C# DecodeWellKnownAttributeArguments类代码示例

        private void DecodeCoClassAttribute(ref DecodeWellKnownAttributeArguments<AttributeSyntax, CSharpAttributeData, AttributeLocation> arguments)
        {
            var attribute = arguments.Attribute;
            Debug.Assert(!attribute.HasErrors);

            if (this.IsInterfaceType() && (!arguments.HasDecodedData || (object)((TypeWellKnownAttributeData)arguments.DecodedData).ComImportCoClass == null))
            {
                TypedConstant argument = attribute.CommonConstructorArguments[0];
                Debug.Assert(argument.Kind == TypedConstantKind.Type);

                var coClassType = argument.Value as NamedTypeSymbol;
                if ((object)coClassType != null && coClassType.TypeKind == TypeKind.Class)
                {
                    arguments.GetOrCreateData<TypeWellKnownAttributeData>().ComImportCoClass = coClassType;
                }
            }
        }

 /// <summary>
 /// This method is called by the binder when it is finished binding a set of attributes on the symbol so that
 /// the symbol can extract data from the attribute arguments and potentially perform validation specific to
 /// some well known attributes.
 /// <para>
 /// NOTE: If we are decoding a well-known attribute that could be queried by the binder, consider decoding it during early decoding pass.
 /// </para>
 /// </summary>
 /// <remarks>
 /// <para>
 /// Symbol types should override this if they want to handle a specific well-known attribute.
 /// If the attribute is of a type that the symbol does not wish to handle, it should delegate back to
 /// this (base) method.
 /// </para>
 /// </remarks>
 internal virtual void DecodeWellKnownAttribute(ref DecodeWellKnownAttributeArguments<AttributeSyntax, CSharpAttributeData, AttributeLocation> arguments)
 {
 }

        internal sealed override void DecodeWellKnownAttribute(ref DecodeWellKnownAttributeArguments<AttributeSyntax, CSharpAttributeData, AttributeLocation> arguments)
        {
            var attribute = arguments.Attribute;
            Debug.Assert(!attribute.HasErrors);
            Debug.Assert(arguments.SymbolPart == AttributeLocation.None);

            if (attribute.IsTargetAttribute(this, AttributeDescription.SpecialNameAttribute))
            {
                arguments.GetOrCreateData<CommonEventWellKnownAttributeData>().HasSpecialNameAttribute = true;
            }
        }

        internal sealed override void DecodeWellKnownAttribute(ref DecodeWellKnownAttributeArguments<AttributeSyntax, CSharpAttributeData, AttributeLocation> arguments)
        {
            Debug.Assert((object)arguments.AttributeSyntaxOpt != null);

            var attribute = arguments.Attribute;
            Debug.Assert(!attribute.HasErrors);
            Debug.Assert(arguments.SymbolPart == AttributeLocation.None);

