From 9e2b88a2959f87e318227c61613df1b54eaa2ca6 Mon Sep 17 00:00:00 2001
From: David Sanders <dpsanders@gmail.com>
Date: Tue, 13 Aug 2019 15:52:06 -0400
Subject: [PATCH 1/3] Fix convert(typeof(x), x)

---
 src/intervals/conversion.jl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/intervals/conversion.jl b/src/intervals/conversion.jl
index 464966499..b6cbb2b02 100644
--- a/src/intervals/conversion.jl
+++ b/src/intervals/conversion.jl
@@ -17,7 +17,7 @@ convert(::Type{Interval{T}}, x::Bool) where {T} = convert(Interval{T}, Int(x))
 convert(::Type{Interval{T}}, x::Real) where {T} = atomic(Interval{T}, x)
 convert(::Type{Interval{T}}, x::T) where {T<:Real} = Interval{T}(x)
 convert(::Type{Interval{T}}, x::Interval{T}) where {T} = x
-convert(::Type{Interval{T}}, x::Interval) where {T} = atomic(Interval{T}, x)
+convert(::Type{Interval{T}}, x::Interval{S}) where {T,S} = atomic(Interval{T}, x)
 
 convert(::Type{Interval}, x::Real) = (T = typeof(float(x)); convert(Interval{T}, x))
 convert(::Type{Interval}, x::Interval) = x

From 100eae45454e3d0e46544219ca18c6ca07872266 Mon Sep 17 00:00:00 2001
From: David Sanders <dpsanders@gmail.com>
Date: Tue, 13 Aug 2019 17:04:07 -0400
Subject: [PATCH 2/3] Add test

---
 test/interval_tests/construction.jl | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/test/interval_tests/construction.jl b/test/interval_tests/construction.jl
index 6544dcc08..c05205e9a 100644
--- a/test/interval_tests/construction.jl
+++ b/test/interval_tests/construction.jl
@@ -5,6 +5,8 @@ using Test
 
 const eeuler = Base.MathConstants.e
 
+using InteractiveUtils
+
 
 @testset "Constructing intervals" begin
     setprecision(Interval, 53)
@@ -340,3 +342,12 @@ import IntervalArithmetic: force_interval
     @test force_interval(Inf, -Inf) == Interval(-Inf, Inf)
     @test_throws ArgumentError force_interval(NaN, 3)
 end
+
+@testset "#320 fixing convert bug" begin
+    x = 3..4
+    T = typeof(x)
+
+    m = @which convert(T, x)
+
+    @test m.sig == Tuple{typeof(convert),Type{Interval{T}},Interval{T}} where T
+end

From 4be62a910ce410fb7f5193207ebf93c6e4c10a81 Mon Sep 17 00:00:00 2001
From: David Sanders <dpsanders@gmail.com>
Date: Tue, 13 Aug 2019 17:21:35 -0400
Subject: [PATCH 3/3] Add test of converting rational

---
 test/interval_tests/construction.jl | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/test/interval_tests/construction.jl b/test/interval_tests/construction.jl
index c05205e9a..d43742a56 100644
--- a/test/interval_tests/construction.jl
+++ b/test/interval_tests/construction.jl
@@ -350,4 +350,8 @@ end
     m = @which convert(T, x)
 
     @test m.sig == Tuple{typeof(convert),Type{Interval{T}},Interval{T}} where T
+
+    x = interval(1//1, 5//3)
+    @test convert(typeof(x), x) == x
+
 end