/**
* Casting an enclosing instance will considered as useful if removing it would actually bind to a
* different type
*/
public static void checkNeedForEnclosingInstanceCast(
BlockScope scope,
Expression enclosingInstance,
TypeBinding enclosingInstanceType,
TypeBinding memberType) {
if (scope.compilerOptions().getSeverity(CompilerOptions.UnnecessaryTypeCheck)
== ProblemSeverities.Ignore) return;
TypeBinding castedExpressionType = ((CastExpression) enclosingInstance).expression.resolvedType;
if (castedExpressionType == null) return; // cannot do better
// obvious identity cast
if (TypeBinding.equalsEquals(castedExpressionType, enclosingInstanceType)) {
scope.problemReporter().unnecessaryCast((CastExpression) enclosingInstance);
} else if (castedExpressionType == TypeBinding.NULL) {
return; // tolerate null enclosing instance cast
} else {
TypeBinding alternateEnclosingInstanceType = castedExpressionType;
if (castedExpressionType.isBaseType() || castedExpressionType.isArrayType())
return; // error case
if (TypeBinding.equalsEquals(
memberType,
scope.getMemberType(
memberType.sourceName(), (ReferenceBinding) alternateEnclosingInstanceType))) {
scope.problemReporter().unnecessaryCast((CastExpression) enclosingInstance);
}
}
}
/**
* Cast expressions will considered as useful if removing them all would actually bind to a
* different method (no fine grain analysis on per casted argument basis, simply separate widening
* cast from narrowing ones)
*/
public static void checkNeedForArgumentCasts(
BlockScope scope,
Expression receiver,
TypeBinding receiverType,
MethodBinding binding,
Expression[] arguments,
TypeBinding[] argumentTypes,
final InvocationSite invocationSite) {
if (scope.compilerOptions().getSeverity(CompilerOptions.UnnecessaryTypeCheck)
== ProblemSeverities.Ignore) return;
int length = argumentTypes.length;
// iterate over arguments, and retrieve original argument types (before cast)
TypeBinding[] rawArgumentTypes = argumentTypes;
for (int i = 0; i < length; i++) {
Expression argument = arguments[i];
if (argument instanceof CastExpression) {
// narrowing conversion on base type may change value, thus necessary
if ((argument.bits & ASTNode.UnnecessaryCast) == 0 && argument.resolvedType.isBaseType()) {
continue;
}
TypeBinding castedExpressionType = ((CastExpression) argument).expression.resolvedType;
if (castedExpressionType == null) return; // cannot do better
// obvious identity cast
if (TypeBinding.equalsEquals(castedExpressionType, argumentTypes[i])) {
scope.problemReporter().unnecessaryCast((CastExpression) argument);
} else if (castedExpressionType == TypeBinding.NULL) {
continue; // tolerate null argument cast
} else if ((argument.implicitConversion & TypeIds.BOXING) != 0) {
continue; // boxing has a side effect: (int) char is not boxed as simple char
} else {
if (rawArgumentTypes == argumentTypes) {
System.arraycopy(
rawArgumentTypes, 0, rawArgumentTypes = new TypeBinding[length], 0, length);
}
// retain original argument type
rawArgumentTypes[i] = castedExpressionType;
}
}
}
// perform alternate lookup with original types
if (rawArgumentTypes != argumentTypes) {
checkAlternateBinding(
scope,
receiver,
receiverType,
binding,
arguments,
argumentTypes,
rawArgumentTypes,
invocationSite);
}
}
/**
* Complain if cast expression is cast, but not actually needed, int i = (int)(Integer) 12; Note
* that this (int) cast is however needed: Integer i = 0; char c = (char)((int) i);
*/
public static void checkNeedForCastCast(BlockScope scope, CastExpression enclosingCast) {
if (scope.compilerOptions().getSeverity(CompilerOptions.UnnecessaryTypeCheck)
== ProblemSeverities.Ignore) return;
CastExpression nestedCast = (CastExpression) enclosingCast.expression;
if ((nestedCast.bits & ASTNode.UnnecessaryCast) == 0) return;
// check if could cast directly to enclosing cast type, without intermediate type cast
CastExpression alternateCast = new CastExpression(null, enclosingCast.type);
alternateCast.resolvedType = enclosingCast.resolvedType;
if (!alternateCast.checkCastTypesCompatibility(
scope,
enclosingCast.resolvedType,
nestedCast.expression.resolvedType,
null /* no expr to avoid side-effects*/)) return;
scope.problemReporter().unnecessaryCast(nestedCast);
}
/**
* Complain if assigned expression is cast, but not actually used as such, e.g. Object o = (List)
* object;
*/
public static void checkNeedForAssignedCast(
BlockScope scope, TypeBinding expectedType, CastExpression rhs) {
CompilerOptions compilerOptions = scope.compilerOptions();
if (compilerOptions.getSeverity(CompilerOptions.UnnecessaryTypeCheck)
== ProblemSeverities.Ignore) return;
TypeBinding castedExpressionType = rhs.expression.resolvedType;
// int i = (byte) n; // cast still had side effect
// double d = (float) n; // cast to float is unnecessary
if (castedExpressionType == null || rhs.resolvedType.isBaseType()) return;
// if (castedExpressionType.id == T_null) return; // tolerate null expression cast
if (castedExpressionType.isCompatibleWith(expectedType, scope)) {
if (scope.environment().usesNullTypeAnnotations()) {
// are null annotations compatible, too?