            if (attribute.IsTargetAttribute(this, AttributeDescription.AttributeUsageAttribute))
            {
                DecodeAttributeUsageAttribute(attribute, arguments.AttributeSyntaxOpt, diagnose: true, diagnosticsOpt: arguments.Diagnostics);
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.DefaultMemberAttribute))
            {
                arguments.GetOrCreateData<TypeWellKnownAttributeData>().HasDefaultMemberAttribute = true;
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.CoClassAttribute))
            {
                DecodeCoClassAttribute(ref arguments);
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.ConditionalAttribute))
            {
                ValidateConditionalAttribute(attribute, arguments.AttributeSyntaxOpt, arguments.Diagnostics);
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.GuidAttribute))
            {
                arguments.GetOrCreateData<TypeWellKnownAttributeData>().GuidString = attribute.DecodeGuidAttribute(arguments.AttributeSyntaxOpt, arguments.Diagnostics);
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.SpecialNameAttribute))
            {
                arguments.GetOrCreateData<TypeWellKnownAttributeData>().HasSpecialNameAttribute = true;
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.SerializableAttribute))
            {
                arguments.GetOrCreateData<TypeWellKnownAttributeData>().HasSerializableAttribute = true;
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.StructLayoutAttribute))
            {
                AttributeData.DecodeStructLayoutAttribute<TypeWellKnownAttributeData, AttributeSyntax, CSharpAttributeData, AttributeLocation>(
                    ref arguments, this.DefaultMarshallingCharSet, defaultAutoLayoutSize: 0, messageProvider: MessageProvider.Instance);
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.SuppressUnmanagedCodeSecurityAttribute))
            {
                arguments.GetOrCreateData<TypeWellKnownAttributeData>().HasSuppressUnmanagedCodeSecurityAttribute = true;
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.ClassInterfaceAttribute))
            {
                attribute.DecodeClassInterfaceAttribute(arguments.AttributeSyntaxOpt, arguments.Diagnostics);
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.InterfaceTypeAttribute))
            {
                attribute.DecodeInterfaceTypeAttribute(arguments.AttributeSyntaxOpt, arguments.Diagnostics);
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.WindowsRuntimeImportAttribute))
            {
                arguments.GetOrCreateData<TypeWellKnownAttributeData>().HasWindowsRuntimeImportAttribute = true;
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.RequiredAttributeAttribute))
            {
                // CS1608: The Required attribute is not permitted on C# types
                arguments.Diagnostics.Add(ErrorCode.ERR_CantUseRequiredAttribute, arguments.AttributeSyntaxOpt.Name.Location);
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.CaseSensitiveExtensionAttribute))
            {
                // ExtensionAttribute should not be set explicitly.
                arguments.Diagnostics.Add(ErrorCode.ERR_ExplicitExtension, arguments.AttributeSyntaxOpt.Location);
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.DynamicAttribute))
            {
                // DynamicAttribute should not be set explicitly.
                arguments.Diagnostics.Add(ErrorCode.ERR_ExplicitDynamicAttr, arguments.AttributeSyntaxOpt.Location);
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.SecurityCriticalAttribute)
                || attribute.IsTargetAttribute(this, AttributeDescription.SecuritySafeCriticalAttribute))
            {
                arguments.GetOrCreateData<TypeWellKnownAttributeData>().HasSecurityCriticalAttributes = true;
            }
            else if (_lazyIsExplicitDefinitionOfNoPiaLocalType == ThreeState.Unknown && attribute.IsTargetAttribute(this, AttributeDescription.TypeIdentifierAttribute))
            {
                _lazyIsExplicitDefinitionOfNoPiaLocalType = ThreeState.True;
            }
            else
            {
                var compilation = this.DeclaringCompilation;
                if (attribute.IsSecurityAttribute(compilation))
                {
                    attribute.DecodeSecurityAttribute<TypeWellKnownAttributeData>(this, compilation, ref arguments);
                }
            }
        }

        /// <summary>
        /// Verify the constant value matches the default value from any earlier attribute
        /// (DateTimeConstantAttribute or DecimalConstantAttribute).
        /// If not, report ERR_FieldHasMultipleDistinctConstantValues.
        /// </summary>
        private void VerifyConstantValueMatches(ConstantValue attrValue, ref DecodeWellKnownAttributeArguments<AttributeSyntax, CSharpAttributeData, AttributeLocation> arguments)
        {
            if (!attrValue.IsBad)
            {
                var data = arguments.GetOrCreateData<CommonFieldWellKnownAttributeData>();
                ConstantValue constValue;

                if (this.IsConst)
                {
                    if (this.Type.SpecialType == SpecialType.System_Decimal)
                    {
                        constValue = this.GetConstantValue(ConstantFieldsInProgress.Empty, earlyDecodingWellKnownAttributes: false);

                        if ((object)constValue != null && !constValue.IsBad && constValue != attrValue)
                        {
                            arguments.Diagnostics.Add(ErrorCode.ERR_FieldHasMultipleDistinctConstantValues, arguments.AttributeSyntaxOpt.Location);
                        }
                    }
                    else
                    {
                        arguments.Diagnostics.Add(ErrorCode.ERR_FieldHasMultipleDistinctConstantValues, arguments.AttributeSyntaxOpt.Location);
                    }

                    if (data.ConstValue == CodeAnalysis.ConstantValue.Unset)
                    {
                        data.ConstValue = attrValue;
                    }
                }
                else
                {
                    constValue = data.ConstValue;

                    if (constValue != CodeAnalysis.ConstantValue.Unset)
                    {
                        if (constValue != attrValue)
                        {
                            arguments.Diagnostics.Add(ErrorCode.ERR_FieldHasMultipleDistinctConstantValues, arguments.AttributeSyntaxOpt.Location);
                        }
                    }
                    else
                    {
                        data.ConstValue = attrValue;
                    }
                }
            }
        }

