Some more automated C# modernization in corelib

src/coreclr/System.Private.CoreLib/src/Internal/Runtime/InteropServices/ComActivator.cs

@@ -842,11 +842,7 @@ public string RequestLicKey(Type type)
 
             ((IDisposable?)parameters[2])?.Dispose();
 
-            var licenseKey = (string?)parameters[3];
-            if (licenseKey == null)
-            {
-                throw new COMException(); // E_FAIL
-            }
+            var licenseKey = (string?)parameters[3] ?? throw new COMException(); // E_FAIL
 
             return licenseKey;
         }

src/coreclr/System.Private.CoreLib/src/Internal/Runtime/InteropServices/InMemoryAssemblyLoader.cs

@@ -66,9 +66,7 @@ public static unsafe void LoadInMemoryAssemblyInContext(IntPtr moduleHandle, Int
         [RequiresUnreferencedCode("C++/CLI is not trim-compatible", Url = "https://aka.ms/dotnet-illink/nativehost")]
         private static void LoadInMemoryAssemblyInContextImpl(IntPtr moduleHandle, IntPtr assemblyPath, AssemblyLoadContext? alc = null)
         {
-            string? assemblyPathString = Marshal.PtrToStringUni(assemblyPath);
-            if (assemblyPathString == null)
-                throw new ArgumentOutOfRangeException(nameof(assemblyPath));
+            string assemblyPathString = Marshal.PtrToStringUni(assemblyPath) ?? throw new ArgumentOutOfRangeException(nameof(assemblyPath));
 
             // We don't cache the ALCs or resolvers here since each IJW assembly will call this method at most once
             // (the load process rewrites the stubs that call here to call the actual methods they're supposed to)

src/coreclr/System.Private.CoreLib/src/System/Delegate.CoreCLR.cs

@@ -61,7 +61,7 @@ protected Delegate([DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.Al
 
             if (target.ContainsGenericParameters)
                 throw new ArgumentException(SR.Arg_UnboundGenParam, nameof(target));
-            if (!(target is RuntimeType rtTarget))
+            if (target is not RuntimeType rtTarget)
                 throw new ArgumentException(SR.Argument_MustBeRuntimeType, nameof(target));
 
             // This API existed in v1/v1.1 and only expected to create open
@@ -130,7 +130,7 @@ public override bool Equals([NotNullWhen(true)] object? obj)
 
             // method ptrs don't match, go down long path
             //
-            if (_methodBase == null || d._methodBase == null || !(_methodBase is MethodInfo) || !(d._methodBase is MethodInfo))
+            if (_methodBase == null || d._methodBase == null || _methodBase is not MethodInfo || d._methodBase is not MethodInfo)
                 return InternalEqualMethodHandles(this, d);
             else
                 return _methodBase.Equals(d._methodBase);
@@ -156,7 +156,7 @@ public override int GetHashCode()
 
         protected virtual MethodInfo GetMethodImpl()
         {
-            if ((_methodBase == null) || !(_methodBase is MethodInfo))
+            if ((_methodBase == null) || _methodBase is not MethodInfo)
             {
                 IRuntimeMethodInfo method = FindMethodHandle();
                 RuntimeType? declaringType = RuntimeMethodHandle.GetDeclaringType(method);
@@ -219,7 +219,7 @@ protected virtual MethodInfo GetMethodImpl()
             ArgumentNullException.ThrowIfNull(target);
             ArgumentNullException.ThrowIfNull(method);
 
