Remove definition of >:

Was added in #336

README.md

@@ -134,8 +134,6 @@ Currently, the `@compat` macro supports the following syntaxes:
 * `transcode` converts between UTF-xx string encodings in Julia 0.5 (as a lightweight
    alternative to the LegacyStrings package) ([#17323])
 
-* `>:`, a supertype operator for symmetry with `issubtype` (`A >: B` is equivalent to `B <: A`), can be used in 0.5 and earlier ([#20407]).
-
 * `.&` and `.|` are short syntax for `broadcast(&, xs...)` and `broadcast(|, xs...)` (respectively) in Julia 0.6 (only supported on Julia 0.5 and above) ([#17623])
 
 * `Compat.isapprox` with `nans` keyword argument ([#20022])
@@ -494,7 +492,6 @@ includes this fix. Find the minimum version from there.
 [#20022]: https://github.com/JuliaLang/julia/issues/20022
 [#20164]: https://github.com/JuliaLang/julia/issues/20164
 [#20321]: https://github.com/JuliaLang/julia/issues/20321
-[#20407]: https://github.com/JuliaLang/julia/issues/20407
 [#20974]: https://github.com/JuliaLang/julia/issues/20974
 [#21197]: https://github.com/JuliaLang/julia/issues/21197
 [#21346]: https://github.com/JuliaLang/julia/issues/21346

src/Compat.jl

@@ -142,15 +142,6 @@ else
     end
 end
 
-# julia　#20407
-@static if !isdefined(Base, :(>:))
-    # 0.6
-    const >: = let
-        _issupertype(a::ANY, b::ANY) = issubtype(b, a)
-    end
-    export >:
-end
-
 # julia#19088
 if VERSION < v"0.6.0-dev.1256"
     Base.take!(io::Base.AbstractIOBuffer) = takebuf_array(io)

test/runtests.jl

@@ -40,10 +40,6 @@ else
     end
 end
 
-# supertype operator
-@test !(Int >: Integer)
-@test Integer >: Int
-
 # julia#19088
 let io = IOBuffer()
     write(io, "aaa")