Use null-coalescing assignment in the rest of /engine (PowerShell#17729)

Molkree · web-flow · commit 17791759356f · 2022-07-26T12:31:14.000-07:00
diff --git a/src/System.Management.Automation/engine/CmdletInfo.cs b/src/System.Management.Automation/engine/CmdletInfo.cs
@@ -380,11 +380,8 @@ public override ReadOnlyCollection<PSTypeName> OutputType
                         }
                     }
 
-                    if (provider == null)
-                    {
-                        // No path argument, so just use the current path to choose the provider.
-                        provider = Context.SessionState.Path.CurrentLocation.Provider;
-                    }
+                    // If no path argument, just use the current path to choose the provider.
+                    provider ??= Context.SessionState.Path.CurrentLocation.Provider;
 
                     provider.GetOutputTypes(Name, providerTypes);
                     if (providerTypes.Count > 0)
diff --git a/src/System.Management.Automation/engine/CmdletParameterBinderController.cs b/src/System.Management.Automation/engine/CmdletParameterBinderController.cs
@@ -270,8 +270,7 @@ internal void BindCommandLineParametersNoValidation(Collection<CommandParameterI
 
             // If this generated an exception (but we didn't have one from the non-dynamic
             // parameters, report on this one.
-            if (reportedBindingException == null)
-                reportedBindingException = currentBindingException;
+            reportedBindingException ??= currentBindingException;
 
             // If the cmdlet implements a ValueFromRemainingArguments parameter (VarArgs)
             // bind the unbound arguments to that parameter.
@@ -1452,8 +1451,7 @@ private bool BindParameter(
 
                     BoundObsoleteParameterNames.Add(parameter.Parameter.Name);
 
-                    if (ObsoleteParameterWarningList == null)
-                        ObsoleteParameterWarningList = new List<WarningRecord>();
+                    ObsoleteParameterWarningList ??= new List<WarningRecord>();
 
                     ObsoleteParameterWarningList.Add(warningRecord);
                 }
diff --git a/src/System.Management.Automation/engine/ComInterop/ComEventsSink.Extended.cs b/src/System.Management.Automation/engine/ComInterop/ComEventsSink.Extended.cs
@@ -18,10 +18,7 @@ private void Initialize(object rcw, Guid iid)
         public void AddHandler(int dispid, object func)
         {
             ComEventsMethod method = FindMethod(dispid);
-            if (method == null)
-            {
-                method = AddMethod(dispid);
-            }
+            method ??= AddMethod(dispid);
 
             if (func is Delegate d)
             {
diff --git a/src/System.Management.Automation/engine/ComInterop/ComInvokeBinder.cs b/src/System.Management.Automation/engine/ComInterop/ComInvokeBinder.cs
@@ -114,10 +114,7 @@ private ParameterExpression ParamVariantsVariable
         {
             get
             {
-                if (_paramVariants == null)
-                {
-                    _paramVariants = Expression.Variable(VariantArray.GetStructType(_args.Length), "paramVariants");
-                }
+                _paramVariants ??= Expression.Variable(VariantArray.GetStructType(_args.Length), "paramVariants");
                 return _paramVariants;
             }
         }
@@ -140,10 +137,7 @@ private static Type MarshalType(DynamicMetaObject mo, bool isByRef)
             if (isByRef)
             {
                 // Null just means that null was supplied.
-                if (marshalType == null)
-                {
-                    marshalType = mo.Expression.Type;
-                }
+                marshalType ??= mo.Expression.Type;
                 marshalType = marshalType.MakeByRefType();
             }
             return marshalType;
diff --git a/src/System.Management.Automation/engine/ComInterop/ComTypeClassDesc.cs b/src/System.Management.Automation/engine/ComInterop/ComTypeClassDesc.cs
@@ -17,10 +17,7 @@ internal class ComTypeClassDesc : ComTypeDesc, IDynamicMetaObjectProvider
 
         public object CreateInstance()
         {
-            if (_typeObj == null)
-            {
-                _typeObj = Type.GetTypeFromCLSID(Guid);
-            }
+            _typeObj ??= Type.GetTypeFromCLSID(Guid);
             return Activator.CreateInstance(Type.GetTypeFromCLSID(Guid));
         }
 
