Clean up string formatting in a variety of places (#50267)

Mostly just replacing string.Format calls with equivalent interpolated string uses.  In some cases, I replaced lots of string creations with a StringBuilder or equivalent.

src/coreclr/System.Private.CoreLib/src/System/Reflection/CustomAttribute.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.
 
-using System.Runtime.CompilerServices;
-using System.Runtime.InteropServices;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Diagnostics.CodeAnalysis;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+using System.Text;
 
 namespace System.Reflection
 {
@@ -439,15 +440,33 @@ private void Init(object pca)
         #region Object Override
         public override string ToString()
         {
-            string ctorArgs = "";
-            for (int i = 0; i < ConstructorArguments.Count; i++)
-                ctorArgs += string.Format(i == 0 ? "{0}" : ", {0}", ConstructorArguments[i]);
+            var vsb = new ValueStringBuilder(stackalloc char[256]);
+
+            vsb.Append('[');
+            vsb.Append(Constructor.DeclaringType!.FullName);
+            vsb.Append('(');
+
+            bool first = true;
+
+            int count = ConstructorArguments.Count;
+            for (int i = 0; i < count; i++)
+            {
+                if (!first) vsb.Append(", ");
+                vsb.Append(ConstructorArguments[i].ToString());
+                first = false;
+            }
+
+            count = NamedArguments.Count;
+            for (int i = 0; i < count; i++)
+            {
+                if (!first) vsb.Append(", ");
+                vsb.Append(NamedArguments[i].ToString());
+                first = false;
+            }
 
-            string namedArgs = "";
-            for (int i = 0; i < NamedArguments.Count; i++)
-                namedArgs += string.Format(i == 0 && ctorArgs.Length == 0 ? "{0}" : ", {0}", NamedArguments[i]);
+            vsb.Append(")]");
 
-            return string.Format("[{0}({1}{2})]", Constructor.DeclaringType!.FullName, ctorArgs, namedArgs);
+            return vsb.ToString();
         }
         public override int GetHashCode() => base.GetHashCode();
         public override bool Equals(object? obj) => obj == (object)this;

src/coreclr/System.Private.CoreLib/src/System/Reflection/MdImport.cs

@@ -557,9 +557,6 @@ internal sealed class MetadataException : Exception
         private int m_hr;
         internal MetadataException(int hr) { m_hr = hr; }
 
-        public override string ToString()
-        {
-            return string.Format("MetadataException HResult = {0:x}.", m_hr);
-        }
+        public override string ToString() => $"MetadataException HResult = {m_hr:x}.";
     }
 }

src/libraries/Common/src/Interop/Windows/Kernel32/Interop.FormatMessage.cs

@@ -71,7 +71,7 @@ internal static unsafe string GetMessage(int errorCode, IntPtr moduleHandle)
             }
 
             // Couldn't get a message, so manufacture one.
-            return string.Format("Unknown error (0x{0:x})", errorCode);
+            return $"Unknown error (0x{errorCode:x})";
         }
 
         private static string GetAndTrimString(Span<char> buffer)

src/libraries/Common/src/System/Net/WebSockets/WebSocketValidate.cs

@@ -58,7 +58,7 @@ internal static void ValidateSubprotocol(string subProtocol)
                 char ch = subProtocol[i];
                 if (ch < 0x21 || ch > 0x7e)
                 {
-                    invalidChar = string.Format(CultureInfo.InvariantCulture, "[{0}]", (int)ch);
+                    invalidChar = $"[{(int)ch}]";
                     break;
                 }
 

src/libraries/Microsoft.CSharp/src/Microsoft/CSharp/RuntimeBinder/ComInterop/ComTypeEnumDesc.cs

@@ -15,10 +15,7 @@ internal sealed class ComTypeEnumDesc : ComTypeDesc, IDynamicMetaObjectProvider
         private readonly string[] _memberNames;
         private readonly object[] _memberValues;
 
-        public override string ToString()
-        {
-            return string.Format(CultureInfo.CurrentCulture, "<enum '{0}'>", TypeName);
-        }
+        public override string ToString() => $"<enum '{TypeName}'>";
 
         internal ComTypeEnumDesc(ComTypes.ITypeInfo typeInfo, ComTypeLibDesc typeLibDesc) :
             base(typeInfo, typeLibDesc)

src/libraries/Microsoft.CSharp/src/Microsoft/CSharp/RuntimeBinder/ComInterop/ComTypeLibDesc.cs