-            if (!(type is RuntimeType rtType))
+            if (type is not RuntimeType rtType)
                 throw new ArgumentException(SR.Argument_MustBeRuntimeType, nameof(type));
             if (!rtType.IsDelegate())
                 throw new ArgumentException(SR.Arg_MustBeDelegate, nameof(type));
@@ -256,9 +256,9 @@ protected virtual MethodInfo GetMethodImpl()
 
             if (target.ContainsGenericParameters)
                 throw new ArgumentException(SR.Arg_UnboundGenParam, nameof(target));
-            if (!(type is RuntimeType rtType))
+            if (type is not RuntimeType rtType)
                 throw new ArgumentException(SR.Argument_MustBeRuntimeType, nameof(type));
-            if (!(target is RuntimeType rtTarget))
+            if (target is not RuntimeType rtTarget)
                 throw new ArgumentException(SR.Argument_MustBeRuntimeType, nameof(target));
 
             if (!rtType.IsDelegate())
@@ -289,10 +289,10 @@ protected virtual MethodInfo GetMethodImpl()
             ArgumentNullException.ThrowIfNull(type);
             ArgumentNullException.ThrowIfNull(method);
 
-            if (!(type is RuntimeType rtType))
+            if (type is not RuntimeType rtType)
                 throw new ArgumentException(SR.Argument_MustBeRuntimeType, nameof(type));
 
-            if (!(method is RuntimeMethodInfo rmi))
+            if (method is not RuntimeMethodInfo rmi)
                 throw new ArgumentException(SR.Argument_MustBeRuntimeMethodInfo, nameof(method));
 
             if (!rtType.IsDelegate())
@@ -324,10 +324,10 @@ protected virtual MethodInfo GetMethodImpl()
             ArgumentNullException.ThrowIfNull(type);
             ArgumentNullException.ThrowIfNull(method);
 
-            if (!(type is RuntimeType rtType))
+            if (type is not RuntimeType rtType)
                 throw new ArgumentException(SR.Argument_MustBeRuntimeType, nameof(type));
 
-            if (!(method is RuntimeMethodInfo rmi))
+            if (method is not RuntimeMethodInfo rmi)
                 throw new ArgumentException(SR.Argument_MustBeRuntimeMethodInfo, nameof(method));
 
             if (!rtType.IsDelegate())
@@ -362,7 +362,7 @@ internal static Delegate CreateDelegateNoSecurityCheck(Type type, object? target
             if (method.IsNullHandle())
                 throw new ArgumentNullException(nameof(method));
 
-            if (!(type is RuntimeType rtType))
+            if (type is not RuntimeType rtType)
                 throw new ArgumentException(SR.Argument_MustBeRuntimeType, nameof(type));
 
             if (!rtType.IsDelegate())

src/coreclr/System.Private.CoreLib/src/System/MulticastDelegate.CoreCLR.cs

@@ -225,7 +225,7 @@ protected sealed override Delegate CombineImpl(Delegate? follow)
                 followCount = (int)dFollow._invocationCount;
 
             int resultCount;
-            if (!(_invocationList is object[] invocationList))
+            if (_invocationList is not object[] invocationList)
             {
                 resultCount = 1 + followCount;
                 resultList = new object[resultCount];
@@ -335,9 +335,9 @@ private static bool EqualInvocationLists(object[] a, object[] b, int start, int
 
             if (v == null)
                 return this;
-            if (!(v._invocationList is object[]))
+            if (v._invocationList is not object[])
             {
-                if (!(_invocationList is object[] invocationList))
+                if (_invocationList is not object[] invocationList)
                 {
                     // they are both not real Multicast
                     if (this.Equals(value))
@@ -401,7 +401,7 @@ private static bool EqualInvocationLists(object[] a, object[] b, int start, int
         public sealed override Delegate[] GetInvocationList()
         {
             Delegate[] del;
-            if (!(_invocationList is object[] invocationList))
+            if (_invocationList is not object[] invocationList)
             {
                 del = new Delegate[1];
                 del[0] = this;
@@ -418,12 +418,12 @@ public sealed override Delegate[] GetInvocationList()
             return del;
         }
 
-        internal new bool HasSingleTarget => !(_invocationList is object[]);
+        internal new bool HasSingleTarget => _invocationList is not object[];
 
