AllTestValuesMustHaveSameType() static private method

ArgumentException with message like "All test values must have the same type."
static private AllTestValuesMustHaveSameType ( string paramName ) : Exception
paramName string
return System.Exception
示例#1
0
        /// <summary>
        /// Creates a <see cref="SwitchExpression"/>.
        /// </summary>
        /// <param name="type">The result type of the switch.</param>
        /// <param name="switchValue">The value to be tested against each case.</param>
        /// <param name="defaultBody">The result of the switch if no cases are matched.</param>
        /// <param name="comparison">The equality comparison method to use.</param>
        /// <param name="cases">The valid cases for this switch.</param>
        /// <returns>The created <see cref="SwitchExpression"/>.</returns>
        public static SwitchExpression Switch(Type type, Expression switchValue, Expression defaultBody, MethodInfo comparison, IEnumerable <SwitchCase> cases)
        {
            ExpressionUtils.RequiresCanRead(switchValue, nameof(switchValue));
            if (switchValue.Type == typeof(void))
            {
                throw Error.ArgumentCannotBeOfTypeVoid(nameof(switchValue));
            }

            ReadOnlyCollection <SwitchCase> caseList = cases.ToReadOnly();

            ContractUtils.RequiresNotNullItems(caseList, nameof(cases));

            // Type of the result. Either provided, or it is type of the branches.
            Type resultType;

            if (type != null)
            {
                resultType = type;
            }
            else if (caseList.Count != 0)
            {
                resultType = caseList[0].Body.Type;
            }
            else if (defaultBody != null)
            {
                resultType = defaultBody.Type;
            }
            else
            {
                resultType = typeof(void);
            }
            bool customType = type != null;

            if (comparison != null)
            {
                ValidateMethodInfo(comparison, nameof(comparison));
                ParameterInfo[] pms = comparison.GetParametersCached();
                if (pms.Length != 2)
                {
                    throw Error.IncorrectNumberOfMethodCallArguments(comparison, nameof(comparison));
                }
                // Validate that the switch value's type matches the comparison method's
                // left hand side parameter type.
                ParameterInfo leftParam  = pms[0];
                bool          liftedCall = false;
                if (!ParameterIsAssignable(leftParam, switchValue.Type))
                {
                    liftedCall = ParameterIsAssignable(leftParam, switchValue.Type.GetNonNullableType());
                    if (!liftedCall)
                    {
                        throw Error.SwitchValueTypeDoesNotMatchComparisonMethodParameter(switchValue.Type, leftParam.ParameterType);
                    }
                }

                ParameterInfo rightParam = pms[1];
                foreach (SwitchCase c in caseList)
                {
                    ContractUtils.RequiresNotNull(c, nameof(cases));
                    ValidateSwitchCaseType(c.Body, customType, resultType, nameof(cases));
                    for (int i = 0, n = c.TestValues.Count; i < n; i++)
                    {
                        // When a comparison method is provided, test values can have different type but have to
                        // be reference assignable to the right hand side parameter of the method.
                        Type rightOperandType = c.TestValues[i].Type;
                        if (liftedCall)
                        {
                            if (!rightOperandType.IsNullableType())
                            {
                                throw Error.TestValueTypeDoesNotMatchComparisonMethodParameter(rightOperandType, rightParam.ParameterType);
                            }
                            rightOperandType = rightOperandType.GetNonNullableType();
                        }
                        if (!ParameterIsAssignable(rightParam, rightOperandType))
                        {
                            throw Error.TestValueTypeDoesNotMatchComparisonMethodParameter(rightOperandType, rightParam.ParameterType);
                        }
                    }
                }

                // if we have a non-boolean user-defined equals, we don't want it.
                if (comparison.ReturnType != typeof(bool))
                {
                    throw Error.EqualityMustReturnBoolean(comparison, nameof(comparison));
                }
            }
            else if (caseList.Count != 0)
            {
                // When comparison method is not present, all the test values must have
                // the same type. Use the first test value's type as the baseline.
                Expression firstTestValue = caseList[0].TestValues[0];
                foreach (SwitchCase c in caseList)
                {
                    ContractUtils.RequiresNotNull(c, nameof(cases));
                    ValidateSwitchCaseType(c.Body, customType, resultType, nameof(cases));
                    // When no comparison method is provided, require all test values to have the same type.
                    for (int i = 0, n = c.TestValues.Count; i < n; i++)
                    {
                        if (!TypeUtils.AreEquivalent(firstTestValue.Type, c.TestValues[i].Type))
                        {
                            throw Error.AllTestValuesMustHaveSameType(nameof(cases));
                        }
                    }
                }

                // Now we need to validate that switchValue.Type and testValueType
                // make sense in an Equal node. Fortunately, Equal throws a
                // reasonable error, so just call it.
                BinaryExpression equal = Equal(switchValue, firstTestValue, false, comparison);

                // Get the comparison function from equals node.
                comparison = equal.Method;
            }

            if (defaultBody == null)
            {
                if (resultType != typeof(void))
                {
                    throw Error.DefaultBodyMustBeSupplied(nameof(defaultBody));
                }
            }
            else
            {
                ValidateSwitchCaseType(defaultBody, customType, resultType, nameof(defaultBody));
            }

            return(new SwitchExpression(resultType, switchValue, defaultBody, comparison, caseList));
        }