@@ -32,10 +32,7 @@ private ComTypeLibDesc()
             _classes = new LinkedList<ComTypeClassDesc>();
         }
 
-        public override string ToString()
-        {
-            return string.Format(CultureInfo.CurrentCulture, "<type library {0}>", Name);
-        }
+        public override string ToString() => $"<type library {Name}>";
 
         public string Documentation
         {

src/libraries/Microsoft.CSharp/src/Microsoft/CSharp/RuntimeBinder/ComInterop/DispCallable.cs

@@ -19,10 +19,7 @@ internal DispCallable(IDispatchComObject dispatch, string memberName, int dispId
             DispId = dispId;
         }
 
-        public override string ToString()
-        {
-            return string.Format(CultureInfo.CurrentCulture, "<bound dispmethod {0}>", MemberName);
-        }
+        public override string ToString() => $"<bound dispmethod {MemberName}>";
 
         public IDispatchComObject DispatchComObject { get; }
 

src/libraries/Microsoft.CSharp/src/Microsoft/CSharp/RuntimeBinder/ComInterop/IDispatchComObject.cs

@@ -99,7 +99,7 @@ public override string ToString()
                 typeName = "IDispatch";
             }
 
-            return string.Format(CultureInfo.CurrentCulture, "{0} ({1})", RuntimeCallableWrapper.ToString(), typeName);
+            return $"{RuntimeCallableWrapper.ToString()} ({typeName})";
         }
 
         public ComTypeDesc ComTypeDesc

src/libraries/Microsoft.CSharp/src/Microsoft/CSharp/RuntimeBinder/ComInterop/Variant.Extended.cs

@@ -281,10 +281,7 @@ internal static System.Reflection.MethodInfo GetByrefSetter(VarEnum varType)
             }
         }
 
-        public override string ToString()
-        {
-            return string.Format(CultureInfo.CurrentCulture, "Variant ({0})", VariantType);
-        }
+        public override string ToString() => $"Variant ({VariantType})";
 
         public void SetAsIConvertible(IConvertible value)
         {

src/libraries/Microsoft.Extensions.Configuration.CommandLine/src/CommandLineConfigurationProvider.cs

@@ -60,7 +60,7 @@ public override void Load()
                     {
                         // "/SomeSwitch" is equivalent to "--SomeSwitch" when interpreting switch mappings
                         // So we do a conversion to simplify later processing
-                        currentArg = string.Format("--{0}", currentArg.Substring(1));
+                        currentArg = $"--{currentArg.Substring(1)}";
                         keyStartIndex = 2;
                     }
 

src/libraries/Microsoft.Extensions.FileSystemGlobbing/src/Abstractions/DirectoryInfoWrapper.cs

@@ -94,8 +94,7 @@ public override DirectoryInfoBase GetDirectory(string name)
                 {
                     // This shouldn't happen. The parameter name isn't supposed to contain wild card.
                     throw new InvalidOperationException(
-                        string.Format("More than one sub directories are found under {0} with name {1}.",
-                            _directoryInfo.FullName, name));
+                        $"More than one sub directories are found under {_directoryInfo.FullName} with name {name}.");
                 }
             }
         }

src/libraries/Microsoft.Extensions.FileSystemGlobbing/src/Internal/MatcherContext.cs

@@ -171,7 +171,7 @@ internal static string CombinePath(string left, string right)
             }
             else
             {
-                return string.Format("{0}/{1}", left, right);
+                return $"{left}/{right}";
             }
         }
 

src/libraries/Microsoft.Win32.Primitives/src/System/ComponentModel/Win32Exception.cs

@@ -87,7 +87,7 @@ public override string ToString()
             string className = GetType().ToString();
             StringBuilder s = new StringBuilder(className);
             string nativeErrorString = NativeErrorCode < 0
-                ? string.Format(CultureInfo.InvariantCulture, "0x{0:X8}", NativeErrorCode)
+                ? $"0x{NativeErrorCode:X8}"
                 : NativeErrorCode.ToString(CultureInfo.InvariantCulture);
             if (HResult == E_FAIL)
             {

src/libraries/Microsoft.Win32.SystemEvents/src/Microsoft/Win32/SystemEvents.cs

@@ -668,9 +668,7 @@ private unsafe void Initialize()
 
