Merge 'main' into 'extensions' (#77216)

Author: AlekseyTs

.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'

Roslyn.sln

@@ -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
@@ -266,23 +275,17 @@ extends:
             useGlobalJson: true
             workingDirectory: '$(Build.SourcesDirectory)'
 
-        # Needed to restore the Microsoft.DevDiv.Optimization.Data.PowerShell package
-        - task: NuGetCommand@2
-          displayName: Restore internal tools
-          inputs:
-            command: restore
-            feedsToUse: config
-            restoreSolution: 'eng\common\internal\Tools.csproj'
-            nugetConfigPath: 'NuGet.config'
-            restoreDirectory: '$(Build.SourcesDirectory)\.packages'
-
         - task: MicroBuildSigningPlugin@4
           inputs:
             signType: $(SignType)
             zipSources: false
             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:
@@ -304,11 +307,11 @@ extends:
                        -officialVisualStudioDropAccessToken $(_DevDivDropAccessToken)
                        /p:RepositoryName=$(Build.Repository.Name)
                        /p:VisualStudioDropName=$(VisualStudio.DropName)
+                       /p:VSCodeOptimizationDataRoot="$(VSCodeOptimizationDataRoot)"
                        /p:DotNetSignType=$(SignType)
                        /p:DotnetPublishUsingPipelines=true
                        /p:IgnoreIbcMergeErrors=true
                        /p:GenerateSbom=true
-                       /p:ForceAzureComSources=true
           condition: succeeded()
 
         - template: /eng/common/templates-official/steps/generate-sbom.yml@self

azure-pipelines-official.yml

@@ -33,8 +33,6 @@ variables:
     value: false
   - name: Codeql.SkipTaskAutoInjection
     value: true
-  - name: SignType
-    value: ''
 
   # To retrieve OptProf data we need to authenticate to the VS drop storage.
   # If the pipeline is running in DevDiv, the account has access to the VS drop storage.
@@ -217,16 +215,6 @@ extends:
             useGlobalJson: true
             workingDirectory: '$(Build.SourcesDirectory)'
 
-        # Needed to restore the Microsoft.DevDiv.Optimization.Data.PowerShell package
-        - task: NuGetCommand@2
-          displayName: Restore internal tools
-          inputs:
-            command: restore
-            feedsToUse: config
-            restoreSolution: 'eng\common\internal\Tools.csproj'
-            nugetConfigPath: 'NuGet.config'
-            restoreDirectory: '$(Build.SourcesDirectory)\.packages'
-
         - task: MicroBuildSigningPlugin@4
           inputs:
             signType: $(SignType)

azure-pipelines-pr-validation.yml

@@ -10,15 +10,17 @@ efforts behind them.
 
 | Feature | Branch | State | Developer | Reviewer | IDE Buddy | LDM Champ |
 | ------- | ------ | ----- | --------- | -------- | --------- | --------- |
-| Runtime Async | [features/runtime-async](https://github.com/dotnet/roslyn/tree/features/runtime-async) | [In Progress](https://github.com/dotnet/roslyn/issues/75960) | [333fred](https://github.com/333fred) | [jcouv](https://github.com/jcouv), [RikkiGibson](https://github.com/RikkiGibson) |  |  |
-| [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) | [In Progress](https://github.com/dotnet/roslyn/issues/76298) | [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) |
+| [User Defined Compound Assignment Operators](https://github.com/dotnet/csharplang/issues/9101) | [UserDefinedCompoundAssignment](https://github.com/dotnet/roslyn/tree/features/UserDefinedCompoundAssignment) | [In Progress](https://github.com/dotnet/roslyn/issues/76934) | [AlekseyTs](https://github.com/AlekseyTs) | [333fred](https://github.com/333fred), [cston](https://github.com/cston) | TBD | [AlekseyTs](https://github.com/AlekseyTs) |
+| [Partial Events and Constructors](https://github.com/dotnet/csharplang/issues/9058) | [PartialEventsCtors](https://github.com/dotnet/roslyn/tree/features/PartialEventsCtors) | [In Progress](https://github.com/dotnet/roslyn/issues/76859) | [jjonescz](https://github.com/jjonescz) | [cston](https://github.com/cston), [RikkiGibson](https://github.com/RikkiGibson) |  |  |
+| Runtime Async | [runtime-async](https://github.com/dotnet/roslyn/tree/features/runtime-async) | [In Progress](https://github.com/dotnet/roslyn/issues/75960) | [333fred](https://github.com/333fred) | [jcouv](https://github.com/jcouv), [RikkiGibson](https://github.com/RikkiGibson) |  |  |
 | [Null-conditional assignment](https://github.com/dotnet/csharplang/issues/6045) | [null-conditional-assignment](https://github.com/dotnet/roslyn/tree/features/null-conditional-assignment) | [In Progress](https://github.com/dotnet/roslyn/issues/75554) | [RikkiGibson](https://github.com/RikkiGibson) | [cston](https://github.com/cston), [jjonescz](https://github.com/jjonescz) | TBD | [RikkiGibson](https://github.com/RikkiGibson) |
 | [Extensions](https://github.com/dotnet/csharplang/issues/8697) | [extensions](https://github.com/dotnet/roslyn/tree/features/extensions) | [In Progress](https://github.com/dotnet/roslyn/issues/76130) | [jcouv](https://github.com/jcouv), [AlekseyTs](https://github.com/AlekseyTs) | [jjonescz](https://github.com/jjonescz), TBD | [CyrusNajmabadi](https://github.com/CyrusNajmabadi) | [MadsTorgersen](https://github.com/MadsTorgersen) |
 | [Dictionary expressions](https://github.com/dotnet/csharplang/issues/8659) | [dictionary-expressions](https://github.com/dotnet/roslyn/tree/features/dictionary-expressions) | [In Progress](https://github.com/dotnet/roslyn/issues/76310) | [cston](https://github.com/cston), [CyrusNajmabadi](https://github.com/CyrusNajmabadi) | [333fred](https://github.com/333fred), [jcouv](https://github.com/jcouv) | [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) | [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
 
