Merge branch 'release/dev17.12' into merges/release/dev17.11-to-release/dev17.12

Author: T-Gro

.devcontainer/devcontainer.json

@@ -1,12 +1,12 @@
 // For format details, see https://aka.ms/vscode-remote/devcontainer.json or this file's README at:
 {
     "name": "F#",
-    "image": "mcr.microsoft.com/dotnet/sdk:9.0.100-preview.5",
+    "image": "mcr.microsoft.com/dotnet/sdk:9.0.100-rc.1",
     "features": {
-        "ghcr.io/devcontainers/features/common-utils:2.4.3": {},
-        "ghcr.io/devcontainers/features/git:1.2.0": {},
-        "ghcr.io/devcontainers/features/github-cli:1.0.11": {},
-        "ghcr.io/devcontainers/features/dotnet:2.1.0": {}
+        "ghcr.io/devcontainers/features/common-utils:2.5.1": {},
+        "ghcr.io/devcontainers/features/git:1.3.2": {},
+        "ghcr.io/devcontainers/features/github-cli:1.0.13": {},
+        "ghcr.io/devcontainers/features/dotnet:2.1.3": {}
     },
     "hostRequirements": {
         "cpus": 2,
@@ -28,7 +28,7 @@
         }
     },
     "remoteEnv": {
-        "TARGET": "net8.0"
+        "TARGET": "net9.0"
     },
     "postCreateCommand": [ "dotnet", "build", "FSharp.Compiler.Service.sln"]
 }

.fantomasignore

@@ -12,7 +12,7 @@ vsintegration/*
 !vsintegration/tests/FSharp.Editor.Tests
 artifacts/
 
-# For some reason, it tries to format files from remotes (Processing .\.git\refs\remotes\<remote>\FSComp.fsi)
+# For some reason, it tries to format files from remotes (Processing ./.git/refs/remotes/<remote>/FSComp.fsi)
 .git/
 
 # Explicitly unformatted implementation
@@ -21,7 +21,7 @@ src/Compiler/Checking/AttributeChecking.fs
 src/Compiler/Checking/AugmentWithHashCompare.fs
 src/Compiler/Checking/CheckBasics.fs
 src/Compiler/Checking/CheckDeclarations.fs
-src/Compiler/Checking/CheckExpressions.fs
+src/Compiler/Checking/Expressions/CheckExpressions.fs
 src/Compiler/Checking/CheckFormatStrings.fs
 src/Compiler/Checking/CheckIncrementalClasses.fs
 src/Compiler/Checking/CheckPatterns.fs
@@ -88,6 +88,35 @@ src/FSharp.Core/Query.fs
 src/FSharp.Core/seqcore.fs
 
 
+# fsharp  (to investigate)
+
+**/TypeProviders.fsi
+**/tainted.fsi
+
+# uses nullness features
+
+**/DependencyProvider.fsi
+src/FSharp.Core/array.fs
+src/FSharp.Core/option.fsi
+src/FSharp.Core/option.fs
+src/fsi/console.fs
+src/FSharp.Build/FSharpCommandLineBuilder.fs
+
+src/Compiler/Utilities/Activity.fs
+src/Compiler/Utilities/sformat.fs
+src/Compiler/Utilities/illib.fsi
+src/Compiler/Utilities/illib.fs
+
+
+src/Compiler/Utilities/NullnessShims.fs
+src/Compiler/Utilities/LruCache.fsi
+src/Compiler/Utilities/LruCache.fs
+src/Compiler/Utilities/HashMultiMap.fsi
+src/Compiler/Utilities/HashMultiMap.fs
+src/Compiler/Facilities/AsyncMemoize.fsi
+src/Compiler/Facilities/AsyncMemoize.fs
+src/Compiler/AbstractIL/il.fs
+
 # Fantomas limitations on implementation files  (to investigate)
 
 src/Compiler/AbstractIL/ilwrite.fs

.git-blame-ignore-revs

@@ -1,2 +1,9 @@
+# Because this repository uses squash/rebase merges, commits added to a branch
+# referencing earlier commits in the same branch and squash/rebased merged as part of a PR
+# will need to be rewritten in a subsequent PR to the corresponding squashed/rebased commit SHAs.
+
 # Format src/Compiler/Checking/CheckComputationExpressions.fs, https://github.com/dotnet/fsharp/pull/16512
-603a310cdfd9902ec1d29b399377dcc9ac56235b
+0318afd91f38533879cc89d598e0431c312ad57e
+
+# Spelling, https://github.com/dotnet/fsharp/pull/16212
+23e91e1322363a7e9c34baaeabbf0391c4b7eafd

