Fix remaining violations and suppress multi-target false positives in .editorconfig

Additional fixes applied:
- IDE0018: Inline variable declaration
- IDE0059: Remove unnecessary value assignments
- IDE0036: Order modifiers
- IDE1005: Use conditional delegate call
- IDE0305: Use collection expression (fluent)
- IDE0083: Use pattern matching 'is not null'
- IDE0300/IDE0301: Use collection expressions
- IDE0290: Additional primary constructor fixes
- CA1854: Prefer TryGetValue over ContainsKey
- CA1860/CA1861: Enumerable.Any, constant array fixes

.editorconfig: Suppress rules that are multi-target false positives:
- IDE0039: Lambda->local function breaks VSTHRD200 naming convention
- IDE0051/IDE0052: Removes members used in other TFMs via #if blocks
- IDE0056: Range/index operator requires .NET 5+
- CA1845/CA1846: Span-based overloads require .NET 5+
- CA1850: HashData requires .NET 5+
- CA2250/CA1512/CA1513: ThrowIfX methods require .NET 6+/8+

Remaining unfixable violations:
- IDE1006 (382): Naming - no Fix All support in dotnet format
- IDE0130 (359): Namespace != folder - crashes dotnet format
- IDE0090 (44): new() in preprocessor blocks
- CA1859 (20): No code fix available
- IDE0060 (16): Unused parameter - no code fix

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: Robbie-Microsoft

.editorconfig

@@ -875,6 +875,30 @@ dotnet_diagnostic.IDE0057.severity = none
 # Disabled: introduces duplicate variable declarations in #if multi-target preprocessor blocks
 dotnet_diagnostic.IDE0019.severity = none
 
+# Use local function instead of lambda (IDE0039)
+# Disabled: local functions require Async suffix per VSTHRD200; lambda conversions break naming convention
+dotnet_diagnostic.IDE0039.severity = none
+
+# Remove unused private members (IDE0051/IDE0052)
+# Disabled: members may be used in other TFMs inside #if preprocessor blocks
+dotnet_diagnostic.IDE0051.severity = none
+dotnet_diagnostic.IDE0052.severity = none
+
+# Use range subscript operator (x[^1]) - requires .NET 5+ (System.Index not available in net462/netstandard2.0)
+dotnet_diagnostic.IDE0056.severity = none
+
+# Use Span-based string comparison / overloads - requires .NET 5+
+dotnet_diagnostic.CA1845.severity = none
+dotnet_diagnostic.CA1846.severity = none
+
+# Use HashData instead of ComputeHash - requires .NET 5+
+dotnet_diagnostic.CA1850.severity = none
+
+# Use ThrowIfCancellationRequested / ThrowIfNegativeOrZero / ObjectDisposedException.ThrowIf - requires .NET 6+/8+
+dotnet_diagnostic.CA2250.severity = none
+dotnet_diagnostic.CA1512.severity = none
+dotnet_diagnostic.CA1513.severity = none
+
 # Dispose objects before losing scope
 dotnet_diagnostic.CA2000.severity = none
 

src/client/Microsoft.Identity.Client/AppConfig/AuthorityInfo.cs

@@ -304,10 +304,10 @@ internal bool IsDefaultAuthority
             }
         }
 
-        internal static readonly char[] separator = new[]
-                {
+        internal static readonly char[] separator =
+                [
                     '/'
-                };
+                ];
 
         internal Authority CreateAuthority()
         {

src/client/Microsoft.Identity.Client/Cache/Items/MsalAccessTokenCacheItem.cs

@@ -215,7 +215,7 @@ internal void InitCacheKey()
                 _credentialDescriptor = StorageJsonValues.CredentialTypeAccessTokenExtended;
                 if (_extraKeyParts != null)
                 {
-                    _extraKeyParts = _extraKeyParts.Concat(new[] { CoreHelpers.ComputeAccessTokenExtCacheKey(AdditionalCacheKeyComponents) }).ToArray();
+                    _extraKeyParts = [.. _extraKeyParts, .. new[] { CoreHelpers.ComputeAccessTokenExtCacheKey(AdditionalCacheKeyComponents) }];
                 }
                 else
                 {

src/client/Microsoft.Identity.Client/ClientApplicationBase.cs

@@ -207,8 +207,8 @@ private async Task<IEnumerable<IAccount>> GetAccountsInternalAsync(ApiIds apiId,
 
