Bugfix :: Nullness in signature file is not considered by implementation and vice versa

.fantomasignore

@@ -42,6 +42,8 @@ src/Compiler/Checking/TypeRelations.fs
 
 # nullness-related problems
 src/Compiler/DependencyManager/DependencyProvider.fs
+src/FSharp.Core/fslib-extra-pervasives.fs
+src/FSharp.Core/fslib-extra-pervasives.fsi
 
 # Incorrectly formatted: https://github.com/dotnet/fsharp/pull/14645/commits/49443a67ea8a17670c8a7c80c8bdf91f82231e91 or https://github.com/fsprojects/fantomas/issues/2733
 # This CompilerImports.fs behavior is not fixed yet, following up in  https://github.com/fsprojects/fantomas/issues/2733
@@ -124,6 +126,9 @@ src/Compiler/SyntaxTree/LexerStore.fs
 src/Compiler/Driver/GraphChecking/Graph.fsi
 src/Compiler/Driver/GraphChecking/Graph.fs
 
+src/Compiler/DependencyManager/NativeDllResolveHandler.fsi
+src/Compiler/DependencyManager/AssemblyResolveHandler.fsi
+
 # Fantomas limitations on implementation files  (to investigate)
 
 src/Compiler/AbstractIL/ilwrite.fs

docs/release-notes/.FSharp.Compiler.Service/9.0.300.md

@@ -11,6 +11,7 @@
 ### Added
 * Added missing type constraints in FCS. ([PR #18241](https://github.com/dotnet/fsharp/pull/18241))
 * The 'use' keyword can be used on IDisposable|null without nullness warnings ([PR #18262](https://github.com/dotnet/fsharp/pull/18262))
+* Nullness warnings are issued for signature<>implementation conformance ([PR #18186](https://github.com/dotnet/fsharp/pull/18186))
 * Symbols: Add FSharpAssembly.IsFSharp ([PR #18290](https://github.com/dotnet/fsharp/pull/18290))
 
 ### Changed

src/Compiler/AbstractIL/ilreflect.fs

@@ -2548,7 +2548,7 @@ let EmitDynamicAssemblyFragment
             ignore (typB.InvokeMemberAndLog(methodName, BindingFlags.InvokeMethod ||| BindingFlags.Public ||| BindingFlags.Static, [||]))
             None
         with :? TargetInvocationException as exn ->
-            Some exn.InnerException
+            Option.ofObj exn.InnerException
 
     let emEnv, entryPts = envPopEntryPts emEnv
     let execs = List.map execEntryPtFun entryPts

src/Compiler/Checking/AttributeChecking.fsi

@@ -24,8 +24,8 @@ type AttribInfo =
     | FSAttribInfo of TcGlobals * Attrib
     | ILAttribInfo of TcGlobals * Import.ImportMap * ILScopeRef * ILAttribute * range
 
-    member ConstructorArguments: (TType * obj) list
-    member NamedArguments: (TType * string * bool * obj) list
+    member ConstructorArguments: (TType * objnull) list
+    member NamedArguments: (TType * string * bool * objnull) list
     member Range: range
     member TyconRef: TyconRef
 

src/Compiler/Checking/CheckDeclarations.fs

@@ -3060,7 +3060,7 @@ module EstablishTypeDefinitionCores =
 
             if not isRootGenerated then 
                 let desig = theRootTypeWithRemapping.TypeProviderDesignation
-                let nm = theRootTypeWithRemapping.PUntaint((fun st -> st.FullName), m)
+                let nm = theRootTypeWithRemapping.PUntaint((fun st -> string st.FullName), m)
                 error(Error(FSComp.SR.etErasedTypeUsedInGeneration(desig, nm), m))
 
             cenv.createsGeneratedProvidedTypes <- true
@@ -3101,7 +3101,7 @@ module EstablishTypeDefinitionCores =
 
                 if not isGenerated then 
                     let desig = st.TypeProviderDesignation
-                    let nm = st.PUntaint((fun st -> st.FullName), m)
+                    let nm = st.PUntaint((fun st -> string st.FullName), m)
                     error(Error(FSComp.SR.etErasedTypeUsedInGeneration(desig, nm), m))
 
