dotnet · Copilot · Nov 13, 2025 · Nov 13, 2025 · Nov 14, 2025 · Nov 14, 2025
diff --git a/src/Tasks/Common/Resources/Strings.resx b/src/Tasks/Common/Resources/Strings.resx
@@ -1010,5 +1010,9 @@ You may need to build the project on another operating system or architecture, o
     <value>NETSDK1233: Targeting .NET 10.0 or higher in Visual Studio 2022 17.14 is not supported.</value>
     <comment>{StrBegins="NETSDK1233: "}</comment>
   </data>
-  <!-- The latest message added is Net10NotCompatibleWithVS17. Please update this value with each PR to catch parallel PRs both adding a new message -->
+  <data name="RoslynCompilerTypeFrameworkIsDeprecated" xml:space="preserve">
+    <value>NETSDK1234: RoslynCompilerType 'Framework' is deprecated and will be removed in a future version. Please refer to {0} for more information.</value>
+    <comment>{StrBegins="NETSDK1234: "}{Locked="RoslynCompilerType"}{Locked="Framework"}{Locked="{0}"}</comment>
+  </data>
+  <!-- The latest message added is RoslynCompilerTypeFrameworkIsDeprecated. Please update this value with each PR to catch parallel PRs both adding a new message -->
 </root>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.cs.xlf b/src/Tasks/Common/Resources/xlf/Strings.cs.xlf
diff --git a/src/Tasks/Common/Resources/xlf/Strings.de.xlf b/src/Tasks/Common/Resources/xlf/Strings.de.xlf
diff --git a/src/Tasks/Common/Resources/xlf/Strings.es.xlf b/src/Tasks/Common/Resources/xlf/Strings.es.xlf
diff --git a/src/Tasks/Common/Resources/xlf/Strings.fr.xlf b/src/Tasks/Common/Resources/xlf/Strings.fr.xlf
diff --git a/src/Tasks/Common/Resources/xlf/Strings.it.xlf b/src/Tasks/Common/Resources/xlf/Strings.it.xlf
diff --git a/src/Tasks/Common/Resources/xlf/Strings.ja.xlf b/src/Tasks/Common/Resources/xlf/Strings.ja.xlf
diff --git a/src/Tasks/Common/Resources/xlf/Strings.ko.xlf b/src/Tasks/Common/Resources/xlf/Strings.ko.xlf
diff --git a/src/Tasks/Common/Resources/xlf/Strings.pl.xlf b/src/Tasks/Common/Resources/xlf/Strings.pl.xlf
diff --git a/src/Tasks/Common/Resources/xlf/Strings.pt-BR.xlf b/src/Tasks/Common/Resources/xlf/Strings.pt-BR.xlf
diff --git a/src/Tasks/Common/Resources/xlf/Strings.ru.xlf b/src/Tasks/Common/Resources/xlf/Strings.ru.xlf
diff --git a/src/Tasks/Common/Resources/xlf/Strings.tr.xlf b/src/Tasks/Common/Resources/xlf/Strings.tr.xlf
diff --git a/src/Tasks/Common/Resources/xlf/Strings.zh-Hans.xlf b/src/Tasks/Common/Resources/xlf/Strings.zh-Hans.xlf
diff --git a/src/Tasks/Common/Resources/xlf/Strings.zh-Hant.xlf b/src/Tasks/Common/Resources/xlf/Strings.zh-Hant.xlf
diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.BeforeCommon.targets b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.BeforeCommon.targets
@@ -361,6 +361,14 @@ Copyright (c) .NET Foundation. All rights reserved.
     </Otherwise>
   </Choose>
 
+  <!-- Warn about deprecated RoslynCompilerType=Framework -->
+  <Target Name="_CheckForDeprecatedRoslynCompilerType"
+          BeforeTargets="PrepareForBuild"
+          Condition="'$(RoslynCompilerType)' == 'Framework'">
+    <NETSdkWarning ResourceName="RoslynCompilerTypeFrameworkIsDeprecated"
+                   FormatArguments="https://aka.ms/roslyn-compiler-type-framework" />
+  </Target>
+
   <!-- NOTE: Compiler toolset packages should set the following properties on their own, hence we set them only for RoslynCompilerType being Core or Framework. -->
   <PropertyGroup Condition="'$(RoslynCompilerType)' == 'Core' or '$(RoslynCompilerType)' == 'Framework'">
     <!-- In Full Framework MSBuild, RoslynTargetsPath originally points to the directory with Full Framework Roslyn assemblies. -->