Fixed code warnings. (#2599)

src/HotChocolate/Core/src/Execution/Caching/DefaultDocumentCache.cs

@@ -6,7 +6,7 @@ namespace HotChocolate.Execution.Caching
 {
     internal sealed class DefaultDocumentCache : IDocumentCache
     {
-        private Cache<DocumentNode> _cache;
+        private readonly Cache<DocumentNode> _cache;
 
         public DefaultDocumentCache(int capacity = 100)
         {

src/HotChocolate/Core/src/Types/Configuration/Contracts/ISchemaOptions.cs

@@ -19,7 +19,7 @@ public interface ISchemaOptions
         /// Defines if fields shall be sorted by name.
         /// Default: <c>false</c>
         /// </summary>
-        bool SortFieldsByName { get; set; }
+        new bool SortFieldsByName { get; set; }
 
         /// <summary>
         /// Defines if types shall be removed from the schema that are

src/HotChocolate/Core/src/Types/Configuration/Validation/ComplexOutputTypeValidationHelper.cs

@@ -26,7 +26,7 @@ internal static class ComplexOutputTypeValidationHelper
             IComplexOutputType type,
             ICollection<ISchemaError> errors)
         {
-            for (int i = 0; i < type.Fields.Count; i++)
+            for (var i = 0; i < type.Fields.Count; i++)
             {
                 IOutputField field = type.Fields[i];
 
@@ -37,7 +37,7 @@ internal static class ComplexOutputTypeValidationHelper
                         errors.Add(TwoUnderscoresNotAllowedField(type, field));
                     }
 
-                    for (int j = 0; j < field.Arguments.Count; j++)
+                    for (var j = 0; j < field.Arguments.Count; j++)
                     {
                         IInputField argument = field.Arguments[j];
 
@@ -77,7 +77,7 @@ internal static class ComplexOutputTypeValidationHelper
 
             foreach (IOutputField implementedField in implementedType.Fields)
             {
-                if (type.Fields.TryGetField(implementedField.Name, out IOutputField field))
+                if (type.Fields.TryGetField(implementedField.Name, out IOutputField? field))
                 {
                     ValidateArguments(field, implementedField, errors);
 
@@ -100,10 +100,9 @@ internal static class ComplexOutputTypeValidationHelper
         {
             var implArgs = implementedField.Arguments.ToDictionary(t => t.Name);
 
-            foreach (Argument argument in field.Arguments)
+            foreach (var argument in field.Arguments)
             {
-                if (implArgs.TryGetValue(
-                    argument.Name, out IInputField? implementedArgument))
+                if (implArgs.TryGetValue(argument.Name, out IInputField? implementedArgument))
                 {
                     implArgs.Remove(argument.Name);
                     if (!argument.Type.IsEqualTo(implementedArgument.Type))
@@ -121,7 +120,7 @@ internal static class ComplexOutputTypeValidationHelper
                 }
             }
 
-            foreach (Argument missingArgument in implArgs.Values)
+            foreach (var missingArgument in implArgs.Values)
             {
                 errors.Add(ArgumentNotImplemented(
                     field, implementedField, missingArgument));
@@ -132,7 +131,7 @@ internal static class ComplexOutputTypeValidationHelper
             IComplexOutputType type,
             IInterfaceType implementedType)
         {
-            foreach (InterfaceType interfaceType in implementedType.Interfaces)
+            foreach (var interfaceType in implementedType.Interfaces)
             {
                 if (!type.IsImplementing(interfaceType))
                 {

src/HotChocolate/Core/src/Types/DataLoader/ObjectFieldDataLoaderExtensions.cs

@@ -26,7 +26,7 @@ public static class DataLoaderObjectFieldExtensions
             this IObjectFieldDescriptor descriptor,
             Type dataLoaderType)
         {
-            FieldMiddleware placeholder = next => context => default;
+            FieldMiddleware placeholder = _ => _ => default;
 
             if (!TryGetDataLoaderTypes(dataLoaderType, out Type? keyType, out Type? valueType))
             {
@@ -43,17 +43,11 @@ public static class DataLoaderObjectFieldExtensions
                         if (!valueType.IsArray)
                         {
                             IExtendedType resolverType =
-                                c.TypeInspector.GetType(definition.ResultType);
-
-                            if (resolverType.IsArrayOrList)
-                            {
-                                schemaType = c.TypeInspector.GetType(
-                                    typeof(IEnumerable<>).MakeGenericType(valueType));
-                            }
-                            else
-                            {
-                                schemaType = c.TypeInspector.GetType(valueType);
-                            }
+                                c.TypeInspector.GetType(definition.ResultType!);
+
+                            schemaType = c.TypeInspector.GetType(resolverType.IsArrayOrList
+                                ? typeof(IEnumerable<>).MakeGenericType(valueType)
+                                : valueType);
                         }
                         else
                         {
@@ -66,7 +60,7 @@ public static class DataLoaderObjectFieldExtensions
                                 .New<ObjectFieldDefinition>()
                                 .Definition(definition)
                                 .Configure(
-                                    (context, def) =>
+                                    (_, def) =>
                                     {
                                         CompileMiddleware(
                                             def,
@@ -94,7 +88,7 @@ public static class DataLoaderObjectFieldExtensions
             {
                 middlewareType =
                     typeof(GroupedDataLoaderMiddleware<,,>)
-                        .MakeGenericType(dataLoaderType, keyType, valueType.GetElementType());
+                        .MakeGenericType(dataLoaderType, keyType, valueType.GetElementType()!);
             }
             else
             {
@@ -145,7 +139,7 @@ public GroupedDataLoaderMiddleware(FieldDelegate next)
 
