Simplify

src/Features/CSharp/Portable/CodeFixes/AddExplicitCast/ArgumentFixer.cs

@@ -20,6 +20,9 @@ public ArgumentFixer(CSharpAddExplicitCastCodeFixProvider provider) : base(provi
             {
             }
 
+            protected override ExpressionSyntax GetExpressionOfArgument(ArgumentSyntax argument)
+                => argument.Expression;
+
             protected override ArgumentSyntax GenerateNewArgument(ArgumentSyntax oldArgument, ITypeSymbol conversionType)
                 => oldArgument.WithExpression(oldArgument.Expression.Cast(conversionType));
 

src/Features/CSharp/Portable/CodeFixes/AddExplicitCast/AttributeArgumentFixer.cs

@@ -20,6 +20,9 @@ public AttributeArgumentFixer(CSharpAddExplicitCastCodeFixProvider provider) : b
             {
             }
 
+            protected override ExpressionSyntax GetExpressionOfArgument(AttributeArgumentSyntax argument)
+                => argument.Expression;
+
             protected override AttributeArgumentSyntax GenerateNewArgument(AttributeArgumentSyntax oldArgument, ITypeSymbol conversionType)
                 => oldArgument.WithExpression(oldArgument.Expression.Cast(conversionType));
 

src/Features/Core/Portable/CodeFixes/AddExplicitCast/Fixer.cs

@@ -26,6 +26,7 @@ protected abstract class Fixer<TArgumentSyntax, TArgumentListSyntax, TInvocation
             protected Fixer(AbstractAddExplicitCastCodeFixProvider<TExpressionSyntax> provider)
                 => _provider = provider;
 
+            protected abstract TExpressionSyntax GetExpressionOfArgument(TArgumentSyntax argument);
             protected abstract TArgumentSyntax GenerateNewArgument(TArgumentSyntax oldArgument, ITypeSymbol conversionType);
             protected abstract TArgumentListSyntax GenerateNewArgumentList(TArgumentListSyntax oldArgumentList, ArrayBuilder<TArgumentSyntax> newArguments);
             protected abstract SeparatedSyntaxList<TArgumentSyntax> GetArgumentsOfArgumentList(TArgumentListSyntax argumentList);
@@ -67,7 +68,7 @@ protected Fixer(AbstractAddExplicitCastCodeFixProvider<TExpressionSyntax> provid
                     if (CanArgumentTypesBeConvertedToParameterTypes(
                             semanticModel, root, argumentList, candidateSymbol.Parameters,
                             targetArgument, cancellationToken, out var targetArgumentConversionType)
-                        && _provider.SyntaxFacts.GetExpressionOfArgument(targetArgument) is TExpressionSyntax argumentExpression)
+                        && GetExpressionOfArgument(targetArgument) is TExpressionSyntax argumentExpression)
                     {
                         mutablePotentialConversionTypes.Add((argumentExpression, targetArgumentConversionType));
                     }
@@ -144,7 +145,7 @@ protected Fixer(AbstractAddExplicitCastCodeFixProvider<TExpressionSyntax> provid
                     }
 
                     // The argument is either in order with parameters, or have a matched name with parameters.
-                    var argumentExpression = syntaxFacts.GetExpressionOfArgument(arguments[i]) as TExpressionSyntax;
+                    var argumentExpression = GetExpressionOfArgument(arguments[i]);
                     if (argumentExpression == null)
                     {
                         // argumentExpression is null when it is an omitted argument in VB .NET

src/Features/VisualBasic/Portable/CodeFixes/AddExplicitCast/ArgumentFixer.vb

@@ -14,6 +14,10 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.CodeFixes.AddExplicitCast
                 MyBase.New(provider)
             End Sub
 
+            Protected Overrides Function GetExpressionOfArgument(argument As ArgumentSyntax) As ExpressionSyntax
+                Return argument.GetArgumentExpression()
+            End Function
+
             Protected Overrides Function GenerateNewArgument(oldArgument As ArgumentSyntax, conversionType As ITypeSymbol) As ArgumentSyntax
                 Select Case oldArgument.Kind
                     Case SyntaxKind.SimpleArgument

src/Workspaces/SharedUtilitiesAndExtensions/Compiler/CSharp/Services/SyntaxFacts/CSharpSyntaxFacts.cs

@@ -570,17 +570,7 @@ public bool IsBaseTypeList(SyntaxNode node)
             => node.IsKind(SyntaxKind.BaseList);
 
         public SyntaxNode GetExpressionOfArgument(SyntaxNode node)
-        {
-            if (node is ArgumentSyntax)
-            {
-                return ((ArgumentSyntax)node).Expression;
-            }
-            else
-            {
-                // node is AttributeArgumentSyntax
-                return ((AttributeArgumentSyntax)node).Expression;
-            }
-        }
+            => (node as ArgumentSyntax)?.Expression;
 
         public RefKind GetRefKindOfArgument(SyntaxNode node)
             => (node as ArgumentSyntax).GetRefKind();