Add more nullable type reference safeties

src/Serilog.Settings.Configuration/Settings/Configuration/Assemblies/DllScanningAssemblyFinder.cs

@@ -32,7 +32,11 @@ public override IReadOnlyList<AssemblyName> FindAssembliesContainingName(string
         }
         else
         {
-            probeDirs.Add(Path.GetDirectoryName(typeof(AssemblyFinder).Assembly.Location));
+            var assemblyLocation = Path.GetDirectoryName(typeof(AssemblyFinder).Assembly.Location);
+            if (assemblyLocation != null)
+            {
+                probeDirs.Add(assemblyLocation);
+            }
         }
 
         var query = from probeDir in probeDirs

src/Serilog.Settings.Configuration/Settings/Configuration/ConfigurationReader.cs

@@ -484,12 +484,12 @@ static bool HasImplicitValueWhenNotSpecified(ParameterInfo paramInfo)
         return selectedMethod;
     }
 
-    static bool ParameterNameMatches(string actualParameterName, string suppliedName)
+    static bool ParameterNameMatches(string? actualParameterName, string suppliedName)
     {
         return suppliedName.Equals(actualParameterName, StringComparison.OrdinalIgnoreCase);
     }
 
-    static bool ParameterNameMatches(string actualParameterName, IEnumerable<string> suppliedNames)
+    static bool ParameterNameMatches(string? actualParameterName, IEnumerable<string> suppliedNames)
     {
         return suppliedNames.Any(s => ParameterNameMatches(actualParameterName, s));
     }

src/Serilog.Settings.Configuration/Settings/Configuration/LoggingFilterSwitchProxy.cs

@@ -15,12 +15,12 @@ class LoggingFilterSwitchProxy
         _setProxy = (Action<string?>)Delegate.CreateDelegate(
             typeof(Action<string?>),
             realSwitch,
-            expressionProperty.GetSetMethod());
+            expressionProperty.GetSetMethod() ?? throw new MissingMethodException(type.FullName, "set_Expression"));
 
         _getProxy = (Func<string?>)Delegate.CreateDelegate(
             typeof(Func<string?>),
             realSwitch,
-            expressionProperty.GetGetMethod());
+            expressionProperty.GetGetMethod() ?? throw new MissingMethodException(type.FullName, "get_Expression"));
     }
 
     public object RealSwitch { get; }
@@ -42,6 +42,7 @@ public string? Expression
             return null;
         }
 
-        return new LoggingFilterSwitchProxy(Activator.CreateInstance(filterSwitchType, expression));
+        var realSwitch = Activator.CreateInstance(filterSwitchType, expression) ?? throw new InvalidOperationException($"Activator.CreateInstance returned null for {filterSwitchType}");
+        return new LoggingFilterSwitchProxy(realSwitch);
     }
 }

src/Serilog.Settings.Configuration/Settings/Configuration/ObjectArgumentValue.cs

@@ -85,7 +85,7 @@ bool TryCreateContainer([NotNullWhen(true)] out object? result)
                 return false;
 
             var configurationElements = _section.GetChildren().ToArray();
-            result = Activator.CreateInstance(toType);
+            result = Activator.CreateInstance(toType) ?? throw new InvalidOperationException($"Activator.CreateInstance returned null for {toType}");
 
             for (int i = 0; i < configurationElements.Length; ++i)
             {
@@ -137,7 +137,7 @@ internal static bool TryBuildCtorExpression(
         var ctor =
             (from c in type.GetConstructors()
              from p in c.GetParameters()
-             let argumentBindResult = suppliedArguments.TryGetValue(p.Name, out var argValue) switch
+             let argumentBindResult = suppliedArguments.TryGetValue(p.Name ?? "", out var argValue) switch
              {
                  true => new { success = true, hasMatch = true, value = (object?)argValue },
                  false => p.HasDefaultValue switch

src/Serilog.Settings.Configuration/Settings/Configuration/StringArgumentValue.cs

@@ -21,7 +21,7 @@ public StringArgumentValue(string providedValue)
         {
             { typeof(Uri), s => new Uri(s) },
             { typeof(TimeSpan), s => TimeSpan.Parse(s) },
-            { typeof(Type), s => Type.GetType(s, throwOnError:true) },
+            { typeof(Type), s => Type.GetType(s, throwOnError:true)! },
         };
 
     public object? ConvertTo(Type toType, ResolutionContext resolutionContext)
@@ -68,7 +68,7 @@ public StringArgumentValue(string providedValue)
             if (toType != typeof(string) &&
                 TryParseStaticMemberAccessor(argumentValue, out var accessorTypeName, out var memberName))
             {
-                var accessorType = Type.GetType(accessorTypeName, throwOnError: true);
+                var accessorType = Type.GetType(accessorTypeName, throwOnError: true)!;
 
                 // if delegate, look for a method and then construct a delegate
                 if (typeof(Delegate).IsAssignableFrom(toType) || typeof(MethodInfo) == toType)
@@ -109,9 +109,7 @@ public StringArgumentValue(string providedValue)
                 // is there a public static property with that name ?
                 var publicStaticPropertyInfo = accessorType.GetTypeInfo().DeclaredProperties
                     .Where(x => x.Name == memberName)
-                    .Where(x => x.GetMethod != null)
-                    .Where(x => x.GetMethod.IsPublic)
-                    .FirstOrDefault(x => x.GetMethod.IsStatic);
+                    .FirstOrDefault(x => x.GetMethod != null && x.GetMethod.IsPublic && x.GetMethod.IsStatic);
 
                 if (publicStaticPropertyInfo != null)
                 {