         // Used by delegate invocation list enumerator
         internal object? /* Delegate? */ TryGetAt(int index)
         {
-            if (!(_invocationList is object[] invocationList))
+            if (_invocationList is not object[] invocationList)
             {
                 return (index == 0) ? this : null;
             }
@@ -447,7 +447,7 @@ public sealed override int GetHashCode()
                 }
             }
 
-            if (!(_invocationList is object[] invocationList))
+            if (_invocationList is not object[] invocationList)
             {
                 return base.GetHashCode();
             }
@@ -515,7 +515,7 @@ protected override MethodInfo GetMethodImpl()
             {
                 // we handle unmanaged function pointers here because the generic ones (used for WinRT) would otherwise
                 // be treated as open delegates by the base implementation, resulting in failure to get the MethodInfo
-                if ((_methodBase == null) || !(_methodBase is MethodInfo))
+                if ((_methodBase == null) || _methodBase is not MethodInfo)
                 {
                     IRuntimeMethodInfo method = FindMethodHandle();
                     RuntimeType declaringType = RuntimeMethodHandle.GetDeclaringType(method);

src/coreclr/System.Private.CoreLib/src/System/Reflection/Emit/CustomAttributeBuilder.cs

@@ -130,9 +130,7 @@ public CustomAttributeBuilder(ConstructorInfo con, object?[] constructorArgs, Pr
             for (i = 0; i < namedProperties.Length; i++)
             {
                 // Validate the property.
-                PropertyInfo property = namedProperties[i];
-                if (property == null)
-                    throw new ArgumentNullException("namedProperties[" + i + "]");
+                PropertyInfo property = namedProperties[i] ?? throw new ArgumentNullException($"namedProperties[{i}]");
 
                 // Allow null for non-primitive types only.
                 Type propType = property.PropertyType;
@@ -150,7 +148,7 @@ public CustomAttributeBuilder(ConstructorInfo con, object?[] constructorArgs, Pr
 
                 // Property has to be from the same class or base class as ConstructorInfo.
                 if (property.DeclaringType != con.DeclaringType
-                    && (!(con.DeclaringType is TypeBuilderInstantiation))
+                    && (con.DeclaringType is not TypeBuilderInstantiation)
                     && !con.DeclaringType!.IsSubclassOf(property.DeclaringType!))
                 {
                     // Might have failed check because one type is a XXXBuilder
@@ -162,7 +160,7 @@ public CustomAttributeBuilder(ConstructorInfo con, object?[] constructorArgs, Pr
                         // the constructor is a TypeBuilder, but we still need
                         // to deal with the case where the property's declaring
                         // type is one.
-                        if (!(property.DeclaringType is TypeBuilder) ||
+                        if (property.DeclaringType is not TypeBuilder ||
                             !con.DeclaringType.IsSubclassOf(((RuntimeTypeBuilder)property.DeclaringType).BakedRuntimeType))
                             throw new ArgumentException(SR.Argument_BadPropertyForConstructorBuilder);
                     }
@@ -188,9 +186,7 @@ public CustomAttributeBuilder(ConstructorInfo con, object?[] constructorArgs, Pr
             for (i = 0; i < namedFields.Length; i++)
             {
                 // Validate the field.
-                FieldInfo namedField = namedFields[i];
-                if (namedField == null)
-                    throw new ArgumentNullException("namedFields[" + i + "]");
+                FieldInfo namedField = namedFields[i] ?? throw new ArgumentNullException($"namedFields[{i}]");
 
                 // Allow null for non-primitive types only.
                 Type fldType = namedField.FieldType;
@@ -204,7 +200,7 @@ public CustomAttributeBuilder(ConstructorInfo con, object?[] constructorArgs, Pr
 
