Upgrade solution to .NET 6.0.9 (Build with .NET SDK v6.0.401) (#1692)

global.json

@@ -1,6 +1,6 @@
 {
     "sdk": {
-        "version": "6.0.301"
+        "version": "6.0.401"
     },
     "msbuild-sdks": {
       "Microsoft.Build.NoTargets": "3.2.9"

src/Microsoft.InsightsGenerator/RulesEngine.cs

@@ -61,10 +61,7 @@ namespace Microsoft.InsightsGenerator
         public static string FindMatchedTemplate(List<List<string>> singleHashHeaders, DataArray columnInfo)
         {
             var resultTemplate = new StringBuilder();
-            if (Templates == null)
+            Templates ??= GetTemplates();
-            {
-                Templates = GetTemplates();
-            }
             var headersWithSingleHash = GetTopHeadersWithHash(singleHashHeaders);
 
             foreach (var template in Templates)

src/Microsoft.Kusto.ServiceLayer/Connection/ConnectionService.cs

@@ -60,10 +60,7 @@ namespace Microsoft.Kusto.ServiceLayer.Connection
         {
             get
             {
-                if (lockedDatabaseManager == null)
+                lockedDatabaseManager ??= DatabaseLocksManager.Instance;
-                {
-                    lockedDatabaseManager = DatabaseLocksManager.Instance;
-                }
                 return lockedDatabaseManager;
             }
             set

src/Microsoft.Kusto.ServiceLayer/LanguageServices/LanguageService.cs

@@ -151,10 +151,7 @@ namespace Microsoft.Kusto.ServiceLayer.LanguageServices
         {
             get
             {
-                if (workspaceServiceInstance == null)
+                workspaceServiceInstance ??=  WorkspaceService<SqlToolsSettings>.Instance;
-                {
-                    workspaceServiceInstance =  WorkspaceService<SqlToolsSettings>.Instance;
-                }
                 return workspaceServiceInstance;
             }
             set
@@ -167,10 +164,7 @@ namespace Microsoft.Kusto.ServiceLayer.LanguageServices
         {
             get
             {
-                if (this.serviceHostInstance == null)
+                this.serviceHostInstance ??= ServiceHost.Instance;
-                {
-                    this.serviceHostInstance = ServiceHost.Instance;
-                }
                 return this.serviceHostInstance;
             }
             set
@@ -872,10 +866,8 @@ namespace Microsoft.Kusto.ServiceLayer.LanguageServices
             }
 
             // if there are no completions then provide the default list
-            if (resultCompletionItems == null)          // this is the getting default keyword option when its not connected
+            // this is the getting default keyword option when its not connected
-            {
+            resultCompletionItems ??= DataSourceFactory.GetDefaultAutoComplete(DataSourceType.Kusto, scriptDocumentInfo, textDocumentPosition.Position);
-                resultCompletionItems = DataSourceFactory.GetDefaultAutoComplete(DataSourceType.Kusto, scriptDocumentInfo, textDocumentPosition.Position);
-            }
 
             return resultCompletionItems;
         }

src/Microsoft.Kusto.ServiceLayer/ObjectExplorer/DataSourceModel/NodePathGenerator.cs

@@ -70,10 +70,7 @@ namespace Microsoft.Kusto.ServiceLayer.ObjectExplorer.DataSourceModel
                 path = schema + "." + path;
             }
 
-            if (path == null)
+            path ??= "";
-            {
-                path = "";
-            }
 
             foreach (var matchingNode in matchingNodes)
             {

src/Microsoft.Kusto.ServiceLayer/ObjectExplorer/ObjectExplorerService.cs

@@ -262,10 +262,7 @@ namespace Microsoft.Kusto.ServiceLayer.ObjectExplorer
         internal async Task HandleFindNodesRequest(FindNodesParams findNodesParams, RequestContext<FindNodesResponse> context)
         {
             var foundNodes = FindNodes(findNodesParams.SessionId, findNodesParams.Type, findNodesParams.Schema, findNodesParams.Name, findNodesParams.Database, findNodesParams.ParentObjectNames);
-            if (foundNodes == null)
+            foundNodes ??= new List<TreeNode>();
-            {
-                foundNodes = new List<TreeNode>();
-            }
             await context.SendResult(new FindNodesResponse { Nodes = foundNodes.Select(node => node.ToNodeInfo()).ToList() });
         }
 

src/Microsoft.Kusto.ServiceLayer/QueryExecution/DataStorage/SaveAsExcelFileStreamWriterHelper.cs

@@ -171,9 +171,9 @@ namespace Microsoft.Kusto.ServiceLayer.QueryExecution.DataStorage
                         AddCell((string)o);
                         break;
                     default:
-                        if (o is TimeSpan) //TimeSpan doesn't have TypeCode
+                        if (o is TimeSpan span) //TimeSpan doesn't have TypeCode
                         {
-                            AddCell((TimeSpan)o);
+                            AddCell(span);
                             break;
                         }
                         AddCell(dbCellValue.DisplayValue);
@@ -510,10 +510,7 @@ namespace Microsoft.Kusto.ServiceLayer.QueryExecution.DataStorage
         public ExcelSheet AddSheet(string sheetName = null)
         {
             string sheetFileName = "sheet" + (sheetNames.Count + 1);
-            if (sheetName == null)
+            sheetName ??= sheetFileName;
-            {
-                sheetName = sheetFileName;
-            }
             EnsureValidSheetName(sheetName);
 
             sheetNames.Add(sheetName);

src/Microsoft.Kusto.ServiceLayer/QueryExecution/QueryExecutionService.cs

@@ -68,13 +68,10 @@ namespace Microsoft.Kusto.ServiceLayer.QueryExecution
         {
             get
             {
-                if (BufferFileStreamFactory == null)
+                BufferFileStreamFactory ??= new ServiceBufferFileStreamFactory
-                {
-                    BufferFileStreamFactory = new ServiceBufferFileStreamFactory
                 {
                     ExecutionSettings = Settings.QueryExecutionSettings
                 };
-                }
                 return BufferFileStreamFactory;
             }
         }

src/Microsoft.Kusto.ServiceLayer/SqlContext/SqlToolsSettings.cs

@@ -20,10 +20,7 @@ namespace Microsoft.Kusto.ServiceLayer.SqlContext
         { 
             get
             {
-                if (this.sqlTools == null)
+                this.sqlTools ??= new CompoundToolsSettingsValues(MssqlTools, AllSqlTools);
-                {
-                    this.sqlTools = new CompoundToolsSettingsValues(MssqlTools, AllSqlTools);
-                }
                 return this.sqlTools;
             } 
             set
@@ -40,10 +37,7 @@ namespace Microsoft.Kusto.ServiceLayer.SqlContext
         { 
             get
             {
-                if (this.mssqlTools == null)
+                this.mssqlTools ??= new SqlToolsSettingsValues(false);
-                {
-                    this.mssqlTools = new SqlToolsSettingsValues(false);
-                }
                 return this.mssqlTools;
             } 
             set
@@ -60,10 +54,7 @@ namespace Microsoft.Kusto.ServiceLayer.SqlContext
         { 
             get
             {
-                if (this.allSqlTools == null)
+                this.allSqlTools ??= new SqlToolsSettingsValues(false);
-                {
-                    this.allSqlTools = new SqlToolsSettingsValues(false);
-                }
                 return this.allSqlTools;
             } 
             set