.github/ISSUE_TEMPLATE/nullness_issue.yml

@@ -0,0 +1,76 @@
+name: Nullness-related report
+title: 'Nullness issue - ....'
+description: Create a report related to nullable reference types handling
+labels:  [Bug, Needs-Triage,Area-Nullness]
+assignees: 'T-Gro'
+body:
+  - type: textarea
+    attributes:
+        label: Issue description
+        description: A concise description of what you're experiencing.
+    validations:
+      required: true
+  - type: markdown
+    attributes:
+      value: |
+        Please check at [Nullable Reference Types RFC](https://github.com/fsharp/fslang-design/blob/main/RFCs/FS-1060-nullable-reference-types.md) if this issue isn't a known limitation, such as missing flow-control analysis after branching constructs like `if` or `while`. Also check at [existing nullness issues](https://github.com/dotnet/fsharp/issues?q=is%3Aissue+label%3AArea-Nullness+) if it hasn't been reported already.
+        Please provide a succinct description of the issue and choose 1 or more from the following categories of impact
+  - type: checkboxes
+    id: categories
+    attributes:
+      label: Choose one or more from the following categories of impact
+      options:
+        - label: Unexpected nullness warning (false positive in nullness checking, code uses --checknulls and langversion:preview).
+        - label: Missing nullness warning in a case which can produce nulls (false negative, code uses --checknulls and langversion:preview).
+        - label: Breaking change related to older `null` constructs in code not using the checknulls switch.
+        - label: Breaking change related to generic code and explicit type constraints (`null`, `not null`).
+        - label: Type inference issue (i.e. code worked without type annotations before, and applying the --checknulls enforces type annotations).
+        - label: C#/F# interop issue related to nullness metadata.
+        - label: Other (none of the categories above apply).
+    validations:
+      required: true
+  - type: dropdown
+    id: os
+    attributes:
+      label: Operating System
+      description: What operating system are you running?
+      options:
+        - Windows (Default)
+        - Linux
+        - macOS
+      default: 0
+    validations:
+      required: true
+  - type: dropdown
+    id: dotnet-kind
+    attributes:
+      label: What .NET runtime/SDK kind are you seeing the issue on
+      multiple: false
+      options:
+        - .NET SDK (.NET Core, .NET 5+)
+        - .NET Framework
+      default: 0
+    validations:
+      required: true
+  - type: input
+    id: dotnet-version
+    attributes:
+      label: .NET Runtime/SDK version
+      placeholder: e.g. .NET 9 or .NET SDK 9.0.100
+  - type: textarea
+    attributes:
+      label: Reproducible code snippet and actual behavior
+      description: |
+        Provide a small code snippet demonstrating the issue. |
+        If referenced code is needed for the repro and cannot be shared (e.g. a private C# nuget package), try to share at least the metadata annotations from the called type+member as seen in `ilspy.exe`. C# compiler produces attributes like `[Nullable]` and `[NullableContext]`, which is what F# compiler tries to load and interpret in C#/F# interop scenarios.
+      placeholder: Code snippet
+    validations:
+      required: false
+  - type: textarea
+    attributes:
+      label: Possible workarounds
+      description: |
+        Are there any language constructs (typically pattern matching, library constructs, Null/NonNull active patterns, explicit type annotations) allowing the same logic be expressed differently in order to mitigate the experienced nullness issue?
+      placeholder: Possible workaround
+    validations:
+      required: false

.github/PULL_REQUEST_TEMPLATE.md

@@ -13,7 +13,7 @@ Fixes # (issue, if applicable)
     >
     > Release notes files:
     > - If anything under `src/Compiler` has been changed, please make sure to make an entry in `docs/release-notes/.FSharp.Compiler.Service/<version>.md`, where `<version>` is usually "highest" one, e.g. `42.8.200`
-    > - If language feature was added (i.e. `LanguageFeatures.fsi` was changed), please add it to `docs/releae-notes/.Language/preview.md`
+    > - If language feature was added (i.e. `LanguageFeatures.fsi` was changed), please add it to `docs/release-notes/.Language/preview.md`
     > - If a change to `FSharp.Core` was made, please make sure to edit `docs/release-notes/.FSharp.Core/<version>.md` where version is "highest" one, e.g. `8.0.200`.
 
     > Information about the release notes entries format can be found in the [documentation](https://fsharp.github.io/fsharp-compiler-docs/release-notes/About.html).

