C++/CLI in Visual Studio

docs/core/compatibility/7.0.md

@@ -26,6 +26,7 @@ If you're migrating an app to .NET 7, the breaking changes listed here might aff
 | Title | Binary compatible | Source compatible | Introduced |
 | - | :-: | :-: | - |
 | [API obsoletions with non-default diagnostic IDs](core-libraries/7.0/obsolete-apis-with-custom-diagnostics.md) | ✔️ | ❌ | Preview 1 |
+| [C++/CLI projects in Visual Studio](core-libraries/7.0/cpluspluscli-compiler-version.md)
 | [FullPath and OldFullPath return fully qualified path](core-libraries/7.0/filesystemeventargs-fullpath.md) | ✔️ | ❌ | Preview 1 |
 | [Generic type constraint on PatternContext\<T>](core-libraries/7.0/patterncontext-generic-constraint.md) | ❌ | ❌ | Preview 3 |
 | [SerializationFormat.Binary is obsolete](core-libraries/7.0/serializationformat-binary.md) | ❌ | ❌ | Preview 2 |

docs/core/compatibility/core-libraries/7.0/cpluspluscli-compiler-version.md

@@ -0,0 +1,50 @@
+---
+title: ".NET 7 breaking change: Compiling C++/CLI projects in Visual Studio"
+description: Learn about the .NET 7 breaking change in core .NET libraries where Visual Studio version 17.2 Preview 2 is required to compile .NET 7 Preview 3 C++/CLI projects.
+ms.date: 03/21/2022
+---
+# C++/CLI projects in Visual Studio
+
+.NET 7 Preview 3 includes *generic math* APIs that use `static abstract` interface members on primitive types, such as <xref:System.Int32>.  Earlier versions of the C++/CLI compiler were incompatible with such members. Because those members are used on many primitive types, compilation errors will occur when targeting `net7.0`, even if you don't use the generic math features directly.
+
+Beyond C++/CLI, it's also possible that the introduction of `static abstract` interface members on primitive <xref:System> types will surface issues in other tools that aren't forward-compatible with the usage of this new language construct. If you're a tool author, you'll need to update any tools impacted by this change to accommodate the usage of `static abstract` interface members. If you need help, [file an issue in the dotnet/runtime repo](https://github.com/dotnet/runtime/issues/new) to request guidance.
+
+## Previous behavior
+
+Previously, compiling .NET projects using C++/CLI did not result in errors related to members on primitive <xref:System> types.
+
+## New behavior
+
+Compiling a .NET 7 Preview 3 `net7.0` project using C++/CLI in a release of Visual Studio version 17.2 prior to Preview 2 will result in many errors similar to this example:
+
+```txt
+error C2253: 'System.Int32.Parse': pure specifier or abstract override specifier only allowed on virtual function
+```
+
+Other than upgrading, there's no way to work around this compiler error. It's generated because of `static abstract` interface members on primitive <xref:System> types. When you upgrade to Visual Studio 2022 version 17.2 Preview 2+, the compilation errors will no longer occur.
+
+Implicitly implemented `static abstract` interface members can be invoked, but even with Visual Studio 2022 version 17.2 Preview 2+, C++/CLI doesn't support invoking explicitly implemented `static abstract` interface members.
+
+## Version introduced
+
+.NET 7 Preview 3
+
+## Type of breaking change
+
+This change can affect [source compatibility](../../categories.md#source-compatibility).
+
+## Reason for change
+
+.NET 7 Preview 3 includes the new API definitions for the *generic math* feature set. These APIs were introduced in .NET 6 as a preview feature and required you to install the `System.Runtime.Experimental` package to gain access. Starting in .NET 7 Preview 3, these generic math APIs are included "in box".
+
+## Recommended action
+
+To continue using C++/CLI with .NET 7 Preview 3+, upgrade to Visual Studio 2022 version 17.2 Preview 2 or a later version.
+
+## Affected APIs
+
+N/A
+
+## See also
+
+- [Visual Studio 2022 version 17.2 Preview - release notes](/visualstudio/releases/2022/release-notes-preview)

docs/core/compatibility/toc.yml

@@ -37,6 +37,8 @@ items:
         items:
         - name: API obsoletions with non-default diagnostic IDs
           href: core-libraries/7.0/obsolete-apis-with-custom-diagnostics.md
+        - name: C++/CLI projects in Visual Studio
+          href: core-libraries/7.0/cpluspluscli-compiler-version.md
         - name: FullPath and OldFullPath return fully qualified path
           href: core-libraries/7.0/filesystemeventargs-fullpath.md
         - name: Generic type constraint on PatternContext<T>
@@ -689,6 +691,8 @@ items:
         items:
         - name: API obsoletions with non-default diagnostic IDs
           href: core-libraries/7.0/obsolete-apis-with-custom-diagnostics.md
+        - name: C++/CLI projects in Visual Studio
+          href: core-libraries/7.0/cpluspluscli-compiler-version.md
         - name: FullPath and OldFullPath return fully qualified path
           href: core-libraries/7.0/filesystemeventargs-fullpath.md
         - name: Generic type constraint on PatternContext<T>