Enable IDE0059 analyzer: Unnecessary assignment of a value (#63340)

Author: marek-safar

eng/CodeAnalysis.src.globalconfig

@@ -1444,7 +1444,7 @@ dotnet_diagnostic.IDE0057.severity = suggestion
 dotnet_diagnostic.IDE0058.severity = silent
 
 # IDE0059: Unnecessary assignment of a value
-dotnet_diagnostic.IDE0059.severity = suggestion
+dotnet_diagnostic.IDE0059.severity = warning
 
 # IDE0060: Remove unused parameter
 dotnet_diagnostic.IDE0060.severity = silent

src/coreclr/nativeaot/System.Private.CoreLib/src/System/Runtime/InteropServices/ComWrappers.CoreRT.cs

@@ -213,8 +213,6 @@ private unsafe IntPtr AsRuntimeDefined(in Guid riid)
                     {
                         return (IntPtr)(Dispatches + i);
                     }
-
-                    i++;
                 }
 
                 return IntPtr.Zero;

src/coreclr/nativeaot/System.Private.CoreLib/src/System/Threading/Thread.CoreRT.Windows.cs

@@ -200,11 +200,10 @@ private unsafe bool CreateThread(GCHandle thisThreadHandle)
                 stackSize = AllocationGranularity;
             }
 
-            uint threadId;
             _osHandle = Interop.Kernel32.CreateThread(IntPtr.Zero, (IntPtr)stackSize,
                 &ThreadEntryPoint, (IntPtr)thisThreadHandle,
                 Interop.Kernel32.CREATE_SUSPENDED | Interop.Kernel32.STACK_SIZE_PARAM_IS_A_RESERVATION,
-                out threadId);
+                out _);
 
             if (_osHandle.IsInvalid)
             {

src/coreclr/nativeaot/System.Private.Interop/src/Internal/Runtime/CompilerHelpers/RuntimeInteropData.CoreRT.cs

@@ -44,10 +44,9 @@ public override bool TryGetStructUnsafeStructSize(RuntimeTypeHandle structureTyp
 
         public override bool TryGetStructFieldOffset(RuntimeTypeHandle structureTypeHandle, string fieldName, out bool structExists, out uint offset)
         {
-            ExternalReferencesTable externalReferences;
             NativeParser entryParser;
             structExists = false;
-            if (TryGetStructData(structureTypeHandle, out externalReferences, out entryParser))
+            if (TryGetStructData(structureTypeHandle, out _, out entryParser))
             {
                 structExists = true;
 

src/coreclr/nativeaot/System.Private.Reflection.Core/src/System/ActivatorImplementation.cs

@@ -88,8 +88,7 @@ public static object CreateInstance(
             if (binder == null)
                 binder = Type.DefaultBinder;
 
-            object state = null;
-            MethodBase invokeMethod = binder.BindToMethod(bindingAttr, matches.ToArray(), ref args, null, culture, null, out state);
+            MethodBase invokeMethod = binder.BindToMethod(bindingAttr, matches.ToArray(), ref args, null, culture, null, out object state);
             if (invokeMethod.GetParametersNoCopy().Length == 0)
             {
                 if (args.Length != 0)

src/coreclr/nativeaot/System.Private.Reflection.Core/src/System/Reflection/Runtime/Assemblies/NativeFormat/NativeFormatRuntimeAssembly.GetTypeCore.CaseInsensitive.cs

@@ -99,8 +99,7 @@ private LowLevelDictionary<string, QHandle> CreateCaseInsensitiveTypeDictionary(
                     foreach (TypeDefinitionHandle typeDefinitionHandle in namespaceDefinition.TypeDefinitions)
                     {
                         string fullName = ns + typeDefinitionHandle.GetTypeDefinition(reader).Name.GetString(reader).ToLowerInvariant();
-                        QHandle existingValue;
-                        if (!dict.TryGetValue(fullName, out existingValue))
+                        if (!dict.TryGetValue(fullName, out _))
                         {
                             dict.Add(fullName, new QHandle(reader, typeDefinitionHandle));
                         }
@@ -109,8 +108,7 @@ private LowLevelDictionary<string, QHandle> CreateCaseInsensitiveTypeDictionary(
                     foreach (TypeForwarderHandle typeForwarderHandle in namespaceDefinition.TypeForwarders)
                     {
                         string fullName = ns + typeForwarderHandle.GetTypeForwarder(reader).Name.GetString(reader).ToLowerInvariant();
-                        QHandle existingValue;
-                        if (!dict.TryGetValue(fullName, out existingValue))
+                        if (!dict.TryGetValue(fullName, out _))
                         {
                             dict.Add(fullName, new QHandle(reader, typeForwarderHandle));
                         }

src/coreclr/nativeaot/System.Private.Reflection.Core/src/System/Reflection/Runtime/BindingFlagSupport/Shared.cs