             IntPtr hInstance = Interop.Kernel32.GetModuleHandle(null);
 
-            s_className = string.Format(
-                ".NET-BroadcastEventWindow.{0:x}.0",
-                AppDomain.CurrentDomain.GetHashCode());
+            s_className = $".NET-BroadcastEventWindow.{AppDomain.CurrentDomain.GetHashCode():x}.0";
 
             fixed (char* className = s_className)
             {

src/libraries/Microsoft.XmlSerializer.Generator/src/Sgen.cs

@@ -453,7 +453,7 @@ private static Assembly LoadAssembly(string assemblyName, bool throwOnFail)
         private void WriteHeader()
         {
             // do not localize Copyright header
-            Console.WriteLine(string.Format(CultureInfo.CurrentCulture, ".NET Xml Serialization Generation Utility, Version {0}]", ThisAssembly.InformationalVersion));
+            Console.WriteLine($".NET Xml Serialization Generation Utility, Version {ThisAssembly.InformationalVersion}]");
         }
 
         private void WriteHelp()

src/libraries/System.Collections.Immutable/src/System/Collections/Immutable/ImmutableArray_1.Minimal.cs

@@ -217,7 +217,7 @@ private string DebuggerDisplay
             get
             {
                 var self = this;
-                return self.IsDefault ? "Uninitialized" : string.Format(CultureInfo.CurrentCulture, "Length = {0}", self.Length);
+                return self.IsDefault ? "Uninitialized" : $"Length = {self.Length}";
             }
         }
 

src/libraries/System.ComponentModel.Composition/src/System/ComponentModel/Composition/Hosting/ApplicationCatalog.cs

@@ -173,14 +173,8 @@ private void ThrowIfDisposed()
             }
         }
 
-        private string GetDisplayName()
-        {
-            return string.Format(CultureInfo.CurrentCulture,
-                                "{0} (Path=\"{1}\") (PrivateProbingPath=\"{2}\")",   // NOLOC
-                                GetType().Name,
-                                AppDomain.CurrentDomain.BaseDirectory,
-                                AppDomain.CurrentDomain.RelativeSearchPath);
-        }
+        private string GetDisplayName() =>
+            $"{GetType().Name} (Path=\"{AppDomain.CurrentDomain.BaseDirectory}\") (PrivateProbingPath=\"{AppDomain.CurrentDomain.RelativeSearchPath}\")";   // NOLOC
 
         /// <summary>
         ///     Returns a string representation of the directory catalog.

src/libraries/System.ComponentModel.Composition/src/System/ComponentModel/Composition/Hosting/AssemblyCatalog.cs

@@ -540,13 +540,8 @@ private void ThrowIfDisposed()
             }
         }
 
-        private string GetDisplayName()
-        {
-            return string.Format(CultureInfo.CurrentCulture,
-                                "{0} (Assembly=\"{1}\")",   // NOLOC
-                                GetType().Name,
-                                Assembly.FullName);
-        }
+        private string GetDisplayName() =>
+            $"{GetType().Name} (Assembly=\"{Assembly.FullName}\")";   // NOLOC
 
         private static Assembly LoadAssembly(string codeBase)
         {

src/libraries/System.ComponentModel.Composition/src/System/ComponentModel/Composition/Hosting/DirectoryCatalog.cs

@@ -732,13 +732,8 @@ private void DiffChanges(string[] beforeFiles, string[] afterFiles,
             }
         }
 
-        private string GetDisplayName()
-        {
-            return string.Format(CultureInfo.CurrentCulture,
-                                "{0} (Path=\"{1}\")",   // NOLOC
-                                GetType().Name,
-                                _path);
-        }
+        private string GetDisplayName() =>
+            $"{GetType().Name} (Path=\"{_path}\")";   // NOLOC
 
         private string[] GetFiles()
         {

src/libraries/System.ComponentModel.Composition/src/System/ComponentModel/Composition/MetadataViewGenerator.cs

