(not into main) - Apply nullable downcasting changes

src/Compiler/AbstractIL/il.fs

@@ -481,11 +481,11 @@ type ILAssemblyRef(data) =
     override x.GetHashCode() = uniqueStamp
 
     override x.Equals yobj =
-        ((yobj :?> ILAssemblyRef).UniqueStamp = uniqueStamp)
+        ((!!yobj :?> ILAssemblyRef).UniqueStamp = uniqueStamp)
 
     interface IComparable with
         override x.CompareTo yobj =
-            compare (yobj :?> ILAssemblyRef).UniqueStamp uniqueStamp
+            compare (!!yobj :?> ILAssemblyRef).UniqueStamp uniqueStamp
 
     static member Create(name, hash, publicKey, retargetable, version, locale) =
         ILAssemblyRef
@@ -750,7 +750,7 @@ type ILTypeRef =
     override x.GetHashCode() = x.hashCode
 
     override x.Equals yobj =
-        let y = (yobj :?> ILTypeRef)
+        let y = (!!yobj :?> ILTypeRef)
 
         (x.ApproxId = y.ApproxId)
         && (x.Scope = y.Scope)
@@ -793,7 +793,7 @@ type ILTypeRef =
     interface IComparable with
 
         override x.CompareTo yobj =
-            let y = (yobj :?> ILTypeRef)
+            let y = (!!yobj :?> ILTypeRef)
             let c = compare x.ApproxId y.ApproxId
 
             if c <> 0 then

src/Compiler/AbstractIL/ilreflect.fs

@@ -1834,7 +1834,7 @@ let rec buildMethodPass2 cenv tref (typB: TypeBuilder) emEnv (mdef: ILMethodDef)
         let methB =
             System.Diagnostics.Debug.Assert(not (isNull definePInvokeMethod), "Runtime does not have DefinePInvokeMethod") // Absolutely can't happen
 
-            (!!definePInvokeMethod)
+            !!(!!definePInvokeMethod)
                 .Invoke(
                     typB,
                     [|

src/Compiler/Checking/MethodCalls.fs

@@ -1771,7 +1771,7 @@ module ProvidedMethodCalls =
                     | _ when typeEquiv g normTy g.float32_ty -> Const.Single(v :?> float32)
                     | _ when typeEquiv g normTy g.float_ty -> Const.Double(v :?> float)
                     | _ when typeEquiv g normTy g.char_ty -> Const.Char(v :?> char)
-                    | _ when typeEquiv g normTy g.string_ty -> Const.String(v :?> string)
+                    | _ when typeEquiv g normTy g.string_ty -> Const.String(!!v :?> string)
                     | _ when typeEquiv g normTy g.decimal_ty -> Const.Decimal(v :?> decimal)
                     | _ when typeEquiv g normTy g.unit_ty -> Const.Unit
                     | _ -> fail()

src/Compiler/DependencyManager/AssemblyResolveHandler.fs

@@ -41,7 +41,7 @@ type AssemblyResolveHandlerCoreclr(assemblyProbingPaths: AssemblyResolutionProbe
 
     member _.ResolveAssemblyNetStandard (ctxt: 'T) (assemblyName: AssemblyName) : Assembly =
         let loadAssembly path =
-            loadFromAssemblyPathMethod.Invoke(ctxt, [| path |]) :?> Assembly
+            !! loadFromAssemblyPathMethod.Invoke(ctxt, [| path |]) :?> Assembly
 
         let assemblyPaths =
             match assemblyProbingPaths with

src/Compiler/DependencyManager/DependencyProvider.fs

@@ -168,7 +168,7 @@ type ReflectionDependencyManagerProvider
     let keyProperty (x: objnull) = x |> keyProperty.GetValue |> string
 
     let helpMessagesProperty (x: objnull) =
-        let toStringArray (o: objnull) = o :?> string[]
+        let toStringArray (o: objnull) = !!o :?> string[]
 
         match helpMessagesProperty with
         | Some helpMessagesProperty -> x |> helpMessagesProperty.GetValue |> toStringArray
@@ -334,31 +334,31 @@ type ReflectionDependencyManagerProvider
             member _.StdOut =
                 match getInstanceProperty<string[]> (result.GetType()) "StdOut" with
                 | None -> [||]
-                | Some p -> p.GetValue(result) :?> string[]
+                | Some p -> !! p.GetValue(result) :?> string[]
 
             /// The resolution error log (* process stderror *)
             member _.StdError =
                 match getInstanceProperty<string[]> (result.GetType()) "StdError" with
                 | None -> [||]
-                | Some p -> p.GetValue(result) :?> string[]
+                | Some p -> !! p.GetValue(result) :?> string[]
 
             /// The resolution paths
             member _.Resolutions =
                 match getInstanceProperty<seq<string>> (result.GetType()) "Resolutions" with
                 | None -> Seq.empty<string>
-                | Some p -> p.GetValue(result) :?> seq<string>
+                | Some p -> !! p.GetValue(result) :?> seq<string>
 
             /// The source code file paths
             member _.SourceFiles =
                 match getInstanceProperty<seq<string>> (result.GetType()) "SourceFiles" with
                 | None -> Seq.empty<string>
-                | Some p -> p.GetValue(result) :?> seq<string>
+                | Some p -> !! p.GetValue(result) :?> seq<string>
 