        internal sealed override void DecodeWellKnownAttribute(ref DecodeWellKnownAttributeArguments<AttributeSyntax, CSharpAttributeData, AttributeLocation> arguments)
        {
            var attribute = arguments.Attribute;
            Debug.Assert(!attribute.HasErrors);
            Debug.Assert(arguments.SymbolPart == AttributeLocation.None);

            if (attribute.IsTargetAttribute(this, AttributeDescription.SpecialNameAttribute))
            {
                arguments.GetOrCreateData<CommonEventWellKnownAttributeData>().HasSpecialNameAttribute = true;
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.ExcludeFromCodeCoverageAttribute))
            {
                arguments.GetOrCreateData<CommonEventWellKnownAttributeData>().HasExcludeFromCodeCoverageAttribute = true;
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.TupleElementNamesAttribute))
            {
                arguments.Diagnostics.Add(ErrorCode.ERR_ExplicitTupleElementNamesAttribute, arguments.AttributeSyntaxOpt.Location);
            }
        }

        private void DecodeDllImportAttribute(ref DecodeWellKnownAttributeArguments<AttributeSyntax, CSharpAttributeData, AttributeLocation> arguments)
        {
            Debug.Assert((object)arguments.AttributeSyntaxOpt != null);

            var attribute = arguments.Attribute;
            Debug.Assert(!attribute.HasErrors);
            bool hasErrors = false;

            if (!this.IsExtern || !this.IsStatic)
            {
                arguments.Diagnostics.Add(ErrorCode.ERR_DllImportOnInvalidMethod, arguments.AttributeSyntaxOpt.Name.Location);
                hasErrors = true;
            }

            if (this.IsGenericMethod || (object)containingType != null && containingType.IsGenericType)
            {
                arguments.Diagnostics.Add(ErrorCode.ERR_DllImportOnGenericMethod, arguments.AttributeSyntaxOpt.Name.Location);
                hasErrors = true;
            }

            string moduleName = attribute.GetConstructorArgument<string>(0, SpecialType.System_String);
            if (!MetadataHelpers.IsValidMetadataIdentifier(moduleName))
            {
                // Dev10 reports CS0647: "Error emitting attribute ..."
                CSharpSyntaxNode attributeArgumentSyntax = attribute.GetAttributeArgumentSyntax(0, arguments.AttributeSyntaxOpt);
                arguments.Diagnostics.Add(ErrorCode.ERR_InvalidAttributeArgument, attributeArgumentSyntax.Location, arguments.AttributeSyntaxOpt.GetErrorDisplayName());
                hasErrors = true;
                moduleName = null;
            }

            // Default value of charset is inherited from the module (only if specified).
            // This might be different from ContainingType.DefaultMarshallingCharSet. If the charset is not specified on module
            // ContainingType.DefaultMarshallingCharSet would be Ansi (the class is emitted with "Ansi" charset metadata flag) 
            // while the charset in P/Invoke metadata should be "None".
            CharSet charSet = this.GetEffectiveDefaultMarshallingCharSet() ?? Cci.Constants.CharSet_None;

            string importName = null;
            bool preserveSig = true;
            CallingConvention callingConvention = System.Runtime.InteropServices.CallingConvention.Winapi;
            bool setLastError = false;
            bool exactSpelling = false;  // C#: ExactSpelling=false for any charset
            bool? bestFitMapping = null;
            bool? throwOnUnmappable = null;

            int position = 1;
            foreach (var namedArg in attribute.CommonNamedArguments)
            {
                switch (namedArg.Key)
                {
                    case "EntryPoint":
                        importName = namedArg.Value.Value as string;
                        if (!MetadataHelpers.IsValidMetadataIdentifier(importName))
                        {
                            // Dev10 reports CS0647: "Error emitting attribute ..."
                            arguments.Diagnostics.Add(ErrorCode.ERR_InvalidNamedArgument, arguments.AttributeSyntaxOpt.ArgumentList.Arguments[position].Location, namedArg.Key);
                            hasErrors = true;
                            importName = null;
                        }

