improve constructor of Set from Set (#24346)

JuliaLang · Oct 30, 2017 · 4aa4652 · 4aa4652
1 parent 03045ca
commit 4aa4652
Show file tree

Hide file tree

Showing 2 changed files with 15 additions and 1 deletion.
diff --git a/base/set.jl b/base/set.jl
@@ -4,6 +4,7 @@ mutable struct Set{T} <: AbstractSet{T}
  dict::Dict{T,Void}
 
  Set{T}() where {T} = new(Dict{T,Void}())
+ Set{T}(s::Set{T}) where {T} = new(Dict{T,Void}(s.dict))
  Set{T}(itr) where {T} = union!(new(Dict{T,Void}()), itr)
 end
 Set() = Set{Any}()
@@ -54,7 +55,7 @@ end
 
 delete!(s::Set, x) = (delete!(s.dict, x); s)
 
-copy(s::Set) = union!(similar(s), s)
+copy(s::Set{T}) where T = Set{T}(s)
 
 sizehint!(s::Set, newsz) = (sizehint!(s.dict, newsz); s)
 empty!(s::Set) = (empty!(s.dict); s)

diff --git a/test/sets.jl b/test/sets.jl
@@ -19,6 +19,19 @@ using Main.TestHelpers.OAs
  @test isa(Set(f17741(x) for x = 1:3), Set{Int})
  @test isa(Set(f17741(x) for x = -1:1), Set{Integer})
  end
+ let s1 = Set(["foo", "bar"]), s2 = Set(s1)
+ @test s1 == s2
+ x = pop!(s1)
+ @test s1 != s2
+ @test !(x in s1)
+ @test x in s2
+ push!(s1, "baz")
+ push!(s2, "baz2")
+ @test "baz" in s1
+ @test !("baz" in s2)
+ @test !("baz2" in s1)
+ @test "baz2" in s2
+ end
 end
 
 @testset "hash" begin