.gitignore

@@ -127,3 +127,6 @@ nCrunchTemp_*
 tests/FSharp.Compiler.Service.Tests/FSharp.CompilerService.SurfaceArea.netstandard.actual
 *.vsp
 /tests/AheadOfTime/Trimming/output.txt
+*.svclog
+micro.exe
+positive.exe

.vscode/launch.json

@@ -23,7 +23,7 @@
             // TODO: Shall we assume that it's already been built, or build it every time we debug?
             "preLaunchTask": "${defaultBuildTask}",
             // If you have changed target frameworks, make sure to update the program p
-            "program": "${workspaceFolder}/artifacts/bin/fsi/Debug/net8.0/fsi.dll",
+            "program": "${workspaceFolder}/artifacts/bin/fsi/Debug/net9.0/fsi.dll",
             "args": [
                 "${input:fsiArgsPrompt}"
             ],
@@ -53,7 +53,7 @@
             // TODO: Shall we assume that it's already been built, or build it every time we debug?
             "preLaunchTask": "${defaultBuildTask}",
             // If you have changed target frameworks, make sure to update the program path.
-            "program": "${workspaceFolder}/artifacts/bin/fsc/Debug/net8.0/fsc.dll",
+            "program": "${workspaceFolder}/artifacts/bin/fsc/Debug/net9.0/fsc.dll",
             "args": [
                 "--targetprofile:netstandard",
                 "--simpleresolution",

.vscode/tasks.json

@@ -101,7 +101,7 @@
                 "Speedscope",
                 "--",
                 "dotnet",
-                "${workspaceFolder}/artifacts/bin/fsi/Debug/net8.0/fsi.dll",
+                "${workspaceFolder}/artifacts/bin/fsi/Debug/net9.0/fsi.dll",
                 "${input:fsiArgsPrompt}"
             ],
             "problemMatcher": "$msCompile",
@@ -118,7 +118,7 @@
                 "Speedscope",
                 "--",
                 "dotnet",
-                "${workspaceFolder}/artifacts/bin/fsc/Debug/net8.0/fsc.dll",
+                "${workspaceFolder}/artifacts/bin/fsc/Debug/net9.0/fsc.dll",
                 "--targetprofile:netstandard",
                 "--simpleresolution",
                 "${input:fscArgsPrompt}"

DEVGUIDE.md

@@ -136,7 +136,7 @@ To use your custom build of `Fsc`, add the `DotnetFscCompilerPath` property to y
 
 ```xml
 <PropertyGroup>
-    <DotnetFscCompilerPath>D:\Git\fsharp\artifacts\bin\fsc\Debug\net8.0\fsc.dll</DotnetFscCompilerPath>
+    <DotnetFscCompilerPath>D:\Git\fsharp\artifacts\bin\fsc\Debug\net9.0\fsc.dll</DotnetFscCompilerPath>
 </PropertyGroup>
 ```
 
@@ -215,6 +215,17 @@ or
 > **Note**
 > Please note, that by default, **Release** version of IL baseline tests will be running in CI, so when updating baseline (.bsl) files, make sure to add `-c Release` flag to the build command.
 
+
+### Updating FCS surface area baselines
+
+```bash
+$env:TEST_UPDATE_BSL=1
+dotnet test tests/FSharp.Compiler.Service.Tests/FSharp.Compiler.Service.Tests.fsproj --filter "SurfaceAreaTest" /p:BUILDING_USING_DOTNET=true
+dotnet test tests/FSharp.Compiler.Service.Tests/FSharp.Compiler.Service.Tests.fsproj --filter "SurfaceAreaTest" /p:BUILDING_USING_DOTNET=true
+dotnet test tests/FSharp.Compiler.Service.Tests/FSharp.Compiler.Service.Tests.fsproj --filter "SurfaceAreaTest" -c Release /p:BUILDING_USING_DOTNET=true
+dotnet test tests/FSharp.Compiler.Service.Tests/FSharp.Compiler.Service.Tests.fsproj --filter "SurfaceAreaTest" -c Release /p:BUILDING_USING_DOTNET=true
+```
+
 ## Automated Source Code Formatting
 
 Some of the code in this repository is formatted automatically by [Fantomas](https://github.com/fsprojects/fantomas). To format all files use:
@@ -331,4 +342,4 @@ See the "Debugging The Compiler" section of this [article](https://medium.com/@w
 
 If you are behind a proxy server, NuGet client tool must be configured to use it:
 