src/Microsoft.Kusto.ServiceLayer/Utility/LongList.cs

@@ -84,13 +84,10 @@ namespace Microsoft.Kusto.ServiceLayer.Utility
                 shortList.Add(val);
             }
             else // need to split values into several arrays 
-            {
-                if (expandedList == null)
             {
                 // very inefficient so delay as much as possible
                 // immediately add 0th array
-                    expandedList = new List<List<T>> {shortList};
+                expandedList ??= new List<List<T>> {shortList};
-                }
 
                 int arrayIndex = (int)(Count / this.ExpandListSize); // 0 based
 

src/Microsoft.SqlTools.Hosting/Extensibility/ExtensionServiceProvider.cs

@@ -185,10 +185,7 @@ namespace Microsoft.SqlTools.Extensibility
 
         public IEnumerable<T> GetExports<T>()
         {
-            if (exports == null)
+            exports ??= host.GetExports(contractType).ToList();
-            {
-                exports = host.GetExports(contractType).ToList();
-            }
             return exports.Cast<T>();
         }
 

src/Microsoft.SqlTools.ResourceProvider.DefaultImpl/AzureResourceWrapper.cs

@@ -78,10 +78,7 @@ namespace Microsoft.SqlTools.ResourceProvider.DefaultImpl
         public string ResourceGroupName {
             get
             {
-                if (this.resourceGroupName == null)
+                this.resourceGroupName ??= ParseResourceGroupNameFromId();
-                {
-                    this.resourceGroupName = ParseResourceGroupNameFromId();
-                }
                 return this.resourceGroupName ?? string.Empty;
             }
             set

src/Microsoft.SqlTools.ServiceLayer/Admin/AdminService.cs

@@ -42,10 +42,7 @@ namespace Microsoft.SqlTools.ServiceLayer.Admin
         {
             get
             {
-                if (AdminService.connectionService == null)
+                AdminService.connectionService ??= ConnectionService.Instance;
-                {
-                    AdminService.connectionService = ConnectionService.Instance;
-                }
                 return AdminService.connectionService;
             }
 

src/Microsoft.SqlTools.ServiceLayer/Agent/AgentService.cs

@@ -51,10 +51,7 @@ namespace Microsoft.SqlTools.ServiceLayer.Agent
         {
             get
             {
-                if (connectionService == null)
+                connectionService ??= ConnectionService.Instance;
-                {
-                    connectionService = ConnectionService.Instance;
-                }
                 return connectionService;
             }
 

src/Microsoft.SqlTools.ServiceLayer/Agent/Common/AgentUtilities.cs

@@ -8,6 +8,7 @@ using System.Data;
 using System.Collections.Generic;
 using Microsoft.SqlServer.Management.Smo.Agent;
 using Microsoft.SqlTools.ServiceLayer.Agent.Contracts;
+using System.Linq;
 
 namespace Microsoft.SqlTools.ServiceLayer.Agent 
 {
@@ -261,7 +262,7 @@ namespace Microsoft.SqlTools.ServiceLayer.Agent
 
                 // Add steps to the job if any
                 var jobSteps = new List<AgentJobStep>();
-                foreach (LogSourceJobHistory.LogEntryJobHistory subEntry in entry.SubEntries)
+                foreach (LogSourceJobHistory.LogEntryJobHistory subEntry in entry.SubEntries.Cast<LogSourceJobHistory.LogEntryJobHistory>())
                 {
                     if (steps.Contains(subEntry.StepName))
                     {                                              
@@ -303,7 +304,7 @@ namespace Microsoft.SqlTools.ServiceLayer.Agent
 
                 // Add steps to the job if any
                 var jobSteps = new List<AgentJobStep>();
-                foreach (LogSourceJobHistory.LogEntryJobHistory subEntry in entry.SubEntries)
+                foreach (LogSourceJobHistory.LogEntryJobHistory subEntry in entry.SubEntries.Cast<LogSourceJobHistory.LogEntryJobHistory>())
                 {
                     if (steps.Contains(subEntry.StepName))
                     {                                              

src/Microsoft.SqlTools.ServiceLayer/Agent/Common/LogAggregator.cs

@@ -416,10 +416,7 @@ namespace Microsoft.SqlTools.ServiceLayer.Agent
         {
             e.Source = sourceName;
 
-            if (m_exceptionList == null)
+            m_exceptionList ??= new List<Exception>();
-            {
-                m_exceptionList = new List<Exception>();
-            }
             m_exceptionList.Add(e);
         }
 

src/Microsoft.SqlTools.ServiceLayer/Agent/Jobs/ScheduleData.cs

@@ -8,6 +8,7 @@ using System.Collections;
 using System.ComponentModel;
 using System.Diagnostics;
 using System.Globalization;
+using System.Linq;
 using System.Text;
 using System.Text.RegularExpressions;
 using Microsoft.SqlServer.Management.Common;
@@ -677,7 +678,7 @@ namespace Microsoft.SqlTools.ServiceLayer.Agent
             {
                 PropertyDescriptorCollection properties = TypeDescriptor.GetProperties(this);
 
-                foreach (Match match in matches)
+                foreach (Match match in matches.Cast<Match>())
                 {
                     string propertyName = match.Groups["property"].Value;
                     PropertyDescriptor property = properties[propertyName];                 

src/Microsoft.SqlTools.ServiceLayer/AutoParameterizaition/TsqlMultiVisitor.cs

@@ -31,11 +31,7 @@ namespace Microsoft.SqlTools.ServiceLayer.AutoParameterizaition
         {
             get
             {
-                if (_executionParameters == null)
+                _executionParameters ??= new Dictionary<string, int>();
-                {
-                    _executionParameters = new Dictionary<string, int>();
-                }
-
                 return _executionParameters;
             }
         }

src/Microsoft.SqlTools.ServiceLayer/Cms/CmsService.cs

@@ -356,10 +356,7 @@ namespace Microsoft.SqlTools.ServiceLayer.Cms
         {
             get
             {
-                if (connectionService == null)
+                connectionService ??= ConnectionService.Instance;
-                {
-                    connectionService = ConnectionService.Instance;
-                }
                 return connectionService;
             }
             set

src/Microsoft.SqlTools.ServiceLayer/Connection/ConnectionService.cs

@@ -84,10 +84,7 @@ namespace Microsoft.SqlTools.ServiceLayer.Connection
         {
             get
             {
-                if (lockedDatabaseManager == null)
+                lockedDatabaseManager ??= DatabaseLocksManager.Instance;
-                {
-                    lockedDatabaseManager = DatabaseLocksManager.Instance;
-                }
                 return lockedDatabaseManager;
             }
             set
@@ -216,10 +213,7 @@ namespace Microsoft.SqlTools.ServiceLayer.Connection
         {
             get
             {
-                if (this.connectionFactory == null)
+                this.connectionFactory ??= new SqlConnectionFactory();
-                {
-                    this.connectionFactory = new SqlConnectionFactory();
-                }
                 return this.connectionFactory;
             }
 

