diff --git a/src/Avalonia.Build.Tasks/Avalonia.Build.Tasks.csproj b/src/Avalonia.Build.Tasks/Avalonia.Build.Tasks.csproj
index 49e793cfda..e200b48166 100644
--- a/src/Avalonia.Build.Tasks/Avalonia.Build.Tasks.csproj
+++ b/src/Avalonia.Build.Tasks/Avalonia.Build.Tasks.csproj
@@ -5,7 +5,7 @@
         <OutputType>exe</OutputType>
         <GenerateDocumentationFile>false</GenerateDocumentationFile>
         <BuildOutputTargetFolder>tools</BuildOutputTargetFolder>
-        <DefineConstants>$(DefineConstants);BUILDTASK;XAMLIL_CECIL_INTERNAL;XAMLIL_INTERNAL</DefineConstants>
+        <DefineConstants>$(DefineConstants);BUILDTASK;XAMLX_CECIL_INTERNAL;XAMLX_INTERNAL</DefineConstants>
         <CopyLocalLockFileAssemblies Condition="$(TargetFramework) == 'netstandard2.0'">true</CopyLocalLockFileAssemblies>
         <NoWarn>NU1605</NoWarn>
     </PropertyGroup>
diff --git a/src/Markup/Avalonia.Markup.Xaml/Avalonia.Markup.Xaml.csproj b/src/Markup/Avalonia.Markup.Xaml/Avalonia.Markup.Xaml.csproj
index 48f4b75e90..7ac349b1b0 100644
--- a/src/Markup/Avalonia.Markup.Xaml/Avalonia.Markup.Xaml.csproj
+++ b/src/Markup/Avalonia.Markup.Xaml/Avalonia.Markup.Xaml.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <TargetFramework>netstandard2.0</TargetFramework>
-    <DefineConstants>PCL;NETSTANDARD;NETSTANDARD2_0;HAS_TYPE_CONVERTER;HAS_CUSTOM_ATTRIBUTE_PROVIDER;XAMLIL_INTERNAL</DefineConstants>
+    <DefineConstants>PCL;NETSTANDARD;NETSTANDARD2_0;HAS_TYPE_CONVERTER;HAS_CUSTOM_ATTRIBUTE_PROVIDER;XAMLX_INTERNAL</DefineConstants>
     <UseCecil>false</UseCecil>
     <DefineConstants Condition="$(UseCecil) == true">$(DefineConstants);RUNTIME_XAML_CECIL</DefineConstants>
     <EnableDefaultCompileItems>False</EnableDefaultCompileItems>