                        break;

                    case "CharSet":
                        // invalid values will be ignored
                        charSet = namedArg.Value.DecodeValue<CharSet>(SpecialType.System_Enum);
                        break;

                    case "SetLastError":
                        // invalid values will be ignored
                        setLastError = namedArg.Value.DecodeValue<bool>(SpecialType.System_Boolean);
                        break;

                    case "ExactSpelling":
                        // invalid values will be ignored
                        exactSpelling = namedArg.Value.DecodeValue<bool>(SpecialType.System_Boolean);
                        break;

                    case "PreserveSig":
                        preserveSig = namedArg.Value.DecodeValue<bool>(SpecialType.System_Boolean);
                        break;

                    case "CallingConvention":
                        // invalid values will be ignored
                        callingConvention = namedArg.Value.DecodeValue<CallingConvention>(SpecialType.System_Enum);
                        break;

                    case "BestFitMapping":
                        bestFitMapping = namedArg.Value.DecodeValue<bool>(SpecialType.System_Boolean);
                        break;

                    case "ThrowOnUnmappableChar":
                        throwOnUnmappable = namedArg.Value.DecodeValue<bool>(SpecialType.System_Boolean);
                        break;
                }

                position++;
            }

            if (!hasErrors)
            {
                arguments.GetOrCreateData<CommonMethodWellKnownAttributeData>().SetDllImport(
//.........这里部分代码省略.........

        internal override void DecodeWellKnownAttribute(ref DecodeWellKnownAttributeArguments<AttributeSyntax, CSharpAttributeData, AttributeLocation> arguments)
        {
            Debug.Assert((object)arguments.AttributeSyntaxOpt != null);

            var attribute = arguments.Attribute;
            Debug.Assert(!attribute.HasErrors);
            Debug.Assert(arguments.SymbolPart == AttributeLocation.None);

            if (attribute.IsTargetAttribute(this, AttributeDescription.DefaultParameterValueAttribute))
            {
                // Attribute decoded and constant value stored during EarlyDecodeWellKnownAttribute.
                DecodeDefaultParameterValueAttribute(AttributeDescription.DefaultParameterValueAttribute, ref arguments);
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.DecimalConstantAttribute))
            {
                // Attribute decoded and constant value stored during EarlyDecodeWellKnownAttribute.
                DecodeDefaultParameterValueAttribute(AttributeDescription.DecimalConstantAttribute, ref arguments);
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.DateTimeConstantAttribute))
            {
                // Attribute decoded and constant value stored during EarlyDecodeWellKnownAttribute.
                DecodeDefaultParameterValueAttribute(AttributeDescription.DateTimeConstantAttribute, ref arguments);
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.OptionalAttribute))
            {
                Debug.Assert(_lazyHasOptionalAttribute == ThreeState.True);

                if (HasDefaultArgumentSyntax)
                {
                    // error CS1745: Cannot specify default parameter value in conjunction with DefaultParameterAttribute or OptionalAttribute
                    arguments.Diagnostics.Add(ErrorCode.ERR_DefaultValueUsedWithAttributes, arguments.AttributeSyntaxOpt.Name.Location);
                }
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.ParamArrayAttribute))
            {
                // error CS0674: Do not use 'System.ParamArrayAttribute'. Use the 'params' keyword instead.
                arguments.Diagnostics.Add(ErrorCode.ERR_ExplicitParamArray, arguments.AttributeSyntaxOpt.Name.Location);
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.InAttribute))
            {
                if (this.RefKind == RefKind.Out)
                {
                    // error CS0036: An out parameter cannot have the In attribute
                    arguments.Diagnostics.Add(ErrorCode.ERR_InAttrOnOutParam, arguments.AttributeSyntaxOpt.Name.Location);
                }
                else
                {
                    arguments.GetOrCreateData<CommonParameterWellKnownAttributeData>().HasInAttribute = true;
                }
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.OutAttribute))
            {
                arguments.GetOrCreateData<CommonParameterWellKnownAttributeData>().HasOutAttribute = true;
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.MarshalAsAttribute))
            {
                MarshalAsAttributeDecoder<CommonParameterWellKnownAttributeData, AttributeSyntax, CSharpAttributeData, AttributeLocation>.Decode(ref arguments, AttributeTargets.Parameter, MessageProvider.Instance);
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.IDispatchConstantAttribute))
            {
                arguments.GetOrCreateData<CommonParameterWellKnownAttributeData>().HasIDispatchConstantAttribute = true;
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.IUnknownConstantAttribute))
            {
                arguments.GetOrCreateData<CommonParameterWellKnownAttributeData>().HasIUnknownConstantAttribute = true;
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.CallerLineNumberAttribute))
            {
                ValidateCallerLineNumberAttribute(arguments.AttributeSyntaxOpt, arguments.Diagnostics);
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.CallerFilePathAttribute))
            {
                ValidateCallerFilePathAttribute(arguments.AttributeSyntaxOpt, arguments.Diagnostics);
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.CallerMemberNameAttribute))
            {
                ValidateCallerMemberNameAttribute(arguments.AttributeSyntaxOpt, arguments.Diagnostics);
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.DynamicAttribute))
            {
                // DynamicAttribute should not be set explicitly.
                arguments.Diagnostics.Add(ErrorCode.ERR_ExplicitDynamicAttr, arguments.AttributeSyntaxOpt.Location);
            }
        }