src/Microsoft.SqlTools.ServiceLayer/DacFx/DacFxService.cs

@@ -347,10 +347,7 @@ namespace Microsoft.SqlTools.ServiceLayer.DacFx
         {
             get
             {
-                if (sqlTaskManagerInstance == null)
+                sqlTaskManagerInstance ??= SqlTaskManager.Instance;
-                {
-                    sqlTaskManagerInstance = SqlTaskManager.Instance;
-                }
                 return sqlTaskManagerInstance;
             }
             set
@@ -366,10 +363,7 @@ namespace Microsoft.SqlTools.ServiceLayer.DacFx
         {
             get
             {
-                if (connectionService == null)
+                connectionService ??= ConnectionService.Instance;
-                {
-                    connectionService = ConnectionService.Instance;
-                }
                 return connectionService;
             }
             set

src/Microsoft.SqlTools.ServiceLayer/DisasterRecovery/DisasterRecoveryService.cs

@@ -52,10 +52,7 @@ namespace Microsoft.SqlTools.ServiceLayer.DisasterRecovery
         {
             get
             {
-                if (connectionService == null)
+                connectionService ??= ConnectionService.Instance;
-                {
-                    connectionService = ConnectionService.Instance;
-                }
                 return connectionService;
             }
             set
@@ -68,10 +65,7 @@ namespace Microsoft.SqlTools.ServiceLayer.DisasterRecovery
         {
             get
             {
-                if (sqlTaskManagerInstance == null)
+                sqlTaskManagerInstance ??= SqlTaskManager.Instance;
-                {
-                    sqlTaskManagerInstance = SqlTaskManager.Instance;
-                }
                 return sqlTaskManagerInstance;
             }
             set
@@ -87,10 +81,7 @@ namespace Microsoft.SqlTools.ServiceLayer.DisasterRecovery
         {
             get
             {
-                if (fileBrowserService == null)
+                fileBrowserService ??= FileBrowserService.Instance;
-                {
-                    fileBrowserService = FileBrowserService.Instance;
-                }
                 return fileBrowserService;
             }
             set

src/Microsoft.SqlTools.ServiceLayer/ExecutionPlan/ShowPlan/ConditionParser.cs

@@ -43,10 +43,7 @@ namespace Microsoft.SqlTools.ServiceLayer.ExecutionPlan.ShowPlan
         {
             get
             {
-                if (conditionParser == null)
+                conditionParser ??= new ConditionParser();
-                {
-                    conditionParser = new ConditionParser();
-                }
                 return conditionParser;
             }
         }

src/Microsoft.SqlTools.ServiceLayer/ExecutionPlan/ShowPlan/CursorOperationParser.cs

@@ -67,10 +67,7 @@ namespace Microsoft.SqlTools.ServiceLayer.ExecutionPlan.ShowPlan
         {
             get
             {
-                if (cursorOperationParser == null)
+                cursorOperationParser ??= new CursorOperationParser();
-                {
-                    cursorOperationParser = new CursorOperationParser();
-                }
                 return cursorOperationParser;
             }
         }

src/Microsoft.SqlTools.ServiceLayer/ExecutionPlan/ShowPlan/CursorStatementParser.cs

@@ -19,10 +19,7 @@ namespace Microsoft.SqlTools.ServiceLayer.ExecutionPlan.ShowPlan
         {
             object cursorType = node["CursorActualType"];
 
-            if (cursorType == null)
+            cursorType ??= node["StatementType"];
-            {
-                cursorType = node["StatementType"];
-            }
 
             Operation cursor = cursorType != null
                 ? OperationTable.GetCursorType(cursorType.ToString())
@@ -46,10 +43,7 @@ namespace Microsoft.SqlTools.ServiceLayer.ExecutionPlan.ShowPlan
         {
             get
             {
-                if (cursorStatementParser == null)
+                cursorStatementParser ??= new CursorStatementParser();
-                {
-                    cursorStatementParser = new CursorStatementParser();
-                }
                 return cursorStatementParser;
             }
         }

src/Microsoft.SqlTools.ServiceLayer/ExecutionPlan/ShowPlan/Edge.cs

@@ -101,10 +101,7 @@ namespace Microsoft.SqlTools.ServiceLayer.ExecutionPlan.ShowPlan
             get
             {
                 object propertyValue = this["EstimateRows"];
-                if (propertyValue == null)
+                propertyValue ??= this["StatementEstRows"];
-                {
-                    propertyValue = this["StatementEstRows"];
-                }
 
                 return propertyValue != null ? Convert.ToDouble(propertyValue, CultureInfo.CurrentCulture) : 0;
             }

src/Microsoft.SqlTools.ServiceLayer/ExecutionPlan/ShowPlan/FilterTypeParser.cs

@@ -51,10 +51,7 @@ namespace Microsoft.SqlTools.ServiceLayer.ExecutionPlan.ShowPlan
         {
             get
             {
-                if (filterTypeParser == null)
+                filterTypeParser ??= new FilterTypeParser();
-                {
-                    filterTypeParser = new FilterTypeParser();
-                }
                 return filterTypeParser;
             }
         }

src/Microsoft.SqlTools.ServiceLayer/ExecutionPlan/ShowPlan/FunctionTypeParser.cs

@@ -80,10 +80,7 @@ namespace Microsoft.SqlTools.ServiceLayer.ExecutionPlan.ShowPlan
         {
             get
             {
-                if (functionTypeParser == null)
+                functionTypeParser ??= new FunctionTypeParser();
-                {
-                    functionTypeParser = new FunctionTypeParser();
-                }
                 return functionTypeParser;
             }
         }

src/Microsoft.SqlTools.ServiceLayer/ExecutionPlan/ShowPlan/IndexOpTypeParser.cs

@@ -28,10 +28,7 @@ namespace Microsoft.SqlTools.ServiceLayer.ExecutionPlan.ShowPlan
         {
             get
             {
-                if (indexOpTypeParser == null)
+                indexOpTypeParser ??= new IndexOpTypeParser();
-                {
-                    indexOpTypeParser = new IndexOpTypeParser();
-                }
                 return indexOpTypeParser;
             }
         }

src/Microsoft.SqlTools.ServiceLayer/ExecutionPlan/ShowPlan/MergeTypeParser.cs

@@ -65,10 +65,7 @@ namespace Microsoft.SqlTools.ServiceLayer.ExecutionPlan.ShowPlan
         {
             get
             {
-                if (mergeTypeParser == null)
+                mergeTypeParser ??= new MergeTypeParser();
-                {
-                    mergeTypeParser = new MergeTypeParser();
-                }
                 return mergeTypeParser;
             }
         }

src/Microsoft.SqlTools.ServiceLayer/ExecutionPlan/ShowPlan/Node.cs

@@ -36,10 +36,7 @@ namespace Microsoft.SqlTools.ServiceLayer.ExecutionPlan.ShowPlan
             this.LogicalOpUnlocName = null;
             this.PhysicalOpUnlocName = null;
             this.root = context.Graph.Root;
-            if (this.root == null)
+            this.root ??= this;
-            {
-                this.root = this;
-            }
             this.Graph = context.Graph;
         }
 

src/Microsoft.SqlTools.ServiceLayer/ExecutionPlan/ShowPlan/OperationTable.cs

@@ -6,7 +6,9 @@
 using System;
 using System.Collections.Generic;
 using System.Diagnostics;
+using System.Linq;
 using System.Reflection;
+using System.Xml.Serialization;
 
