Add Nothing and Cvoid

Author: ararslan

README.md

@@ -258,6 +258,8 @@ Currently, the `@compat` macro supports the following syntaxes:
 
 * `indices` is now `axes` ([#25057]).
 
+* `Void` is now `Nothing` with an alias `Cvoid` for C interop ([#25162]).
+
 ## New macros
 
 * `@__DIR__` has been added ([#18380])
@@ -413,3 +415,4 @@ includes this fix. Find the minimum version from there.
 [#25012]: https://github.com/JuliaLang/julia/issues/25012
 [#25056]: https://github.com/JuliaLang/julia/issues/25056
 [#25057]: https://github.com/JuliaLang/julia/issues/25057
+[#25162]: https://github.com/JuliaLang/julia/issues/25162

src/Compat.jl

@@ -960,6 +960,13 @@ end
     export axes
 end
 
+# 0.7.0-DEV.3137
+@static if !isdefined(Base, :Nothing)
+    const Nothing = Void
+    const Cvoid = Void
+    export Nothing, Cvoid
+end
+
 @static if !isdefined(Base, :Some)
     import Base: promote_rule, convert
     if VERSION >= v"0.6.0"
@@ -968,35 +975,35 @@ end
                 value::T
             end
             promote_rule(::Type{Some{S}}, ::Type{Some{T}}) where {S,T} = Some{promote_type(S, T)}
-            promote_rule(::Type{Some{T}}, ::Type{Void}) where {T} = Union{Some{T}, Void}
+            promote_rule(::Type{Some{T}}, ::Type{Nothing}) where {T} = Union{Some{T}, Nothing}
             convert(::Type{Some{T}}, x::Some) where {T} = Some{T}(convert(T, x.value))
-            convert(::Type{Union{Some{T}, Void}}, x::Some) where {T} = convert(Some{T}, x)
-            convert(::Type{Union{T, Void}}, x::Any) where {T} = convert(T, x)
+            convert(::Type{Union{Some{T}, Nothing}}, x::Some) where {T} = convert(Some{T}, x)
+            convert(::Type{Union{T, Nothing}}, x::Any) where {T} = convert(T, x)
         """)
     else
         include_string(@__MODULE__, """
             immutable Some{T}
                 value::T
             end
             promote_rule{S,T}(::Type{Some{S}}, ::Type{Some{T}}) = Some{promote_type(S, T)}
-            promote_rule{T}(::Type{Some{T}}, ::Type{Void}) = Union{Some{T}, Void}
+            promote_rule{T}(::Type{Some{T}}, ::Type{Nothing}) = Union{Some{T}, Nothing}
             convert{T}(::Type{Some{T}}, x::Some) = Some{T}(convert(T, x.value))
-            convert{T}(::Type{Union{Some{T}, Void}}, x::Some) = convert(Some{T}, x)
-            convert{T}(::Type{Union{T, Void}}, x::Any) = convert(T, x)
+            convert{T}(::Type{Union{Some{T}, Nothing}}, x::Some) = convert(Some{T}, x)
+            convert{T}(::Type{Union{T, Nothing}}, x::Any) = convert(T, x)
         """)
     end
-    convert(::Type{Void}, x::Any) = throw(MethodError(convert, (Void, x)))
-    convert(::Type{Void}, x::Void) = nothing
+    convert(::Type{Nothing}, x::Any) = throw(MethodError(convert, (Nothing, x)))
+    convert(::Type{Nothing}, x::Nothing) = nothing
     coalesce(x::Any) = x
     coalesce(x::Some) = x.value
-    coalesce(x::Void) = nothing
+    coalesce(x::Nothing) = nothing
     #coalesce(x::Missing) = missing
     coalesce(x::Any, y...) = x
     coalesce(x::Some, y...) = x.value
-    coalesce(x::Void, y...) = coalesce(y...)
-    #coalesce(x::Union{Void, Missing}, y...) = coalesce(y...)
+    coalesce(x::Nothing, y...) = coalesce(y...)
+    #coalesce(x::Union{Nothing, Missing}, y...) = coalesce(y...)
     notnothing(x::Any) = x
-    notnothing(::Void) = throw(ArgumentError("nothing passed to notnothing"))
+    notnothing(::Nothing) = throw(ArgumentError("nothing passed to notnothing"))
     export Some, coalesce
 else
     import Base: notnothing

test/runtests.jl

@@ -1023,6 +1023,10 @@ end
 @test axes(1) == ()
 @test axes(1,1) == 1:1
 
+# 0.7.0-DEV.3137
+@test Nothing === (isdefined(Base, :Nothing) ? Base.Nothing : Base.Void)
+@test Nothing === Cvoid
+
 # 0.7.0-DEV.3017
 @test isa(Some(1), Some{Int})
 @test convert(Some{Float64}, Some(1)) == Some(1.0)