        private bool VerifyObsoleteAttributeAppliedToMethod(
            ref DecodeWellKnownAttributeArguments<AttributeSyntax, CSharpAttributeData, AttributeLocation> arguments,
            AttributeDescription description)
        {
            if (arguments.Attribute.IsTargetAttribute(this, description))
        {
            if (this.IsAccessor())
            {
                // CS1667: Attribute '{0}' is not valid on property or event accessors. It is only valid on '{1}' declarations.
                    AttributeUsageInfo attributeUsage = arguments.Attribute.AttributeClass.GetAttributeUsageInfo();
                    arguments.Diagnostics.Add(ErrorCode.ERR_AttributeNotOnAccessor, arguments.AttributeSyntaxOpt.Name.Location, description.FullName, attributeUsage.GetValidTargetsString());
                }

                return true;
            }

            return false;
        }

        private void DecodeWellKnownAttributeAppliedToReturnValue(ref DecodeWellKnownAttributeArguments<AttributeSyntax, CSharpAttributeData, AttributeLocation> arguments)
        {
            Debug.Assert((object)arguments.AttributeSyntaxOpt != null);

            var attribute = arguments.Attribute;
            Debug.Assert(!attribute.HasErrors);

            if (attribute.IsTargetAttribute(this, AttributeDescription.MarshalAsAttribute))
            {
                // MarshalAs applied to the return value:
                MarshalAsAttributeDecoder<CommonReturnTypeWellKnownAttributeData, AttributeSyntax, CSharpAttributeData, AttributeLocation>.Decode(ref arguments, AttributeTargets.ReturnValue, MessageProvider.Instance);
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.DynamicAttribute))
            {
                // DynamicAttribute should not be set explicitly.
                arguments.Diagnostics.Add(ErrorCode.ERR_ExplicitDynamicAttr, arguments.AttributeSyntaxOpt.Location);
            }
        }

        private void DecodeWellKnownAttributeAppliedToMethod(ref DecodeWellKnownAttributeArguments<AttributeSyntax, CSharpAttributeData, AttributeLocation> arguments)
        {
            Debug.Assert((object)arguments.AttributeSyntaxOpt != null);

            var attribute = arguments.Attribute;
            Debug.Assert(!attribute.HasErrors);