             public async Task InvokeAsync(IMiddlewareContext context)
             {
-                var dataloader = context.DataLoader<TDataLoader>();
+                TDataLoader dataloader = context.DataLoader<TDataLoader>();
 
                 await _next(context).ConfigureAwait(false);
 
@@ -159,7 +153,7 @@ public async Task InvokeAsync(IMiddlewareContext context)
                     {
                         for (var n = 0; n < data[m].Length; n++)
                         {
-                            result.Add(data[m][n]);
+                            result.Add(data[m][n]!);
                         }
                     }
 
@@ -185,7 +179,7 @@ public DataLoaderMiddleware(FieldDelegate next)
 
             public async Task InvokeAsync(IMiddlewareContext context)
             {
-                var dataloader = context.DataLoader<TDataLoader>();
+                TDataLoader dataloader = context.DataLoader<TDataLoader>();
 
                 await _next(context).ConfigureAwait(false);
 

src/HotChocolate/Core/src/Types/Types/Descriptors/Conventions/DescriptorContext.cs

@@ -10,11 +10,8 @@ namespace HotChocolate.Types.Descriptors
 {
     public sealed class DescriptorContext : IDescriptorContext
     {
-        private readonly Dictionary<(Type, string?), IConvention> _conventions =
-            new Dictionary<(Type, string?), IConvention>();
-
-        private readonly IReadOnlyDictionary<(Type, string?), List<CreateConvention>>
-            _convFactories;
+        private readonly Dictionary<(Type, string?), IConvention> _conventions = new();
+        private readonly IReadOnlyDictionary<(Type, string?), List<CreateConvention>> _cFactories;
 
         private readonly IServiceProvider _services;
 
@@ -25,15 +22,15 @@ public sealed class DescriptorContext : IDescriptorContext
 
         private DescriptorContext(
             IReadOnlySchemaOptions options,
-            IReadOnlyDictionary<(Type, string?), List<CreateConvention>> convFactories,
+            IReadOnlyDictionary<(Type, string?), List<CreateConvention>> conventionFactories,
             IServiceProvider services,
             IDictionary<string, object?> contextData,
             SchemaBuilder.LazySchema schema,
             ISchemaInterceptor schemaInterceptor,
             ITypeInterceptor typeInterceptor)
         {
             Options = options;
-            _convFactories = convFactories;
+            _cFactories = conventionFactories;
             _services = services;
             ContextData = contextData;
             SchemaInterceptor = schemaInterceptor;
@@ -137,7 +134,7 @@ public ITypeInspector TypeInspector
             createdConvention = null;
             extensions = new List<IConventionExtension>();
 
-            if (_convFactories.TryGetValue(
+            if (_cFactories.TryGetValue(
                 (typeof(T), scope),
                 out List<CreateConvention>? factories))
             {
@@ -190,7 +187,7 @@ public ITypeInspector TypeInspector
             ISchemaInterceptor? schemaInterceptor = null,
             ITypeInterceptor? typeInterceptor = null)
         {
-            return new DescriptorContext(
+            return new(
                 options ?? new SchemaOptions(),
                 conventions ?? new Dictionary<(Type, string?), List<CreateConvention>>(),
                 services ?? new EmptyServiceProvider(),

src/HotChocolate/Core/src/Types/Types/Descriptors/ObjectFieldDescriptor.cs

@@ -291,7 +291,7 @@ public new IObjectFieldDescriptor Ignore(bool ignore = true)
         }
 
         public IObjectFieldDescriptor ResolveWith<TResolver>(
-            Expression<Func<TResolver, object>> propertyOrMethod)
+            Expression<Func<TResolver, object?>> propertyOrMethod)
         {
             if (propertyOrMethod is null)
             {

src/HotChocolate/Core/src/Types/Types/Descriptors/ObjectTypeDescriptor.cs

@@ -4,7 +4,6 @@
 using System.Linq.Expressions;
 using System.Reflection;
 using HotChocolate.Language;
-using HotChocolate.Properties;
 using HotChocolate.Types.Descriptors.Definitions;
 using HotChocolate.Utilities;
 using static HotChocolate.Properties.TypeResources;
@@ -176,7 +175,7 @@ public IObjectTypeDescriptor Interface<TInterface>()
             if (typeof(TInterface) == typeof(InterfaceType))
             {
                 throw new ArgumentException(
-                    TypeResources.ObjectTypeDescriptor_InterfaceBaseClass);
+                    ObjectTypeDescriptor_InterfaceBaseClass);
             }
 
