dotnet · JoeRobich · Sep 27, 2024 · Aug 29, 2024 · Aug 29, 2024 · Aug 29, 2024
diff --git a/.editorconfig b/.editorconfig
@@ -151,6 +151,19 @@ dotnet_public_api_analyzer.require_api_files = true
 # Workaround for https://github.com/dotnet/roslyn/issues/70570
 dotnet_diagnostic.IDE0055.severity = warning
 
+# These xUnit analyzers were disabled temporarily to let us move to the 
+# new xUnit and get past several component governance issues. The
+# following issue tracks enabling them
+#
+# https://github.com/dotnet/roslyn/issues/75093
+dotnet_diagnostic.xUnit1012.severity = none
+dotnet_diagnostic.xUnit1030.severity = none
+dotnet_diagnostic.xUnit1031.severity = none
+dotnet_diagnostic.xUnit2005.severity = none
+dotnet_diagnostic.xUnit2020.severity = none
+dotnet_diagnostic.xUnit2023.severity = none
+dotnet_diagnostic.xUnit2029.severity = none
+
 # CSharp code style settings:
 [*.cs]
 # Newline settings
@@ -300,4 +313,4 @@ dotnet_diagnostic.RS0057.severity = error
 dotnet_diagnostic.RS0058.severity = error
 dotnet_diagnostic.RS0059.severity = error
 dotnet_diagnostic.RS0060.severity = error
-dotnet_diagnostic.RS0061.severity = error
+dotnet_diagnostic.RS0061.severity = error
diff --git a/.vscode/tasks.json b/.vscode/tasks.json
@@ -25,22 +25,6 @@
         "problemMatcher": "$msCompile",
         "group": "build"
     },
-    {
-        "label": "build with analyzers",
-        "command": "./build.sh",
-        "type": "shell",
-        "args": [
-          "--runAnalyzers"
-        ],
-        "windows": {
-          "command": "${workspaceFolder}/build.cmd",
-          "args": [
-            "-runAnalyzers"
-          ],
-        },
-        "problemMatcher": "$msCompile",
-        "group": "build"
-    },
     {
         "label": "build csc",
         "command": "dotnet",
@@ -49,6 +33,7 @@
           "msbuild",
           "-p:RunAnalyzersDuringBuild=false",
           "-p:GenerateFullPaths=true",
+          "-tl:off",
           "src/Compilers/CSharp/csc/AnyCpu/csc.csproj"
         ],
         "problemMatcher": "$msCompile",
@@ -62,6 +47,7 @@
           "build",
           "-p:RunAnalyzersDuringBuild=false",
           "-p:GenerateFullPaths=true",
+          "-tl:off",
           "Compilers.slnf"
         ],
         "problemMatcher": "$msCompile",
@@ -75,6 +61,21 @@
           "build",
           "-p:RunAnalyzersDuringBuild=false",
           "-p:GenerateFullPaths=true",
+          "-tl:off",
+          "Roslyn.sln"
+        ],
+        "problemMatcher": "$msCompile",
+        "group": "build"
+    },
+    {
+        "label": "build Roslyn.sln with analyzers",
+        "command": "dotnet",
+        "type": "shell",
+        "args": [
+          "build",
+          "-p:RunAnalyzersDuringBuild=true",
+          "-p:GenerateFullPaths=true",
+          "-tl:off",
           "Roslyn.sln"
         ],
         "problemMatcher": "$msCompile",

diff --git a/Directory.Build.rsp b/Directory.Build.rsp
@@ -1,2 +1 @@
-# Workaround for https://github.com/dotnet/sdk/issues/41791
--p:_IsDisjointMSBuildVersion=false
+# This file intentionally left blank to avoid accidental import during build.
diff --git a/README.md b/README.md
@@ -32,7 +32,7 @@ If you are interested in fixing issues and contributing directly to the code bas
 
 The Roslyn community can be found on [GitHub Discussions](https://github.com/dotnet/roslyn/discussions), where you can ask questions, voice ideas, and share your projects.
 
