/** @apilevel internal */
private TypeDecl binaryNumericPromotedType_compute() {
TypeDecl leftType = left().type();
TypeDecl rightType = right().type();
if (leftType.isString()) return leftType;
if (rightType.isString()) return rightType;
if (leftType.isNumericType() && rightType.isNumericType())
return leftType.binaryNumericPromotion(rightType);
if (leftType.isBoolean() && rightType.isBoolean()) return leftType;
return unknownType();
}
