Updated to use is / is not for null comparisons

Author: FlorianRappl

src/Mages.Core.Tests/ExtensibilityTests.cs

@@ -561,7 +561,7 @@ public void FunctionTakingComplexObjectShouldBeUnwrappedIfSpecified()
         {
             var engine = new Engine();
             engine.SetStatic(typeof(WrapUnwrapTest)).WithName("Test");
-            var func = new Func<WrapUnwrapTest, Boolean>((obj) => obj != null);
+            var func = new Func<WrapUnwrapTest, Boolean>((obj) => obj is not null);
             engine.SetFunction("verify", func.Method, func.Target);
 
             var result = engine.Interpret("x = Test.create(); verify(x)");

src/Mages.Core.Tests/InvalidInputTests.cs

@@ -279,7 +279,7 @@ private static ParameterDefinition Po(String v)
 
         private static ParameterDefinition P(String v, Boolean r)
         {
-            if (v != null)
+            if (v is not null)
             {
                 return new ParameterDefinition(v, r);
             }

src/Mages.Core.Tests/Mages.Core.Tests.csproj

@@ -6,6 +6,7 @@
     <AppDesignerFolder>Properties</AppDesignerFolder>
     <RootNamespace>Mages.Core.Tests</RootNamespace>
     <AssemblyName>Mages.Core.Tests</AssemblyName>
+    <LangVersion>latest</LangVersion>
     <ApplicationIcon />
     <StartupObject />
     <Platforms>x64</Platforms>

src/Mages.Core.Tests/ObservableTests.cs

@@ -65,7 +65,7 @@ public void ClearObservableDictionaryEmitsEvents()
             var keys = new List<String>();
             obs.Changed += (s, ev) => 
             {
-                if (ev.NewValue == null && ev.OldValue != null)
+                if (ev.NewValue is null && ev.OldValue is not null)
                 {
                     keys.Add(ev.Key);
                 }

src/Mages.Core/Ast/ExpressionParser.cs

@@ -639,7 +639,7 @@ private IExpression ParsePower(IEnumerator<IToken> tokens)
                     var x = ParseUnary(tokens);
                     expressions.Push(x);
                 }
-                while (tokens.Current.Type == TokenType.Power && tokens.NextNonIgnorable() != null);
+                while (tokens.Current.Type == TokenType.Power && tokens.NextNonIgnorable() is not null);
 
                 do
                 {
@@ -1247,7 +1247,7 @@ private static ConstantExpression ParseNumber(IEnumerator<IToken> tokens)
     private static ParameterExpression GetParameters(IExpression x)
     {
         var args = x as ArgumentsExpression;
-        return args != null ?
+        return args is not null ?
             new ParameterExpression(args.Arguments, args.Start, args.End) :
             new ParameterExpression([x], x.Start, x.End);
     }

src/Mages.Core/Ast/Expressions/AssignmentExpression.cs

@@ -30,10 +30,8 @@ public sealed class AssignmentExpression(IExpression variable, IExpression value
     public String VariableName 
     {
         get 
-        { 
-            var variable = Variable as VariableExpression;
-
-            if (variable != null)
+        {
+            if (Variable is VariableExpression variable)
             {
                 return variable.Name;
             }

src/Mages.Core/Ast/Expressions/DeleteExpression.cs

@@ -46,7 +46,7 @@ public void Validate(IValidationContext context)
         var member = _payload as MemberExpression;
         var isIdentifier = _payload is VariableExpression;
 
-        if (member != null)
+        if (member is not null)
         {
             expression = member.Member;
             isIdentifier = expression is IdentifierExpression;

src/Mages.Core/Ast/Expressions/ParameterExpression.cs

@@ -34,14 +34,14 @@ public ParameterDefinition[] Names
             {
                 var identifier = _parameters[i] as VariableExpression;
                 var assignment = _parameters[i] as AssignmentExpression;
-                var required = assignment == null;
+                var required = assignment is null;
 
                 if (!required)
                 {
                     identifier = assignment.Variable as VariableExpression;
                 }
 
-                if (identifier != null)
+                if (identifier is not null)
                 {
                     names[i] = new ParameterDefinition(identifier.Name, required);
                 }
@@ -86,7 +86,7 @@ public void Validate(IValidationContext context)
             {
                 var assignment = (AssignmentExpression)parameter;
 
-                if (assignment.VariableName == null)
+                if (assignment.VariableName is null)
                 {
                     var error = new ParseError(ErrorCode.OptionalArgumentRequired, parameter);
                     context.Report(error);

src/Mages.Core/Ast/StatementExtensions.cs

@@ -81,7 +81,7 @@ public static IOperation[] MakeRunnable(this IEnumerable<IStatement> statements)
     public static Boolean IsEmpty(this IStatement statement)
     {
         var simple = statement as SimpleStatement;
-        return simple != null && simple.Expression.IsEmpty();
+        return simple is not null && simple.Expression.IsEmpty();
     }
 
     /// <summary>

src/Mages.Core/Ast/Statements/VarStatement.cs

@@ -38,11 +38,11 @@ public void Validate(IValidationContext context)
     {
         var assignment = _assignment as AssignmentExpression;
 