@@ -46,19 +43,12 @@ private void AddInterface(ComTypes.ITypeInfo itfTypeInfo, bool isSourceItf)
 
             if (isSourceItf)
             {
-                if (_sourceItfs == null)
-                {
-                    _sourceItfs = new LinkedList<string>();
-                }
+                _sourceItfs ??= new LinkedList<string>();
                 _sourceItfs.AddLast(itfName);
             }
             else
             {
-                if (_itfs == null)
-                {
-                    _itfs = new LinkedList<string>();
-                }
-
+                _itfs ??= new LinkedList<string>();
                 _itfs.AddLast(itfName);
             }
         }
diff --git a/src/System.Management.Automation/engine/ComInterop/IDispatchComObject.cs b/src/System.Management.Automation/engine/ComInterop/IDispatchComObject.cs
@@ -271,10 +271,7 @@ internal override IList<string> GetMemberNames(bool dataOnly)
 
         internal override IList<KeyValuePair<string, object>> GetMembers(IEnumerable<string> names)
         {
-            if (names == null)
-            {
-                names = GetMemberNames(true);
-            }
+            names ??= GetMemberNames(true);
 
             Type comType = RuntimeCallableWrapper.GetType();
 
diff --git a/src/System.Management.Automation/engine/ComInterop/InteropServices/ComEventsMethod.cs b/src/System.Management.Automation/engine/ComInterop/InteropServices/ComEventsMethod.cs
@@ -83,10 +83,7 @@ private void PreProcessSignature()
                         && pi.ParameterType.HasElementType
                         && pi.ParameterType.GetElementType()!.IsEnum)
                     {
-                        if (targetTypes == null)
-                        {
-                            targetTypes = new Type?[_expectedParamsCount];
-                        }
+                        targetTypes ??= new Type?[_expectedParamsCount];
 
                         targetTypes[i] = pi.ParameterType.GetElementType();
                     }
diff --git a/src/System.Management.Automation/engine/ComInterop/SplatCallSite.cs b/src/System.Management.Automation/engine/ComInterop/SplatCallSite.cs
@@ -30,10 +30,7 @@ internal object Invoke(object[] args)
             Debug.Assert(args != null);
 
             // Create a CallSite and invoke it.
-            if (_site == null)
-            {
-                _site = CallSite<Func<CallSite, object, object[], object>>.Create(SplatInvokeBinder.Instance);
-            }
+            _site ??= CallSite<Func<CallSite, object, object[], object>>.Create(SplatInvokeBinder.Instance);
 
             return _site.Target(_site, _callable, args);
         }
diff --git a/src/System.Management.Automation/engine/ComInterop/TypeUtils.cs b/src/System.Management.Automation/engine/ComInterop/TypeUtils.cs
@@ -102,11 +102,9 @@ internal static MethodInfo GetUserDefinedCoercionMethod(Type convertFrom, Type c
             // try lifted conversion
             if (nnExprType != convertFrom || nnConvType != convertToType)
             {
-                method = FindConversionOperator(eMethods, nnExprType, nnConvType, implicitOnly);
-                if (method == null)
-                {
-                    method = FindConversionOperator(cMethods, nnExprType, nnConvType, implicitOnly);
-                }
+                method =
+                    FindConversionOperator(eMethods, nnExprType, nnConvType, implicitOnly) ??
+                    FindConversionOperator(cMethods, nnExprType, nnConvType, implicitOnly);
                 if (method != null)
                 {
                     return method;
diff --git a/src/System.Management.Automation/engine/CommandCompletion/CompletionAnalysis.cs b/src/System.Management.Automation/engine/CommandCompletion/CompletionAnalysis.cs
@@ -183,10 +183,7 @@ private CompletionContext InitializeCompletionContext(TypeInferenceContext typeI
         {
             var astContext = ExtractAstContext(_ast, _tokens, _cursorPosition);
 
-            if (typeInferenceContext.CurrentTypeDefinitionAst == null)
-            {
-                typeInferenceContext.CurrentTypeDefinitionAst = Ast.GetAncestorTypeDefinitionAst(astContext.RelatedAsts.Last());
-            }
+            typeInferenceContext.CurrentTypeDefinitionAst ??= Ast.GetAncestorTypeDefinitionAst(astContext.RelatedAsts.Last());
 
             ExecutionContext executionContext = typeInferenceContext.ExecutionContext;
 
@@ -1894,10 +1891,7 @@ private static List<CompletionResult> GetResultForIdentifierInConfiguration(
                         usageString = Microsoft.PowerShell.DesiredStateConfiguration.Internal.DscClassCache.GetDSCResourceUsageString(keyword);
                     }
 