                 // Embed the type into the module we're compiling
@@ -4251,7 +4251,7 @@ module TcDeclarations =
                 // For historical reasons we only give a warning for incorrect type parameters on intrinsic extensions
                 if nReqTypars <> synTypars.Length then 
                     errorR(Error(FSComp.SR.tcDeclaredTypeParametersForExtensionDoNotMatchOriginal(tcref.DisplayNameWithStaticParametersAndUnderscoreTypars), m))
-                if not (typarsAEquiv g TypeEquivEnv.Empty reqTypars declaredTypars) then 
+                if not (typarsAEquiv g (TypeEquivEnv.EmptyWithNullChecks g) reqTypars declaredTypars) then 
                     warning(Error(FSComp.SR.tcDeclaredTypeParametersForExtensionDoNotMatchOriginal(tcref.DisplayNameWithStaticParametersAndUnderscoreTypars), m))
                 // Note we return 'reqTypars' for intrinsic extensions since we may only have given warnings
                 IntrinsicExtensionBinding, reqTypars
@@ -4260,7 +4260,7 @@ module TcDeclarations =
                     errorR(Error(FSComp.SR.tcMembersThatExtendInterfaceMustBePlacedInSeparateModule(), tcref.Range))
                 if nReqTypars <> synTypars.Length then 
                     error(Error(FSComp.SR.tcDeclaredTypeParametersForExtensionDoNotMatchOriginal(tcref.DisplayNameWithStaticParametersAndUnderscoreTypars), m))
-                if not (typarsAEquiv g TypeEquivEnv.Empty reqTypars declaredTypars) then 
+                if not (typarsAEquiv g (TypeEquivEnv.EmptyWithNullChecks g) reqTypars declaredTypars) then 
                     errorR(Error(FSComp.SR.tcDeclaredTypeParametersForExtensionDoNotMatchOriginal(tcref.DisplayNameWithStaticParametersAndUnderscoreTypars), m))
                 ExtrinsicExtensionBinding, declaredTypars
 
@@ -5702,7 +5702,7 @@ let CheckModuleSignature g (cenv: cenv) m denvAtEnd rootSigOpt implFileTypePrior
                 |]
 
         // We want to show imperative type variables in any types in error messages at this late point 
-        let denv = { denvAtEnd with showInferenceTyparAnnotations=true }
+        let denv = { denvAtEnd with showInferenceTyparAnnotations=true;showNullnessAnnotations=Some g.checkNullness }
         try 
 
             // As typechecked the signature and implementation use different tycons etc. 
@@ -5714,7 +5714,7 @@ let CheckModuleSignature g (cenv: cenv) m denvAtEnd rootSigOpt implFileTypePrior
             // Compute the remapping from implementation to signature
             let remapInfo, _ = ComputeRemappingFromInferredSignatureToExplicitSignature g implFileTypePriorToSig sigFileType
 
-            let aenv = { TypeEquivEnv.Empty with EquivTycons = TyconRefMap.OfList remapInfo.RepackagedEntities }
+            let aenv = { TypeEquivEnv.EmptyWithNullChecks g with EquivTycons = TyconRefMap.OfList remapInfo.RepackagedEntities }
 
             if not (SignatureConformance.Checker(g, cenv.amap, denv, remapInfo, true).CheckSignature aenv cenv.infoReader (mkLocalModuleRef implFileSpecPriorToSig) sigFileType) then
                 // We can just raise 'ReportedError' since CheckModuleOrNamespace raises its own error 

src/Compiler/Checking/ConstraintSolver.fs

@@ -345,7 +345,7 @@ let MakeConstraintSolverEnv contextInfo css m denv =
       eContextInfo = contextInfo
       MatchingOnly = false
       ErrorOnFailedMemberConstraintResolution = false
-      EquivEnv = TypeEquivEnv.Empty 
+      EquivEnv = TypeEquivEnv.EmptyIgnoreNulls
       DisplayEnv = denv
       IsSpeculativeForMethodOverloading = false
       IsSupportsNullFlex = false

src/Compiler/Checking/Expressions/CheckExpressions.fs

@@ -12687,7 +12687,7 @@ and FixupLetrecBind (cenv: cenv) denv generalizedTyparsForRecursiveBlock (bind:
     | Some _ ->
        match PartitionValTyparsForApparentEnclosingType g vspec with
        | Some(parentTypars, memberParentTypars, _, _, _) ->
-          ignore(SignatureConformance.Checker(g, cenv.amap, denv, SignatureRepackageInfo.Empty, false).CheckTypars vspec.Range TypeEquivEnv.Empty memberParentTypars parentTypars)
+          ignore(SignatureConformance.Checker(g, cenv.amap, denv, SignatureRepackageInfo.Empty, false).CheckTypars vspec.Range TypeEquivEnv.EmptyIgnoreNulls memberParentTypars parentTypars)
        | None ->
           errorR(Error(FSComp.SR.tcMemberIsNotSufficientlyGeneric(), vspec.Range))
     | _ -> ()

