/**
* 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 (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 (memberType
== scope.getMemberType(
memberType.sourceName(), (ReferenceBinding) alternateEnclosingInstanceType)) {
scope.problemReporter().unnecessaryCast((CastExpression) enclosingInstance);
}
}
}
/**
* 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) {
if (scope.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.problemReporter().unnecessaryCast(rhs);
}
}
void checkAssignment(BlockScope scope, TypeBinding lhsType, TypeBinding rhsType) {
FieldBinding leftField = getLastField(this.lhs);
if (leftField != null
&& rhsType != TypeBinding.NULL
&& (lhsType.kind() == Binding.WILDCARD_TYPE)
&& ((WildcardBinding) lhsType).boundKind != Wildcard.SUPER) {
scope.problemReporter().wildcardAssignment(lhsType, rhsType, this.expression);
} else if (leftField != null
&& !leftField.isStatic()
&& leftField.declaringClass != null /*length pseudo field*/
&& leftField.declaringClass.isRawType()) {
scope.problemReporter().unsafeRawFieldAssignment(leftField, rhsType, this.lhs);
} else if (rhsType.needsUncheckedConversion(lhsType)) {
scope.problemReporter().unsafeTypeConversion(this.expression, rhsType, lhsType);
}
}
public TypeBinding resolveType(BlockScope scope) {
// due to syntax lhs may be only a NameReference, a FieldReference or an ArrayReference
this.constant = Constant.NotAConstant;
if (!(this.lhs instanceof Reference) || this.lhs.isThis()) {
scope.problemReporter().expressionShouldBeAVariable(this.lhs);
return null;
}
TypeBinding lhsType = lhs.resolveType(scope);
this.expression.setExpectedType(lhsType); // needed in case of generic method invocation
if (lhsType != null) {
this.resolvedType = lhsType.capture(scope, this.sourceEnd);
}
TypeBinding rhsType = this.expression.resolveType(scope);
if (lhsType == null || rhsType == null) {
return null;
}
// check for assignment with no effect
Binding left = getDirectBinding(this.lhs);
if (left != null && left == getDirectBinding(this.expression)) {
scope.problemReporter().assignmentHasNoEffect(this, left.shortReadableName());
}
// Compile-time conversion of base-types : implicit narrowing integer into byte/short/character
// may require to widen the rhs expression at runtime
if (lhsType != rhsType) { // must call before computeConversion() and typeMismatchError()
scope.compilationUnitScope().recordTypeConversion(lhsType, rhsType);
}
if ((this.expression.isConstantValueOfTypeAssignableToType(rhsType, lhsType)
|| (lhsType.isBaseType() && BaseTypeBinding.isWidening(lhsType.id, rhsType.id)))
|| rhsType.isCompatibleWith(lhsType)) {
this.expression.computeConversion(scope, lhsType, rhsType);
checkAssignment(scope, lhsType, rhsType);
if (this.expression instanceof CastExpression
&& (this.expression.bits & ASTNode.UnnecessaryCast) == 0) {
CastExpression.checkNeedForAssignedCast(scope, lhsType, (CastExpression) this.expression);
}
return this.resolvedType;
} else if (scope.isBoxingCompatibleWith(rhsType, lhsType)
|| (rhsType.isBaseType() // narrowing then boxing ?
&& scope.compilerOptions().sourceLevel >= ClassFileConstants.JDK1_5 // autoboxing
&& !lhsType.isBaseType()
&& this.expression.isConstantValueOfTypeAssignableToType(
rhsType, scope.environment().computeBoxingType(lhsType)))) {
this.expression.computeConversion(scope, lhsType, rhsType);
if (this.expression instanceof CastExpression
&& (this.expression.bits & ASTNode.UnnecessaryCast) == 0) {
CastExpression.checkNeedForAssignedCast(scope, lhsType, (CastExpression) this.expression);
}
return this.resolvedType;
}
scope.problemReporter().typeMismatchError(rhsType, lhsType, this.expression, this.lhs);
return lhsType;
}
public TypeBinding resolveType(BlockScope scope) {
// compute a new constant if the cast is effective
// due to the fact an expression may start with ( and that a cast can also start with (
// the field is an expression....it can be a TypeReference OR a NameReference Or
// any kind of Expression <-- this last one is invalid.......