 namespace Microsoft.SqlTools.ServiceLayer.ExecutionPlan.ShowPlan
 {
@@ -372,7 +374,7 @@ namespace Microsoft.SqlTools.ServiceLayer.ExecutionPlan.ShowPlan
                 if (member.Name == enumMemberName)
                 {
                     object[] attributes = member.GetCustomAttributes(typeof(System.Xml.Serialization.XmlEnumAttribute), true);
-                    foreach (System.Xml.Serialization.XmlEnumAttribute attribute in attributes)
+                    foreach (System.Xml.Serialization.XmlEnumAttribute attribute in attributes.Cast<XmlEnumAttribute>())
                     {
                         return attribute.Name;
                     }

src/Microsoft.SqlTools.ServiceLayer/ExecutionPlan/ShowPlan/PropertyValue.cs

@@ -139,11 +139,7 @@ namespace Microsoft.SqlTools.ServiceLayer.ExecutionPlan.ShowPlan
 
                 if (this.displayName != null || this.displayNameKey != null)
                 {
-                    if (this.displayName == null)
+                    this.displayName ??= SR.Keys.GetString(this.displayNameKey);
-                    {
-                        this.displayName = SR.Keys.GetString(this.displayNameKey);
-                    }
-
                     return this.displayName;
                 }
 
@@ -159,11 +155,7 @@ namespace Microsoft.SqlTools.ServiceLayer.ExecutionPlan.ShowPlan
 
                 if (this.description != null || this.descriptionKey != null)
                 {
-                    if (this.description == null)
+                    this.description ??= SR.Keys.GetString(this.descriptionKey);
-                    {
-                        this.description = SR.Keys.GetString(this.descriptionKey);
-                    }
-
                     return this.description;
                 }
 
@@ -188,10 +180,7 @@ namespace Microsoft.SqlTools.ServiceLayer.ExecutionPlan.ShowPlan
             {
                 this.displayNameKey = displayNameDescriptionAttribute.DisplayName;
                 this.descriptionKey = displayNameDescriptionAttribute.Description;
-                if (this.descriptionKey == null)
+                this.descriptionKey ??= this.displayNameKey;
-                {
-                    this.descriptionKey = this.displayNameKey;
-                }
             }
 
             DisplayOrderAttribute displayOrderAttribute =

src/Microsoft.SqlTools.ServiceLayer/ExecutionPlan/ShowPlan/RelOpBaseTypeParser.cs

@@ -40,9 +40,9 @@ namespace Microsoft.SqlTools.ServiceLayer.ExecutionPlan.ShowPlan
                 object value = relOpProperty.GetValue(parsedItem);
                 if (value != null)
                 {
-                    if (value is IEnumerable)
+                    if (value is IEnumerable enumerable)
                     {
-                        foreach (object item in (IEnumerable)value)
+                        foreach (object item in enumerable)
                         {
                             yield return item;
                         }
@@ -72,10 +72,7 @@ namespace Microsoft.SqlTools.ServiceLayer.ExecutionPlan.ShowPlan
         {
             get
             {
-                if (relOpBaseTypeParser == null)
+                relOpBaseTypeParser ??= new RelOpBaseTypeParser();
-                {
-                    relOpBaseTypeParser = new RelOpBaseTypeParser();
-                }
                 return relOpBaseTypeParser;
             }
         }

src/Microsoft.SqlTools.ServiceLayer/ExecutionPlan/ShowPlan/RelOpTypeParser.cs

@@ -722,10 +722,7 @@ namespace Microsoft.SqlTools.ServiceLayer.ExecutionPlan.ShowPlan
         {
             get
             {
-                if (relOpTypeParser == null)
+                relOpTypeParser ??= new RelOpTypeParser();
-                {
-                    relOpTypeParser = new RelOpTypeParser();
-                }
                 return relOpTypeParser;
             }
         }

src/Microsoft.SqlTools.ServiceLayer/ExecutionPlan/ShowPlan/StatementParser.cs

@@ -133,10 +133,7 @@ namespace Microsoft.SqlTools.ServiceLayer.ExecutionPlan.ShowPlan
         {
             get
             {
-                if (statementParser == null)
+                statementParser ??= new StatementParser();
-                {
-                    statementParser = new StatementParser();
-                }
                 return statementParser;
             }
         }

src/Microsoft.SqlTools.ServiceLayer/ExecutionPlan/ShowPlan/XmlPlanHierarchyParser.cs

@@ -56,10 +56,7 @@ namespace Microsoft.SqlTools.ServiceLayer.ExecutionPlan.ShowPlan
         {
             get
             {
-                if (xmlPlanHierarchyParser == null)
+                xmlPlanHierarchyParser ??= new XmlPlanHierarchyParser();
-                {
-                    xmlPlanHierarchyParser = new XmlPlanHierarchyParser();
-                }
                 return xmlPlanHierarchyParser;
             }
         }

src/Microsoft.SqlTools.ServiceLayer/ExecutionPlan/ShowPlan/XmlPlanNodeBuilder.cs

@@ -12,6 +12,7 @@ using System.Xml;
 using System.Text;
 using System.Xml.Serialization;
 using System.Reflection;
+using System.Linq;
 
 namespace Microsoft.SqlTools.ServiceLayer.ExecutionPlan.ShowPlan
 {
@@ -40,10 +41,7 @@ namespace Microsoft.SqlTools.ServiceLayer.ExecutionPlan.ShowPlan
         public ShowPlanGraph[] Execute(object dataSource)
         {
             ShowPlanXML plan = dataSource as ShowPlanXML;
-            if (plan == null)
+            plan ??= ReadXmlShowPlan(dataSource);
-            {
-                plan = ReadXmlShowPlan(dataSource);
-            }
             List<ShowPlanGraph> graphs = new List<ShowPlanGraph>();
 
             int statementIndex = 0;
@@ -238,7 +236,7 @@ namespace Microsoft.SqlTools.ServiceLayer.ExecutionPlan.ShowPlan
             {
                 ArrayList targetStatementList = new ArrayList();
 
-                foreach (BaseStmtInfoType statement in statementBlock.Items)
+                foreach (BaseStmtInfoType statement in statementBlock.Items.Cast<BaseStmtInfoType>())
                 {
                     targetStatementList.Add(statement);
 
@@ -264,7 +262,7 @@ namespace Microsoft.SqlTools.ServiceLayer.ExecutionPlan.ShowPlan
                     //add this element and its children
                     if (stmtThen.Statements != null && stmtThen.Statements.Items != null)
                     {
-                        foreach (BaseStmtInfoType subStatement in stmtThen.Statements.Items)
+                        foreach (BaseStmtInfoType subStatement in stmtThen.Statements.Items.Cast<BaseStmtInfoType>())
                         {
                             targetStatementList.Add(subStatement);
                             FlattenConditionClauses(subStatement, targetStatementList);
@@ -280,7 +278,7 @@ namespace Microsoft.SqlTools.ServiceLayer.ExecutionPlan.ShowPlan
                         //add this element and its children
                         if (stmtElse.Statements != null && stmtElse.Statements.Items != null)
                         {
-                            foreach (BaseStmtInfoType subStatement in stmtElse.Statements.Items)
+                            foreach (BaseStmtInfoType subStatement in stmtElse.Statements.Items.Cast<BaseStmtInfoType>())
                             {
                                 targetStatementList.Add(subStatement);
                                 FlattenConditionClauses(subStatement, targetStatementList);
@@ -302,7 +300,7 @@ namespace Microsoft.SqlTools.ServiceLayer.ExecutionPlan.ShowPlan
             {
                 ArrayList targetStatementList = new ArrayList();
 
