From 22987e393241514ee16a7d04e7db053ee2833953 Mon Sep 17 00:00:00 2001
From: Rafael Fourquet <fourquet.rafael@gmail.com>
Date: Fri, 8 Sep 2017 08:05:11 +0200
Subject: [PATCH] fix #19182: convert([Un]Signed, x::BigInt) (#23474)

---
 base/gmp.jl    | 5 +++--
 test/bigint.jl | 7 +++++++
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/base/gmp.jl b/base/gmp.jl
index 2b2afc9fcc558..04e627881c8b9 100644
--- a/base/gmp.jl
+++ b/base/gmp.jl
@@ -229,6 +229,7 @@ widen(::Type{BigInt})  = BigInt
 signed(x::BigInt) = x
 
 convert(::Type{BigInt}, x::BigInt) = x
+convert(::Type{Signed}, x::BigInt) = x
 
 hastypemax(::Type{BigInt}) = false
 
@@ -323,7 +324,7 @@ end
 
 rem(x::Integer, ::Type{BigInt}) = convert(BigInt, x)
 
-function convert(::Type{T}, x::BigInt) where T<:Unsigned
+function convert(::Type{T}, x::BigInt) where T<:Base.BitUnsigned
     if sizeof(T) < sizeof(Limb)
         convert(T, convert(Limb,x))
     else
@@ -332,7 +333,7 @@ function convert(::Type{T}, x::BigInt) where T<:Unsigned
     end
 end
 
-function convert(::Type{T}, x::BigInt) where T<:Signed
+function convert(::Type{T}, x::BigInt) where T<:Base.BitSigned
     n = abs(x.size)
     if sizeof(T) < sizeof(Limb)
         SLimb = typeof(Signed(one(Limb)))
diff --git a/test/bigint.jl b/test/bigint.jl
index 6dadc6556cece..180fca5ee4d33 100644
--- a/test/bigint.jl
+++ b/test/bigint.jl
@@ -374,3 +374,10 @@ end
 
 @test BigInt <: Signed
 @test big(1) isa Signed
+
+let x = big(1)
+    @test signed(x) === x
+    @test convert(Signed, x) === x
+    @test Signed(x) === x
+    @test_throws MethodError convert(Unsigned, x) # could change in the future
+end