@@ -67,7 +67,7 @@ internal static class MetadataViewGenerator
 
         private static readonly Lock _lock = new Lock();
         private static readonly Dictionary<Type, MetadataViewFactory> _metadataViewFactories = new Dictionary<Type, MetadataViewFactory>();
-        private static readonly AssemblyName ProxyAssemblyName = new AssemblyName(string.Format(CultureInfo.InvariantCulture, "MetadataViewProxies_{0}", Guid.NewGuid()));
+        private static readonly AssemblyName ProxyAssemblyName = new AssemblyName($"MetadataViewProxies_{Guid.NewGuid()}");
         private static ModuleBuilder? transparentProxyModuleBuilder;
 
         private static readonly Type[] CtorArgumentTypes = new Type[] { typeof(IDictionary<string, object>) };
@@ -193,7 +193,7 @@ private static void GenerateLocalAssignmentFromFlag(this ILGenerator IL, LocalBu
 
             var proxyModuleBuilder = GetProxyModuleBuilder(requiresCritical);
             proxyTypeBuilder = proxyModuleBuilder.DefineType(
-                string.Format(CultureInfo.InvariantCulture, "_proxy_{0}_{1}", viewType.FullName, Guid.NewGuid()),
+                $"_proxy_{viewType.FullName}_{Guid.NewGuid()}",
                 TypeAttributes.Public,
                 typeof(object),
                 interfaces);
@@ -214,7 +214,7 @@ private static void GenerateLocalAssignmentFromFlag(this ILGenerator IL, LocalBu
             // Implement interface properties
             foreach (PropertyInfo propertyInfo in viewType.GetAllProperties())
             {
-                string fieldName = string.Format(CultureInfo.InvariantCulture, "_{0}_{1}", propertyInfo.Name, Guid.NewGuid());
+                string fieldName = $"_{propertyInfo.Name}_{Guid.NewGuid()}";
 
                 // Cache names and type for exception
                 string propertyName = propertyInfo.Name;

src/libraries/System.ComponentModel.Composition/src/System/ComponentModel/Composition/Primitives/ContractBasedImportDefinition.cs

@@ -371,19 +371,19 @@ public override string ToString()
         {
             var sb = new StringBuilder();
 
-            sb.Append(string.Format("\n\tContractName\t{0}", ContractName));
-            sb.Append(string.Format("\n\tRequiredTypeIdentity\t{0}", RequiredTypeIdentity));
+            sb.Append("\n\tContractName\t").Append(ContractName);
+            sb.Append("\n\tRequiredTypeIdentity\t").Append(RequiredTypeIdentity);
             if (_requiredCreationPolicy != CreationPolicy.Any)
             {
-                sb.Append(string.Format("\n\tRequiredCreationPolicy\t{0}", RequiredCreationPolicy));
+                sb.Append("\n\tRequiredCreationPolicy\t").Append(RequiredCreationPolicy);
             }
 
             if (_requiredMetadata.Any())
             {
                 sb.Append("\n\tRequiredMetadata");
                 foreach (KeyValuePair<string, Type> metadataItem in _requiredMetadata)
                 {
-                    sb.Append(string.Format("\n\t\t{0}\t({1})", metadataItem.Key, metadataItem.Value));
+                    sb.Append("\n\t\t").Append(metadataItem.Key).Append("\t(").Append(metadataItem.Value).Append(')');
                 }
             }
             return sb.ToString();

src/libraries/System.ComponentModel.Composition/src/System/ComponentModel/Composition/ReflectionModel/ReflectionMemberExportDefinition.cs

@@ -78,12 +78,7 @@ private ReflectionMember ToReflectionMember()
             return ExportingLazyMember.ToReflectionMember();
         }
 
-        private string GetDisplayName()
-        {
-            return string.Format(CultureInfo.CurrentCulture,
-                   "{0} (ContractName=\"{1}\")",    // NOLOC
-                   ToReflectionMember().GetDisplayName(),
-                   ContractName);
-        }
+        private string GetDisplayName() =>
+            $"{ToReflectionMember().GetDisplayName()} (ContractName=\"{ContractName}\")";    // NOLOC
     }
 }

src/libraries/System.ComponentModel.Composition/src/System/ComponentModel/Composition/ReflectionModel/ReflectionMemberImportDefinition.cs