-                foreach (BaseStmtInfoType statement in statementBlock.Items)
+                foreach (BaseStmtInfoType statement in statementBlock.Items.Cast<BaseStmtInfoType>())
                 {
                     targetStatementList.Add(statement);
 
@@ -351,7 +349,7 @@ namespace Microsoft.SqlTools.ServiceLayer.ExecutionPlan.ShowPlan
                     // Call itself recursively.
                     if (functionItem.Function.Statements != null && functionItem.Function.Statements.Items != null)
                     {
-                        foreach (BaseStmtInfoType functionStatement in functionItem.Function.Statements.Items)
+                        foreach (BaseStmtInfoType functionStatement in functionItem.Function.Statements.Items.Cast<BaseStmtInfoType>())
                         {
                             ExtractFunctions(functionStatement, targetStatementList);
                         }
@@ -369,7 +367,7 @@ namespace Microsoft.SqlTools.ServiceLayer.ExecutionPlan.ShowPlan
         {
             if (statementBlock != null && statementBlock.Items != null)
             {
-                foreach (BaseStmtInfoType statement in statementBlock.Items)
+                foreach (BaseStmtInfoType statement in statementBlock.Items.Cast<BaseStmtInfoType>())
                 {
                     yield return statement;
                 }
@@ -402,10 +400,8 @@ namespace Microsoft.SqlTools.ServiceLayer.ExecutionPlan.ShowPlan
                 // check Memory Optimized table.
                 bool memoryOptimzed = false;
                 XmlNode scan = rootNode.SelectSingleNode("descendant::shp:IndexScan", nsMgr);
-                if (scan == null)
+                scan ??= rootNode.SelectSingleNode("descendant::shp:TableScan", nsMgr);
-                {
+                
-                    scan = rootNode.SelectSingleNode("descendant::shp:TableScan", nsMgr);
-                }
                 if (scan != null && scan.Attributes["Storage"] != null)
                 {
                     if (0 == string.Compare(scan.Attributes["Storage"].Value, "MemoryOptimized", StringComparison.Ordinal))

src/Microsoft.SqlTools.ServiceLayer/ExecutionPlan/ShowPlan/XmlPlanParser.cs

@@ -155,10 +155,7 @@ namespace Microsoft.SqlTools.ServiceLayer.ExecutionPlan.ShowPlan
         /// <param name="node">Node being parsed.</param>
         protected virtual void SetNodeSpecialProperties(Node node)
         {
-            if (node.Operation == null)
+            node.Operation ??= GetNodeOperation(node);
-            {
-                node.Operation = GetNodeOperation(node);
-            }
 
             // Retrieve Subtree cost for this node
             node.SubtreeCost = GetNodeSubtreeCost(node);
@@ -242,9 +239,9 @@ namespace Microsoft.SqlTools.ServiceLayer.ExecutionPlan.ShowPlan
                         continue;
                     }
 
-                    if (value is IEnumerable)
+                    if (value is IEnumerable enumerable)
                     {
-                        foreach (object item in (IEnumerable)value)
+                        foreach (object item in enumerable)
                         {
                             if (XmlPlanParserFactory.GetParser(item.GetType()) != null)
                             {

src/Microsoft.SqlTools.ServiceLayer/LanguageExtensibility/ExternalLanguageService.cs

@@ -36,10 +36,7 @@ namespace Microsoft.SqlTools.ServiceLayer.LanguageExtensibility
         {
             get
             {
-                if (connectionService == null)
+                connectionService ??= ConnectionService.Instance;
-                {
-                    connectionService = ConnectionService.Instance;
-                }
                 return connectionService;
             }
 

src/Microsoft.SqlTools.ServiceLayer/LanguageServices/Completion/CompletionService.cs

@@ -37,10 +37,7 @@ namespace Microsoft.SqlTools.ServiceLayer.LanguageServices.Completion
         {
             get
             {
-                if(this.sqlParserWrapper == null)
+                this.sqlParserWrapper ??= new SqlParserWrapper();
-                {
-                    this.sqlParserWrapper = new SqlParserWrapper();
-                }
                 return this.sqlParserWrapper;
             }
             set

src/Microsoft.SqlTools.ServiceLayer/LanguageServices/ConnectedBindingContext.cs

@@ -169,14 +169,11 @@ namespace Microsoft.SqlTools.ServiceLayer.LanguageServices
         {
             get
             {
-                if (this.parseOptions == null)
+                this.parseOptions ??= new ParseOptions(
-                {
-                    this.parseOptions = new ParseOptions(
                         batchSeparator: LanguageService.DefaultBatchSeperator,
                         isQuotedIdentifierSet: true, 
                         compatibilityLevel: DatabaseCompatibilityLevel,
                         transactSqlVersion: TransactSqlVersion);
-                }
                 return this.parseOptions;
             }
         }

src/Microsoft.SqlTools.ServiceLayer/LanguageServices/LanguageService.cs

@@ -191,10 +191,7 @@ namespace Microsoft.SqlTools.ServiceLayer.LanguageServices
         {
             get
             {
-                if (workspaceServiceInstance == null)
+                workspaceServiceInstance ??= WorkspaceService<SqlToolsSettings>.Instance;
-                {
-                    workspaceServiceInstance = WorkspaceService<SqlToolsSettings>.Instance;
-                }
                 return workspaceServiceInstance;
             }
             set
@@ -207,10 +204,7 @@ namespace Microsoft.SqlTools.ServiceLayer.LanguageServices
         {
             get
             {
-                if (this.serviceHostInstance == null)
+                this.serviceHostInstance ??= ServiceHost.Instance;
-                {
-                    this.serviceHostInstance = ServiceHost.Instance;
-                }
                 return this.serviceHostInstance;
             }
             set

src/Microsoft.SqlTools.ServiceLayer/Management/Common/DataContainer.cs

@@ -101,11 +101,7 @@ namespace Microsoft.SqlTools.ServiceLayer.Management
         {
             get
             {
-                if (m_hashTable == null)
+                m_hashTable ??= new Hashtable();
-                {
-                    m_hashTable = new Hashtable();
-                }
-
                 return m_hashTable;
             }
         }
@@ -808,11 +804,8 @@ namespace Microsoft.SqlTools.ServiceLayer.Management
                     throw new InvalidOperationException();
                 }
 