-To chat with other community members, you can join the Roslyn [Discord](https://discord.com/invite/tGJvv88) or [Gitter](https://gitter.im/dotnet/roslyn).
+To chat with other community members, you can join the Roslyn channel on the [CSharp Community Discord](https://discord.com/invite/tGJvv88).
 
 Our [Code of Conduct](CODE-OF-CONDUCT.md) applies to all Roslyn community channels and has adopted the [.NET Foundation Code of Conduct](https://dotnetfoundation.org/code-of-conduct).
 

@@ -27,10 +27,10 @@ resources:
 parameters:
   - name: prNumber
     type: string
-    default: ''
+    default: 'None'
   - name: sha
     type: string
-    default: ''
+    default: 'None'
 
 variables:
 - name: XUNIT_LOGS
@@ -41,7 +41,7 @@ variables:
   value: true
 
 stages:
-- ${{ if ne(parameters.prNumber, '') }}:
+- ${{ if ne(parameters.prNumber, 'None') }}:
   - stage: GitHubCommentFirst
     jobs:
       - job: GitHubCommentFirstJob
@@ -98,7 +98,7 @@ stages:
         lspEditor: false
         skipCheckout: true
 
-- ${{ if ne(parameters.prNumber, '') }}:
+- ${{ if ne(parameters.prNumber, 'None') }}:
   - stage: GitHubCommentCompleted
     condition: always()
     dependsOn: VSIntegration

@@ -49,12 +49,7 @@ schedules:
     always: true # Run even if there have been no source code changes since the last successful scheduled run
     batch: false # Do not run the pipeline if the previously scheduled run is in-progress
 
-# The variables `_DotNetArtifactsCategory` and `_DotNetValidationArtifactsCategory` are required for proper publishing of build artifacts. See https://github.com/dotnet/roslyn/pull/38259
 variables:
-  - name: _DotNetArtifactsCategory
-    value: .NETCore
-  - name: _DotNetValidationArtifactsCategory
-    value: .NETCoreValidation
   - group: DotNet-Roslyn-SDLValidation-Params
   - name: Codeql.Enabled
     value: true
@@ -308,8 +303,6 @@ extends:
                        /p:RepositoryName=$(Build.Repository.Name)
                        /p:VisualStudioDropName=$(VisualStudio.DropName)
                        /p:DotNetSignType=$(SignType)
-                       /p:PublishToSymbolServer=true
-                       /p:DotNetArtifactsCategory=$(_DotNetArtifactsCategory)
                        /p:DotnetPublishUsingPipelines=true
                        /p:IgnoreIbcMergeErrors=true
                        /p:GenerateSbom=true

@@ -26,12 +26,7 @@ parameters:
   type: boolean
   default: false
 
-# The variables `_DotNetArtifactsCategory` and `_DotNetValidationArtifactsCategory` are required for proper publishing of build artifacts. See https://github.com/dotnet/roslyn/pull/38259
 variables:
-  - name: _DotNetArtifactsCategory
-    value: .NETCore
-  - name: _DotNetValidationArtifactsCategory
-    value: .NETCoreValidation
   - group: DotNet-Roslyn-SDLValidation-Params
   - group: DotNet-Roslyn-Insertion-Variables
   - name: Codeql.Enabled
@@ -253,8 +248,6 @@ extends:
                        /p:RepositoryName=$(Build.Repository.Name)
                        /p:VisualStudioDropName=$(VisualStudio.DropName)
                        /p:DotNetSignType=$(SignType)
-                       /p:PublishToSymbolServer=true
-                       /p:DotNetArtifactsCategory=$(_DotNetArtifactsCategory)
                        /p:DotnetPublishUsingPipelines=true
                        /p:IgnoreIbcMergeErrors=true
                        /p:GenerateSbom=true