if (NullAnnotationMatching.analyse(expectedType, castedExpressionType, -1).isAnyMismatch())
return; // already reported unchecked cast (nullness), say no more.
}
scope.problemReporter().unnecessaryCast(rhs);
}
}
/**
* Only complain for identity cast, since other type of casts may be useful: e.g. ~((~(long) 0) <<
* 32) is different from: ~((~0) << 32)
*/
public static void checkNeedForArgumentCast(
BlockScope scope,
int operator,
int operatorSignature,
Expression expression,
int expressionTypeId) {
if (scope.compilerOptions().getSeverity(CompilerOptions.UnnecessaryTypeCheck)
== ProblemSeverities.Ignore) return;
// check need for left operand cast
if ((expression.bits & ASTNode.UnnecessaryCast) == 0 && expression.resolvedType.isBaseType()) {
// narrowing conversion on base type may change value, thus necessary
return;
} else {
TypeBinding alternateLeftType = ((CastExpression) expression).expression.resolvedType;
if (alternateLeftType == null) return; // cannot do better
if (alternateLeftType.id == expressionTypeId) { // obvious identity cast
scope.problemReporter().unnecessaryCast((CastExpression) expression);
return;
}
}
}
public TypeBinding resolveType(BlockScope scope) {
// compute a new constant if the cast is effective
this.constant = Constant.NotAConstant;
this.implicitConversion = TypeIds.T_undefined;
boolean exprContainCast = false;
TypeBinding castType = this.resolvedType = this.type.resolveType(scope);
if (scope.compilerOptions().sourceLevel >= ClassFileConstants.JDK1_8) {
this.expression.setExpressionContext(CASTING_CONTEXT);
if (this.expression instanceof FunctionalExpression) {
this.expression.setExpectedType(this.resolvedType);
this.bits |= ASTNode.DisableUnnecessaryCastCheck;
}
}
if (this.expression instanceof CastExpression) {
this.expression.bits |= ASTNode.DisableUnnecessaryCastCheck;
exprContainCast = true;
}
TypeBinding expressionType = this.expression.resolveType(scope);
if (this.expression instanceof MessageSend) {
MessageSend messageSend = (MessageSend) this.expression;
MethodBinding methodBinding = messageSend.binding;
if (methodBinding != null && methodBinding.isPolymorphic()) {
messageSend.binding =
scope
.environment()
.updatePolymorphicMethodReturnType(
(PolymorphicMethodBinding) methodBinding, castType);
if (TypeBinding.notEquals(expressionType, castType)) {
expressionType = castType;
this.bits |= ASTNode.DisableUnnecessaryCastCheck;
}
}
}
if (castType != null) {
if (expressionType != null) {
boolean nullAnnotationMismatch =
scope.compilerOptions().isAnnotationBasedNullAnalysisEnabled
&& NullAnnotationMatching.analyse(castType, expressionType, -1).isAnyMismatch();
boolean isLegal =
checkCastTypesCompatibility(scope, castType, expressionType, this.expression);
if (isLegal) {
this.expression.computeConversion(scope, castType, expressionType);
if ((this.bits & ASTNode.UnsafeCast) != 0) { // unsafe cast
if (scope.compilerOptions().reportUnavoidableGenericTypeProblems
|| !(expressionType.isRawType()
&& this.expression.forcedToBeRaw(scope.referenceContext()))) {
scope.problemReporter().unsafeCast(this, scope);
}
} else if (nullAnnotationMismatch) {
// report null annotation issue at medium priority
scope.problemReporter().unsafeNullnessCast(this, scope);
} else {
if (castType.isRawType()
&& scope.compilerOptions().getSeverity(CompilerOptions.RawTypeReference)
!= ProblemSeverities.Ignore) {
scope.problemReporter().rawTypeReference(this.type, castType);
}
if ((this.bits & (ASTNode.UnnecessaryCast | ASTNode.DisableUnnecessaryCastCheck))
== ASTNode.UnnecessaryCast) { // unnecessary cast
if (!isIndirectlyUsed()) // used for generic type inference or boxing ?
