Merge branch 'main' into reenable-tests-3

README.md

@@ -57,6 +57,12 @@ After it's finished, open `FSharp.sln` in your editor of choice.
 
 Even if you find a single-character typo, we're happy to take the change! Although the codebase can feel daunting for beginners, we and other contributors are happy to help you along.
 
+Not sure where to contribute?
+Look at the [curated list of issues asking for help](https://github.com/dotnet/fsharp/issues?q=is%3Aissue%20state%3Aopen%20label%3A%22help%20wanted%22). If you want to tackle any of those, use the comments section of the chosen issue to indicate interest and feel free to ask for initial guidance. We are happy to help with resolving outstanding issues while making a successful PR addressing the issue.
+
+The issues in this repository can have big differences in the complexity for fixing them.
+Are you getting started? We do have a label for [good first issues](https://github.com/dotnet/fsharp/issues?q=is%3Aissue%20state%3Aopen%20label%3A%22good%20first%20issue%22) as well.
+
 ## Per-build NuGet packages
 
 ### 7.0.40x series

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

@@ -9,6 +9,7 @@
 * Fix concurrency issue in `ILPreTypeDefImpl`  ([PR #17812](https://github.com/dotnet/fsharp/pull/17812))
 * Fix nullness inference for member val and other OO scenarios  ([PR #17845](https://github.com/dotnet/fsharp/pull/17845))
 * Fix internal error when analyzing incomplete inherit member ([PR #17905](https://github.com/dotnet/fsharp/pull/17905))
+* Fix missing nullness warning in case of method resolution multiple candidates ([PR #17917](https://github.com/dotnet/fsharp/pull/17918))
 
 ### Added
 

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.1.24521.1">
+    <Dependency Name="Microsoft.SourceBuild.Intermediate.source-build-reference-packages" Version="10.0.0-alpha.1.24554.1">
       <Uri>https://github.com/dotnet/source-build-reference-packages</Uri>
-      <Sha>ccd0927e3823fb178c7151594f5d2eaba81bba81</Sha>
+      <Sha>e781442b88c4d939f06a94f38f24a5dc18c383d4</Sha>
       <SourceBuild RepoName="source-build-reference-packages" ManagedOnly="true" />
     </Dependency>
     <!-- Intermediate is necessary for source build. -->

src/Compiler/Checking/ConstraintSolver.fs

@@ -1035,7 +1035,6 @@ and SolveTypMeetsTyparConstraints (csenv: ConstraintSolverEnv) ndeep m2 trace ty
 
 and shouldWarnUselessNullCheck (csenv:ConstraintSolverEnv) =
     csenv.g.checkNullness &&
-    csenv.IsSpeculativeForMethodOverloading = false &&
     csenv.SolverState.WarnWhenUsingWithoutNullOnAWithNullTarget.IsSome    
 
 // nullness1: actual
@@ -1102,7 +1101,7 @@ and SolveNullnessSubsumesNullness (csenv: ConstraintSolverEnv) m2 (trace: Option
         | NullnessInfo.WithNull, NullnessInfo.WithoutNull ->             
             CompleteD
         | NullnessInfo.WithoutNull, NullnessInfo.WithNull -> 
-            if csenv.g.checkNullness && not csenv.IsSpeculativeForMethodOverloading then               
+            if csenv.g.checkNullness then               
                  WarnD(ConstraintSolverNullnessWarningWithTypes(csenv.DisplayEnv, ty1, ty2, n1, n2, csenv.m, m2)) 
             else
                 CompleteD

tests/FSharp.Compiler.ComponentTests/Language/Nullness/NullableReferenceTypesTests.fs

@@ -19,6 +19,23 @@ let typeCheckWithStrictNullness cu =
 
 
 
+[<FSharp.Test.FactForNETCOREAPPAttribute>]
+let ``Does report when null goes to DateTime Parse`` () =
+
+    FSharp """module TestLib
+open System
+let parsedDate = DateTime.Parse(null:(string|null))
+let parseDate2(s:string|null) = DateTime.Parse(s)
+let parsedDate3 = DateTime.Parse(null)
+    """
+    |> asLibrary
+    |> typeCheckWithStrictNullness
+    |> shouldFail
+    |> withDiagnostics     
+                [Error 3261, Line 3, Col 18, Line 3, Col 52, "Nullness warning: The types 'string' and 'string | null' do not have compatible nullability."
+                 Error 3261, Line 4, Col 33, Line 4, Col 50, "Nullness warning: The types 'string' and 'string | null' do not have compatible nullability."
+                 Error 3261, Line 5, Col 19, Line 5, Col 39, "Nullness warning: The type 'string' does not support 'null'."]
+
 [<Fact>]
 let ``Can convert generic value to objnull arg`` () =
     FSharp """module TestLib