-                if (m_server == null)
-                {
                 // NOTE: ServerConnection property will constuct the object if needed
-                    m_server = new Server(ServerConnection);
+                m_server ??= new Server(ServerConnection);
-                }
             }           
             else if (this.serverType == ServerType.SQLCE)
             {
@@ -933,10 +926,7 @@ namespace Microsoft.SqlTools.ServiceLayer.Management
         public string GetDocumentPropertyString(string propertyName)
         {
             object result = GetDocumentPropertyValue(propertyName);
-            if (result == null)
+            result ??= string.Empty;
-            {
-                result = string.Empty;
-            }
 
             return (string)result;
         }
@@ -1203,10 +1193,7 @@ namespace Microsoft.SqlTools.ServiceLayer.Management
             bool databaseExists = false,
             XmlDocument containerDoc = null)
         {
-            if (containerDoc == null)
+            containerDoc ??= CreateDataContainerDocument(connInfo, databaseExists);
-            {
-                containerDoc = CreateDataContainerDocument(connInfo, databaseExists);
-            }
 
             var serverConnection = ConnectionService.OpenServerConnection(connInfo, "DataContainer");
 

src/Microsoft.SqlTools.ServiceLayer/Management/Common/IManagedConnection.cs

@@ -95,24 +95,21 @@ namespace Microsoft.SqlTools.ServiceLayer.Management
                         this.connection = (SqlOlapConnectionInfoBase)cloneable.Clone();
                         this.closeOnDispose = true;
                     }
-                    else if (sourceConnection is SqlConnectionInfoWithConnection)
+                    else if (sourceConnection is SqlConnectionInfoWithConnection connection2)
                     {
-                        this.connection = ((SqlConnectionInfoWithConnection)sourceConnection).Copy();
+                        this.connection = connection2.Copy();
                         this.closeOnDispose = true;
                     }
                 }
             }
             // if everything else has failed just use to passed in connection.
-            if (this.connection == null)
+            this.connection ??= sourceConnection;
-            {
-                this.connection = sourceConnection;
-            }
 
             // always set the lock timeout to prevent the shell from not responding
-            if (this.connection is SqlConnectionInfoWithConnection)
+            if (this.connection is SqlConnectionInfoWithConnection connection1)
             {
                 // set lock_timeout to 10 seconds
-                ((SqlConnectionInfoWithConnection)this.connection).ServerConnection.LockTimeout = 10;
+                connection1.ServerConnection.LockTimeout = 10;
             }
         }
         #endregion
@@ -190,10 +187,7 @@ namespace Microsoft.SqlTools.ServiceLayer.Management
         {
             get
             {
-                if (activeConnections == null)
+                activeConnections ??= new Hashtable();
-                {
-                    activeConnections = new Hashtable();
-                }
                 return activeConnections;
             }
         }

src/Microsoft.SqlTools.ServiceLayer/Management/Common/ManagementActionBase.cs

@@ -94,15 +94,12 @@ namespace Microsoft.SqlTools.ServiceLayer.Management
             }
 
             // allow to be sited only once
-            if (this.serviceProvider == null)
-            {                             
             // cache the service provider
-                this.serviceProvider = sp;             
+            this.serviceProvider ??= sp;
 
             // call protected virtual method to enable derived classes to do initialization
             // OnHosted();
         }
-        }
 
         #endregion
 
@@ -502,10 +499,7 @@ namespace Microsoft.SqlTools.ServiceLayer.Management
         {
             get
             {
-                if (this.cachedExecutionHandlerDelegate == null)
+                this.cachedExecutionHandlerDelegate ??= new ExecutionHandlerDelegate(this);
-                {                   
-                    this.cachedExecutionHandlerDelegate = new ExecutionHandlerDelegate(this);
-                }
                 return this.cachedExecutionHandlerDelegate;
             }
         }

src/Microsoft.SqlTools.ServiceLayer/Management/Common/Utils.cs

@@ -32,11 +32,8 @@ namespace Microsoft.SqlTools.ServiceLayer.Management
         {         
             //first, see if the object implemented this interface to override standard behavior
             System.Reflection.ICustomAttributeProvider attribProvider = objectToGetAttributeFrom as System.Reflection.ICustomAttributeProvider;
-            if (attribProvider == null)
-            {
             //if not, get it from its type
-                attribProvider = (System.Reflection.ICustomAttributeProvider)objectToGetAttributeFrom.GetType();
+            attribProvider ??= (System.Reflection.ICustomAttributeProvider)objectToGetAttributeFrom.GetType();
-            }
 
             object[] attribs = attribProvider.GetCustomAttributes(customAttribute, true);
             if (attribs != null && attribs.Length > 0)

src/Microsoft.SqlTools.ServiceLayer/Metadata/MetadataService.cs

@@ -33,10 +33,7 @@ namespace Microsoft.SqlTools.ServiceLayer.Metadata
         {
             get
             {
-                if (connectionService == null)
+                connectionService ??= ConnectionService.Instance;
-                {
-                    connectionService = ConnectionService.Instance;
-                }
                 return connectionService;
             }
 

src/Microsoft.SqlTools.ServiceLayer/Migration/MigrationService.cs

@@ -75,10 +75,7 @@ namespace Microsoft.SqlTools.ServiceLayer.Migration
         {
             get
             {
-                if (connectionService == null)
+                connectionService ??= ConnectionService.Instance;
-                {
-                    connectionService = ConnectionService.Instance;
-                }
                 return connectionService;
             }
             set

src/Microsoft.SqlTools.ServiceLayer/ModelManagement/ModelManagementService.cs

@@ -38,10 +38,7 @@ namespace Microsoft.SqlTools.ServiceLayer.ModelManagement
         {
             get
             {
-                if (connectionService == null)
+                connectionService ??= ConnectionService.Instance;
-                {
-                    connectionService = ConnectionService.Instance;
-                }
                 return connectionService;
             }
 

src/Microsoft.SqlTools.ServiceLayer/ObjectExplorer/ObjectExplorerService.cs

@@ -279,10 +279,8 @@ namespace Microsoft.SqlTools.ServiceLayer.ObjectExplorer
         internal async Task HandleFindNodesRequest(FindNodesParams findNodesParams, RequestContext<FindNodesResponse> context)
         {
             var foundNodes = FindNodes(findNodesParams.SessionId, findNodesParams.Type, findNodesParams.Schema, findNodesParams.Name, findNodesParams.Database, findNodesParams.ParentObjectNames);
-            if (foundNodes == null)
+            foundNodes ??= new List<TreeNode>();
-            {
+            
-                foundNodes = new List<TreeNode>();
-            }
             await context.SendResult(new FindNodesResponse { Nodes = foundNodes.Select(node => node.ToNodeInfo()).ToList() });
         }
 

src/Microsoft.SqlTools.ServiceLayer/ObjectExplorer/SmoModel/NodePathGenerator.cs

@@ -70,10 +70,7 @@ namespace Microsoft.SqlTools.ServiceLayer.ObjectExplorer.SmoModel
                 path = schema + "." + path;
             }
 
-            if (path == null)
+            path ??= "";
-            {
-                path = "";
-            }
 
             foreach (var matchingNode in matchingNodes)
             {

src/Microsoft.SqlTools.ServiceLayer/ObjectExplorer/SmoModel/ServerNode.cs

@@ -53,10 +53,7 @@ namespace Microsoft.SqlTools.ServiceLayer.ObjectExplorer.SmoModel
         {
             get
             {
-                if (smoWrapper == null)
+                smoWrapper ??= new SmoWrapper();
-                {
-                    smoWrapper = new SmoWrapper();
-                }
                 return smoWrapper;
             }
             set

src/Microsoft.SqlTools.ServiceLayer/Profiler/ProfilerService.cs

@@ -55,10 +55,7 @@ namespace Microsoft.SqlTools.ServiceLayer.Profiler
         {
             get
             {
-                if (connectionService == null)
+                connectionService ??= ConnectionService.Instance;
-                {
-                    connectionService = ConnectionService.Instance;
-                }
                 return connectionService;
             }
 
@@ -144,11 +141,8 @@ namespace Microsoft.SqlTools.ServiceLayer.Profiler
                 }
                 catch { }
 