-                    if (results == null)
-                    {
-                        results = new List<CompletionResult>();
-                    }
+                    results ??= new List<CompletionResult>();
 
                     results.Add(new CompletionResult(
                         keyword.Keyword,
diff --git a/src/System.Management.Automation/engine/CommandCompletion/CompletionCompleters.cs b/src/System.Management.Automation/engine/CommandCompletion/CompletionCompleters.cs
@@ -333,10 +333,7 @@ internal static List<CompletionResult> MakeCommandsUnique(IEnumerable<PSObject>
                 var commandList = keyValuePair.Value as List<object>;
                 if (commandList != null)
                 {
-                    if (endResults == null)
-                    {
-                        endResults = new List<CompletionResult>();
-                    }
+                    endResults ??= new List<CompletionResult>();
 
                     // The first command might be an un-prefixed commandInfo that we get by importing a module with the -Prefix parameter,
                     // in that case, we should add the module name qualification because if the module is not in the module path, calling
@@ -495,8 +492,7 @@ internal static List<CompletionResult> CompleteCommandParameter(CompletionContex
             DynamicKeywordStatementAst keywordAst = null;
             for (int i = context.RelatedAsts.Count - 1; i >= 0; i--)
             {
-                if (keywordAst == null)
-                    keywordAst = context.RelatedAsts[i] as DynamicKeywordStatementAst;
+                keywordAst ??= context.RelatedAsts[i] as DynamicKeywordStatementAst;
                 parameterAst = (context.RelatedAsts[i] as CommandParameterAst);
                 if (parameterAst != null) break;
             }
@@ -1624,8 +1620,7 @@ private static void CompletePositionalArgument(
                         }
                         else
                         {
-                            if (positionalParam == null)
-                                positionalParam = param;
+                            positionalParam ??= param;
                         }
                     }
                     else
@@ -5762,9 +5757,9 @@ internal static List<CompletionResult> CompleteMember(CompletionContext context,
                 // a MemberExpressionAst '$xml.$xml', whose parent is still a MemberExpressionAst '$xml.$xml.Save'.
                 // But here we DO NOT want to re-assign 'targetExpr' to be '$xml.$xml'. 'targetExpr' in this case
                 // should be '$xml'.
-                else if (targetExpr is null)
+                else
                 {
-                    targetExpr = parentAsMemberExpression.Expression;
+                    targetExpr ??= parentAsMemberExpression.Expression;
                 }
             }
             else if (lastAst.Parent is BinaryExpressionAst binaryExpression && context.TokenAtCursor.Kind.Equals(TokenKind.Multiply))
diff --git a/src/System.Management.Automation/engine/CommandDiscovery.cs b/src/System.Management.Automation/engine/CommandDiscovery.cs
@@ -809,10 +809,7 @@ internal static CommandInfo LookupCommandInfo(
                     }
 
                     // Otherwise, invoke the CommandNotFound handler
-                    if (result == null)
-                    {
-                        result = InvokeCommandNotFoundHandler(commandName, context, originalCommandName, commandOrigin);
-                    }
+                    result ??= InvokeCommandNotFoundHandler(commandName, context, originalCommandName, commandOrigin);
                 } while (false);
             }
             else
diff --git a/src/System.Management.Automation/engine/CommandParameter.cs b/src/System.Management.Automation/engine/CommandParameter.cs
@@ -124,10 +124,7 @@ internal bool ArgumentToBeSplatted
         /// </summary>
         internal void SetArgumentValue(Ast ast, object value)
         {
-            if (_argument == null)
-            {
-                _argument = new Argument();
-            }
+            _argument ??= new Argument();
 
             _argument.value = value;
             _argument.ast = ast;
diff --git a/src/System.Management.Automation/engine/CommandPathSearch.cs b/src/System.Management.Automation/engine/CommandPathSearch.cs
@@ -493,8 +493,7 @@ private void GetNewDirectoryResults(string pattern, string directory)
                         if (name.Equals(baseNames[i], StringComparison.OrdinalIgnoreCase)
                             || (!Platform.IsWindows && Platform.NonWindowsIsExecutable(name)))
                         {
-                            if (result == null)
-                                result = new Collection<string>();
+                            result ??= new Collection<string>();
                             result.Add(fileNames[i]);
                             break;
                         }
@@ -520,8 +519,7 @@ private void GetNewDirectoryResults(string pattern, string directory)
                     if (fileName.EndsWith(allowedExt, StringComparison.OrdinalIgnoreCase)
                         || (!Platform.IsWindows && Platform.NonWindowsIsExecutable(fileName)))
                     {
-                        if (result == null)
-                            result = new Collection<string>();
+                        result ??= new Collection<string>();
                         result.Add(fileName);
                     }
                 }
diff --git a/src/System.Management.Automation/engine/CommandProcessorBase.cs b/src/System.Management.Automation/engine/CommandProcessorBase.cs
@@ -352,10 +352,7 @@ internal void SetCurrentScopeToExecutionScope()
             // Make sure we have a session state instance for this command.
             // If one hasn't been explicitly set, then use the session state
             // available on the engine execution context...
-            if (CommandSessionState == null)
-            {
-                CommandSessionState = Context.EngineSessionState;
-            }
+            CommandSessionState ??= Context.EngineSessionState;
 
