Merge pull request #1085 from kerams/main

Improve null comparisons

Author: edgarfgp

src/Fabulous/Cmd.fs

@@ -196,7 +196,7 @@ module Cmd =
         fun (value: 'value) ->
             [ fun dispatch ->
                   lock funLock (fun () ->
-                      if cts <> null then
+                      if not(isNull cts) then
                           cts.Cancel()
                           cts.Dispose()
 
@@ -209,7 +209,7 @@ module Cmd =
                               lock funLock (fun () ->
                                   dispatch(fn value)
 
-                                  if cts <> null then
+                                  if not(isNull cts) then
                                       cts.Dispose()
                                       cts <- null)
                           },

src/Fabulous/Component.fs

@@ -304,7 +304,7 @@ type Component(componentDataKey: ScalarAttributeKey, treeContext: ViewTreeContex
         node
 
     member private this.RenderInternal() =
-        if _body = null then
+        if isNull body then
             () // Component has been disposed
         else
             let prevRootWidget = _widget
@@ -322,10 +322,10 @@ type Component(componentDataKey: ScalarAttributeKey, treeContext: ViewTreeContex
             Reconciler.update treeContext.CanReuseView (ValueSome prevRootWidget) currRootWidget viewNode
 
     member this.Dispose() =
-        if _contextSubscription <> null then
+        if not(isNull _contextSubscription) then
             _contextSubscription.Dispose()
 
-        if _context <> null then
+        if not(isNull _context) then
             _context.Dispose()
 
         _body <- null
@@ -338,7 +338,7 @@ type Component(componentDataKey: ScalarAttributeKey, treeContext: ViewTreeContex
         member this.Dispose() = this.Dispose()
 
     member this.Render(_) =
-        if _body = null then
+        if isNull _body then
             () // Component has been disposed
         else
             treeContext.SyncAction(this.RenderInternal)

src/Fabulous/View.fs

@@ -37,7 +37,7 @@ module View =
             let fnWithBoxing (msg: obj) =
                 let oldFn = unbox<obj -> obj> oldAttr.Value
 
-                if msg <> null && typeof<'newMsg>.IsAssignableFrom(msg.GetType()) then
+                if not(isNull msg) && typeof<'newMsg>.IsAssignableFrom(msg.GetType()) then
                     box msg
                 else
                     oldFn msg |> unbox<'oldMsg> |> fn |> box
@@ -46,7 +46,7 @@ module View =
 
         let defaultWith () =
             let mappedFn (msg: obj) =
-                if msg <> null && typeof<'newMsg>.IsAssignableFrom(msg.GetType()) then
+                if not(isNull msg) && typeof<'newMsg>.IsAssignableFrom(msg.GetType()) then
                     box msg
                 else
                     unbox<'oldMsg> msg |> fn |> box

src/Fabulous/ViewNode.fs

@@ -155,7 +155,7 @@ type ViewNode =
             if this.targetRef.IsAlive then
                 let comp = this.treeContext.GetComponent(this.targetRef.Target) :?> IDisposable
 
-                if comp <> null then
+                if not(isNull comp) then
                     comp.Dispose()
                     this.treeContext.SetComponent null this.targetRef.Target