@@ -391,6 +391,8 @@ stages:
       - powershell: eng/build.ps1 -configuration Release -prepareMachine -ci -build -pack -publish -sign -binaryLogName Build.binlog /p:DotnetPublishUsingPipelines=true
         displayName: Build
 
+      # While this task is not executed in the official build, this serves as a PR check for whether symbol exclusions
+      # are properly set up.
       - task: PowerShell@2
         displayName: Publish Symbols Dry-Run
         inputs:

diff --git a/docs/Language Feature Status.md b/docs/Language Feature Status.md
@@ -11,24 +11,24 @@ efforts behind them.
 | Feature | Branch | State | Developer | Reviewer | IDE Buddy | LDM Champ |
 | ------- | ------ | ----- | --------- | -------- | --------- | --------- |
 | [First-class Span Types](https://github.com/dotnet/csharplang/issues/7905) | [FirstClassSpan](https://github.com/dotnet/roslyn/tree/features/FirstClassSpan) | [In Progress](https://github.com/dotnet/roslyn/issues/73445) | [jjonescz](https://github.com/jjonescz) | [cston](https://github.com/cston), [333fred](https://github.com/333fred) | | [333fred](https://github.com/333fred), [stephentoub](https://github.com/stephentoub) |
-| [Semi-auto-properties](https://github.com/dotnet/csharplang/issues/140) | [semi-auto-props](https://github.com/dotnet/roslyn/tree/features/semi-auto-props) | [In Progress](https://github.com/dotnet/roslyn/issues/57012) | [Youssef1313](https://github.com/Youssef1313) | [333fred](https://github.com/333fred), [RikkiGibson](https://github.com/RikkiGibson) | [CyrusNajmabadi](https://github.com/CyrusNajmabadi) | [CyrusNajmabadi](https://github.com/CyrusNajmabadi) |
+| [`field` keyword in properties](https://github.com/dotnet/csharplang/issues/140) | [field-keyword](https://github.com/dotnet/roslyn/tree/features/field-keyword) | [In Progress](https://github.com/dotnet/roslyn/issues/57012) | [Youssef1313](https://github.com/Youssef1313), [cston](https://github.com/cston) | [333fred](https://github.com/333fred), [RikkiGibson](https://github.com/RikkiGibson) | [CyrusNajmabadi](https://github.com/CyrusNajmabadi) | [CyrusNajmabadi](https://github.com/CyrusNajmabadi) |
 | [Default in deconstruction](https://github.com/dotnet/roslyn/pull/25562) | [decon-default](https://github.com/dotnet/roslyn/tree/features/decon-default) | [In Progress](https://github.com/dotnet/roslyn/issues/25559) | [jcouv](https://github.com/jcouv) | [gafter](https://github.com/gafter) |  | [jcouv](https://github.com/jcouv) |
 | [Roles/Extensions](https://github.com/dotnet/csharplang/issues/5497) | [roles](https://github.com/dotnet/roslyn/tree/features/roles) | [In Progress](https://github.com/dotnet/roslyn/issues/66722) | [jcouv](https://github.com/jcouv) | [AlekseyTs](https://github.com/AlekseyTs), [jjonescz](https://github.com/jjonescz) | [CyrusNajmabadi](https://github.com/CyrusNajmabadi) | [MadsTorgersen](https://github.com/MadsTorgersen) |
-| [Ref Struct Interfaces](https://github.com/dotnet/csharplang/issues/7608) | [RefStructInterfaces](https://github.com/dotnet/roslyn/tree/features/RefStructInterfaces) | [Merged into 17.11p2](https://github.com/dotnet/roslyn/issues/72124) | [AlekseyTs](https://github.com/AlekseyTs) | [cston](https://github.com/cston), [jjonescz](https://github.com/jjonescz) | [ToddGrun](https://github.com/ToddGrun) |  [agocke](https://github.com/agocke), [jaredpar](https://github.com/jaredpar) |
 
