Fix

src/Features/CSharp/Portable/TypeStyle/UseExplicitTypeCodeFixProvider.cs

@@ -130,7 +130,7 @@ private static ExpressionSyntax GenerateTupleDeclaration(ITypeSymbol typeSymbol,
                 {
                     case SyntaxKind.SingleVariableDesignation:
                     case SyntaxKind.DiscardDesignation:
-                        var typeName = type.GenerateTypeSyntax();
+                        var typeName = type.GenerateTypeSyntax(allowVar: false);
                         newDeclaration = SyntaxFactory.DeclarationExpression(typeName, designation);
                         break;
                     case SyntaxKind.ParenthesizedVariableDesignation:

src/Workspaces/CSharp/Portable/Utilities/CSharpTypeStyleHelper.State.cs

@@ -160,7 +160,7 @@ private TypeSyntax GetTypeSyntaxFromDeclaration(SyntaxNode declarationStatement)
                     _ => null,
                 };
 
-            private static UseVarPreference GetCurrentTypeStylePreferences(OptionSet optionSet)
+            private UseVarPreference GetCurrentTypeStylePreferences(OptionSet optionSet)
             {
                 var stylePreferences = UseVarPreference.None;