@@ -120,17 +122,17 @@ efforts behind them.
 | [Skip locals init](https://github.com/dotnet/csharplang/issues/1738)                               | [localsinit](https://github.com/dotnet/roslyn/tree/features/localsinit)                                        | [Merged](https://github.com/dotnet/roslyn/issues/25780) | [t-camaia](https://github.com/t-camaia), [agocke](https://github.com/agocke)      | [jaredpar](https://github.com/jaredpar)                                            | [agocke](https://github.com/agocke)     |
 | [Lambda discard parameters](https://github.com/dotnet/csharplang/issues/111)                       | main                                                                                                         | [Merged](https://github.com/dotnet/roslyn/issues/38820)      | [jcouv](https://github.com/jcouv)                                            | [AlekseyTs](https://github.com/AlekseyTs), [chsienki](https://github.com/chsienki) | [jcouv](https://github.com/jcouv)       |
 | [Native ints](https://github.com/dotnet/csharplang/issues/435)                                     | main                                 | [Merged into 16.7p1](https://github.com/dotnet/roslyn/issues/38821) | [cston](https://github.com/cston)                                     | [333fred](https://github.com/333fred), [gafter](https://github.com/gafter)         | [jaredpar](https://github.com/jaredpar) |
-| [Attributes on local functions](https://github.com/dotnet/csharplang/issues/1888)                  | [features/local-function-attributes](https://github.com/dotnet/roslyn/tree/features/local-function-attributes) | [Merged](https://github.com/dotnet/roslyn/issues/38801) | [RikkiGibson](https://github.com/RikkiGibson)                                     | [agocke](https://github.com/agocke)                                                | [agocke](https://github.com/agocke)     |
+| [Attributes on local functions](https://github.com/dotnet/csharplang/issues/1888)                  | [local-function-attributes](https://github.com/dotnet/roslyn/tree/features/local-function-attributes) | [Merged](https://github.com/dotnet/roslyn/issues/38801) | [RikkiGibson](https://github.com/RikkiGibson)                                     | [agocke](https://github.com/agocke)                                                | [agocke](https://github.com/agocke)     |
 | [Function pointers](https://github.com/dotnet/csharplang/issues/191)                               | main                          | [Merged into 16.7p3](https://github.com/dotnet/roslyn/issues/43321) | [333fred](https://github.com/333fred)                                        | [AlekseyTs](https://github.com/AlekseyTs)                                          | [jaredpar](https://github.com/jaredpar) |
 | [Pattern matching improvements](https://github.com/dotnet/csharplang/issues/2850)                  | main                                | [Merged into 16.7p1](https://github.com/dotnet/roslyn/issues/40727)                        | [gafter](https://github.com/gafter)                                                | [RikkiGibson](https://github.com/RikkiGibson),[agocke](https://github.com/agocke)  | [gafter](https://github.com/gafter)     |
 | [Static lambdas](https://github.com/dotnet/csharplang/issues/275)                                  | main                       | [Merged in 16.7p4](https://github.com/dotnet/roslyn/issues/39606) | [CyrusNajmabadi](https://github.com/CyrusNajmabadi)                          | [jcouv](https://github.com/jcouv)                                                  | [jcouv](https://github.com/jcouv)       |
 | [Records](https://github.com/dotnet/csharplang/issues/39)                                          | main                                     | [Merged into 16.7p3](https://github.com/dotnet/roslyn/issues/40726) | [agocke](https://github.com/agocke)                                          | [gafter](https://github.com/gafter), [333fred](https://github.com/333fred)         | [agocke](https://github.com/agocke)     |
-| [Target-typed conditional](https://github.com/dotnet/csharplang/issues/2460)                       | [features/target-typing](https://github.com/dotnet/roslyn/tree/features/target-typing)                         | [Merged into 16.7p4](https://github.com/dotnet/roslyn/issues/43186) | [gafter](https://github.com/gafter)                                          | [agocke](https://github.com/agocke), [RikkiGibson](https://github.com/RikkiGibson) | [gafter](https://github.com/gafter) |