             // Store off the current scope
             _previousScope = CommandSessionState.CurrentScope;
diff --git a/src/System.Management.Automation/engine/CommandSearcher.cs b/src/System.Management.Automation/engine/CommandSearcher.cs
@@ -928,10 +928,7 @@ private static bool ShouldSkipCommandResolutionForConstrainedLanguage(CommandInf
                     }
                 }
 
-                if (module == null)
-                {
-                    module = modules[0];
-                }
+                module ??= modules[0];
             }
 
             return module;
diff --git a/src/System.Management.Automation/engine/Modules/ImportModuleCommand.cs b/src/System.Management.Automation/engine/Modules/ImportModuleCommand.cs
@@ -661,11 +661,8 @@ private PSModuleInfo ImportModule_LocallyViaName(ImportModuleOptions importModul
                     }
                 }
 
-                if (rootedPath == null)
-                {
-                    // Check for full-qualified paths - either absolute or relative
-                    rootedPath = ResolveRootedFilePath(name, this.Context);
-                }
+                // If null check for full-qualified paths - either absolute or relative
+                rootedPath ??= ResolveRootedFilePath(name, this.Context);
 
                 bool alreadyLoaded = false;
                 var manifestProcessingFlags = ManifestProcessingFlags.LoadElements | ManifestProcessingFlags.NullOnFirstError;
@@ -1413,21 +1410,15 @@ private bool IsPs1xmlFileHelper(RemoteDiscoveryHelper.CimModuleFile cimModuleFil
                 goodEntries = new List<string>();
             }
 
-            if (goodEntries == null)
-            {
-                goodEntries = new List<string>();
-            }
+            goodEntries ??= new List<string>();
 
             List<string> badEntries;
             if (!this.GetListOfStringsFromData(manifestData, null, badKey, 0, out badEntries))
             {
                 badEntries = new List<string>();
             }
 
-            if (badEntries == null)
-            {
-                badEntries = new List<string>();
-            }
+            badEntries ??= new List<string>();
 
             bool presentInGoodEntries = IsPs1xmlFileHelper_IsPresentInEntries(cimModuleFile, goodEntries);
             bool presentInBadEntries = IsPs1xmlFileHelper_IsPresentInEntries(cimModuleFile, badEntries);
diff --git a/src/System.Management.Automation/engine/Modules/ModuleCmdletBase.cs b/src/System.Management.Automation/engine/Modules/ModuleCmdletBase.cs
diff --git a/src/System.Management.Automation/engine/Modules/ModuleIntrinsics.cs b/src/System.Management.Automation/engine/Modules/ModuleIntrinsics.cs
diff --git a/src/System.Management.Automation/engine/Modules/NewModuleManifestCommand.cs b/src/System.Management.Automation/engine/Modules/NewModuleManifestCommand.cs