@@ -149,11 +149,9 @@ public static bool QualifiesBasedOnParameterCount(this MethodBase methodBase, Bi
         public static M GetImplicitlyOverriddenBaseClassMember<M>(this M member) where M : MemberInfo
         {
             MemberPolicies<M> policies = MemberPolicies<M>.Default;
-            MethodAttributes visibility;
-            bool isStatic;
             bool isVirtual;
             bool isNewSlot;
-            policies.GetMemberAttributes(member, out visibility, out isStatic, out isVirtual, out isNewSlot);
+            policies.GetMemberAttributes(member, out _, out _, out isVirtual, out isNewSlot);
             if (isNewSlot || !isVirtual)
             {
                 return null;
@@ -174,11 +172,8 @@ public static M GetImplicitlyOverriddenBaseClassMember<M>(this M member) where M
                     {
                         continue;
                     }
-                    MethodAttributes candidateVisibility;
-                    bool isCandidateStatic;
                     bool isCandidateVirtual;
-                    bool isCandidateNewSlot;
-                    policies.GetMemberAttributes(member, out candidateVisibility, out isCandidateStatic, out isCandidateVirtual, out isCandidateNewSlot);
+                    policies.GetMemberAttributes(member, out _, out _, out isCandidateVirtual, out _);
                     if (!isCandidateVirtual)
                     {
                         continue;

src/coreclr/nativeaot/System.Private.Reflection.Core/src/System/Reflection/Runtime/CustomAttributes/RuntimeCustomAttributeData.cs

@@ -146,11 +146,10 @@ private static string ComputeTypedArgumentString(CustomAttributeTypedArgument ca
 
             else if (argumentType.IsArray)
             {
-                string result = null;
                 IList<CustomAttributeTypedArgument> array = value as IList<CustomAttributeTypedArgument>;
 
                 Type elementType = argumentType.GetElementType();
-                result = string.Format(@"new {0}[{1}] {{ ", elementType.IsEnum ? elementType.FullName : elementType.Name, array.Count);
+                string result = string.Format(@"new {0}[{1}] {{ ", elementType.IsEnum ? elementType.FullName : elementType.Name, array.Count);
 
                 for (int i = 0; i < array.Count; i++)
                     result += string.Format(i == 0 ? "{0}" : ", {0}", ComputeTypedArgumentString(array[i], elementType != typeof(object)));

src/coreclr/nativeaot/System.Private.Reflection.Core/src/System/Reflection/Runtime/General/NamespaceChain.cs

@@ -21,7 +21,7 @@ internal NamespaceChain(MetadataReader reader, NamespaceDefinitionHandle innerMo
         {
             NamespaceDefinition currentNamespaceDefinition = innerMostNamespaceHandle.GetNamespaceDefinition(reader);
             ConstantStringValueHandle currentNameHandle = currentNamespaceDefinition.Name;
-            Handle currentNamespaceHandle = innerMostNamespaceHandle.ToHandle(reader);
+            Handle currentNamespaceHandle;
             LowLevelList<string> names = new LowLevelList<string>();
             for (;;)
             {

src/coreclr/nativeaot/System.Private.Reflection.Core/src/System/Reflection/Runtime/General/ReflectionCoreCallbacksImplementation.cs

@@ -164,7 +164,6 @@ private FieldInfo GetFieldInfo(RuntimeTypeHandle declaringTypeHandle, FieldHandl
         {
             RuntimeTypeInfo contextTypeInfo = declaringTypeHandle.GetTypeForRuntimeTypeHandle();
             NativeFormatRuntimeNamedTypeInfo definingTypeInfo = contextTypeInfo.AnchoringTypeDefinitionForDeclaredMembers.CastToNativeFormatRuntimeNamedTypeInfo();
-            MetadataReader reader = definingTypeInfo.Reader;
 
             // RuntimeFieldHandles always yield FieldInfo's whose ReflectedType equals the DeclaringType.
             RuntimeTypeInfo reflectedType = contextTypeInfo;