Some small fixes

src/HotChocolate/Language/src/Language.SyntaxTree/OptionalModifierNode.cs

@@ -111,7 +111,7 @@ public override bool Equals(object? obj)
     /// hashing algorithms and data structures such as a hash table.
     /// </returns>
     public override int GetHashCode()
-       => HashCode.Combine(Kind, Element?.GetHashCode());
+       => HashCode.Combine(Kind, Element);
 
     public static bool operator ==(
         OptionalModifierNode? left,

src/HotChocolate/Language/src/Language.SyntaxTree/ScalarTypeDefinitionNode.cs

@@ -7,7 +7,7 @@ namespace HotChocolate.Language;
 /// <summary>
 /// <para>Represents the scalar definition syntax.</para>
 /// <para>
-/// Scalar types represent primitive leaf values in a GraphQL type system. 
+/// Scalar types represent primitive leaf values in a GraphQL type system.
 /// GraphQL responses take the form of a hierarchical tree;
 /// the leaves of this tree are typically GraphQL Scalar types
 /// (but may also be Enum types or null values).
@@ -182,7 +182,7 @@ public override bool Equals(object? obj)
     /// hashing algorithms and data structures such as a hash table.
     /// </returns>
     public override int GetHashCode()
-       => HashCode.Combine(base.GetHashCode(), Kind, Description?.GetHashCode());
+       => HashCode.Combine(base.GetHashCode(), Kind, Description);
 
     /// <summary>
     /// The equal operator.

src/HotChocolate/Language/src/Language.SyntaxTree/SchemaDefinitionNode.cs

@@ -63,7 +63,7 @@ public IEnumerable<ISyntaxNode> GetNodes()
     public SchemaDefinitionNode WithLocation(Location? location)
     {
         return new SchemaDefinitionNode(
-            Location, Description, Directives, OperationTypes);
+            location, Description, Directives, OperationTypes);
     }
 
     public SchemaDefinitionNode WithDirectives(

src/HotChocolate/Language/src/Language.SyntaxTree/SchemaDefinitionNodeBase.cs

@@ -11,11 +11,14 @@ public abstract class SchemaDefinitionNodeBase
         IReadOnlyList<DirectiveNode> directives,
         IReadOnlyList<OperationTypeDefinitionNode> operationTypes)
     {
-        Location = location;
         Directives = directives
             ?? throw new ArgumentNullException(nameof(directives));
         OperationTypes = operationTypes
             ?? throw new ArgumentNullException(nameof(operationTypes));
+
+        Location = location;
+        Directives = directives;
+        OperationTypes = operationTypes;
     }
 
     public abstract SyntaxKind Kind { get; }

src/HotChocolate/Language/src/Language.SyntaxTree/SchemaExtensionNode.cs

@@ -54,7 +54,7 @@ public IEnumerable<ISyntaxNode> GetNodes()
     public SchemaExtensionNode WithLocation(Location? location)
     {
         return new SchemaExtensionNode(
-            Location, Directives, OperationTypes);
+            location, Directives, OperationTypes);
     }
 
     public SchemaExtensionNode WithDirectives(

src/HotChocolate/Language/src/Language.SyntaxTree/SelectionSetNode.cs

@@ -60,11 +60,6 @@ public SelectionSetNode WithLocation(Location? location)
     public SelectionSetNode WithSelections(
         IReadOnlyList<ISelectionNode> selections)
     {
-        if (selections == null)
-        {
-            throw new ArgumentNullException(nameof(selections));
-        }
-
         return new SelectionSetNode(
             Location, selections);
     }
@@ -77,8 +72,7 @@ public SelectionSetNode WithLocation(Location? location)
             throw new ArgumentNullException(nameof(selection));
         }
 
-        var selections = new List<ISelectionNode>(Selections);
-        selections.Add(selection);
+        var selections = new List<ISelectionNode>(Selections) { selection };
 
         return new SelectionSetNode(
             Location, selections);