            if (attribute.IsTargetAttribute(this, AttributeDescription.PreserveSigAttribute))
            {
                arguments.GetOrCreateData<CommonMethodWellKnownAttributeData>().SetPreserveSignature(arguments.Index);
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.MethodImplAttribute))
            {
                AttributeData.DecodeMethodImplAttribute<CommonMethodWellKnownAttributeData, AttributeSyntax, CSharpAttributeData, AttributeLocation>(ref arguments, MessageProvider.Instance);
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.DllImportAttribute))
            {
                DecodeDllImportAttribute(ref arguments);
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.SpecialNameAttribute))
            {
                arguments.GetOrCreateData<CommonMethodWellKnownAttributeData>().HasSpecialNameAttribute = true;
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.ConditionalAttribute))
            {
                ValidateConditionalAttribute(attribute, arguments.AttributeSyntaxOpt, arguments.Diagnostics);
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.SuppressUnmanagedCodeSecurityAttribute))
            {
                arguments.GetOrCreateData<CommonMethodWellKnownAttributeData>().HasSuppressUnmanagedCodeSecurityAttribute = true;
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.DynamicSecurityMethodAttribute))
            {
                arguments.GetOrCreateData<CommonMethodWellKnownAttributeData>().HasDynamicSecurityMethodAttribute = true;
            }
            else if (VerifyObsoleteAttributeAppliedToMethod(ref arguments, AttributeDescription.ObsoleteAttribute))
            {
            }
            else if (VerifyObsoleteAttributeAppliedToMethod(ref arguments, AttributeDescription.DeprecatedAttribute))
            {
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.CaseSensitiveExtensionAttribute))
            {
                // [Extension] attribute should not be set explicitly.
                arguments.Diagnostics.Add(ErrorCode.ERR_ExplicitExtension, arguments.AttributeSyntaxOpt.Location);
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.SecurityCriticalAttribute)
                || attribute.IsTargetAttribute(this, AttributeDescription.SecuritySafeCriticalAttribute))
            {
                if (IsAsync)
                {
                    arguments.Diagnostics.Add(ErrorCode.ERR_SecurityCriticalOrSecuritySafeCriticalOnAsync, arguments.AttributeSyntaxOpt.Location, arguments.AttributeSyntaxOpt.GetErrorDisplayName());
                }
            }
            else
            {
                var compilation = this.DeclaringCompilation;
                if (attribute.IsSecurityAttribute(compilation))
                {
                    attribute.DecodeSecurityAttribute<CommonMethodWellKnownAttributeData>(this, compilation, ref arguments);
                }
            }
        }

        internal override void DecodeWellKnownAttribute(ref DecodeWellKnownAttributeArguments<AttributeSyntax, CSharpAttributeData, AttributeLocation> arguments)
        {
            Debug.Assert(!arguments.Attribute.HasErrors);
            Debug.Assert(arguments.SymbolPart == AttributeLocation.None || arguments.SymbolPart == AttributeLocation.Return);

            if (arguments.SymbolPart == AttributeLocation.None)
            {
                DecodeWellKnownAttributeAppliedToMethod(ref arguments);
            }
            else
            {
                DecodeWellKnownAttributeAppliedToReturnValue(ref arguments);
            }
        }

        private void DecodeDefaultParameterValueAttribute(AttributeDescription description, ref DecodeWellKnownAttributeArguments<AttributeSyntax, CSharpAttributeData, AttributeLocation> arguments)
        {
            var attribute = arguments.Attribute;
            var syntax = arguments.AttributeSyntaxOpt;
            var diagnostics = arguments.Diagnostics;

            Debug.Assert(syntax != null);
            Debug.Assert(diagnostics != null);

            var value = DecodeDefaultParameterValueAttribute(description, attribute, syntax, diagnose: true, diagnosticsOpt: diagnostics);
            if (!value.IsBad)
            {
                VerifyParamDefaultValueMatchesAttributeIfAny(value, syntax, diagnostics);
            }
        }

        /// <summary>
        /// This method validates attribute usage for each bound attribute and calls <see cref="DecodeWellKnownAttribute"/>
        /// on attributes with valid attribute usage.
        /// This method is called by the binder when it is finished binding a set of attributes on the symbol so that
        /// the symbol can extract data from the attribute arguments and potentially perform validation specific to
        /// some well known attributes.
        /// </summary>
        private WellKnownAttributeData ValidateAttributeUsageAndDecodeWellKnownAttributes(
            ImmutableArray<Binder> binders,
            ImmutableArray<AttributeSyntax> attributeSyntaxList,
            ImmutableArray<CSharpAttributeData> boundAttributes,
            DiagnosticBag diagnostics,
            AttributeLocation symbolPart)
        {
            Debug.Assert(binders.Any());
            Debug.Assert(attributeSyntaxList.Any());
            Debug.Assert(boundAttributes.Any());
            Debug.Assert(binders.Length == boundAttributes.Length);
            Debug.Assert(attributeSyntaxList.Length == boundAttributes.Length);

            int totalAttributesCount = boundAttributes.Length;
            HashSet<NamedTypeSymbol> uniqueAttributeTypes = new HashSet<NamedTypeSymbol>();
            var arguments = new DecodeWellKnownAttributeArguments<AttributeSyntax, CSharpAttributeData, AttributeLocation>();
            arguments.Diagnostics = diagnostics;
            arguments.AttributesCount = totalAttributesCount;
            arguments.SymbolPart = symbolPart;

            for (int i = 0; i < totalAttributesCount; i++)
            {
                CSharpAttributeData boundAttribute = boundAttributes[i];
                AttributeSyntax attributeSyntax = attributeSyntaxList[i];
                Binder binder = binders[i];