scope.problemReporter().unnecessaryCast(this);
}
}
} else { // illegal cast
if ((castType.tagBits & TagBits.HasMissingType) == 0) { // no complaint if secondary error
scope.problemReporter().typeCastError(this, castType, expressionType);
}
this.bits |= ASTNode.DisableUnnecessaryCastCheck; // disable further secondary diagnosis
}
}
this.resolvedType =
castType.capture(
scope,
this.type.sourceStart,
this.type.sourceEnd); // make it unique, a cast expression shares source end with the
// expression.
if (exprContainCast) {
checkNeedForCastCast(scope, this);
}
}
return this.resolvedType;
}
/** Check binary operator casted arguments */
public static void checkNeedForArgumentCasts(
BlockScope scope,
int operator,
int operatorSignature,
Expression left,
int leftTypeId,
boolean leftIsCast,
Expression right,
int rightTypeId,
boolean rightIsCast) {
if (scope.compilerOptions().getSeverity(CompilerOptions.UnnecessaryTypeCheck)
== ProblemSeverities.Ignore) return;
// check need for left operand cast
int alternateLeftTypeId = leftTypeId;
if (leftIsCast) {
if ((left.bits & ASTNode.UnnecessaryCast) == 0 && left.resolvedType.isBaseType()) {
// narrowing conversion on base type may change value, thus necessary
leftIsCast = false;
} else {
TypeBinding alternateLeftType = ((CastExpression) left).expression.resolvedType;
if (alternateLeftType == null) return; // cannot do better
if ((alternateLeftTypeId = alternateLeftType.id) == leftTypeId
|| scope.environment().computeBoxingType(alternateLeftType).id
== leftTypeId) { // obvious identity cast
scope.problemReporter().unnecessaryCast((CastExpression) left);
leftIsCast = false;
} else if (alternateLeftTypeId == TypeIds.T_null) {
alternateLeftTypeId = leftTypeId; // tolerate null argument cast
leftIsCast = false;
}
}
}
// check need for right operand cast
int alternateRightTypeId = rightTypeId;
if (rightIsCast) {
if ((right.bits & ASTNode.UnnecessaryCast) == 0 && right.resolvedType.isBaseType()) {
// narrowing conversion on base type may change value, thus necessary
rightIsCast = false;
} else {
TypeBinding alternateRightType = ((CastExpression) right).expression.resolvedType;
if (alternateRightType == null) return; // cannot do better
if ((alternateRightTypeId = alternateRightType.id) == rightTypeId
|| scope.environment().computeBoxingType(alternateRightType).id
== rightTypeId) { // obvious identity cast
scope.problemReporter().unnecessaryCast((CastExpression) right);
rightIsCast = false;
} else if (alternateRightTypeId == TypeIds.T_null) {
alternateRightTypeId = rightTypeId; // tolerate null argument cast
rightIsCast = false;
}
}
}
if (leftIsCast || rightIsCast) {
if (alternateLeftTypeId > 15
|| alternateRightTypeId > 15) { // must convert String + Object || Object + String
if (alternateLeftTypeId == TypeIds.T_JavaLangString) {
alternateRightTypeId = TypeIds.T_JavaLangObject;
} else if (alternateRightTypeId == TypeIds.T_JavaLangString) {
alternateLeftTypeId = TypeIds.T_JavaLangObject;
} else {
return; // invalid operator
}
}
int alternateOperatorSignature =
OperatorExpression.OperatorSignatures[operator][
(alternateLeftTypeId << 4) + alternateRightTypeId];
// (cast) left Op (cast) right --> result
// 1111 0000 1111 0000 1111
// <<16 <<12 <<8 <<4 <<0
final int CompareMASK = (0xF << 16) + (0xF << 8) + 0xF; // mask hiding compile-time types
if ((operatorSignature & CompareMASK)
== (alternateOperatorSignature & CompareMASK)) { // same promotions and result
if (leftIsCast) scope.problemReporter().unnecessaryCast((CastExpression) left);
if (rightIsCast) scope.problemReporter().unnecessaryCast((CastExpression) right);
}
}
}