additional check deferred from LocalDeclaration.resolve():
			if (this.elementVariable.binding != null && this.elementVariable.binding.isValidBinding()) {
				this.elementVariable.validateNullAnnotations(this.scope);
			}
		}

		TypeBinding expectedCollectionType = null;
		if (elementType != null && collectionType != null) {
			boolean isTargetJsr14 = this.scope.compilerOptions().targetJDK == ClassFileConstants.JDK1_4;
			if (collectionType.isCapture()) {
				TypeBinding upperBound = ((CaptureBinding)collectionType).firstBound;
				if (upperBound != null && upperBound.isArrayType())
					collectionType = upperBound; // partially anticipating the fix for https://bugs.openjdk.java.net/browse/JDK-8013843
			}
			if (collectionType.isArrayType()) { // for(E e : E[])
				this.kind = ARRAY;
				this.collectionElementType = ((ArrayBinding) collectionType).elementsType();
				if (!this.collectionElementType.isCompatibleWith(elementType)
						&& !this.scope.isBoxingCompatibleWith(this.collectionElementType, elementType)) {
					this.scope.problemReporter().notCompatibleTypesErrorInForeach(this.collection, this.collectionElementType, elementType);
				} else if (this.collectionElementType.needsUncheckedConversion(elementType)) { // https://bugs.eclipse.org/bugs/show_bug.cgi?id=321085
				    this.scope.problemReporter().unsafeElementTypeConversion(this.collection, this.collectionElementType, elementType);
				}
				// in case we need to do a conversion
				int compileTimeTypeID = this.collectionElementType.id;
				if (elementType.isBaseType()) {
					this.collection.computeConversion(this.scope, collectionType, collectionType);
					if (!this.collectionElementType.isBaseType()) {
						compileTimeTypeID = this.scope.environment().computeBoxingType(this.collectionElementType).id;
						this.elementVariableImplicitWidening = UNBOXING;
						if (elementType.isBaseType()) {
							this.elementVariableImplicitWidening |= (elementType.id << 4) + compileTimeTypeID;
							this.scope.problemReporter().autoboxing(this.collection, this.collectionElementType, elementType);
						}
					} else {
						this.elementVariableImplicitWidening = (elementType.id << 4) + compileTimeTypeID;
					}
				} else if (this.collectionElementType.isBaseType()) {
					this.collection.computeConversion(this.scope, collectionType, collectionType);
					int boxedID = this.scope.environment().computeBoxingType(this.collectionElementType).id;
					this.elementVariableImplicitWidening = BOXING | (compileTimeTypeID << 4) | compileTimeTypeID; // use primitive type in implicit conversion
					compileTimeTypeID = boxedID;
					this.scope.problemReporter().autoboxing(this.collection, this.collectionElementType, elementType);
				} else {
					expectedCollectionType = upperScope.createArrayType(elementType, 1);
					this.collection.computeConversion(this.scope, expectedCollectionType, collectionType);
				}
			} else if (collectionType instanceof ReferenceBinding) {
				ReferenceBinding iterableType = ((ReferenceBinding)collectionType).findSuperTypeOriginatingFrom(T_JavaLangIterable, false /*Iterable is not a class*/);
				if (iterableType == null && isTargetJsr14) {
					iterableType = ((ReferenceBinding)collectionType).findSuperTypeOriginatingFrom(T_JavaUtilCollection, false /*Iterable is not a class*/);
				}
				checkIterable: {
					if (iterableType == null) break checkIterable;

					this.iteratorReceiverType = collectionType.erasure();
					if (isTargetJsr14) {
						if (((ReferenceBinding)this.iteratorReceiverType).findSuperTypeOriginatingFrom(T_JavaUtilCollection, false) == null) {
							this.iteratorReceiverType = iterableType; // handle indirect inheritance thru variable secondary bound
							this.collection.computeConversion(this.scope, iterableType, collectionType);
						} else {
							this.collection.computeConversion(this.scope, collectionType, collectionType);
						}
					} else if (((ReferenceBinding)this.iteratorReceiverType).findSuperTypeOriginatingFrom(T_JavaLangIterable, false) == null) {
						this.iteratorReceiverType = iterableType; // handle indirect inheritance thru variable secondary bound
						this.collection.computeConversion(this.scope, iterableType, collectionType);
					} else {
						this.collection.computeConversion(this.scope, collectionType, collectionType);
					}