             Definition.Interfaces.Add(
@@ -269,7 +268,7 @@ public IObjectFieldDescriptor Field(NameString name)
             {
                 ObjectFieldDescriptor fieldDescriptor =
                     Fields.FirstOrDefault(t => t.Definition.Member == propertyOrMethod);
-                if (fieldDescriptor is { })
+                if (fieldDescriptor is not null)
                 {
                     return fieldDescriptor;
                 }

src/HotChocolate/Core/src/Types/Types/Directives/DeferDirective.cs

@@ -1,3 +1,5 @@
+#nullable enable
+
 namespace HotChocolate.Types
 {
     /// <summary>

src/HotChocolate/Core/src/Types/Types/Relay/IdSerializer.cs

@@ -204,7 +204,7 @@ public IdValue Deserialize(string serializedId)
 
                 Span<byte> decoded = serialized.Slice(0, bytesWritten);
 
-                NameString schemaName;
+                NameString schemaName = null;
 
                 if (decoded[0] == _schema)
                 {

src/HotChocolate/Core/src/Types/Types/Scalars/UrlType.cs

@@ -1,13 +1,13 @@
 using System;
+using System.Diagnostics.CodeAnalysis;
 using HotChocolate.Language;
 using HotChocolate.Properties;
 
 #nullable enable
 
 namespace HotChocolate.Types
 {
-    public sealed class UrlType
-        : ScalarType<Uri, StringValueNode>
+    public sealed class UrlType : ScalarType<Uri, StringValueNode>
     {
         /// <summary>
         /// Initializes a new instance of the <see cref="UrlType"/> class.
@@ -41,7 +41,7 @@ protected override bool IsInstanceOfType(StringValueNode valueSyntax)
 
         protected override Uri ParseLiteral(StringValueNode valueSyntax)
         {
-            if (TryParseUri(valueSyntax.Value, out Uri uri))
+            if (TryParseUri(valueSyntax.Value, out Uri? uri))
             {
                 return uri;
             }
@@ -53,7 +53,7 @@ protected override Uri ParseLiteral(StringValueNode valueSyntax)
 
         protected override StringValueNode ParseValue(Uri runtimeValue)
         {
-            return new StringValueNode(runtimeValue.AbsoluteUri);
+            return new(runtimeValue.AbsoluteUri);
         }
 
         public override IValueNode ParseResult(object? resultValue)
@@ -104,7 +104,7 @@ public override bool TryDeserialize(object? resultValue, out object? runtimeValu
                 return true;
             }
 
-            if (resultValue is string s && TryParseUri(s, out Uri uri))
+            if (resultValue is string s && TryParseUri(s, out Uri? uri))
             {
                 runtimeValue = uri;
                 return true;
@@ -120,7 +120,7 @@ public override bool TryDeserialize(object? resultValue, out object? runtimeValu
             return false;
         }
 
-        private bool TryParseUri(string value, out Uri uri) =>
+        private bool TryParseUri(string value, [NotNullWhen(true)] out Uri? uri) =>
             Uri.TryCreate(value, UriKind.Absolute, out uri);
     }
 }

src/HotChocolate/Filters/src/Types.Filters/Expressions/FilterExpressionBuilder.cs

@@ -82,7 +82,7 @@ public static Expression Not(Expression expression)
             return Expression.Call(
                 typeof(Enumerable),
                 nameof(Enumerable.Contains),
-                new Type[] { genericType },
+                new[] { genericType },
                 Expression.Constant(parsedValue),
                 property);
         }

src/HotChocolate/Filters/src/Types.Filters/Expressions/OperationHandlers/Comparable/ComparableInOperationHandler.cs

@@ -51,7 +51,7 @@ public sealed class ComparableInOperationHandler
 
             object ParseValue()
             {
-                var parsedValue = type.ParseLiteral(value);
+                object? parsedValue = type.ParseLiteral(value);
                 Type elementType = type.ElementType().ToRuntimeType();
 
                 if (operation.Property.PropertyType != elementType)

src/HotChocolate/Filters/src/Types.Filters/Expressions/OperationHandlers/Comparable/ComparableOperationHandlerBase.cs

@@ -38,7 +38,7 @@ public abstract class ComparableOperationHandlerBase
             object ParseValue()
             {
 
-                var parsedValue = type.ParseLiteral(value);
+                object? parsedValue = type.ParseLiteral(value);
 
                 if (!operation.Property.PropertyType.IsInstanceOfType(parsedValue))
                 {

src/HotChocolate/Filters/src/Types.Filters/Expressions/OperationHandlers/String/StringOperationHandlerBase.cs

@@ -17,7 +17,7 @@ public abstract class StringOperationHandlerBase
             if (operation.Type == typeof(string) &&
                     type.IsInstanceOfType(value))
             {
-                object parsedValue = type.ParseLiteral(value);
+                object? parsedValue = type.ParseLiteral(value);
 
                 Expression property = context.GetInstance();