                 // Field has to be from the same class or base class as ConstructorInfo.
                 if (namedField.DeclaringType != con.DeclaringType
-                    && (!(con.DeclaringType is TypeBuilderInstantiation))
+                    && (con.DeclaringType is not TypeBuilderInstantiation)
                     && !con.DeclaringType!.IsSubclassOf(namedField.DeclaringType!))
                 {
                     // Might have failed check because one type is a XXXBuilder
@@ -216,7 +212,7 @@ public CustomAttributeBuilder(ConstructorInfo con, object?[] constructorArgs, Pr
                         // the constructor is a TypeBuilder, but we still need
                         // to deal with the case where the field's declaring
                         // type is one.
-                        if (!(namedField.DeclaringType is TypeBuilder) ||
+                        if (namedField.DeclaringType is not TypeBuilder ||
                             !con.DeclaringType.IsSubclassOf(((RuntimeTypeBuilder)namedFields[i].DeclaringType!).BakedRuntimeType))
                             throw new ArgumentException(SR.Argument_BadFieldForConstructorBuilder);
                     }
@@ -255,20 +251,11 @@ private static bool ValidateType(Type t)
             }
             if (t.IsEnum)
             {
-                switch (Type.GetTypeCode(Enum.GetUnderlyingType(t)))
-                {
-                    case TypeCode.SByte:
-                    case TypeCode.Byte:
-                    case TypeCode.Int16:
-                    case TypeCode.UInt16:
-                    case TypeCode.Int32:
-                    case TypeCode.UInt32:
-                    case TypeCode.Int64:
-                    case TypeCode.UInt64:
-                        return true;
-                    default:
-                        return false;
-                }
+                return Type.GetTypeCode(Enum.GetUnderlyingType(t)) is
+                    TypeCode.SByte or TypeCode.Byte or
+                    TypeCode.Int16 or TypeCode.UInt16 or
+                    TypeCode.Int32 or TypeCode.UInt32 or
+                    TypeCode.Int64 or TypeCode.UInt64;
             }
             if (t.IsArray)
             {
@@ -429,8 +416,7 @@ private static void EmitValue(BinaryWriter writer, Type type, object? value)
                     writer.Write((byte)0xff);
                 else
                 {
-                    string? typeName = TypeNameBuilder.ToString((Type)value, TypeNameBuilder.Format.AssemblyQualifiedName);
-                    if (typeName == null)
+                    string typeName = TypeNameBuilder.ToString((Type)value, TypeNameBuilder.Format.AssemblyQualifiedName) ??
                         throw new ArgumentException(SR.Format(SR.Argument_InvalidTypeForCA, value.GetType()));
                     EmitString(writer, typeName);
                 }

src/coreclr/System.Private.CoreLib/src/System/Reflection/Emit/DynamicILGenerator.cs

@@ -35,16 +35,13 @@ internal void GetCallableMethod(RuntimeModule module, DynamicMethod dm)
         public override LocalBuilder DeclareLocal(Type localType, bool pinned)
         {
             ArgumentNullException.ThrowIfNull(localType);
-
-            RuntimeLocalBuilder localBuilder;
-
-            RuntimeType? rtType = localType as RuntimeType;
-
-            if (rtType == null)
+            if (localType is not RuntimeType)
+            {
                 throw new ArgumentException(SR.Argument_MustBeRuntimeType);
+            }
 
-            localBuilder = new RuntimeLocalBuilder(m_localCount, localType, m_methodBuilder, pinned);
             // add the localType to local signature
+            RuntimeLocalBuilder localBuilder = new RuntimeLocalBuilder(m_localCount, localType, m_methodBuilder, pinned);
             m_localSignature.AddArgument(localType, pinned);
             m_localCount++;
             return localBuilder;
@@ -64,10 +61,7 @@ public override void Emit(OpCode opcode, MethodInfo meth)
             DynamicMethod? dynMeth = meth as DynamicMethod;
             if (dynMeth == null)
             {
-                RuntimeMethodInfo? rtMeth = meth as RuntimeMethodInfo;
-                if (rtMeth == null)
-                    throw new ArgumentException(SR.Argument_MustBeRuntimeMethodInfo, nameof(meth));
-
+                RuntimeMethodInfo rtMeth = meth as RuntimeMethodInfo ?? throw new ArgumentException(SR.Argument_MustBeRuntimeMethodInfo, nameof(meth));
                 RuntimeType declaringType = rtMeth.GetRuntimeType();
                 if (declaringType != null && (declaringType.IsGenericType || declaringType.IsArray))
                     token = GetTokenFor(rtMeth, declaringType);
@@ -112,10 +106,7 @@ public override void Emit(OpCode opcode, ConstructorInfo con)
         {
             ArgumentNullException.ThrowIfNull(con);
 
