From 8e3aa66ab7084e04b77ce8f08fddd39340e70351 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sebastian=20Miclu=C8=9Ba-C=C3=A2mpeanu?=
 <31181429+SebastianM-C@users.noreply.github.com>
Date: Fri, 21 Feb 2020 18:00:05 +0200
Subject: [PATCH] Fix #34316 (#34817)

Fix hypot with both arguments 0

Remove hypot from Furlongs in order to test the defined fallback
---
 base/math.jl                 | 14 ++++++++++++--
 test/math.jl                 | 19 ++++++++++++-------
 test/testhelpers/Furlongs.jl |  4 ++--
 3 files changed, 26 insertions(+), 11 deletions(-)

diff --git a/base/math.jl b/base/math.jl
index 875a2be7d1998..19ed2bbb4e13d 100644
--- a/base/math.jl
+++ b/base/math.jl
@@ -629,9 +629,19 @@ julia> hypot(3, 4im)
 hypot(x::Number, y::Number) = hypot(promote(x, y)...)
 hypot(x::Complex, y::Complex) = hypot(abs(x), abs(y))
 hypot(x::T, y::T) where {T<:Real} = hypot(float(x), float(y))
-hypot(x::T, y::T) where {T<:Number} = (z = y/x; abs(x) * sqrt(one(z) + z*z))
+function hypot(x::T, y::T) where {T<:Number}
+    if !iszero(x)
+        z = y/x
+        z2 = z*z
+
+        abs(x) * sqrt(oneunit(z2) + z2)
+    else
+        abs(y)
+    end
+end
+
 function hypot(x::T, y::T) where T<:AbstractFloat
-    #Return Inf if either or both imputs is Inf (Compliance with IEEE754)
+    # Return Inf if either or both inputs is Inf (Compliance with IEEE754)
     if isinf(x) || isinf(y)
         return T(Inf)
     end
diff --git a/test/math.jl b/test/math.jl
index 22d7f91685a0a..382c84f4dd655 100644
--- a/test/math.jl
+++ b/test/math.jl
@@ -1035,10 +1035,15 @@ end
     end
 end
 
-isdefined(Main, :Furlongs) || @eval Main include("testhelpers/Furlongs.jl")
-using .Main.Furlongs
-@test hypot(Furlong(0), Furlong(0)) == Furlong(0.0)
-@test hypot(Furlong(3), Furlong(4)) == Furlong(5.0)
-@test hypot(Furlong(NaN), Furlong(Inf)) == Furlong(Inf)
-@test hypot(Furlong(Inf), Furlong(NaN)) == Furlong(Inf)
-@test hypot(Furlong(Inf), Furlong(Inf)) == Furlong(Inf)
+@testset "hypot" begin
+    @test hypot(0, 0) == 0.0
+    @test hypot(3, 4) == 5.0
+    @test hypot(NaN, Inf) == Inf
+    @test hypot(Inf, NaN) == Inf
+    @test hypot(Inf, Inf) == Inf
+
+    isdefined(Main, :Furlongs) || @eval Main include("testhelpers/Furlongs.jl")
+    using .Main.Furlongs
+    @test hypot(Furlong(0), Furlong(0)) == Furlong(0.0)
+    @test hypot(Furlong(3), Furlong(4)) == Furlong(5.0)
+end
diff --git a/test/testhelpers/Furlongs.jl b/test/testhelpers/Furlongs.jl
index d9a0226c0ee9d..20b9ae89ac000 100644
--- a/test/testhelpers/Furlongs.jl
+++ b/test/testhelpers/Furlongs.jl
@@ -46,8 +46,8 @@ for f in (:real,:imag,:complex,:+,:-)
     @eval Base.$f(x::Furlong{p}) where {p} = Furlong{p}($f(x.val))
 end
 
-import Base: +, -, ==, !=, <, <=, isless, isequal, *, /, //, div, rem, mod, ^, hypot
-for op in (:+, :-, :hypot)
+import Base: +, -, ==, !=, <, <=, isless, isequal, *, /, //, div, rem, mod, ^
+for op in (:+, :-)
     @eval function $op(x::Furlong{p}, y::Furlong{p}) where {p}
         v = $op(x.val, y.val)
         Furlong{p}(v)