fix isvatuple to properly handle UnionAlls (JuliaLang#27018)

* fix isvatuple to properly handle UnionAlls * add tests for JuliaLang#27018
lazarusA · May 8, 2018 · b19ba88 · b19ba88
1 parent 024bfdb
commit b19ba88
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Showing 2 changed files with 19 additions and 1 deletion.
diff --git a/base/essentials.jl b/base/essentials.jl
@@ -207,7 +207,15 @@ function isvarargtype(@nospecialize(t))
  return isa(t, DataType) && (t::DataType).name === _va_typename
 end
 
-isvatuple(t::DataType) = (n = length(t.parameters); n > 0 && isvarargtype(t.parameters[n]))
+function isvatuple(@nospecialize(t))
+ t = unwrap_unionall(t)
+ if isa(t, DataType)
+ n = length(t.parameters)
+ return n > 0 && isvarargtype(t.parameters[n])
+ end
+ return false
+end
+
 function unwrapva(@nospecialize(t))
  # NOTE: this returns a related type, but it's NOT a subtype of the original tuple
  t2 = unwrap_unionall(t)

diff --git a/test/core.jl b/test/core.jl
@@ -6051,3 +6051,13 @@ g2_23206(::Tuple{Type{Int}}) = 1
 let x26739 = Int[1]
  @test eval(:(identity.($x26739))) == x26739
 end
+
+# issue #27018
+@test Base.isvatuple(Tuple{Float64,Vararg{Int}})
+@test Base.isvatuple(Tuple{T,Vararg{Int}} where T)
+@test Base.isvatuple(Tuple{Int,Int,Vararg{Int,N}} where N)
+@test Base.isvatuple(Tuple{T,S,Vararg{T}} where T<:S where S)
+@test Base.isvatuple(Tuple{T,S,Vararg{T,3}} where T<:S where S)
+@test !Base.isvatuple(Tuple{Float64,Vararg{Int,1}})
+@test !Base.isvatuple(Tuple{T,Vararg{Int,2}} where T)
+@test !Base.isvatuple(Tuple{Int,Int,Vararg{Int,2}})