src/Compiler/Checking/InfoReader.fs

@@ -63,7 +63,8 @@ let rec GetImmediateIntrinsicMethInfosOfTypeAux (optFilter, ad) g amap m withExp
             let st = info.ProvidedType
             let meths = 
                 match optFilter with
-                | Some name ->  st.PApplyArray ((fun st -> st.GetMethods() |> Array.filter (fun mi -> mi.Name = name) ), "GetMethods", m)
+                | Some name ->  
+                    st.PApplyFilteredArray ((fun st -> st.GetMethods()),(fun mi -> mi.Name = name), "GetMethods", m)                        
                 | None -> st.PApplyArray ((fun st -> st.GetMethods()), "GetMethods", m)
             [   for mi in meths -> ProvidedMeth(amap, mi.Coerce(m), None, m) ]
 #endif

src/Compiler/Checking/MethodCalls.fs

@@ -1120,7 +1120,7 @@ let TryImportProvidedMethodBaseAsLibraryIntrinsic (amap: Import.ImportMap, m: ra
     match tryTcrefOfAppTy amap.g declaringType with
     | ValueSome declaringEntity ->
         if not declaringEntity.IsLocalRef && ccuEq declaringEntity.nlr.Ccu amap.g.fslibCcu then
-            let n = mbase.PUntaint((fun x -> x.GetParameters().Length), m)
+            let n = mbase.PApplyArray((fun x -> x.GetParameters()),"GetParameters", m).Length
             match amap.g.knownIntrinsics.TryGetValue ((declaringEntity.LogicalName, None, methodName, n)) with 
             | true, vref -> Some vref
             | _ -> 
@@ -1815,14 +1815,14 @@ module ProvidedMethodCalls =
         let rec loop (st: Tainted<ProvidedType>) = 
             if st.PUntaint((fun st -> st.IsGenericParameter), m) then st
             elif st.PUntaint((fun st -> st.IsArray), m) then 
-                let et = st.PApply((fun st -> st.GetElementType()), m)
+                let et = st.PApply((fun st -> !! st.GetElementType()), m)
                 let rank = st.PUntaint((fun st -> st.GetArrayRank()), m)
                 (loop et).PApply((fun st -> if rank = 1 then st.MakeArrayType() else st.MakeArrayType(rank)), m)
             elif st.PUntaint((fun st -> st.IsByRef), m) then 
-                let et = st.PApply((fun st -> st.GetElementType()), m)
+                let et = st.PApply((fun st -> !! st.GetElementType()), m)
                 (loop et).PApply((fun st -> st.MakeByRefType()), m)
             elif st.PUntaint((fun st -> st.IsPointer), m) then 
-                let et = st.PApply((fun st -> st.GetElementType()), m)
+                let et = st.PApply((fun st -> !! st.GetElementType()), m)
                 (loop et).PApply((fun st -> st.MakePointerType()), m)
             else
                 let isGeneric = st.PUntaint((fun st -> st.IsGenericType), m)
@@ -1863,7 +1863,7 @@ module ProvidedMethodCalls =
              allArgs: Exprs,
              paramVars: Tainted<ProvidedVar>[],
              g, amap, mut, isProp, isSuperInit, m,
-             expr: Tainted<ProvidedExpr>) = 
+             expr: Tainted<ProvidedExpr MaybeNull>) = 
 
         let varConv =
             // note: Assuming the size based on paramVars
@@ -1873,7 +1873,7 @@ module ProvidedMethodCalls =
                 dict.Add(v, (None, e))
             dict
 
-        let rec exprToExprAndWitness top (ea: Tainted<ProvidedExpr>) =
+        let rec exprToExprAndWitness top (ea: Tainted<ProvidedExpr MaybeNull>) =
             let fail() = error(Error(FSComp.SR.etUnsupportedProvidedExpression(ea.PUntaint((fun etree -> etree.UnderlyingExpressionString), m)), m))
             match ea with
             | Tainted.Null -> error(Error(FSComp.SR.etNullProvidedExpression(ea.TypeProviderDesignation), m))
@@ -2115,7 +2115,7 @@ module ProvidedMethodCalls =
             methInfoOpt, expr, exprTy
         with
             | :? TypeProviderError as tpe ->
-                let typeName = mi.PUntaint((fun mb -> (nonNull<ProvidedType> mb.DeclaringType).FullName), m)
+                let typeName = mi.PUntaint((fun mb -> (nonNull<ProvidedType> mb.DeclaringType).FullName |> string), m)
                 let methName = mi.PUntaint((fun mb -> mb.Name), m)
                 raise( tpe.WithContext(typeName, methName) )  // loses original stack trace
 #endif

