Fix implicit framework defines (NET6_0, NET6_0_OR_GREATER) not being defined

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Issue #279: Implicit framework defines like NET6_0 and NET6_0_OR_GREATER were not being defined for .NET 6+ projects, breaking conditional compilation and breaking top-level statements.

Root Cause

DisableImplicitFrameworkDefines was left uncommented (but inactive), creating ambiguity. When not explicitly set to false, the Microsoft.NET.Sdk's implicit define logic may be disabled, preventing defines like NET6_0, NET6_0_OR_GREATER, and platform-specific constants from being added.

Changes

• Platforms.targets (line 45): Explicitly set DisableImplicitFrameworkDefines=false to ensure SDK implicit defines are always generated
• Test project: Added Tests/ImplicitFrameworkDefines/ to verify defines are present using #error directives that fail compilation if missing

Example

With this fix, projects can now use:

#if NET6_0_OR_GREATER
    // Modern .NET 6+ code
#endif

#if NET6_0_WINDOWS
    // Windows-specific .NET 6 code
#endif

And top-level statements work correctly in multi-targeted projects.

Warning

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  • Triggering command: dotnet restore --no-dependencies /home/REDACTED/work/MSBuildSdkExtras/.codeql-scratch/dbs/csharp/working/011FD41CC6F94F07FDAE78E0AF58AFF4/missingpackages_workingdir --packages /home/REDACTED/work/MSBuildSdkExtras/.codeql-scratch/dbs/csharp/working/missingpackages /p:DisableImplicitNuGetFallbackFolder=true --verbosity normal --configfile /home/REDACTED/work/MSBuildSdkExtras/.codeql-scratch/dbs/csharp/working/nugetconfig/nuget.config --force (dns block)

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Original prompt

---

This section details on the original issue you should resolve

<issue_title>NET6_0 constants not properly defined</issue_title>
<issue_description># Context

For LibVLCSharp, we need to support Xamarin.Forms projects and old .net versions as well as the new .net6.0 tfms

The issue

A repro can be found here : https://github.com/jeremyVignelles/repro-tfm-msbuild-sdk-extras

It seems that NET6_0_OR_GREATER is not defined anywhere and NET6_0 is only defined in net6.0 and not net6.0-windows

It also seem that I can't use the new top-level statements in such projects.

</issue_description>

Comments on the Issue (you are @copilot in this section)

@clairernovotny I noticed this earlier this week as well.

@dsplaisted Before I hunt this down, do you recall where these are defined or what controls them being defined?</comment_new>
<comment_new>@clairernovotny
As a workaround, you should be able to set the DisableImplicitFrameworkDefines property to false. For some reason, the extras is setting that to true here:

https://github.com/novotnyllc/MSBuildSdkExtras/blob/main/Source/MSBuild.Sdk.Extras/Build/Platforms.targets#L45

I'm not sure exactly why anymore and I'll need to look closer to see what the side-effects are for all of the other project types.</comment_new>

• Fixes NET6_0 constants not properly defined #279

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Pull Request Overview

This PR enables implicit framework defines (like NET8_0, NET8_0_OR_GREATER, NET8_0_WINDOWS) from the Microsoft.NET.Sdk to work correctly alongside the custom defines provided by MSBuild.Sdk.Extras. Previously, these standard SDK defines were being disabled.

Key changes:

• Explicitly sets DisableImplicitFrameworkDefines to false to ensure Microsoft.NET.Sdk adds its standard framework defines
• Adds a test project to verify that implicit framework defines are working correctly

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
Source/MSBuild.Sdk.Extras/Build/Platforms.targets	Uncomments and modifies the DisableImplicitFrameworkDefines property to explicitly set it to false, ensuring Microsoft.NET.Sdk adds implicit framework defines
Tests/ImplicitFrameworkDefines/ImplicitFrameworkDefines.csproj	Adds test project that validates implicit framework defines work correctly by building for net8.0 and net8.0-windows
Tests/ImplicitFrameworkDefines/Class1.cs	Adds test class with preprocessor directives that will fail compilation if the required defines are missing

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