             /// The roots to package directories
             member _.Roots =
                 match getInstanceProperty<seq<string>> (result.GetType()) "Roots" with
                 | None -> Seq.empty<string>
-                | Some p -> p.GetValue(result) :?> seq<string>
+                | Some p -> !! p.GetValue(result) :?> seq<string>
         }
 
     static member MakeResultFromFields
@@ -473,8 +473,8 @@ type ReflectionDependencyManagerProvider
                         match tupleFields |> Array.length with
                         | 3 ->
                             tupleFields[0] :?> bool,
-                            tupleFields[1] :?> string list |> List.toSeq,
-                            tupleFields[2] :?> string list |> List.distinct |> List.toSeq
+                            !!tupleFields[1] :?> string list |> List.toSeq,
+                            !!tupleFields[2] :?> string list |> List.distinct |> List.toSeq
                         | _ -> false, seqEmpty, seqEmpty
 
                     ReflectionDependencyManagerProvider.MakeResultFromFields(success, [||], [||], Seq.empty, sourceFiles, packageRoots)

src/Compiler/Interactive/fsi.fs

@@ -122,7 +122,7 @@ module internal Utilities =
             }
         else
             let specialized = typedefof<AnyToLayoutSpecialization<_>>.MakeGenericType [| ty |]
-            Activator.CreateInstance(specialized) :?> IAnyToLayoutCall
+            !!Activator.CreateInstance(specialized) :?> IAnyToLayoutCall
 
     let callStaticMethod (ty: Type) name args =
         ty.InvokeMember(
@@ -4762,7 +4762,7 @@ type FsiEvaluationSession
     let makeNestedException (userExn: #Exception) =
         // clone userExn -- make userExn the inner exception, to retain the stacktrace on raise
         let arguments = [| userExn.Message :> obj; userExn :> obj |]
-        Activator.CreateInstance(userExn.GetType(), arguments) :?> Exception
+        !!Activator.CreateInstance(userExn.GetType(), arguments) :?> Exception
 
     let commitResult res =
         match res with

src/Compiler/TypedTree/TypeProviders.fs

@@ -141,10 +141,10 @@ let CreateTypeProvider (
                 IsHostedExecution= isInteractive, 
                 SystemRuntimeAssemblyVersion = systemRuntimeAssemblyVersion)
 #endif
-        protect (fun () -> Activator.CreateInstance(typeProviderImplementationType, [| box e|]) :?> ITypeProvider )
+        protect (fun () -> !!(Activator.CreateInstance(typeProviderImplementationType, [| box e|])) :?> ITypeProvider )
 
     elif not(isNull(typeProviderImplementationType.GetConstructor [| |])) then 
-        protect (fun () -> Activator.CreateInstance typeProviderImplementationType :?> ITypeProvider )
+        protect (fun () -> !!(Activator.CreateInstance typeProviderImplementationType) :?> ITypeProvider )
 
     else
         // No appropriate constructor found
@@ -739,7 +739,7 @@ type ProvidedMethodBase (x: MethodBase, ctxt) =
                 let paramsAsObj = 
                     try (!!meth).Invoke(provider, bindingFlags ||| BindingFlags.InvokeMethod, null, [| box x |], null) 
                     with err -> raise (StripException (StripException err))
-                paramsAsObj :?> ParameterInfo[] 
+                !!paramsAsObj :?> ParameterInfo[] 
 
         staticParams |> ProvidedParameterInfo.CreateArrayNonNull ctxt
 

src/Compiler/Utilities/TaggedCollections.fs

@@ -667,8 +667,8 @@ type internal Set<'T, 'ComparerTag> when 'ComparerTag :> IComparer<'T>(comparer:
     interface System.IComparable with
         // Cast s2 to the exact same type as s1, see 4884.
         // It is not OK to cast s2 to seq<'T>, since different compares could permute the elements.
-        member s1.CompareTo(s2: obj) =
-            SetTree.compare s1.Comparer s1.Tree (s2 :?> Set<'T, 'ComparerTag>).Tree
+        member s1.CompareTo(s2: objnull) =
+            SetTree.compare s1.Comparer s1.Tree (!!s2 :?> Set<'T, 'ComparerTag>).Tree
 
     member this.ComputeHashCode() =
         let combineHash x y = (x <<< 1) + y + 631
@@ -1239,7 +1239,7 @@ type internal Map<'Key, 'T, 'ComparerTag> when 'ComparerTag :> IComparer<'Key>(c
         | _ -> false
 
     interface System.IComparable with
-        member m1.CompareTo(m2: obj) =
+        member m1.CompareTo(m2: objnull) =
             Seq.compareWith
                 (fun (kvp1: KeyValuePair<_, _>) (kvp2: KeyValuePair<_, _>) ->
                     let c = m1.Comparer.Compare(kvp1.Key, kvp2.Key) in
@@ -1251,7 +1251,7 @@ type internal Map<'Key, 'T, 'ComparerTag> when 'ComparerTag :> IComparer<'Key>(c
                 // Cast m2 to the exact same type as m1, see 4884.
                 // It is not OK to cast m2 to seq<KeyValuePair<'Key,'T>>, since different compares could permute the KVPs.
                 m1
-                (m2 :?> Map<'Key, 'T, 'ComparerTag>)
+                (!!m2 :?> Map<'Key, 'T, 'ComparerTag>)
 
     member this.ComputeHashCode() =
         let combineHash x y = (x <<< 1) + y + 631