Nullness - include in QuickInfo and in general in "typeEnc" (string representation of a type)

src/Compiler/Symbols/SymbolHelpers.fs

@@ -546,7 +546,7 @@ module internal SymbolHelpers =
     let SimplerDisplayEnv denv = 
         { denv with shortConstraints=true
                     showStaticallyResolvedTyparAnnotations=false
-                    showNullnessAnnotations = Some false
+                    showNullnessAnnotations = Some true
                     abbreviateAdditionalConstraints=false
                     suppressNestedTypes=true
                     maxMembers=Some EnvMisc2.maxMembers }

src/Compiler/TypedTree/TypedTree.fs

@@ -4227,6 +4227,8 @@ type Nullness =
 
    override n.ToString() = match n.Evaluate() with NullnessInfo.WithNull -> "?"  | NullnessInfo.WithoutNull -> "" | NullnessInfo.AmbivalentToNull -> "%"
 
+   member n.ToFsharpCodeString() = match n.Evaluate() with NullnessInfo.WithNull -> " | null "  | NullnessInfo.WithoutNull -> "" | NullnessInfo.AmbivalentToNull -> ""
+
 // Note, nullness variables are only created if the nullness checking feature is on
 [<NoComparison;NoEquality>]
 type NullnessVar() = 

src/Compiler/TypedTree/TypedTree.fsi

@@ -3043,6 +3043,8 @@ type Nullness =
 
     member TryEvaluate: unit -> NullnessInfo voption
 
+    member ToFsharpCodeString: unit -> string
+
 [<NoComparison; NoEquality>]
 type NullnessVar =
     new: unit -> NullnessVar

src/Compiler/TypedTree/TypedTreeOps.fs

@@ -8776,26 +8776,26 @@ let rec typeEnc g (gtpsType, gtpsMethod) ty =
         let ety = destNativePtrTy g ty
         typeEnc g (gtpsType, gtpsMethod) ety + "*"
 
-    | _ when isArrayTy g ty -> 
-        let tcref, tinst = destAppTy g ty
+    | TType_app (_, _, nullness) when isArrayTy g ty -> 
+        let tcref, tinst = destAppTy g ty        
         let rank = rankOfArrayTyconRef g tcref
         let arraySuffix = "[" + String.concat ", " (List.replicate (rank-1) "0:") + "]"
-        typeEnc g (gtpsType, gtpsMethod) (List.head tinst) + arraySuffix
+        typeEnc g (gtpsType, gtpsMethod) (List.head tinst) + arraySuffix + nullness.ToFsharpCodeString()
 
     | TType_ucase (_, tinst)   
     | TType_app (_, tinst, _) -> 
-        let tyName = 
+        let tyName,nullness = 
             let ty = stripTyEqnsAndMeasureEqns g ty
             match ty with
-            | TType_app (tcref, _tinst, _) -> 
+            | TType_app (tcref, _tinst, nullness) -> 
                 // Generic type names are (name + "`" + digits) where name does not contain "`".
                 // In XML doc, when used in type instances, these do not use the ticks.
                 let path = Array.toList (fullMangledPathToTyconRef tcref) @ [tcref.CompiledName]
-                textOfPath (List.map DemangleGenericTypeName path)
+                textOfPath (List.map DemangleGenericTypeName path),nullness
             | _ ->
                 assert false
                 failwith "impossible"
-        tyName + tyargsEnc g (gtpsType, gtpsMethod) tinst
+        tyName + tyargsEnc g (gtpsType, gtpsMethod) tinst + nullness.ToFsharpCodeString()
 
     | TType_anon (anonInfo, tinst) -> 
         sprintf "%s%s" anonInfo.ILTypeRef.FullName (tyargsEnc g (gtpsType, gtpsMethod) tinst)
@@ -8806,11 +8806,11 @@ let rec typeEnc g (gtpsType, gtpsMethod) ty =
         else 
             sprintf "System.Tuple%s"(tyargsEnc g (gtpsType, gtpsMethod) tys)
 
-    | TType_fun (domainTy, rangeTy, _) -> 
-        "Microsoft.FSharp.Core.FSharpFunc" + tyargsEnc g (gtpsType, gtpsMethod) [domainTy; rangeTy]
+    | TType_fun (domainTy, rangeTy, nullness) -> 
+        "Microsoft.FSharp.Core.FSharpFunc" + tyargsEnc g (gtpsType, gtpsMethod) [domainTy; rangeTy] + nullness.ToFsharpCodeString()
 
-    | TType_var (typar, _) -> 
-        typarEnc g (gtpsType, gtpsMethod) typar
+    | TType_var (typar, nullness) -> 
+        typarEnc g (gtpsType, gtpsMethod) typar + nullness.ToFsharpCodeString()
 
     | TType_measure _ -> "?"
 
@@ -8822,7 +8822,7 @@ and tyargsEnc g (gtpsType, gtpsMethod) args =
 
 let XmlDocArgsEnc g (gtpsType, gtpsMethod) argTys =
     if isNil argTys then "" 
-    else "(" + String.concat "," (List.map (typeEnc g (gtpsType, gtpsMethod)) argTys) + ")"
+    else "(" + String.concat "," (List.map (typeEnc g (gtpsType, gtpsMethod)) argTys) + ")"    
 
 let buildAccessPath (cp: CompilationPath option) =
     match cp with