-                if (xeSession == null)
-                {
                 // create a new XEvent session and Profiler session
-                    xeSession = this.XEventSessionFactory.CreateXEventSession(parameters.Template.CreateStatement, parameters.SessionName, connInfo);
+                xeSession ??= this.XEventSessionFactory.CreateXEventSession(parameters.Template.CreateStatement, parameters.SessionName, connInfo);
-                }
 
                 // start monitoring the profiler session
                 monitor.StartMonitoringSession(parameters.OwnerUri, xeSession);

src/Microsoft.SqlTools.ServiceLayer/Profiler/ProfilerSessionMonitor.cs

@@ -76,10 +76,7 @@ namespace Microsoft.SqlTools.ServiceLayer.Profiler
             lock (this.sessionsLock)
             {
                 // start the monitoring thread
-                if (this.processorThread == null)
+                this.processorThread ??= Task.Factory.StartNew(ProcessSessions);
-                {
-                    this.processorThread = Task.Factory.StartNew(ProcessSessions);
-                }
 
                 // create new profiling session if needed
                 if (!this.monitoredSessions.ContainsKey(session.Id))

src/Microsoft.SqlTools.ServiceLayer/QueryExecution/DataStorage/SaveAsExcelFileStreamWriterHelper.cs

@@ -172,9 +172,9 @@ namespace Microsoft.SqlTools.ServiceLayer.QueryExecution.DataStorage
                         AddCell((string)o);
                         break;
                     default:
-                        if (o is TimeSpan) //TimeSpan doesn't have TypeCode
+                        if (o is TimeSpan span) //TimeSpan doesn't have TypeCode
                         {
-                            AddCell((TimeSpan)o);
+                            AddCell(span);
                         }
                         // We need to handle SqlDecimal and SqlMoney types here because we can't convert them to .NET types due to different precisons in SQL Server and .NET.
                         else if (o is SqlDecimal || o is SqlMoney)
@@ -518,10 +518,7 @@ namespace Microsoft.SqlTools.ServiceLayer.QueryExecution.DataStorage
         public ExcelSheet AddSheet(string sheetName = null)
         {
             string sheetFileName = "sheet" + (sheetNames.Count + 1);
-            if (sheetName == null)
+            sheetName ??= sheetFileName;
-            {
-                sheetName = sheetFileName;
-            }
             EnsureValidSheetName(sheetName);
 
             sheetNames.Add(sheetName);

src/Microsoft.SqlTools.ServiceLayer/QueryExecution/QueryExecutionService.cs

@@ -72,13 +72,10 @@ namespace Microsoft.SqlTools.ServiceLayer.QueryExecution
         {
             get
             {
-                if (BufferFileStreamFactory == null)
+                BufferFileStreamFactory ??= new ServiceBufferFileStreamFactory
-                {
-                    BufferFileStreamFactory = new ServiceBufferFileStreamFactory
                     {
                         QueryExecutionSettings = Settings.QueryExecutionSettings
                     };
-                }
                 return BufferFileStreamFactory;
             }
         }

src/Microsoft.SqlTools.ServiceLayer/SchemaCompare/SchemaCompareService.cs

@@ -405,10 +405,7 @@ namespace Microsoft.SqlTools.ServiceLayer.SchemaCompare
         {
             get
             {
-                if (sqlTaskManagerInstance == null)
+                sqlTaskManagerInstance ??= SqlTaskManager.Instance;
-                {
-                    sqlTaskManagerInstance = SqlTaskManager.Instance;
-                }
                 return sqlTaskManagerInstance;
             }
             set
@@ -421,10 +418,7 @@ namespace Microsoft.SqlTools.ServiceLayer.SchemaCompare
         {
             get
             {
-                if (connectionService == null)
+                connectionService ??= ConnectionService.Instance;
-                {
-                    connectionService = ConnectionService.Instance;
-                }
                 return connectionService;
             }
             set

src/Microsoft.SqlTools.ServiceLayer/Scripting/ScriptingService.cs

@@ -15,6 +15,7 @@ using Microsoft.SqlTools.ServiceLayer.Hosting;
 using Microsoft.SqlTools.ServiceLayer.Scripting.Contracts;
 using Microsoft.SqlTools.Utility;
 using Microsoft.SqlTools.ServiceLayer.Utility;
+using System.Linq;
 
 namespace Microsoft.SqlTools.ServiceLayer.Scripting
 {
@@ -43,10 +44,7 @@ namespace Microsoft.SqlTools.ServiceLayer.Scripting
         {
             get
             {
-                if (connectionService == null)
+                connectionService ??= ConnectionService.Instance;
-                {
-                    connectionService = ConnectionService.Instance;
-                }
                 return connectionService;
             }
             set
@@ -117,11 +115,8 @@ namespace Microsoft.SqlTools.ServiceLayer.Scripting
                 }
             }
 
-            if (parameters.FilePath == null)
-            {
             // Create a temporary and random path to handle this operation
-                parameters.FilePath = Path.GetTempFileName();
+            parameters.FilePath ??= Path.GetTempFileName();
-            }
 
             if (!ShouldCreateScriptAsOperation(parameters))
             {
@@ -229,7 +224,7 @@ namespace Microsoft.SqlTools.ServiceLayer.Scripting
             {
                 disposed = true;
 
-                foreach (ScriptingScriptOperation operation in this.ActiveOperations.Values)
+                foreach (ScriptingScriptOperation operation in this.ActiveOperations.Values.Cast<ScriptingScriptOperation>())
                 {
                     operation.Dispose();
                 }

src/Microsoft.SqlTools.ServiceLayer/Security/SecurityService.cs

@@ -47,10 +47,7 @@ namespace Microsoft.SqlTools.ServiceLayer.Security
         {
             get
             {
-                if (connectionService == null)
+                connectionService ??= ConnectionService.Instance;
-                {
-                    connectionService = ConnectionService.Instance;
-                }
                 return connectionService;
             }
 

src/Microsoft.SqlTools.ServiceLayer/ServerConfigurations/ServerConfigService.cs

@@ -37,10 +37,7 @@ namespace Microsoft.SqlTools.ServiceLayer.ServerConfigurations
         {
             get
             {
-                if (connectionService == null)
+                connectionService ??= ConnectionService.Instance;
-                {
-                    connectionService = ConnectionService.Instance;
-                }
                 return connectionService;
             }
 

src/Microsoft.SqlTools.ServiceLayer/SqlContext/SqlToolsSettings.cs

@@ -20,10 +20,7 @@ namespace Microsoft.SqlTools.ServiceLayer.SqlContext
         { 
             get
             {
-                if (this.sqlTools == null)
+                this.sqlTools ??= new CompoundToolsSettingsValues(MssqlTools, AllSqlTools);
-                {
-                    this.sqlTools = new CompoundToolsSettingsValues(MssqlTools, AllSqlTools);
-                }
                 return this.sqlTools;
             } 
             set
@@ -40,10 +37,7 @@ namespace Microsoft.SqlTools.ServiceLayer.SqlContext
         { 
             get
             {
-                if (this.mssqlTools == null)
+                this.mssqlTools ??= new SqlToolsSettingsValues(false);
-                {
-                    this.mssqlTools = new SqlToolsSettingsValues(false);
-                }
                 return this.mssqlTools;
             } 
             set
@@ -60,10 +54,7 @@ namespace Microsoft.SqlTools.ServiceLayer.SqlContext
         { 
             get
             {
-                if (this.allSqlTools == null)
+                this.allSqlTools ??= new SqlToolsSettingsValues(false);
-                {
-                    this.allSqlTools = new SqlToolsSettingsValues(false);
-                }
                 return this.allSqlTools;
             } 
             set

src/Microsoft.SqlTools.ServiceLayer/TaskServices/SmoScriptableOperationWithFullDbAccess.cs