 # C# 13.0
 
 | Feature | Branch | State | Developer | Reviewer | IDE Buddy | LDM Champ |
 | ------- | ------ | ----- | --------- | -------- | --------- | --------- |
 | [Escape character](https://github.com/dotnet/csharplang/issues/7400) | N/A | [Merged into 17.9p1](https://github.com/dotnet/roslyn/pull/70497) | [CyrusNajmabadi](https://github.com/CyrusNajmabadi) | [jcouv](https://github.com/jcouv), [RikkiGibson](https://github.com/RikkiGibson) | (no IDE impact) | [CyrusNajmabadi](https://github.com/CyrusNajmabadi) | 
-| [Method group natural type improvements](https://github.com/dotnet/csharplang/blob/main/proposals/method-group-natural-type-improvements.md) | main | [Merged into 17.9p2](https://github.com/dotnet/roslyn/issues/69432) | [jcouv](https://github.com/jcouv) | [AlekseyTs](https://github.com/AlekseyTs), [cston](https://github.com/cston) | (no IDE impact) | [jcouv](https://github.com/jcouv) |
+| [Method group natural type improvements](https://github.com/dotnet/csharplang/blob/main/proposals/csharp-13.0/method-group-natural-type-improvements.md) | main | [Merged into 17.9p2](https://github.com/dotnet/roslyn/issues/69432) | [jcouv](https://github.com/jcouv) | [AlekseyTs](https://github.com/AlekseyTs), [cston](https://github.com/cston) | (no IDE impact) | [jcouv](https://github.com/jcouv) |
 | [`Lock` object](https://github.com/dotnet/csharplang/issues/7104) | [LockObject](https://github.com/dotnet/roslyn/tree/features/LockObject) | [Merged into 17.10p2](https://github.com/dotnet/roslyn/issues/71888) | [jjonescz](https://github.com/jjonescz) | [cston](https://github.com/cston), [RikkiGibson](https://github.com/RikkiGibson) | [CyrusNajmabadi](https://github.com/CyrusNajmabadi) (needs IDE fixer) | [stephentoub](https://github.com/stephentoub) |
 | Implicit indexer access in object initializers | main | [Merged into 17.9p3](https://github.com/dotnet/roslyn/pull/70649) | [jcouv](https://github.com/jcouv) | [AlekseyTs](https://github.com/AlekseyTs), [cston](https://github.com/cston) | (no IDE impact) |  |
 | [Params-collections](https://github.com/dotnet/csharplang/issues/7700) | main | [Merged to 17.10p3](https://github.com/dotnet/roslyn/issues/71137) | [AlekseyTs](https://github.com/AlekseyTs) | [RikkiGibson](https://github.com/RikkiGibson), [333fred](https://github.com/333fred) | [akhera99](https://github.com/akhera99) (needs IDE fixer) |  [MadsTorgersen](https://github.com/MadsTorgersen), [AlekseyTs](https://github.com/AlekseyTs) |
-| [Ref/unsafe in iterators/async](https://github.com/dotnet/csharplang/blob/main/proposals/ref-unsafe-in-iterators-async.md) | [RefInAsync](https://github.com/dotnet/roslyn/tree/features/RefInAsync) | [Merged into 17.11p2](https://github.com/dotnet/roslyn/issues/72662) | [jjonescz](https://github.com/jjonescz) | [AlekseyTs](https://github.com/AlekseyTs), [cston](https://github.com/cston) | (no IDE impact) | |
