Merge pull request #18108 from dotnet/merges/main-to-release/dev17.13

FSharp.sln

@@ -48,6 +48,8 @@ Project("{6EC3EE1D-3C4E-46DD-8F32-0CC8E7565705}") = "TestTP", "tests\service\dat
 EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Docs", "Docs", "{4E4F41D9-86A7-4F5D-B735-1A0744AB68AC}"
 	ProjectSection(SolutionItems) = preProject
+		docs\builder-caches.md = docs\builder-caches.md
+		docs\changing-the-ast.md = docs\changing-the-ast.md
 		docs\coding-standards.md = docs\coding-standards.md
 		docs\compiler-startup-performance.md = docs\compiler-startup-performance.md
 		docs\debug-emit.md = docs\debug-emit.md
@@ -57,12 +59,10 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Docs", "Docs", "{4E4F41D9-8
 		docs\index.md = docs\index.md
 		docs\large-inputs-and-stack-overflows.md = docs\large-inputs-and-stack-overflows.md
 		docs\memory-usage.md = docs\memory-usage.md
-		docs\optimizations.md = docs\optimizations.md
+		docs\names.md = docs\names.md
 		docs\optimizations-equality.md = docs\optimizations-equality.md
+		docs\optimizations.md = docs\optimizations.md
 		docs\overview.md = docs\overview.md
-		docs\builder-caches.md = docs\builder-caches.md
-		docs\changing-the-ast.md = docs\changing-the-ast.md
-		docs\names.md = docs\names.md
 		docs\perf-discussions-archive.md = docs\perf-discussions-archive.md
 		docs\project-builds.md = docs\project-builds.md
 		docs\representations.md = docs\representations.md
@@ -84,8 +84,8 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "fcs", "fcs", "{B86EBFF1-E03
 		docs\fcs\symbols.fsx = docs\fcs\symbols.fsx
 		docs\fcs\tokenizer.fsx = docs\fcs\tokenizer.fsx
 		docs\fcs\typedtree.fsx = docs\fcs\typedtree.fsx
-		docs\fcs\untypedtree.fsx = docs\fcs\untypedtree.fsx
 		docs\fcs\untypedtree-apis.fsx = docs\fcs\untypedtree-apis.fsx
+		docs\fcs\untypedtree.fsx = docs\fcs\untypedtree.fsx
 	EndProjectSection
 EndProject
 Project("{6EC3EE1D-3C4E-46DD-8F32-0CC8E7565705}") = "fsc", "src\fsc\fscProject\fsc.fsproj", "{10D15DBB-EFF0-428C-BA83-41600A93EEC4}"
@@ -142,6 +142,9 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = ".FSharp.Compiler.Service",
 		docs\release-notes\.FSharp.Compiler.Service\8.0.200.md = docs\release-notes\.FSharp.Compiler.Service\8.0.200.md
 		docs\release-notes\.FSharp.Compiler.Service\8.0.202.md = docs\release-notes\.FSharp.Compiler.Service\8.0.202.md
 		docs\release-notes\.FSharp.Compiler.Service\8.0.300.md = docs\release-notes\.FSharp.Compiler.Service\8.0.300.md
+		docs\release-notes\.FSharp.Compiler.Service\8.0.400.md = docs\release-notes\.FSharp.Compiler.Service\8.0.400.md
+		docs\release-notes\.FSharp.Compiler.Service\9.0.100.md = docs\release-notes\.FSharp.Compiler.Service\9.0.100.md
+		docs\release-notes\.FSharp.Compiler.Service\9.0.200.md = docs\release-notes\.FSharp.Compiler.Service\9.0.200.md
 	EndProjectSection
 EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = ".FSharp.Core", ".FSharp.Core", "{23798638-A1E9-4DAE-9C9C-F5D87499ADD6}"
@@ -158,8 +161,8 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = ".Language", ".Language", "{
 EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = ".VisualStudio", ".VisualStudio", "{AF70EC5A-8E7C-4FDA-857D-AF08082CFC64}"
 	ProjectSection(SolutionItems) = preProject
-		docs\release-notes\.VisualStudio\17.9.md = docs\release-notes\.VisualStudio\17.9.md
 		docs\release-notes\.VisualStudio\17.10.md = docs\release-notes\.VisualStudio\17.10.md
+		docs\release-notes\.VisualStudio\17.9.md = docs\release-notes\.VisualStudio\17.9.md
 	EndProjectSection
 EndProject
 Global