this.constant = Constant.NotAConstant;
this.implicitConversion = TypeIds.T_undefined;
if ((this.type instanceof TypeReference)
|| (this.type instanceof NameReference)
&& ((this.type.bits & ASTNode.ParenthesizedMASK) >> ASTNode.ParenthesizedSHIFT)
== 0) { // no extra parenthesis around type: ((A))exp
boolean exprContainCast = false;
TypeBinding castType = this.resolvedType = this.type.resolveType(scope);
// expression.setExpectedType(this.resolvedType); // needed in case of generic method
// invocation
if (this.expression instanceof CastExpression) {
this.expression.bits |= ASTNode.DisableUnnecessaryCastCheck;
exprContainCast = true;
}
TypeBinding expressionType = this.expression.resolveType(scope);
if (castType != null) {
if (expressionType != null) {
boolean isLegal =
checkCastTypesCompatibility(scope, castType, expressionType, this.expression);
if (isLegal) {
this.expression.computeConversion(scope, castType, expressionType);
if ((this.bits & ASTNode.UnsafeCast) != 0) { // unsafe cast
scope.problemReporter().unsafeCast(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.sourceEnd);
if (exprContainCast) {
checkNeedForCastCast(scope, this);
}
}
return this.resolvedType;
} else { // expression as a cast
TypeBinding expressionType = this.expression.resolveType(scope);
if (expressionType == null) return null;
scope.problemReporter().invalidTypeReference(this.type);
return null;
}
}
public boolean checkUnsafeCast(
Scope scope,
TypeBinding castType,
TypeBinding expressionType,
TypeBinding match,
boolean isNarrowing) {
if (match == castType) {
if (!isNarrowing
&& match
== this.resolvedType
.leafComponentType()) { // do not tag as unnecessary when recursing through upper
// bounds
tagAsUnnecessaryCast(scope, castType);
}
return true;
}
if (match != null) {
if (isNarrowing
? match.isProvablyDistinct(expressionType)
: castType.isProvablyDistinct(match)) {
return false;
}
}
switch (castType.kind()) {
case Binding.PARAMETERIZED_TYPE:
if (castType.isBoundParameterizedType()) {
if (match == null) { // unrelated types
this.bits |= ASTNode.UnsafeCast;
return true;
}
switch (match.kind()) {
case Binding.PARAMETERIZED_TYPE:
if (isNarrowing) {
// [JLS 5.5] T <: S
if (expressionType.isRawType() || !expressionType.isEquivalentTo(match)) {
this.bits |= ASTNode.UnsafeCast;
return true;
}
// [JLS 5.5] S has no subtype X != T, such that |X| == |T|
// if I2<T,U> extends I1<T>, then cast from I1<T> to I2<T,U> is unchecked
ParameterizedTypeBinding paramCastType = (ParameterizedTypeBinding) castType;
ParameterizedTypeBinding paramMatch = (ParameterizedTypeBinding) match;
// easy case if less parameters on match
TypeBinding[] castArguments = paramCastType.arguments;
int length = castArguments.length;
if (paramMatch.arguments == null || length > paramMatch.arguments.length) {
this.bits |= ASTNode.UnsafeCast;
} else if ((paramCastType.tagBits
& (TagBits.HasDirectWildcard | TagBits.HasTypeVariable))
!= 0) {
// verify alternate cast type, substituting different type arguments
nextAlternateArgument:
for (int i = 0; i < length; i++) {
switch (castArguments[i].kind()) {
case Binding.WILDCARD_TYPE:
case Binding.TYPE_PARAMETER:
break; // check substituting with other
default:
continue nextAlternateArgument; // no alternative possible
}
TypeBinding[] alternateArguments;
// need to clone for each iteration to avoid env paramtype cache interference
System.arraycopy(
paramCastType.arguments,
0,
alternateArguments = new TypeBinding[length],
