+ DateOnly as Monoid and Zero for TimeOnly

Author: gusty

src/FSharpPlus/Control/Monoid.fs

@@ -26,6 +26,11 @@ type Plus =
     static member        ``+`` (x: array<_>          , y                    , [<Optional>]_mthd: Plus    ) = Array.append x y
     static member        ``+`` (()                   , ()                   , [<Optional>]_mthd: Plus    ) = ()
     static member        ``+`` (x: bool              , y: bool              , [<Optional>]_mthd: Plus    ) = x <> y
+    
+    #if NET6_0_OR_GREATER
+    static member        ``+`` (x: DateOnly          , y: DateOnly          , [<Optional>]_mthd: Plus    ) = DateOnly.FromDayNumber (x.DayNumber + y.DayNumber)
+    #endif
+
     static member        ``+`` (x: Set<_>            , y                    , [<Optional>]_mthd: Plus    ) = Set.union x y
 
     #if !FABLE_COMPILER

src/FSharpPlus/Control/Numeric.fs

@@ -99,6 +99,10 @@ type FromInt32 =
     static member        FromInt32 (_: uint64    , _: FromInt32) = fun (x: int32) -> uint64          x
     static member        FromInt32 (_: float32   , _: FromInt32) = fun (x: int32) -> float32         x
     static member        FromInt32 (_: decimal   , _: FromInt32) = fun (x: int32) -> decimal         x
+    
+    #if NET6_0_OR_GREATER
+    static member        FromInt32 (_: System.DateOnly  , _: FromInt32) = fun (x: int32) -> System.DateOnly.FromDayNumber x
+    #endif
 
     static member inline Invoke (x: int32) : 'Num =
         let inline call_2 (a: ^a, b: ^b) = ((^a or ^b) : (static member FromInt32 : _*_ -> _) b, a)
@@ -133,6 +137,8 @@ type Zero =
     inherit Default1
 
     static member        Zero (_: System.TimeSpan                , _: Zero    ) = System.TimeSpan ()
+    static member        Zero (_: System.DateOnly                , _: Zero    ) = System.DateOnly.MinValue
+    static member        Zero (_: System.TimeOnly                , _: Zero    ) = System.TimeOnly.MinValue
     static member        Zero (_: DmStruct                       , _: Zero    ) = Unchecked.defaultof<DmStruct>
     static member        Zero (_: list<'a>                       , _: Zero    ) = []   :   list<'a>
     static member        Zero (_: option<'a>                     , _: Zero    ) = None : option<'a>