INTERNAL.md

@@ -116,19 +116,20 @@ https://github.com/dotnet/roslyn-tools/blob/6d7c182c46f8319d7922561e2c1586c7aadc
 5. Set the new branch to receive auto-merges from `main`, and also set the old release branch to flow into the new one.  [This PR](https://github.com/dotnet/roslyn-tools/pull/1245/files) is a good example of what to do when a new `release/dev17.4` branch is created that should receive merges from both `main` and the previous release branch, `release/dev17.3`. Old release branch should stop receiving updates from the `main`.
 
 6. Set the packages from the new branch to flow into the correct package feeds via the `darc` tool.  To do this:
-   1. Ensure the latest `darc` tool is installed by running `eng/common/darc-init.ps1`.
-   2. (only needed once) Run the command `darc authenticate`.  A text file will be opened with instructions on how to populate access tokens.
-   3. Check the current package/channel subscriptions by running `darc get-default-channels --source-repo fsharp`.  For this example, notice that the latest subscription shows the F# branch `release/dev17.3` is getting added to the `VS 17.3` channel.
-   4. Get the list of `darc` channels and determine the appropriate one to use for the new branch via the command `darc get-channels`.  For this example, notice that a channel named `VS 17.4` is listed.
-   5. Add the new F# branch to the appropriate `darc` channel.  In this example, run `darc add-default-channel --channel "VS 17.4" --branch release/dev17.4 --repo https://github.com/dotnet/fsharp`
-   6. Ensure the subscription was added by repeating step 3 above.
-   7. Note, the help in the `darc` tool is really good.  E.g., you can simply run `darc` to see a list of all commands available, and if you run `darc <some-command>` with no arguments, you'll be given a list of arguments you can use.
-   8. Ensure that version numbers are bumped for a new branch.
-   9. Change needed subscriptions for arcade and SDK:
+
+   1. To use `darc` you need to be a member of the `dotnetes-maestro-users` entitlement. You can request access at [coreidentity.microsoft.com](https://coreidentity.microsoft.com/manage/Entitlement/entitlement/dotnetesmaes-z54r)   
+   2. Ensure the latest `darc` tool is installed by running `eng/common/darc-init.ps1`.
+   3. (only needed once) Run the command `darc authenticate`.  A text file will be opened with instructions on how to populate access tokens.
+   4. Check the current package/channel subscriptions by running `darc get-default-channels --source-repo fsharp`.  For this example, notice that the latest subscription shows the F# branch `release/dev17.3` is getting added to the `VS 17.3` channel.
+   5. Get the list of `darc` channels and determine the appropriate one to use for the new branch via the command `darc get-channels`.  For this example, notice that a channel named `VS 17.4` is listed.
+   6. Add the new F# branch to the appropriate `darc` channel.  In this example, run `darc add-default-channel --channel "VS 17.4" --branch release/dev17.4 --repo https://github.com/dotnet/fsharp`
+   7. Ensure the subscription was added by repeating step 3 above.
+   8. Note, the help in the `darc` tool is really good.  E.g., you can simply run `darc` to see a list of all commands available, and if you run `darc <some-command>` with no arguments, you'll be given a list of arguments you can use.
+   9. Ensure that version numbers are bumped for a new branch.
+   10. Change needed subscriptions for arcade and SDK:
       1. `darc get-subscriptions --target-repo fsharp`, and then use `darc update-subscription --id <subscription id>` for corresponding channels (e.g. target new VS channel to specific SDK channel, or set up arcade auto-merges to release/* or main branch, depending on the timeline of release/upgrade cycle).
       2. If new subscription needs to be added, the following command should be used `darc add-subscription --source-repo https://github.com/dotnet/arcade --target-repo https://github.com/dotnet/fsharp --target-branch <target_branch> --channel "<target_channel>" --update-frequency everyDay --standard-automerge
-   10. Update mibc and other dependencies if needed, refer to https://github.com/dotnet/arcade/blob/main/Documentation/Darc.md#updating-dependencies-in-your-local-repository for more information 
-`
+   11. Update mibc and other dependencies if needed, refer to https://github.com/dotnet/arcade/blob/main/Documentation/Darc.md#updating-dependencies-in-your-local-repository for more information 
 