0,
length);
alternateArguments[i] = scope.getJavaLangObject();
LookupEnvironment environment = scope.environment();
ParameterizedTypeBinding alternateCastType =
environment.createParameterizedType(
(ReferenceBinding) castType.erasure(),
alternateArguments,
castType.enclosingType());
if (alternateCastType.findSuperTypeOriginatingFrom(expressionType) == match) {
this.bits |= ASTNode.UnsafeCast;
break;
}
}
}
return true;
} else {
// [JLS 5.5] T >: S
if (!match.isEquivalentTo(castType)) {
this.bits |= ASTNode.UnsafeCast;
return true;
}
}
break;
case Binding.RAW_TYPE:
this.bits |=
ASTNode.UnsafeCast; // upcast since castType is known to be bound paramType
return true;
default:
if (isNarrowing) {
// match is not parameterized or raw, then any other subtype of match will erase to
// |T|
this.bits |= ASTNode.UnsafeCast;
return true;
}
break;
}
}
break;
case Binding.ARRAY_TYPE:
TypeBinding leafType = castType.leafComponentType();
if (isNarrowing && (leafType.isBoundParameterizedType() || leafType.isTypeVariable())) {
this.bits |= ASTNode.UnsafeCast;
return true;
}
break;
case Binding.TYPE_PARAMETER:
this.bits |= ASTNode.UnsafeCast;
return true;
}
if (!isNarrowing
&& match
== this.resolvedType
.leafComponentType()) { // do not tag as unnecessary when recursing through upper
// bounds
tagAsUnnecessaryCast(scope, castType);
}
return true;
}
private static void checkAlternateBinding(
BlockScope scope,
Expression receiver,
TypeBinding receiverType,
MethodBinding binding,
Expression[] arguments,
TypeBinding[] originalArgumentTypes,
TypeBinding[] alternateArgumentTypes,
final InvocationSite invocationSite) {
InvocationSite fakeInvocationSite =
new InvocationSite() {
public TypeBinding[] genericTypeArguments() {
return null;
}
public boolean isSuperAccess() {
return invocationSite.isSuperAccess();
}
public boolean isTypeAccess() {
return invocationSite.isTypeAccess();
}
public void setActualReceiverType(ReferenceBinding actualReceiverType) {
/* ignore */
}
public void setDepth(int depth) {
/* ignore */
}
public void setFieldIndex(int depth) {
/* ignore */
}
public int sourceStart() {
return 0;
}
public int sourceEnd() {
return 0;
}
};
MethodBinding bindingIfNoCast;
if (binding.isConstructor()) {
bindingIfNoCast =
scope.getConstructor(
(ReferenceBinding) receiverType, alternateArgumentTypes, fakeInvocationSite);
} else {
bindingIfNoCast =
receiver.isImplicitThis()
? scope.getImplicitMethod(
binding.selector, alternateArgumentTypes, fakeInvocationSite)
: scope.getMethod(
receiverType, binding.selector, alternateArgumentTypes, fakeInvocationSite);
}
if (bindingIfNoCast == binding) {
int argumentLength = originalArgumentTypes.length;
if (binding.isVarargs()) {
int paramLength = binding.parameters.length;
if (paramLength == argumentLength) {
int varargsIndex = paramLength - 1;
ArrayBinding varargsType = (ArrayBinding) binding.parameters[varargsIndex];
TypeBinding lastArgType = alternateArgumentTypes[varargsIndex];
// originalType may be compatible already, but cast mandated
// to clarify between varargs/non-varargs call
if (varargsType.dimensions != lastArgType.dimensions()) {
return;
}
if (lastArgType.isCompatibleWith(varargsType.elementsType())
&& lastArgType.isCompatibleWith(varargsType)) {
return;
}
}
}
for (int i = 0; i < argumentLength; i++) {
if (originalArgumentTypes[i] != alternateArgumentTypes[i]) {
scope.problemReporter().unnecessaryCast((CastExpression) arguments[i]);
}
}
}
}