-| [Covariant](https://github.com/dotnet/csharplang/issues/49) [Returns](https://github.com/dotnet/csharplang/issues/2844) | [features/covariant-returns](https://github.com/dotnet/roslyn/tree/features/covariant-returns) | [Merged into 16.8p2](https://github.com/dotnet/roslyn/issues/43188) | [gafter](https://github.com/gafter)                                     | [AlekseyTs](https://github.com/AlekseyTs), [agocke](https://github.com/agocke)                                                                            | [gafter](https://github.com/gafter) |
+| [Target-typed conditional](https://github.com/dotnet/csharplang/issues/2460)                       | [target-typing](https://github.com/dotnet/roslyn/tree/features/target-typing)                         | [Merged into 16.7p4](https://github.com/dotnet/roslyn/issues/43186) | [gafter](https://github.com/gafter)                                          | [agocke](https://github.com/agocke), [RikkiGibson](https://github.com/RikkiGibson) | [gafter](https://github.com/gafter) |
+| [Covariant](https://github.com/dotnet/csharplang/issues/49) [Returns](https://github.com/dotnet/csharplang/issues/2844) | [covariant-returns](https://github.com/dotnet/roslyn/tree/features/covariant-returns) | [Merged into 16.8p2](https://github.com/dotnet/roslyn/issues/43188) | [gafter](https://github.com/gafter)                                     | [AlekseyTs](https://github.com/AlekseyTs), [agocke](https://github.com/agocke)                                                                            | [gafter](https://github.com/gafter) |
 | [Extension GetEnumerator](https://github.com/dotnet/csharplang/issues/3194)                        | main                 | [Merged into 16.8p2](https://github.com/dotnet/roslyn/issues/43184) | [YairHalberstadt](https://github.com/YairHalberstadt)                        | [333fred](https://github.com/333fred)                                              | [333fred](https://github.com/333fred) |
 | [Module initializers](https://github.com/dotnet/csharplang/blob/main/proposals/csharp-9.0/module-initializers.md) | main                                                                                    | [Merged in 16.7p4](https://github.com/dotnet/roslyn/issues/40500)                                         | [RikkiGibson](https://github.com/RikkiGibson) [jnm2](https://github.com/jnm2)| [AlekseyTs](https://github.com/AlekseyTs)                                          | [gafter](https://github.com/gafter) |
 | [Extending Partial](https://github.com/dotnet/csharplang/blob/main/proposals/csharp-9.0/extending-partial-methods.md) | main       | [Merged into 16.7p2](https://github.com/dotnet/roslyn/issues/43795) | [RikkiGibson](https://github.com/RikkiGibson)                                | [chsienki](https://github.com/chsienki)                                            | [jaredpar](https://github.com/jaredpar) |
-| [Top-level statements](https://github.com/dotnet/csharplang/blob/main/proposals/csharp-9.0/top-level-statements.md) | [features/SimplePrograms](https://github.com/dotnet/roslyn/tree/features/SimplePrograms)       | [Merged into 16.7p3](https://github.com/dotnet/roslyn/issues/43563)                                                  | [AlekseyTs](https://github.com/AlekseyTs)                                | [cston](https://github.com/cston), [RikkiGibson](https://github.com/RikkiGibson)                                            | [MadsTorgersen](https://github.com/MadsTorgersen) |
+| [Top-level statements](https://github.com/dotnet/csharplang/blob/main/proposals/csharp-9.0/top-level-statements.md) | [SimplePrograms](https://github.com/dotnet/roslyn/tree/features/SimplePrograms)       | [Merged into 16.7p3](https://github.com/dotnet/roslyn/issues/43563)                                                  | [AlekseyTs](https://github.com/AlekseyTs)                                | [cston](https://github.com/cston), [RikkiGibson](https://github.com/RikkiGibson)                                            | [MadsTorgersen](https://github.com/MadsTorgersen) |
 
 # C# 8.0
 

docs/Language Feature Status.md

@@ -292,6 +292,29 @@ unsafe record struct R(
 }
 ```
 
+## 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.
+
 ## `extension` treated as a contextual keyword
 
 PROTOTYPE record which version this break is introduced in