             IEnumerable<IAccount> accountsFromCache = await cacheSessionManager.GetAccountsAsync().ConfigureAwait(false);
             IEnumerable<IAccount> accountsFromBroker = await GetAccountsFromBrokerAsync(homeAccountIdFilter, cacheSessionManager, cancellationToken).ConfigureAwait(false);
-            accountsFromCache ??= Enumerable.Empty<IAccount>();
-            accountsFromBroker ??= Enumerable.Empty<IAccount>();
+            accountsFromCache ??= [];
+            accountsFromBroker ??= [];
 
             ServiceBundle.ApplicationLogger.Info(() => $"Found {accountsFromCache.Count()} cache accounts and {accountsFromBroker.Count()} broker accounts");
             IEnumerable<IAccount> cacheAndBrokerAccounts = MergeAccounts(accountsFromCache, accountsFromBroker);
@@ -249,7 +249,7 @@ private async Task<IEnumerable<IAccount>> GetAccountsFromBrokerAsync(
                 }
             }
 
-            return Enumerable.Empty<IAccount>();
+            return [];
         }
 
         // Not all brokers return the accounts only for the given env

src/client/Microsoft.Identity.Client/Instance/Discovery/InstanceDiscoveryManager.cs

@@ -208,7 +208,7 @@ private async Task<InstanceDiscoveryMetadataEntry> FetchNetworkMetadataOrFallbac
                     $" Exception: {e} ");
 
                 return
-                    _knownMetadataProvider.GetMetadata(authorityUri.Host, Enumerable.Empty<string>(), requestContext.Logger)
+                    _knownMetadataProvider.GetMetadata(authorityUri.Host, [], requestContext.Logger)
                 ?? CreateEntryForSingleAuthority(authorityUri);
             }
         }

src/client/Microsoft.Identity.Client/Instance/Discovery/KnownMetadataProvider.cs

@@ -122,7 +122,7 @@ public InstanceDiscoveryMetadataEntry GetMetadata(
             IEnumerable<string> existingEnvironmentsInCache,
             ILoggerAdapter logger)
         {
-            existingEnvironmentsInCache ??= Enumerable.Empty<string>();
+            existingEnvironmentsInCache ??= [];
 
             bool canUseProvider = existingEnvironmentsInCache.All(e => s_knownEnvironments.ContainsOrdinalIgnoreCase(e));
 

src/client/Microsoft.Identity.Client/Internal/Broker/BrokerInteractiveRequestComponent.cs

@@ -115,12 +115,12 @@ private static string ExtractAppLink(string authCode)
 
             Dictionary<string, string> queryDict = CoreHelpers.ParseKeyValueList(query, '&', true, true, null);
 
-            if (!queryDict.ContainsKey(BrokerParameter.AppLink))
+            if (!queryDict.TryGetValue(BrokerParameter.AppLink, out string value))
             {
                 return null;
             }
 
-            return queryDict[BrokerParameter.AppLink];
+            return value;
         }
     }
 }

src/client/Microsoft.Identity.Client/Kerberos/KerberosSupplementalTicketManager.cs

@@ -29,8 +29,6 @@ public static class KerberosSupplementalTicketManager
     {
         private const int DefaultLogonId = 0;
         private const string KerberosClaimType = "xms_as_rep";
-        private const string IdTokenAsRepTemplate = @"{{""id_token"": {{ ""xms_as_rep"":{{""essential"":""false"",""value"":""{0}""}} }} }}";
-        private const string AccessTokenAsRepTemplate = @"{{""access_token"": {{ ""xms_as_rep"":{{""essential"":""false"",""value"":""{0}""}} }} }}";
 
         /// <summary>
         /// Creates a <see cref="KerberosSupplementalTicket"/> object from given ID token string..

src/client/Microsoft.Identity.Client/ManagedIdentity/AzureArcManagedIdentitySource.cs

@@ -21,7 +21,7 @@ internal class AzureArcManagedIdentitySource : AbstractManagedIdentity
         private const string AzureArc = "Azure Arc";
 
         private readonly Uri _endpoint;
-        internal static readonly char[] separator = new char[] { '=' };
+        internal static readonly char[] separator = ['='];
 
         public static AbstractManagedIdentity Create(RequestContext requestContext)
         {

src/client/Microsoft.Identity.Client/ManagedIdentity/MachineLearningManagedIdentitySource.cs

@@ -11,8 +11,6 @@ namespace Microsoft.Identity.Client.ManagedIdentity
 {
     internal class MachineLearningManagedIdentitySource : AbstractManagedIdentity
     {
-        private const string MachineLearning = "Machine Learning";
-
         private const string MachineLearningMsiApiVersion = "2017-09-01";
         private const string SecretHeaderName = "secret";