@@ -27,10 +27,7 @@ namespace Microsoft.SqlTools.ServiceLayer.TaskServices
         {
             get
             {
-                if (lockedDatabaseManager == null)
+                lockedDatabaseManager ??= ConnectionService.Instance.LockedDatabaseManager;
-                {
-                    lockedDatabaseManager = ConnectionService.Instance.LockedDatabaseManager;
-                }
                 return lockedDatabaseManager;
             }
             set

src/Microsoft.SqlTools.ServiceLayer/TaskServices/TaskService.cs

@@ -36,10 +36,7 @@ namespace Microsoft.SqlTools.ServiceLayer.TaskServices
         {
             get
             {
-                if(taskManager == null)
+                taskManager ??= SqlTaskManager.Instance;
-                {
-                    taskManager = SqlTaskManager.Instance;
-                }
                 return taskManager;
             }
             set

src/Microsoft.SqlTools.ServiceLayer/Utility/LongList.cs

@@ -84,13 +84,10 @@ namespace Microsoft.SqlTools.ServiceLayer.Utility
                 shortList.Add(val);
             }
             else // need to split values into several arrays 
-            {
-                if (expandedList == null)
             {
                 // very inefficient so delay as much as possible
                 // immediately add 0th array
-                    expandedList = new List<List<T>> {shortList};
+                expandedList ??= new List<List<T>> {shortList};
-                }
 
                 int arrayIndex = (int)(Count / this.ExpandListSize); // 0 based
 

test/Microsoft.SqlTools.ServiceLayer.IntegrationTests/Agent/AgentTestUtils.cs

@@ -357,10 +357,7 @@ namespace Microsoft.SqlTools.ServiceLayer.IntegrationTests.Agent
             AgentNotebookInfo notebook = null)
         {
             var service = new AgentService();
-            if (notebook == null)
+            notebook ??= GetTestNotebookInfo("myTestNotebookJob" + Guid.NewGuid().ToString(), "master");
-            {
-                notebook = GetTestNotebookInfo("myTestNotebookJob" + Guid.NewGuid().ToString(), "master");
-            }
             string tempNotebookPath = CreateTemplateNotebookFile();
 
             await AgentNotebookHelper.CreateNotebook(

test/Microsoft.SqlTools.ServiceLayer.IntegrationTests/DisasterRecovery/RestoreDatabaseServiceTests.cs

@@ -50,18 +50,12 @@ namespace Microsoft.SqlTools.ServiceLayer.IntegrationTests.DisasterRecovery
 
         private async Task VerifyBackupFileCreated()
         {
-            if (fullBackupFilePath == null)
+            fullBackupFilePath ??= await CreateBackupFile();
-            {
-                fullBackupFilePath = await CreateBackupFile();
-            }
         }
 
         private async Task<string[]> GetBackupFilesToRecoverDatabaseCreated()
         {
-            if (backupFilesToRecoverDatabase == null)
+            backupFilesToRecoverDatabase ??= await CreateBackupSetsToRecoverDatabase();
-            {
-                backupFilesToRecoverDatabase = await CreateBackupSetsToRecoverDatabase();
-            }
             return backupFilesToRecoverDatabase;
         }
 

test/Microsoft.SqlTools.ServiceLayer.PerfTests/Tests/IntellisenseTests.cs

@@ -283,10 +283,7 @@ namespace Microsoft.SqlTools.ServiceLayer.PerfTests
             TestTimer timer = null,
             [CallerMemberName] string testName = "")
         {
-            if (timer == null)
+            timer ??= new TestTimer { PrintResult = false };
-            {
-                timer = new TestTimer { PrintResult = false };
-            }
             bool isReady = !waitForIntelliSense;
             await testService.ExecuteWithTimeout(timer, 550000, async () =>
             {

test/Microsoft.SqlTools.ServiceLayer.Test.Common/Baselined/BaselinedTest.cs

@@ -146,8 +146,7 @@ namespace Microsoft.SqlTools.ServiceLayer.Test.Common.Baselined
         {
             get 
             {
-                if (this._baselineSubDir == null)
+                this._baselineSubDir ??= string.Empty;
-                    this._baselineSubDir = string.Empty;
                 return this._baselineSubDir; 
             }
             set { this._baselineSubDir = value; }

test/Microsoft.SqlTools.ServiceLayer.Test.Common/TestLogger.cs

@@ -65,10 +65,7 @@ namespace Microsoft.SqlTools.ServiceLayer.Test.Common
         {
             get
             {
-                if (pendingVerifications == null)
+                pendingVerifications ??= new List<Action>();
-                {
-                    pendingVerifications = new List<Action>();
-                }
                 return pendingVerifications;
             }
             set => pendingVerifications = value;

test/Microsoft.SqlTools.ServiceLayer.TestEnvConfig/Program.cs

@@ -13,6 +13,7 @@ namespace Microsoft.SqlTools.ServiceLayer.TestEnvConfig
 {
     class Program
     {
+        [System.Diagnostics.CodeAnalysis.SuppressMessage("Style", "IDE0210:Convert to top-level statements", Justification = "Structure retained for readability.")]
         static void Main(string[] args)
         {
             if (args.Length == 1)

test/Microsoft.SqlTools.ServiceLayer.UnitTests/Messaging/MessageReaderTests.cs

@@ -236,10 +236,7 @@ namespace Microsoft.SqlTools.ServiceLayer.UnitTests.Messaging
 
         private byte[] GetMessageBytes(string messageString, Encoding encoding = null)
         {
-            if (encoding == null)
+            encoding ??= Encoding.UTF8;
-            {
-                encoding = Encoding.UTF8;
-            }
 
             byte[] messageBytes = Encoding.UTF8.GetBytes(messageString);
             byte[] headerBytes = Encoding.ASCII.GetBytes(string.Format(Constants.ContentLengthFormatString, messageBytes.Length));

test/Microsoft.SqlTools.ServiceLayer.UnitTests/ServiceHost/ScriptFileTests.cs

@@ -24,10 +24,7 @@ namespace Microsoft.SqlTools.ServiceLayer.UnitTests.ServiceHost
 
         public static ScriptFile GetTestScriptFile(string initialText = null)
         {
-            if (initialText == null)
+            initialText ??= ScriptFileTests.query;
-            {
-                initialText = ScriptFileTests.query;
-            }
 
             string ownerUri = System.IO.Path.GetTempFileName();
 

test/Microsoft.SqlTools.ServiceLayer.UnitTests/Utility/TestDbDataReader.cs

@@ -68,10 +68,7 @@ namespace Microsoft.SqlTools.ServiceLayer.UnitTests.Utility
             {
                 throw new TestDbException();
             }
-            if (RowEnumerator == null)
+            RowEnumerator ??= ResultSetEnumerator.Current.GetEnumerator();
-            {
-                RowEnumerator = ResultSetEnumerator.Current.GetEnumerator();
-            }
             return RowEnumerator.MoveNext();
         }