                // Decode attribute as a possible well-known attribute only if it has no binding errors and has valid AttributeUsage.
                if (!boundAttribute.HasErrors && ValidateAttributeUsage(boundAttribute, attributeSyntax, binder.Compilation, symbolPart, diagnostics, uniqueAttributeTypes))
                {
                    arguments.Attribute = boundAttribute;
                    arguments.AttributeSyntaxOpt = attributeSyntax;
                    arguments.Index = i;

                    this.DecodeWellKnownAttribute(ref arguments);
                }
            }

            return arguments.HasDecodedData ? arguments.DecodedData : null;
        }

        internal sealed override void DecodeWellKnownAttribute(ref DecodeWellKnownAttributeArguments<AttributeSyntax, CSharpAttributeData, AttributeLocation> arguments)
        {
            Debug.Assert((object)arguments.AttributeSyntaxOpt != null);

            var attribute = arguments.Attribute;
            Debug.Assert(!attribute.HasErrors);
            Debug.Assert(arguments.SymbolPart == AttributeLocation.None);

            if (attribute.IsTargetAttribute(this, AttributeDescription.SpecialNameAttribute))
            {
                arguments.GetOrCreateData<CommonFieldWellKnownAttributeData>().HasSpecialNameAttribute = true;
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.NonSerializedAttribute))
            {
                arguments.GetOrCreateData<CommonFieldWellKnownAttributeData>().HasNonSerializedAttribute = true;
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.FieldOffsetAttribute))
            {
                if (this.IsStatic || this.IsConst)
                {
                    // CS0637: The FieldOffset attribute is not allowed on static or const fields
                    arguments.Diagnostics.Add(ErrorCode.ERR_StructOffsetOnBadField, arguments.AttributeSyntaxOpt.Name.Location, arguments.AttributeSyntaxOpt.GetErrorDisplayName());
                }
                else
                {
                    int offset = attribute.CommonConstructorArguments[0].DecodeValue<int>(SpecialType.System_Int32);
                    if (offset < 0)
                    {
                        // Dev10 reports CS0647: "Error emitting attribute ..."
                        CSharpSyntaxNode attributeArgumentSyntax = attribute.GetAttributeArgumentSyntax(0, arguments.AttributeSyntaxOpt);
                        arguments.Diagnostics.Add(ErrorCode.ERR_InvalidAttributeArgument, attributeArgumentSyntax.Location, arguments.AttributeSyntaxOpt.GetErrorDisplayName());
                        offset = 0;
                    }

                    // Set field offset even if the attribute specifies an invalid value, so that
                    // post-validation knows that the attribute is applied and reports better errors.
                    arguments.GetOrCreateData<CommonFieldWellKnownAttributeData>().SetFieldOffset(offset);
                }
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.MarshalAsAttribute))
            {
                MarshalAsAttributeDecoder<CommonFieldWellKnownAttributeData, AttributeSyntax, CSharpAttributeData, AttributeLocation>.Decode(ref arguments, AttributeTargets.Field, MessageProvider.Instance);
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.FixedBufferAttribute))
            {
                // error CS1716: Do not use 'System.Runtime.CompilerServices.FixedBuffer' attribute. Use the 'fixed' field modifier instead.
                arguments.Diagnostics.Add(ErrorCode.ERR_DoNotUseFixedBufferAttr, arguments.AttributeSyntaxOpt.Name.Location);
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.DynamicAttribute))
            {
                // DynamicAttribute should not be set explicitly.
                arguments.Diagnostics.Add(ErrorCode.ERR_ExplicitDynamicAttr, arguments.AttributeSyntaxOpt.Location);
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.DateTimeConstantAttribute))
            {
                VerifyConstantValueMatches(attribute.DecodeDateTimeConstantValue(), ref arguments);
            }
            else if (attribute.IsTargetAttribute(this, AttributeDescription.DecimalConstantAttribute))
            {
                VerifyConstantValueMatches(attribute.DecodeDecimalConstantValue(), ref arguments);
            }
        }