-| [`allows ref struct` constraint](https://github.com/dotnet/csharplang/issues/7608) | [RefStructInterfaces](https://github.com/dotnet/roslyn/tree/features/RefStructInterfaces) | [Merged into 17.11p2](https://github.com/dotnet/roslyn/issues/72124) | [AlekseyTs](https://github.com/AlekseyTs) | [cston](https://github.com/cston), [jjonescz](https://github.com/jjonescz) | [ToddGrun](https://github.com/ToddGrun) |  [agocke](https://github.com/agocke), [jaredpar](https://github.com/jaredpar) |
+| [Ref/unsafe in iterators/async](https://github.com/dotnet/csharplang/blob/main/proposals/csharp-13.0/ref-unsafe-in-iterators-async.md) | [RefInAsync](https://github.com/dotnet/roslyn/tree/features/RefInAsync) | [Merged into 17.11p2](https://github.com/dotnet/roslyn/issues/72662) | [jjonescz](https://github.com/jjonescz) | [AlekseyTs](https://github.com/AlekseyTs), [cston](https://github.com/cston) | (no IDE impact) | |
 | [Overload Resolution Priority](https://github.com/dotnet/csharplang/issues/7706) | main | [Merged to 17.12p1](https://github.com/dotnet/roslyn/issues/74131) | [333fred](https://github.com/333fred) | [jcouv](https://github.com/jcouv), [cston](https://github.com/cston) | Not yet assigned | [333fred](https://github.com/333fred) |
 | [Partial properties](https://github.com/dotnet/csharplang/issues/6420) | [partial-properties](https://github.com/dotnet/roslyn/tree/features/partial-properties) | [Merged into 17.11p3](https://github.com/dotnet/roslyn/issues/73090) | [RikkiGibson](https://github.com/RikkiGibson) | [jcouv](https://github.com/jcouv), [333fred](https://github.com/333fred) | [Cosifne](https://github.com/Cosifne) | [333fred](https://github.com/333fred), [RikkiGibson](https://github.com/RikkiGibson) |
+| [Ref Struct Interfaces/`allows ref struct` constraint](https://github.com/dotnet/csharplang/issues/7608) | [RefStructInterfaces](https://github.com/dotnet/roslyn/tree/features/RefStructInterfaces) | [Merged into 17.11p2](https://github.com/dotnet/roslyn/issues/72124) | [AlekseyTs](https://github.com/AlekseyTs) | [cston](https://github.com/cston), [jjonescz](https://github.com/jjonescz) | [ToddGrun](https://github.com/ToddGrun) |  [agocke](https://github.com/agocke), [jaredpar](https://github.com/jaredpar) |
+| [Collection expression better conversion from expression](https://github.com/dotnet/csharplang/issues/8374) | main | [Merged into 17.12p3](https://github.com/dotnet/roslyn/pull/74993) | [333fred](https://github.com/333fred) | [cston](https://github.com/cston), [AlekseyTs](https://github.com/AlekseyTs) | (no IDE impact) | [333fred](https://github.com/333fred), [CyrusNajmabadi](https://github.com/CyrusNajmabadi) |
 