-        if (assignment == null)
+        if (assignment is null)
         {
             //TODO Report invalid construction
         }
-        else if (assignment.VariableName == null)
+        else if (assignment.VariableName is null)
         {
             //TODO Report invalid construction
         }

src/Mages.Core/Ast/Walkers/CompletionTreeWalker.cs

@@ -88,13 +88,13 @@ public override void Visit(VarStatement statement)
     {
         var assignment = statement.Assignment as AssignmentExpression;
 
-        if (assignment != null)
+        if (assignment is not null)
         {
             var c = _variables.Count - 1;
             var variables = _variables[c];
             var variable = assignment.VariableName;
 
-            if (variable != null && !variables.Contains(variable))
+            if (variable is not null && !variables.Contains(variable))
             {
                 variables.Add(variable);
             }
@@ -148,7 +148,7 @@ public override void Visit(AssignmentExpression expression)
     {
         var name = expression.VariableName;
 
-        if (name != null)
+        if (name is not null)
         {
             var c = _variables.Count - 1;
 
@@ -186,7 +186,7 @@ public override void Visit(ParameterExpression expression)
         {
             var variable = parameter as VariableExpression;
 
-            if (variable != null)
+            if (variable is not null)
             {
                 var variables = _variables[_variables.Count - 1];
 
@@ -243,13 +243,13 @@ public override void Visit(MemberExpression expression)
             var prefix = String.Empty;
             var obj = Resolve(expression.Object);
 
-            if (member != null)
+            if (member is not null)
             {
                 var length = _position.Index - member.Start.Index;
                 prefix = member.Name.Substring(0, length);
             }
 
-            if (obj != null)
+            if (obj is not null)
             {
                 AddSuggestions(prefix, obj.Select(m => m.Key));
             }
@@ -273,11 +273,11 @@ private IDictionary<String, Object> Resolve(IExpression expression)
         var host = _symbols;
         var name = default(String);
 
-        if (member != null)
+        if (member is not null)
         {
             var child = member.Member as IdentifierExpression;
 
-            if (child != null)
+            if (child is not null)
             {
                 host = Resolve(member.Object);
                 name = child.Name;
@@ -287,13 +287,13 @@ private IDictionary<String, Object> Resolve(IExpression expression)
         {
             var variable = expression as VariableExpression;
 
-            if (variable != null)
+            if (variable is not null)
             {
                 name = variable.Name;
             }
         }
 
-        if (!String.IsNullOrEmpty(name) && host != null)
+        if (!String.IsNullOrEmpty(name) && host is not null)
         {
             host.TryGetValue(name, out value);
             return value as IDictionary<String, Object>;

src/Mages.Core/Ast/Walkers/SymbolTreeWalker.cs

@@ -120,12 +120,12 @@ public override void Visit(VariableExpression expression)
     {
         var list = Find(expression.Name, expression.Scope);
 
-        if (list == null && _assigning)
+        if (list is null && _assigning)
         {
             list = [expression];
             _collector[expression] = list;
         }
-        else if (list != null)
+        else if (list is not null)
         {
             list.Add(expression);
         }

src/Mages.Core/Ast/Walkers/ValidationTreeWalker.cs

@@ -24,7 +24,7 @@ public sealed class ValidationTreeWalker(List<ParseError> errors) : ITreeWalker,
 
     #region Properties
 
-    Boolean IValidationContext.IsInLoop => _loops.Count != 0 && _loops.Peek() != null;
+    Boolean IValidationContext.IsInLoop => _loops.Count != 0 && _loops.Peek() is not null;
 
     #endregion
 

src/Mages.Core/EngineExtensions.cs

@@ -101,7 +101,7 @@ public static IPlacement SetStatic(this Engine engine, Assembly lib, Predicate<T
 
         foreach (var type in types)
         {
-            if (shouldInclude == null || shouldInclude.Invoke(type))
+            if (shouldInclude is null || shouldInclude.Invoke(type))
             {
                 var name = obj.Keys.FindName(type);
                 var value = type.Expose();
@@ -203,7 +203,7 @@ public static Plugin AddPlugin(this Engine engine, Type type)
 
             var constructor = type.GetConstructor([typeof(Engine)]);
 
-            if (constructor != null)
+            if (constructor is not null)
             {
                 var obj = constructor.Invoke(new[] { engine });
                 var plugin = ConstructInstancePlugin(obj);
@@ -230,7 +230,7 @@ public static IEnumerable<Plugin> AddPlugins(this Engine engine, Assembly assemb
         {
             var plugin = engine.AddPlugin(type);
 
-            if (plugin != null)
+            if (plugin is not null)
             {
                 plugins.Add(plugin);
             }

src/Mages.Core/Function.cs

@@ -30,7 +30,7 @@ public static Object Call(this Function function, params Object[] arguments)
         {
             var argument = arguments[i];
 