					TypeBinding[] arguments = null;
					switch (iterableType.kind()) {
						case Binding.RAW_TYPE : // for(Object o : Iterable)
							this.kind = RAW_ITERABLE;
							this.collectionElementType = this.scope.getJavaLangObject();
							if (!this.collectionElementType.isCompatibleWith(elementType)
									&& !this.scope.isBoxingCompatibleWith(this.collectionElementType, elementType)) {
								this.scope.problemReporter().notCompatibleTypesErrorInForeach(this.collection, this.collectionElementType, elementType);
							}
							// no conversion needed as only for reference types
							break checkIterable;

						case Binding.GENERIC_TYPE : // for (T t : Iterable<T>) - in case used inside Iterable itself
							arguments = iterableType.typeVariables();
							break;

						case Binding.PARAMETERIZED_TYPE : // for(E e : Iterable<E>)
							arguments = ((ParameterizedTypeBinding)iterableType).arguments;
							break;

						default:
							break checkIterable;
					}
					// generic or parameterized case
					if (arguments.length != 1) break checkIterable; // per construction can only be one
					this.kind = GENERIC_ITERABLE;

					this.collectionElementType = arguments[0];
					if (!this.collectionElementType.isCompatibleWith(elementType)
							&& !this.scope.isBoxingCompatibleWith(this.collectionElementType, elementType)) {
						this.scope.problemReporter().notCompatibleTypesErrorInForeach(this.collection, this.collectionElementType, elementType);
					} else if (this.collectionElementType.needsUncheckedConversion(elementType)) { // https://bugs.eclipse.org/bugs/show_bug.cgi?id=393719
					    this.scope.problemReporter().unsafeElementTypeConversion(this.collection, this.collectionElementType, elementType);
					}
					int compileTimeTypeID = this.collectionElementType.id;
					// no conversion needed as only for reference types
					if (elementType.isBaseType()) {
						if (!this.collectionElementType.isBaseType()) {
							compileTimeTypeID = this.scope.environment().computeBoxingType(this.collectionElementType).id;
							this.elementVariableImplicitWidening = UNBOXING;
							if (elementType.isBaseType()) {
								this.elementVariableImplicitWidening |= (elementType.id << 4) + compileTimeTypeID;
							}
						} else {
							this.elementVariableImplicitWidening = (elementType.id << 4) + compileTimeTypeID;
						}
					} else {
						if (this.collectionElementType.isBaseType()) {
							this.elementVariableImplicitWidening = BOXING | (compileTimeTypeID << 4) | compileTimeTypeID; // use primitive type in implicit conversion
						}
					}
				}
			}
			switch(this.kind) {
				case ARRAY :
					// allocate #index secret variable (of type int)
					this.indexVariable = new LocalVariableBinding(SecretIndexVariableName, TypeBinding.INT, ClassFileConstants.AccDefault, false);
					this.scope.addLocalVariable(this.indexVariable);
					this.indexVariable.setConstant(Constant.NotAConstant); // not inlinable
					// allocate #max secret variable
					this.maxVariable = new LocalVariableBinding(SecretMaxVariableName, TypeBinding.INT, ClassFileConstants.AccDefault, false);
					this.scope.addLocalVariable(this.maxVariable);
					this.maxVariable.setConstant(Constant.NotAConstant); // not inlinable
					// add #array secret variable (of collection type)
					if (expectedCollectionType == null) {
						this.collectionVariable = new LocalVariableBinding(SecretCollectionVariableName, collectionType, ClassFileConstants.AccDefault, false);
					} else {
						this.collectionVariable = new LocalVariableBinding(SecretCollectionVariableName, expectedCollectionType, ClassFileConstants.AccDefault, false);
					}
					this.scope.addLocalVariable(this.collectionVariable);
					this.collectionVariable.setConstant(Constant.NotAConstant); // not inlinable
					break;
				case RAW_ITERABLE :
				case GENERIC_ITERABLE :
					// allocate #index secret variable (of type Iterator)
					this.indexVariable = new LocalVariableBinding(SecretIteratorVariableName, this.scope.getJavaUtilIterator(), ClassFileConstants.AccDefault, false);
					this.scope.addLocalVariable(this.indexVariable);
					this.indexVariable.setConstant(Constant.NotAConstant); // not inlinable
					break;
				default :
					if (isTargetJsr14) {
						this.scope.problemReporter().invalidTypeForCollectionTarget14(this.collection);
					} else {
						this.scope.problemReporter().invalidTypeForCollection(this.collection);
					}
			}
		}
		if (this.action != null) {
			this.action.resolve(this.scope);
		}
	}

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

		if (visitor.visit(this, blockScope)) {
			this.elementVariable.traverse(visitor, this.scope);
			if (this.collection != null) {
				this.collection.traverse(visitor, this.scope);
			}
			if (this.action != null) {
				this.action.traverse(visitor, this.scope);
			}
		}
		visitor.endVisit(this, blockScope);
	}

	@Override
	public boolean doesNotCompleteNormally() {
		return false; // may not be entered at all.
	}
}