@@ -43,13 +43,7 @@ public LazyMemberInfo ImportingLazyMember
             get { return _importingLazyMember; }
         }
 
-        protected override string GetDisplayName()
-        {
-            return string.Format(
-                CultureInfo.CurrentCulture,
-                "{0} (ContractName=\"{1}\")",    // NOLOC
-                ImportingLazyMember.ToReflectionMember().GetDisplayName(),
-                ContractName);
-        }
+        protected override string GetDisplayName() =>
+            $"{ImportingLazyMember.ToReflectionMember().GetDisplayName()} (ContractName=\"{ContractName}\")";    // NOLOC
     }
 }

src/libraries/System.ComponentModel.Composition/src/System/ComponentModel/Composition/ReflectionModel/ReflectionParameter.cs

@@ -31,14 +31,8 @@ public override string? Name
             get { return UnderlyingParameter.Name; }
         }
 
-        public override string GetDisplayName()
-        {
-            return string.Format(
-                CultureInfo.CurrentCulture,
-                "{0} (Parameter=\"{1}\")",  // NOLOC
-                UnderlyingParameter.Member.GetDisplayName(),
-                UnderlyingParameter.Name);
-        }
+        public override string GetDisplayName() =>
+            $"{UnderlyingParameter.Member.GetDisplayName()} (Parameter=\"{UnderlyingParameter.Name}\")";  // NOLOC
 
         public override Type ReturnType
         {

src/libraries/System.ComponentModel.Composition/src/System/ComponentModel/Composition/ReflectionModel/ReflectionParameterImportDefinition.cs

@@ -45,12 +45,7 @@ public Lazy<ParameterInfo> ImportingLazyParameter
         protected override string GetDisplayName()
         {
             ParameterInfo parameter = ImportingLazyParameter.GetNotNullValue("parameter");
-            return string.Format(
-                CultureInfo.CurrentCulture,
-                "{0} (Parameter=\"{1}\", ContractName=\"{2}\")",  // NOLOC
-                parameter.Member.GetDisplayName(),
-                parameter.Name,
-                ContractName);
+            return $"{parameter.Member.GetDisplayName()} (Parameter=\"{parameter.Name}\", ContractName=\"{ContractName}\")";  // NOLOC
         }
     }
 }

src/libraries/System.Composition.Hosting/src/System/Composition/Hosting/Util/Formatters.cs

@@ -47,7 +47,7 @@ private static string FormatClosedGeneric(Type closedGenericType)
 
             var name = closedGenericType.Name.Substring(0, closedGenericType.Name.IndexOf('`'));
             var args = closedGenericType.GenericTypeArguments.Select(t => Format(t));
-            return string.Format("{0}<{1}>", name, string.Join(", ", args));
+            return $"{name}<{string.Join(", ", args)}>";
         }
     }
 }

src/libraries/System.Composition.Runtime/src/System/Composition/Hosting/Core/CompositionContract.cs

@@ -110,7 +110,7 @@ public override string ToString()
             if (_metadataConstraints != null)
                 result += string.Format(" {{ {0} }}",
                     string.Join(SR.Formatter_ListSeparatorWithSpace,
-                        _metadataConstraints.Select(kv => string.Format("{0} = {1}", kv.Key, Formatters.Format(kv.Value)))));
+                        _metadataConstraints.Select(kv => $"{kv.Key} = {Formatters.Format(kv.Value)}")));
 
             return result;
         }

src/libraries/System.Composition.Runtime/src/System/Composition/Runtime/Util/Formatters.cs

@@ -36,7 +36,7 @@ private static string FormatClosedGeneric(Type closedGenericType)
             Debug.Assert(closedGenericType.IsConstructedGenericType);
             var name = closedGenericType.Name.Substring(0, closedGenericType.Name.IndexOf('`'));
             IEnumerable<string> args = closedGenericType.GenericTypeArguments.Select(t => Format(t));
-            return string.Format("{0}<{1}>", name, string.Join(SR.Formatter_ListSeparatorWithSpace, args));
+            return $"{name}<{string.Join(SR.Formatter_ListSeparatorWithSpace, args)}>";
         }
     }
 }