-            if (argument != null)
+            if (argument is not null)
             {
                 var from = argument.GetType();
                 var type = from.FindPrimitive();
@@ -92,7 +92,7 @@ public static String[] GetParameterNames(this Function function)
         var local = function.Target as LocalFunction;
         var parameters = local?.Parameters;
 
-        if (parameters == null)
+        if (parameters is null)
         {
             var nativeParams = function.Method.GetParameters();
             var parameterNames = new String[nativeParams.Length];

src/Mages.Core/Runtime/Container.cs

@@ -22,7 +22,7 @@ public static class Container
     /// <returns>The optional lifetime controlling instance.</returns>
     public static IDisposable Register<T>(T service)
     {
-        if (service != null && !_container.Contains(service))
+        if (service is not null && !_container.Contains(service))
         {
             _container.Add(service);
             return new ServiceLifeTime(service);

src/Mages.Core/Runtime/Converters/CamelNameSelector.cs

@@ -43,7 +43,7 @@ public String Select(IEnumerable<String> registered, MemberInfo member)
 
     private static String ConvertToCamelCase(String str)
     {
-        if (str != null)
+        if (str is not null)
         {
             if (str.Length > 1)
             {

src/Mages.Core/Runtime/Converters/ConverterExtensions.cs

@@ -157,7 +157,7 @@ public static IDictionary<String, Object> ToObject(this Object value)
         {
             var result = new Dictionary<String, Object>();
 
-            if (value != null)
+            if (value is not null)
             {
                 result["0"] = value;
             }

src/Mages.Core/Runtime/Converters/TypeConverterMap.cs

@@ -15,7 +15,7 @@ public Func<Object, Object> FindConverter(Type to)
 
             return obj =>
             {
-                if (obj != null)
+                if (obj is not null)
                 {
                     var converter = default(Func<Object, Object>);
                     var type = obj.GetType();
@@ -63,7 +63,7 @@ public Func<Object, Object> FindConverter(Type from, Type to)
                 var p = inv.GetParameters();
                 var t = TargetWrapper.Construct(inv.ReturnType, p);
 
-                if (t != null)
+                if (t is not null)
                 {
                     return obj =>
                     {

src/Mages.Core/Runtime/Functions/Curry.cs

@@ -82,12 +82,12 @@ public static Function Shuffle(Object[] args)
         var end = args.Length - 1;
         var target = args[end] as Function;
 
-        if (target != null)
+        if (target is not null)
         {
             var wrapper = target.Target as LocalFunction;
             var parameters = wrapper?.Parameters;
 
-            if (parameters != null)
+            if (parameters is not null)
             {
                 var indices = new Int32[parameters.Length];
                 var result = default(Function);
@@ -152,7 +152,7 @@ private static Int32 ShuffleParameters(Object[] args, ParameterDefinition[] para
         {
             var s = arg as String;
 
-            if (s != null)
+            if (s is not null)
             {
                 for (var j = 0; j < parameters.Length; j++)
                 {

src/Mages.Core/Runtime/Functions/SimpleRandom.cs

@@ -56,9 +56,6 @@ private static Int32 ToInteger(Double argument)
 
     private static void EnsureRandom()
     {
-        if (_random == null)
-        {
-            _random = new Random();
-        }
+        _random ??= new Random();
     }
 }

src/Mages.Core/Runtime/Helpers.cs

@@ -120,7 +120,7 @@ public static Boolean Satisfies(this IDictionary<String, Object> constraints, Ob
     {
         var obj = value as IDictionary<String, Object>;
 
-        if (obj != null && obj.Count >= constraints.Count)
+        if (obj is not null && obj.Count >= constraints.Count)
         {
             foreach (var constraint in constraints)
             {
@@ -129,8 +129,8 @@ public static Boolean Satisfies(this IDictionary<String, Object> constraints, Ob
                     var simple = constraint.Value as String;
                     var extended = constraint.Value as IDictionary<String, Object>;
 
-                    if ((simple == null || val.ToType()["name"].ToString() == simple) &&
-                        (extended == null || extended.Satisfies(val)))
+                    if ((simple is null || val.ToType()["name"].ToString() == simple) &&
+                        (extended is null || extended.Satisfies(val)))
                     {
                         continue;
                     }
@@ -367,7 +367,7 @@ public static Function WrapFunction(this MethodInfo method, Object target)
             {
                 var result = Curry.Min(parameters.Length, f, args);
 
-                if (result == null && method.TryMatch(parameters, ref args))
+                if (result is null && method.TryMatch(parameters, ref args))
                 {
                     result = method.Call(target, args);
                 }
@@ -390,7 +390,7 @@ public static Object WrapObject(this Object value)
             return new Future(task);
         }
 
-        if (value != null)
+        if (value is not null)
         {
             var type = value.GetType();
             var target = type.FindPrimitive();

src/Mages.Core/Runtime/JsonSerializer.cs

@@ -47,7 +47,7 @@ private void SerializeTo(IDictionary<String, Object> obj, StringBuilder buffer,
 
     private void SerializeTo(Object value, StringBuilder buffer, Int32 level)
     {
-        if (value == null)
+        if (value is null)
         {
             buffer.Append("null");
         }