Nullable: System.Xml, part 6 (XSLT minus XSLT.Runtime)

src/libraries/System.Private.Xml/src/System/Xml/XPath/Internal/BooleanFunctions.cs

@@ -42,7 +42,7 @@ public override object Evaluate(XPathNodeIterator nodeIterator) =>
                 FT.FuncNot => Not(nodeIterator),
                 FT.FuncTrue => true,
                 FT.FuncFalse => false,
-                FT.FuncLang => Lang(nodeIterator),
+                FT.FuncLang => Lang(nodeIterator!),
                 _ => false,
             };
 

src/libraries/System.Private.Xml/src/System/Xml/XPath/Internal/CompiledXPathExpr.cs

@@ -162,7 +162,7 @@ internal sealed class XPathComparerHelper : IComparer
         private readonly CultureInfo _cinfo;
         private readonly XmlDataType _dataType;
 
-        public XPathComparerHelper(XmlSortOrder order, XmlCaseOrder caseOrder, string lang, XmlDataType dataType)
+        public XPathComparerHelper(XmlSortOrder order, XmlCaseOrder caseOrder, string? lang, XmlDataType dataType)
         {
             if (lang == null)
             {

src/libraries/System.Private.Xml/src/System/Xml/XPath/Internal/ContextQuery.cs

@@ -14,10 +14,12 @@ public ContextQuery()
         {
             this.count = 0;
         }
+
         protected ContextQuery(ContextQuery other) : base(other)
         {
             this.contextNode = other.contextNode;   // Don't need to clone here
         }
+
         public override void Reset()
         {
             count = 0;

src/libraries/System.Private.Xml/src/System/Xml/XPath/Internal/FunctionQuery.cs

@@ -82,7 +82,7 @@ public override object Evaluate(XPathNodeIterator nodeIterator)
             try
             {
                 Debug.Assert(_function != null);
-                object? retVal = ProcessResult(_function.Invoke(xsltContext, argVals, nodeIterator.Current));
+                object? retVal = ProcessResult(_function.Invoke(xsltContext, argVals, nodeIterator.Current!));
 
                 // ProcessResult may return null when the input value is XmlNode and here doesn't seem to be the case.
                 Debug.Assert(retVal != null);

src/libraries/System.Private.Xml/src/System/Xml/XPath/Internal/NumberFunctions.cs

@@ -59,7 +59,7 @@ private double Number(XPathNodeIterator nodeIterator)
         {
             if (_arg == null)
             {
-                Debug.Assert(nodeIterator.Current != null);
+                Debug.Assert(nodeIterator!.Current != null);
                 return XmlConvert.ToXPathDouble(nodeIterator.Current.Value);
             }
             object argVal = _arg.Evaluate(nodeIterator);

src/libraries/System.Private.Xml/src/System/Xml/XPath/Internal/StringFunctions.cs

@@ -212,7 +212,7 @@ private double StringLength(XPathNodeIterator nodeIterator)
             {
                 return _argList[0].Evaluate(nodeIterator).ToString()!.Length;
             }
-            Debug.Assert(nodeIterator.Current != null);
+            Debug.Assert(nodeIterator!.Current != null);
             return nodeIterator.Current.Value.Length;
         }
 
@@ -225,7 +225,7 @@ private string Normalize(XPathNodeIterator nodeIterator)
             }
             else
             {
-                Debug.Assert(nodeIterator.Current != null);
+                Debug.Assert(nodeIterator!.Current != null);
                 value = nodeIterator.Current.Value;
             }
             int modifyPos = -1;

src/libraries/System.Private.Xml/src/System/Xml/Xsl/ISourceLineInfo.cs

@@ -1,11 +1,12 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+#nullable enable
 namespace System.Xml.Xsl
 {
     internal interface ISourceLineInfo
     {
-        string Uri { get; }
+        string? Uri { get; }
         bool IsNoSource { get; }
         Location Start { get; }
         Location End { get; }