 ## Labeling issues on GitHub
 
@@ -160,4 +161,4 @@ You need the following permissions to do the above investigations:
 - "Queue builds"
 - "Edit queue build configuration"
 
-If anything, reach out to the "First Responders" team.
+If anything, reach out to the "First Responders" team.

docs/release-notes/.FSharp.Compiler.Service/9.0.200.md

@@ -15,13 +15,15 @@
 * Fix locals allocating for the special `copyOfStruct` defensive copy ([PR #18025](https://github.com/dotnet/fsharp/pull/18025))
 * Fix lowering of computed array expressions when the expression consists of a simple mapping from a `uint64` or `unativeint` array. [PR #18081](https://github.com/dotnet/fsharp/pull/18081)
 
+
 ### Added
 
 * Let `dotnet fsi --help` print a link to the documentation website. ([PR #18006](https://github.com/dotnet/fsharp/pull/18006))
 * Deprecate places where `seq` can be omitted. ([Language suggestion #1033](https://github.com/fsharp/fslang-suggestions/issues/1033), [PR #17772](https://github.com/dotnet/fsharp/pull/17772))
 * Support literal attribute on decimals ([PR #17769](https://github.com/dotnet/fsharp/pull/17769))
 * Added type conversions cache, only enabled for compiler runs, guarded by language version preview ([PR #17668](https://github.com/dotnet/fsharp/pull/17668))
 * Added project property ParallelCompilation which turns on graph based type checking, parallel ILXGen and parallel optimization. By default on for users of langversion=preview ([PR #17948](https://github.com/dotnet/fsharp/pull/17948))
+* Adding warning when consuming generic method returning T|null for types not supporting nullness (structs,anons,tuples) ([PR #18057](https://github.com/dotnet/fsharp/pull/18057))
 
 ### Changed
 

eng/Version.Details.xml

@@ -1,9 +1,9 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Dependencies>
   <ProductDependencies>
-    <Dependency Name="Microsoft.SourceBuild.Intermediate.source-build-reference-packages" Version="10.0.0-alpha.1.24558.1">
+    <Dependency Name="Microsoft.SourceBuild.Intermediate.source-build-reference-packages" Version="9.0.0-alpha.1.24568.3">
       <Uri>https://github.com/dotnet/source-build-reference-packages</Uri>
-      <Sha>1ebd9ce245112164207d961c0d2faea741c7c489</Sha>
+      <Sha>a3776f67d97bd5d9ada92122330454b284bfe915</Sha>
       <SourceBuild RepoName="source-build-reference-packages" ManagedOnly="true" />
     </Dependency>
     <!-- Intermediate is necessary for source build. -->

src/Compiler/Checking/Expressions/CheckExpressions.fs

@@ -9728,10 +9728,13 @@ and TcMethodApplicationThen
         let (CallerNamedArg(id, _)) = List.head attributeAssignedNamedItems
         errorR(Error(FSComp.SR.tcNamedArgumentDidNotMatch(id.idText), id.idRange))
 
-
     // Resolve the "delayed" lookups
     let exprTy = (tyOfExpr g expr)
 
+    for problematicTy in GetDisallowedNullness g exprTy do
+        let denv = env.DisplayEnv
+        warning(Error(FSComp.SR.tcDisallowedNullableApplication(methodName,NicePrint.minimalStringOfType denv problematicTy), m))
+
     PropagateThenTcDelayed cenv overallTy env tpenv mWholeExpr (MakeApplicableExprNoFlex cenv expr) exprTy atomicFlag delayed
 
 /// Infer initial type information at the callsite from the syntax of an argument, prior to overload resolution.