-            RuntimeConstructorInfo? rtConstructor = con as RuntimeConstructorInfo;
-            if (rtConstructor == null)
-                throw new ArgumentException(SR.Argument_MustBeRuntimeMethodInfo, nameof(con));
-
+            RuntimeConstructorInfo rtConstructor = con as RuntimeConstructorInfo ?? throw new ArgumentException(SR.Argument_MustBeRuntimeMethodInfo, nameof(con));
             RuntimeType declaringType = rtConstructor.GetRuntimeType();
             int token;
 
@@ -137,11 +128,7 @@ public override void Emit(OpCode opcode, Type type)
         {
             ArgumentNullException.ThrowIfNull(type);
 
-            RuntimeType? rtType = type as RuntimeType;
-
-            if (rtType == null)
-                throw new ArgumentException(SR.Argument_MustBeRuntimeType);
-
+            RuntimeType rtType = type as RuntimeType ?? throw new ArgumentException(SR.Argument_MustBeRuntimeType);
             int token = GetTokenFor(rtType);
             EnsureCapacity(7);
             InternalEmit(opcode);
@@ -152,10 +139,7 @@ public override void Emit(OpCode opcode, FieldInfo field)
         {
             ArgumentNullException.ThrowIfNull(field);
 
-            RuntimeFieldInfo? runtimeField = field as RuntimeFieldInfo;
-            if (runtimeField == null)
-                throw new ArgumentException(SR.Argument_MustBeRuntimeFieldInfo, nameof(field));
-
+            RuntimeFieldInfo runtimeField = field as RuntimeFieldInfo ?? throw new ArgumentException(SR.Argument_MustBeRuntimeFieldInfo, nameof(field));
             int token;
             if (field.DeclaringType == null)
                 token = GetTokenFor(runtimeField);
@@ -280,7 +264,7 @@ public override void EmitCall(OpCode opcode, MethodInfo methodInfo, Type[]? opti
             stackchange -= methodInfo.GetParameterTypes().Length;
             // Pop the this parameter if the method is non-static and the
             // instruction is not newobj.
-            if (!(methodInfo is SymbolMethod) && !methodInfo.IsStatic && !opcode.Equals(OpCodes.Newobj))
+            if (methodInfo is not SymbolMethod && !methodInfo.IsStatic && !opcode.Equals(OpCodes.Newobj))
                 stackchange--;
             // Pop the optional parameters off the stack.
             if (optionalParameterTypes != null)
@@ -783,11 +767,7 @@ internal override void ResolveToken(int token, out IntPtr typeHandle, out IntPtr
             methodHandle = default;
             fieldHandle = default;
 
-            object? handle = m_scope[token];
-
-            if (handle == null)
-                throw new InvalidProgramException();
-
+            object handle = m_scope[token] ?? throw new InvalidProgramException();
             if (handle is RuntimeTypeHandle)
             {
                 typeHandle = ((RuntimeTypeHandle)handle).Value;
@@ -1010,7 +990,7 @@ internal int GetTokenFor(VarArgMethod varArgMethod)
             if (fromMethod == 0)
                 return (byte[]?)this[token];
 
-            if (!(this[token] is VarArgMethod vaMethod))
+            if (this[token] is not VarArgMethod vaMethod)
                 return null;
 
             return vaMethod.m_signature.GetSignature(true);