src/Compiler/Checking/MethodOverrides.fs

@@ -269,7 +269,7 @@ module DispatchSlotChecking =
         // Compare the types. CompiledSigOfMeth, GetObjectExprOverrideInfo and GetTypeMemberOverrideInfo have already 
         // applied all relevant substitutions except the renamings from fvtmps <-> methTypars 
 
-        let aenv = TypeEquivEnv.FromEquivTypars fvmethTypars methTypars 
+        let aenv = (TypeEquivEnv.EmptyIgnoreNulls).FromEquivTypars fvmethTypars methTypars 
 
         List.forall2 (List.lengthsEqAndForall2 (typeAEquiv g aenv)) vargTys argTys &&
         returnTypesAEquiv g aenv vrty retTy &&
@@ -305,7 +305,7 @@ module DispatchSlotChecking =
                 ComposeTyparInsts ttpinst (ReverseTyparRenaming g memberToParentInst)
 
         // Compare under the composed substitutions 
-        let aenv = TypeEquivEnv.FromTyparInst ttpinst 
+        let aenv = (TypeEquivEnv.EmptyIgnoreNulls).FromTyparInst ttpinst 
 
         typarsAEquiv g aenv fvmethTypars methTypars
 

src/Compiler/Checking/NameResolution.fs

@@ -991,7 +991,7 @@ let ResolveProvidedTypeNameInEntity (amap, m, typeName, modref: ModuleOrNamespac
             //if staticResInfo.NumStaticArgs > 0 then
             //    error(Error(FSComp.SR.etNestedProvidedTypesDoNotTakeStaticArgumentsOrGenericParameters(), m))
             []
-        | nestedSty ->
+        | Tainted.NonNull nestedSty ->
             [AddEntityForProvidedType (amap, modref, resolutionEnvironment, nestedSty, m) ]
     | _ -> []
 #endif

src/Compiler/Checking/NicePrint.fs

@@ -764,7 +764,7 @@ module PrintTypes =
             |> ListSet.setify (fun (_, cx1) (_, cx2) ->
                 match cx1, cx2 with 
                 | TyparConstraint.MayResolveMember(traitInfo1, _),
-                  TyparConstraint.MayResolveMember(traitInfo2, _) -> traitsAEquiv denv.g TypeEquivEnv.Empty traitInfo1 traitInfo2
+                  TyparConstraint.MayResolveMember(traitInfo2, _) -> traitsAEquiv denv.g (TypeEquivEnv.EmptyWithNullChecks denv.g) traitInfo1 traitInfo2
                 | _ -> false)
 
         let cxsL = List.collect (layoutConstraintWithInfo denv env) cxs
@@ -2177,7 +2177,7 @@ module TastDefinitionPrinting =
                 match tcref.TypeReprInfo with 
                 | TProvidedTypeRepr info ->
                     [ 
-                        for nestedType in info.ProvidedType.PApplyArray((fun sty -> sty.GetNestedTypes() |> Array.filter (fun t -> t.IsPublic || t.IsNestedPublic)), "GetNestedTypes", m) do 
+                        for nestedType in info.ProvidedType.PApplyFilteredArray((fun sty -> sty.GetNestedTypes()),(fun t -> t.IsPublic || t.IsNestedPublic), "GetNestedTypes", m) do 
                             yield nestedType.PUntaint((fun t -> t.IsClass, t.Name), m)
                     ] 
                     |> List.sortBy snd
@@ -2930,7 +2930,7 @@ let minimalStringsOfTwoTypes denv ty1 ty2 =
         let denv = denv.SetOpenPaths []
         let denv = { denv with includeStaticParametersInTypeNames=true }
         let makeName t =
-            let assemblyName = PrintTypes.layoutAssemblyName denv t |> function Null | NonNull "" -> "" | NonNull name -> sprintf " (%s)" name
+            let assemblyName = PrintTypes.layoutAssemblyName denv t |> function | "" -> "" | name -> $" (%s{name})"
             sprintf "%s%s" (stringOfTy denv t) assemblyName
 
         (makeName ty1, makeName ty2, stringOfTyparConstraints denv tpcs)