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;
}
/**
* 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);
}
}
}