Merge branch 'main' into darc-main-1fec9736-6591-4ca2-8394-7040044cda12

.config/branch-merge.json

@@ -0,0 +1,9 @@
+{
+    "merge-flow-configurations": {
+        // Merge any main changes to release/dev18.0.
+        "main": {
+            "MergeToBranch": "release/dev18.0",
+            "ExtraSwitches": "-QuietComments"
+        }
+    }
+}

.github/workflows/main-merge.yml

@@ -0,0 +1,18 @@
+# Merges any changes from release/prerelease to main (e.g. servicing changes)
+
+name: Flow main to release/dev18.0
+on:
+  schedule:
+    # once a day at 13:00 UTC to cleanup old runs
+    - cron: '0 13 * * *'
+  workflow_dispatch:
+
+permissions:
+  contents: write
+  pull-requests: write
+
+jobs:
+  check-script:
+    uses: dotnet/arcade/.github/workflows/inter-branch-merge-base.yml@main
+    with:
+      configuration_file_path: '.config/branch-merge.json'

azure-pipelines-official.yml

@@ -5,6 +5,7 @@ trigger:
     - main-vs-deps
     - release/dev16.*-vs-deps
     - release/dev17.*
+    - release/dev18.*
     - features/lsp_tools_host
     exclude:
     - release/dev17.0
@@ -16,6 +17,11 @@ resources:
     type: git
     name: 1ESPipelineTemplates/1ESPipelineTemplates
     ref: refs/tags/release
+  pipelines:
+    - pipeline: profilingInputs
+      source: dotnet-vscode-csharp-profiling
+      branch: main
+      trigger: none
 
 parameters:
 - name: IbcDrop
@@ -89,6 +95,9 @@ variables:
   - ${{ if and(notin(variables['Build.Reason'], 'PullRequest'), eq(variables['Build.SourceBranch'], 'refs/heads/main')) }}:
     - name: enableSourceIndex
       value: true
+  - name: VSCodeOptimizationDataRoot
+    value: $(Pipeline.Workspace)/profilingInputs/merged mibc
+
 
 extends:
   template: v1/1ES.Official.PipelineTemplate.yml@1ESPipelineTemplates
@@ -273,6 +282,10 @@ extends:
             feedSource: https://dnceng.pkgs.visualstudio.com/_packaging/MicroBuildToolset/nuget/v3/index.json
           condition: and(succeeded(), in(variables['SignType'], 'test', 'real'))
 
+        - download: profilingInputs
+          artifact: merged mibc
+          displayName: Download VSCode optimization inputs
+
         - task: PowerShell@2
           displayName: Build
           inputs:
@@ -294,6 +307,7 @@ extends:
                        -officialVisualStudioDropAccessToken $(_DevDivDropAccessToken)
                        /p:RepositoryName=$(Build.Repository.Name)
                        /p:VisualStudioDropName=$(VisualStudio.DropName)
+                       /p:VSCodeOptimizationDataRoot="$(VSCodeOptimizationDataRoot)"
                        /p:DotNetSignType=$(SignType)
                        /p:DotnetPublishUsingPipelines=true
                        /p:IgnoreIbcMergeErrors=true

azure-pipelines-pr-validation.yml

@@ -143,6 +143,9 @@ extends:
             ArtifactName: AssetManifests
 
         steps:
+        - pwsh: Set-MpPreference -DisableRealtimeMonitoring $true
+          displayName: Disable Real-time Monitoring
+
         - task: Powershell@2
           displayName: Setting OriginalBuildNumber variable
           condition: succeeded()

docs/Language Feature Status.md

@@ -19,7 +19,7 @@ efforts behind them.
 | [`field` keyword in properties](https://github.com/dotnet/csharplang/issues/140) | [field-keyword](https://github.com/dotnet/roslyn/tree/features/field-keyword) | [Merged into 17.12p3](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) |
 | [First-class Span Types](https://github.com/dotnet/csharplang/issues/7905) | [FirstClassSpan](https://github.com/dotnet/roslyn/tree/features/FirstClassSpan) | [Merged into 17.13p1](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) |
 | [Unbound generic types in `nameof`](https://github.com/dotnet/csharplang/issues/8480) | [PR](https://github.com/dotnet/roslyn/pull/75368) | [Merged into 17.13p2](https://github.com/dotnet/roslyn/pull/75368) | [CyrusNajmabadi](https://github.com/CyrusNajmabadi) | [jcouv](https://github.com/jcouv), [AlekseyTs](https://github.com/AlekseyTs) | [CyrusNajmabadi](https://github.com/CyrusNajmabadi) | [CyrusNajmabadi](https://github.com/CyrusNajmabadi) |
-| [String literals in data section as UTF8](https://github.com/dotnet/roslyn/blob/main/docs/features/string-literals-data-section.md) | [PR](https://github.com/dotnet/roslyn/pull/76036) | [Merged into 17.14p1](https://github.com/dotnet/roslyn/issues/76234) | [jjonescz](https://github.com/jjonescz) | [AlekseyTs](https://github.com/AlekseyTs), [cston](https://github.com/cston) | N/A | N/A |
+| [String literals in data section as UTF8](https://github.com/dotnet/roslyn/blob/main/docs/features/string-literals-data-section.md) | [PR](https://github.com/dotnet/roslyn/pull/76036) | [Merged into 17.13p4](https://github.com/dotnet/roslyn/issues/76234) | [jjonescz](https://github.com/jjonescz) | [AlekseyTs](https://github.com/AlekseyTs), [cston](https://github.com/cston) | N/A | N/A |
 | [Simple lambda parameters with modifiers](https://github.com/dotnet/csharplang/blob/main/proposals/simple-lambda-parameters-with-modifiers.md) | [PR](https://github.com/dotnet/roslyn/pull/75400) | [Merged into 17.14p1](https://github.com/dotnet/roslyn/pull/75400) | [CyrusNajmabadi](https://github.com/CyrusNajmabadi) | [jjonescz](https://github.com/jjonescz), [cston](https://github.com/cston) | [CyrusNajmabadi](https://github.com/CyrusNajmabadi) | [CyrusNajmabadi](https://github.com/CyrusNajmabadi) |
 