src/Compiler/FSComp.txt

@@ -1538,6 +1538,7 @@ tcPassingWithoutNullToNonNullQuickAP,"You can remove this |NonNullQuick| pattern
 tcPassingWithoutNullTononNullFunction,"You can remove this `nonNull` assertion."
 3263,tcNullableToStringOverride,"With nullness checking enabled, overrides of .ToString() method must return a non-nullable string. You can handle potential nulls via the built-in string function."
 3264,tcDowncastFromNullableToWithoutNull,"Nullness warning: Downcasting from '%s' into '%s' can introduce unexpected null values. Cast to '%s|null' instead or handle the null before downcasting."
+3265,tcDisallowedNullableApplication,"Application of method '%s' attempted to create a nullable type ('T | null) for '%s'. Nullness warnings won't be reported correctly for such types."
 3268,csNullNotNullConstraintInconsistent,"The constraints 'null' and 'not null' are inconsistent"
 3271,tcNullnessCheckingNotEnabled,"The 'nullness checking' language feature is not enabled. This use of a nullness checking construct will be ignored."
 csTypeHasNullAsTrueValue,"The type '%s' uses 'null' as a representation value but a non-null type is expected"

src/Compiler/TypedTree/TypedTreeOps.fs

@@ -9215,6 +9215,57 @@ let reqTyForArgumentNullnessInference g actualTy reqTy =
         changeWithNullReqTyToVariable g reqTy       
     | _ -> reqTy
 
+
+let GetDisallowedNullness (g:TcGlobals) (ty:TType) =
+    if g.checkNullness then
+        let rec hasWithNullAnyWhere ty alreadyWrappedInOuterWithNull = 
+            match ty with
+            | TType_var (tp, n) -> 
+                let withNull = alreadyWrappedInOuterWithNull || n.TryEvaluate() = (ValueSome NullnessInfo.WithNull)
+                match tp.Solution with
+                | None -> []
+                | Some t -> hasWithNullAnyWhere t withNull
+
+            | TType_app (tcr, tinst, nullnessOrig) -> 
+                let tyArgs = tinst |> List.collect (fun t -> hasWithNullAnyWhere t false)
+
+                match alreadyWrappedInOuterWithNull, tcr.TypeAbbrev with
+                | true, _ when isStructTyconRef tcr -> ty :: tyArgs
+                | true, _ when tcr.IsMeasureableReprTycon -> 
+                    match tcr.TypeReprInfo with
+                    | TMeasureableRepr realType ->
+                        if hasWithNullAnyWhere realType true |> List.isEmpty then
+                            []
+                        else [ty]
+                    | _ -> []
+                | true, Some tAbbrev -> (hasWithNullAnyWhere tAbbrev true) @ tyArgs
+                | _ -> tyArgs
+
+            | TType_tuple (_,tupTypes) ->
+                let inner = tupTypes |> List.collect (fun t -> hasWithNullAnyWhere t false)
+                if alreadyWrappedInOuterWithNull then ty :: inner else inner
+
+            | TType_anon (anon,tys) -> 
+                let inner = tys |> List.collect (fun t -> hasWithNullAnyWhere t false)
+                if alreadyWrappedInOuterWithNull then ty :: inner else inner
+            | TType_fun (d, r, _) ->
+                (hasWithNullAnyWhere d false) @ (hasWithNullAnyWhere r false)
+
+            | TType_forall _ -> []
+            | TType_ucase _ -> []
+            | TType_measure m ->
+                if alreadyWrappedInOuterWithNull then 
+                    let measuresInside = 
+                        ListMeasureVarOccs m 
+                        |> List.choose (fun x -> x.Solution)
+                        |> List.collect (fun x -> hasWithNullAnyWhere x true)
+                    ty :: measuresInside
+                else []
+
+        hasWithNullAnyWhere ty false
+    else
+        []
+
 let TypeHasAllowNull (tcref:TyconRef) g m =
     not tcref.IsStructOrEnumTycon &&
     not (isByrefLikeTyconRef g m tcref) && 

src/Compiler/TypedTree/TypedTreeOps.fsi

@@ -1815,6 +1815,11 @@ val TypeNullIsTrueValue: TcGlobals -> TType -> bool
 
 val TypeNullIsExtraValue: TcGlobals -> range -> TType -> bool
 
+/// A type coming via interop from C# can be holding a nullness combination not supported in F#.
+/// Prime example are APIs marked as T|null applied to structs, tuples and anons.
+/// Unsupported values can also be nested within generic type arguments, e.g. a List<Tuple<string,T|null>> applied to an anon.
+val GetDisallowedNullness: TcGlobals -> TType -> TType list
+
 val TypeHasAllowNull: TyconRef -> TcGlobals -> range -> bool
 
 val TypeNullIsExtraValueNew: TcGlobals -> range -> TType -> bool