-See the Nuget config file documention for use with a proxy server [https://learn.microsoft.com/nuget/reference/nuget-config-file](https://learn.microsoft.com/nuget/reference/nuget-config-file)
+See the Nuget config file documentation for use with a proxy server [https://learn.microsoft.com/nuget/reference/nuget-config-file](https://learn.microsoft.com/nuget/reference/nuget-config-file)

Directory.Build.props

@@ -6,14 +6,15 @@
     <LangVersion Condition="'$(FSharpLangVersion)' != ''">$(FSharpLangVersion)</LangVersion>
     <RepoRoot Condition="'$(RepoRoot)' == ''">$(MSBuildThisFileDirectory)</RepoRoot>
     <AccelerateBuildsInVisualStudio>true</AccelerateBuildsInVisualStudio>
-    <FSharpNetCoreProductDefaultTargetFramework>net8.0</FSharpNetCoreProductDefaultTargetFramework>
+    <FSharpNetCoreProductDefaultTargetFramework>net9.0</FSharpNetCoreProductDefaultTargetFramework>
+    <IgnoreMibc Condition="'$(IgnoreMibc)' == ''">$(DotNetBuildSourceOnly)</IgnoreMibc>
   </PropertyGroup>
 
   <!--
    When developers load the FSharp.Compiler.Service solution we set FSHARPCORE_USE_PACKAGE to true if it hasn't already been set to a value.
    This option ensures that building and testing uses the specified FSharp.Core nuget package instead of the local FSharp.Core project.
    We also disable arcade and reset certain artifacts and compiler paths to use default ones.
-   All settings below can be overriden via CLI switches if needed. -->
+   All settings below can be overridden via CLI switches if needed. -->
 
   <PropertyGroup Condition="'$(SolutionName)' == 'FSharp.Compiler.Service' and '$(BUILDING_USING_DOTNET)' != 'false'">
       <BUILDING_USING_DOTNET>true</BUILDING_USING_DOTNET>
@@ -45,7 +46,10 @@
 
   <PropertyGroup Condition="'$(BUILDING_USING_DOTNET)' == 'true'">
     <DisableAutoSetFscCompilerPath>false</DisableAutoSetFscCompilerPath>
-    <FSHARPCORE_USE_PACKAGE Condition="'$(FSHARPCORE_USE_PACKAGE)' == ''">true</FSHARPCORE_USE_PACKAGE>
+
+    <!-- TODO(vlza): This probably should be `true` once fslib with nullness ships, since shipped library is preferred by default when building this solution. -->
+    <FSHARPCORE_USE_PACKAGE Condition="'$(FSHARPCORE_USE_PACKAGE)' == ''">false</FSHARPCORE_USE_PACKAGE>
+
     <DISABLE_ARCADE Condition="'$(DISABLE_ARCADE)' == ''">true</DISABLE_ARCADE>
     <ArtifactsDir>$(MSBuildThisFileDirectory)artifacts/</ArtifactsDir>
     <OutputPath>$(ArtifactsDir)/bin/$(MSBuildProjectName)/$(Configuration)/</OutputPath>
@@ -56,6 +60,7 @@
     <FsYaccPath>$(ArtifactsDir)/bin/fsyacc/$(Configuration)/$(FSharpNetCoreProductDefaultTargetFramework)/$(RuntimeIdentifier)/fsyacc.dll</FsYaccPath>
     <DefineConstants>NO_CHECKNULLS;BUILDING_WITH_LKG;NO_NULLCHECKING_LIB_SUPPORT;$(DefineConstants)</DefineConstants>
   </PropertyGroup>
+
   <Import Project="$(MSBuildThisFileDirectory)/eng/Versions.props" Condition="'$(DISABLE_ARCADE)' == 'true'" />
 
   <Import Project="FSharpBuild.Directory.Build.props" Condition=" '$(FSharpTestCompilerVersion)' == '' " />
@@ -68,7 +73,7 @@
          we should also support $(NetPrevious) for all releases.
          This will likely include FCS and FSharp.Core as well as shipped products.
          Right now, it only covers products we ship (FSC and FSI), not NuGet packages. -->
-    <When Condition="'$(DotNetBuildFromSource)' == 'true' AND '$(DotNetBuildFromSourceFlavor)' == 'Product'">
+    <When Condition="'$(DotNetBuildSourceOnly)' == 'true' AND '$(DotNetBuildOrchestrator)' == 'true'">
       <PropertyGroup>
         <FSharpNetCoreProductTargetFramework>$(NetCurrent)</FSharpNetCoreProductTargetFramework>
       </PropertyGroup>