 # Working Set VB

docs/compilers/CSharp/Compiler Breaking Changes - DotNet 10.md

@@ -291,3 +291,26 @@ unsafe record struct R(
     public bool Equals(R other) => true;
 }
 ```
+
+## Emitting metadata-only executables requires an entrypoint
+
+***Introduced in Visual Studio 2022 version 17.14***
+
+Previously, the entrypoint was [unintentionally unset](https://github.com/dotnet/roslyn/issues/76707)
+when emitting executables in metadata-only mode (also known as ref assemblies).
+That is now corrected but it also means that a missing entrypoint is a compilation error:
+
+```cs
+// previously successful, now fails:
+CSharpCompilation.Create("test").Emit(new MemoryStream(),
+    options: EmitOptions.Default.WithEmitMetadataOnly(true))
+
+CSharpCompilation.Create("test",
+    // workaround - mark as DLL instead of EXE (the default):
+    options: new CSharpCompilationOptions(OutputKind.DynamicallyLinkedLibrary))
+    .Emit(new MemoryStream(),
+        options: EmitOptions.Default.WithEmitMetadataOnly(true))
+```
+
+Similarly this can be observed when using the command-line argument `/refonly`
+or the `ProduceOnlyReferenceAssembly` MSBuild property.

docs/compilers/CSharp/Compiler Breaking Changes - DotNet 8.md

@@ -35,7 +35,7 @@ public class C
 ***Introduced in Visual Studio 2022 version 17.10***
 
 *Conversion* of a collection expression to a `struct` or `class` that implements `System.Collections.IEnumerable` and *does not* have a strongly-typed `GetEnumerator()`
-requires the elements in the collection expression are implicitly convertible to the `object`.
+requires that the elements in the collection expression are implicitly convertible to `object`.
 Previously, the elements of a collection expression targeting an `IEnumerable` implementation were assumed to be convertible to `object`, and converted only when binding to the applicable `Add` method.
 
 This additional requirement means that collection expression conversions to `IEnumerable` implementations are treated consistently with other target types where the elements in the collection expression must be implicitly convertible to the *iteration type* of the target type.

docs/compilers/CSharp/Compiler Breaking Changes - DotNet 9.md

@@ -157,3 +157,30 @@ class C
 ```
 
 A workaround is to use explicit delegate types instead of relying on `var` inference in those cases.
+
+## `dotnet_style_require_accessibility_modifiers` now consistently applies to interface members
+
+PR: https://github.com/dotnet/roslyn/pull/76324
+
+Prior to this change, the analyzer for dotnet_style_require_accessibility_modifiers would simply ignore interface
+members.  This was because C# initially disallowed modifiers for interface members entirely, having them always
+be public.
+
+Later versions of the language relaxed this restriction, allowing users to provide accessibility modifiers on
+interface members, including a redundant `public` modifier.
+
+The analyzer was updated to now enforce the value for this option on interface members as well.  The meaning
+of the value is as follows:
+
+1. `never`.  The analyzer does no analysis.  Redundant modifiers are allowed on all members.
+2. `always`.  Redundant modifiers are always required on all members (including interface members).  For example:
+   a `private` modifier on a class member, and a `public` modifier on an interface member.  This is the option to
+   use if you feel that all members no matter what should state their accessibility explicitly.
+4. `for_non_interface_members`.  Redundant modifiers are required on all members *that are not* part of an interface,
+   but disallowed for interface members. For example: `private` will be required on private class members.  However,
+   a public interface member will not be allowed to have redundant `public` modifiers.  This matches the standard
+   modifier approach present prior to the language allowing modifiers on interface members.
+5. `omit_if_default`.  Redundant modifiers are disallowed.  For example a private class member will be disallowed from
+   using `private`, and a public interface member will be disallowed from using `public`.  This is the option to use
+   if you feel that restating the accessibility when it matches what the language chooses by default is redundant and
+   should be disalloed.