Original file line number	Diff line number	Diff line change
`@@ -380,11 +380,8 @@ public override ReadOnlyCollection<PSTypeName> OutputType`
`380`	`380`	`}`
`381`	`381`	`}`
`382`	`382`
`383`		`- if (provider == null)`
`384`		`- {`
`385`		`- // No path argument, so just use the current path to choose the provider.`
`386`		`- provider = Context.SessionState.Path.CurrentLocation.Provider;`
`387`		`- }`
	`383`	`+ // If no path argument, just use the current path to choose the provider.`
	`384`	`+ provider ??= Context.SessionState.Path.CurrentLocation.Provider;`
`388`	`385`
`389`	`386`	`provider.GetOutputTypes(Name, providerTypes);`
`390`	`387`	`if (providerTypes.Count > 0)`
Original file line number	Diff line number	Diff line change
`@@ -18,10 +18,7 @@ private void Initialize(object rcw, Guid iid)`
`18`	`18`	`public void AddHandler(int dispid, object func)`
`19`	`19`	`{`
`20`	`20`	`ComEventsMethod method = FindMethod(dispid);`
`21`		`- if (method == null)`
`22`		`- {`
`23`		`- method = AddMethod(dispid);`
`24`		`- }`
	`21`	`+ method ??= AddMethod(dispid);`
`25`	`22`
`26`	`23`	`if (func is Delegate d)`
`27`	`24`	`{`
Original file line number	Diff line number	Diff line change
`@@ -114,10 +114,7 @@ private ParameterExpression ParamVariantsVariable`
`114`	`114`	`{`
`115`	`115`	`get`
`116`	`116`	`{`
`117`		`- if (_paramVariants == null)`
`118`		`- {`
`119`		`- _paramVariants = Expression.Variable(VariantArray.GetStructType(_args.Length), "paramVariants");`
`120`		`- }`
	`117`	`+ _paramVariants ??= Expression.Variable(VariantArray.GetStructType(_args.Length), "paramVariants");`
`121`	`118`	`return _paramVariants;`
`122`	`119`	`}`
`123`	`120`	`}`
`@@ -140,10 +137,7 @@ private static Type MarshalType(DynamicMetaObject mo, bool isByRef)`
`140`	`137`	`if (isByRef)`
`141`	`138`	`{`
`142`	`139`	`// Null just means that null was supplied.`
`143`		`- if (marshalType == null)`
`144`		`- {`
`145`		`- marshalType = mo.Expression.Type;`
`146`		`- }`
	`140`	`+ marshalType ??= mo.Expression.Type;`
`147`	`141`	`marshalType = marshalType.MakeByRefType();`
`148`	`142`	`}`
`149`	`143`	`return marshalType;`
Original file line number	Diff line number	Diff line change
`@@ -17,10 +17,7 @@ internal class ComTypeClassDesc : ComTypeDesc, IDynamicMetaObjectProvider`
`17`	`17`
`18`	`18`	`public object CreateInstance()`
`19`	`19`	`{`
`20`		`- if (_typeObj == null)`
`21`		`- {`
`22`		`- _typeObj = Type.GetTypeFromCLSID(Guid);`
`23`		`- }`
	`20`	`+ _typeObj ??= Type.GetTypeFromCLSID(Guid);`
`24`	`21`	`return Activator.CreateInstance(Type.GetTypeFromCLSID(Guid));`
`25`	`22`	`}`
`26`	`23`
`@@ -46,19 +43,12 @@ private void AddInterface(ComTypes.ITypeInfo itfTypeInfo, bool isSourceItf)`
`46`	`43`
`47`	`44`	`if (isSourceItf)`
`48`	`45`	`{`
`49`		`- if (_sourceItfs == null)`
`50`		`- {`
`51`		`- _sourceItfs = new LinkedList<string>();`
`52`		`- }`
	`46`	`+ _sourceItfs ??= new LinkedList<string>();`
`53`	`47`	`_sourceItfs.AddLast(itfName);`
`54`	`48`	`}`
`55`	`49`	`else`
`56`	`50`	`{`
`57`		`- if (_itfs == null)`
`58`		`- {`
`59`		`- _itfs = new LinkedList<string>();`
`60`		`- }`
`61`		`-`
	`51`	`+ _itfs ??= new LinkedList<string>();`
`62`	`52`	`_itfs.AddLast(itfName);`
`63`	`53`	`}`
`64`	`54`	`}`
Original file line number	Diff line number	Diff line change
`@@ -271,10 +271,7 @@ internal override IList<string> GetMemberNames(bool dataOnly)`
`271`	`271`
`272`	`272`	`internal override IList<KeyValuePair<string, object>> GetMembers(IEnumerable<string> names)`
`273`	`273`	`{`
`274`		`- if (names == null)`
`275`		`- {`
`276`		`- names = GetMemberNames(true);`
`277`		`- }`
	`274`	`+ names ??= GetMemberNames(true);`
`278`	`275`
`279`	`276`	`Type comType = RuntimeCallableWrapper.GetType();`
`280`	`277`
Original file line number	Diff line number	Diff line change
`@@ -83,10 +83,7 @@ private void PreProcessSignature()`
`83`	`83`	`&& pi.ParameterType.HasElementType`
`84`	`84`	`&& pi.ParameterType.GetElementType()!.IsEnum)`
`85`	`85`	`{`
`86`		`- if (targetTypes == null)`
`87`		`- {`
`88`		`- targetTypes = new Type?[_expectedParamsCount];`
`89`		`- }`
	`86`	`+ targetTypes ??= new Type?[_expectedParamsCount];`
`90`	`87`
`91`	`88`	`targetTypes[i] = pi.ParameterType.GetElementType();`
`92`	`89`	`}`