 # C# 12.0
 

@@ -44,3 +44,52 @@ unsafe class C // unsafe context
 ```
 
 You can work around the break simply by adding the `unsafe` modifier to the local function.
+
+## Collection expression breaking changes with overload resolution in C# 13 and newer
+
+***Introduced in Visual Studio 2022 Version 17.12 and newer when using C# 13+***
+
+There are a few changes in collection expression binding in C# 13. Most of these are turning ambiguities into successful compilations,
+but a couple are breaking changes that either result in a new compilation error, or are a behavior breaking change. They are detailed
+below.
+
+### Empty collection expressions no longer use whether an API is a span to tiebreak on overloads
+
+When an empty collection expression is provided to an overloaded method, and there isn't a clear element type, we no longer use whether
+an API takes a `ReadOnlySpan<T>` or a `Span<T>` to decide whether to prefer that API. For example:
+
+```cs
+class C
+{
+    static void M(ReadOnlySpan<int> ros) {}
+    static void M(Span<object> s) {}
+
+    static void Main()
+    {
+        M([]); // C.M(ReadOnlySpan<int>) in C# 12, error in C# 13.
+    }
+}
+```
+
+### Exact element type is preferred over all else
+
+In C# 13, we prefer an exact element type match, looking at conversions from expressions. This can result in a behavior change when involving
+constants:
+
+```cs
+class C
+{
+    static void M1(ReadOnlySpan<byte> ros) {}
+    static void M1(Span<int> s) {}
+
+    static void M2(ReadOnlySpan<string> ros) {}
+    static void M2(Span<CustomInterpolatedStringHandler> ros) {}
+
+    static void Main()
+    {
+        M1([1]); // C.M(ReadOnlySpan<byte>) in C# 12, C.M(Span<int>) in C# 13
+
+        M2([$"{1}"]); // C.M(ReadOnlySpan<string>) in C# 12, C.M(Span<CustomInterpolatedStringHandler>) in C# 13
+    }
+}
+```
diff --git a/docs/contributing/Building, Debugging, and Testing on Unix.md b/docs/contributing/Building, Debugging, and Testing on Unix.md
@@ -12,7 +12,7 @@ Particularly for developers who aren't experienced with .NET Core development on
 1. Install [VS Code](https://code.visualstudio.com/Download)
     - After you install VS Code, install the [C# extension](https://marketplace.visualstudio.com/items?itemName=ms-dotnettools.csharp)
     - Important tip: You can look up editor commands by name by hitting *Ctrl+Shift+P*, or by hitting *Ctrl+P* and typing a `>` character. This will help you get familiar with editor commands mentioned below. On a Mac, use *⌘* instead of *Ctrl*.
-1. Install the [.NET 8.0 SDK](https://dotnet.microsoft.com/en-us/download/dotnet/8.0) which matches the `sdk.version` property in [global.json](../../global.json#L3)
+1. Install the [.NET 9.0 SDK](https://dotnet.microsoft.com/en-us/download/dotnet/9.0) which matches the `sdk.version` property in [global.json](../../global.json#L3)
 3. You can build from VS Code by running the *Run Build Task* command, then selecting an appropriate task such as *build* or *build current project* (the latter builds the containing project for the current file you're viewing in the editor).
 4. You can run tests from VS Code by opening a test class in the editor, then using the *Run Tests in Context* and *Debug Tests in Context* editor commands. You may want to bind these commands to keyboard shortcuts that match their Visual Studio equivalents (**Ctrl+R, T** for *Run Tests in Context* and **Ctrl+R, Ctrl+T** for *Debug Tests in Context*).
 5. You can launch a new VS Code instance with the language server from your current code by running the "launch vscode with language server" task.

diff --git a/docs/contributing/Building, Debugging, and Testing on Windows.md b/docs/contributing/Building, Debugging, and Testing on Windows.md
@@ -20,7 +20,7 @@ The minimal required version of .NET Framework is 4.7.2.
     - Ensure C# and Visual Basic, MSBuild, and .NET Core are included in the selected individual components
     - Ensure "Use previews of the .NET Core SDK" is checked in Tools -> Options -> Environment -> Preview Features
     - Restart Visual Studio
-1. Install the [.NET 8.0 SDK](https://dotnet.microsoft.com/en-us/download/dotnet/8.0) which matches the `sdk.version` property in [global.json](../../global.json#L3)
+1. Install the [.NET 9.0 SDK](https://dotnet.microsoft.com/en-us/download/dotnet/9.0) which matches the `sdk.version` property in [global.json](../../global.json#L3)
 1. [PowerShell 5.0 or newer](https://docs.microsoft.com/en-us/powershell/scripting/setup/installing-windows-powershell). If you are on Windows 10, you are fine; you'll only need to upgrade if you're on earlier versions of Windows. The download link is under the ["Upgrading existing Windows PowerShell"](https://docs.microsoft.com/en-us/powershell/scripting/install/installing-windows-powershell?view=powershell-6#upgrading-existing-windows-powershell) heading.
 1. Run Restore.cmd
 1. Open Roslyn.sln