From 7d120b92b18a6f8f2e9771d878ccb83d42c73fc5 Mon Sep 17 00:00:00 2001
From: pabloferz <pabloferz@yahoo.com.mx>
Date: Sat, 15 Oct 2016 14:28:10 -0500
Subject: [PATCH] Make Ref behave as a scalar wrapper for broadcast

---
 base/abstractarray.jl | 6 ++++++
 base/broadcast.jl     | 5 +++++
 test/broadcast.jl     | 6 ++++++
 3 files changed, 17 insertions(+)

diff --git a/base/abstractarray.jl b/base/abstractarray.jl
index abd6772288d96d..576e58d9c071ed 100644
--- a/base/abstractarray.jl
+++ b/base/abstractarray.jl
@@ -1754,9 +1754,15 @@ end
 # These are needed because map(eltype, As) is not inferrable
 promote_eltype_op(::Any) = (@_pure_meta; Any)
 promote_eltype_op(op, A) = (@_pure_meta; promote_op(op, eltype(A)))
+promote_eltype_op(op, A::Ref) = (@_pure_meta; promote_op(op, typeof(A)))
+promote_eltype_op(op, A, B::Ref) = (@_pure_meta; promote_op(op, eltype(A), typeof(B)))
+promote_eltype_op(op, A::Ref, B) = (@_pure_meta; promote_op(op, typeof(A), eltype(B)))
+promote_eltype_op(op, A::Ref, B::Ref) = (@_pure_meta; promote_op(op, typeof(A), typeof(B)))
 promote_eltype_op{T}(op, ::AbstractArray{T}) = (@_pure_meta; promote_op(op, T))
 promote_eltype_op{T}(op, ::AbstractArray{T}, A) = (@_pure_meta; promote_op(op, T, eltype(A)))
 promote_eltype_op{T}(op, A, ::AbstractArray{T}) = (@_pure_meta; promote_op(op, eltype(A), T))
+promote_eltype_op{T}(op, ::AbstractArray{T}, A::Ref) = (@_pure_meta; promote_op(op, T, typeof(A)))
+promote_eltype_op{T}(op, A::Ref, ::AbstractArray{T}) = (@_pure_meta; promote_op(op, typeof(A), T))
 promote_eltype_op{R,S}(op, ::AbstractArray{R}, ::AbstractArray{S}) = (@_pure_meta; promote_op(op, R, S))
 promote_eltype_op(op, A, B) = (@_pure_meta; promote_op(op, eltype(A), eltype(B)))
 promote_eltype_op(op, A, B, C, D...) = (@_pure_meta; promote_eltype_op(op, promote_eltype_op(op, A, B), C, D...))
diff --git a/base/broadcast.jl b/base/broadcast.jl
index 917a9be9f3a5a6..31cce7fed06eb7 100644
--- a/base/broadcast.jl
+++ b/base/broadcast.jl
@@ -9,6 +9,8 @@ import Base: broadcast
 export broadcast!, bitbroadcast, dotview
 export broadcast_getindex, broadcast_setindex!
 
+typealias RefArrOrVal Union{Base.RefArray, Base.RefValue}
+
 ## Broadcasting utilities ##
 
 # fallback for broadcasting with zero arguments and some special cases
@@ -30,6 +32,7 @@ end
 containertype(x) = containertype(typeof(x))
 containertype(::Type) = Any
 containertype{T<:Tuple}(::Type{T}) = Tuple
+containertype{T<:RefArrOrVal}(::Type{T}) = Array
 containertype{T<:AbstractArray}(::Type{T}) = Array
 containertype(ct1, ct2) = promote_containertype(containertype(ct1), containertype(ct2))
 @inline containertype(ct1, ct2, cts...) = promote_containertype(containertype(ct1), containertype(ct2, cts...))
@@ -48,6 +51,7 @@ broadcast_indices(A) = broadcast_indices(containertype(A), A)
 broadcast_indices(::Type{Any}, A) = ()
 broadcast_indices(::Type{Tuple}, A) = (OneTo(length(A)),)
 broadcast_indices(::Type{Array}, A) = indices(A)
+broadcast_indices(::Type{Array}, A::RefArrOrVal) = ()
 @inline broadcast_indices(A, B...) = broadcast_shape((), broadcast_indices(A), map(broadcast_indices, B)...)
 # shape (i.e., tuple-of-indices) inputs
 broadcast_shape(shape::Tuple) = shape
@@ -127,6 +131,7 @@ dumpbitcache(Bc::Vector{UInt64}, bind::Int, C::Vector{Bool}) =
     Base.copy_to_bitarray_chunks!(Bc, ((bind - 1) << 6) + 1, C, 1, min(bitcache_size, (length(Bc)-bind+1) << 6))
 
 @inline _broadcast_getindex(A, I) = _broadcast_getindex(containertype(A), A, I)
+@inline _broadcast_getindex(A::RefArrOrVal, I) = A.x
 @inline _broadcast_getindex(::Type{Any}, A, I) = A
 @inline _broadcast_getindex(::Any, A, I) = A[I]
 
diff --git a/test/broadcast.jl b/test/broadcast.jl
index 7dca2095bff7e2..963da1678d90db 100644
--- a/test/broadcast.jl
+++ b/test/broadcast.jl
@@ -337,3 +337,9 @@ end
 @test broadcast(+, 1.0, (0, -2.0)) == (1.0,-1.0)
 @test broadcast(+, 1.0, (0, -2.0), [1]) == [2.0, 0.0]
 @test broadcast(*, ["Hello"], ", ", ["World"], "!") == ["Hello, World!"]
+
+# Issue #18379
+@test (+).(1, Ref(2)) == fill(3)
+@test (+).(Ref(1), Ref(2)) == fill(3)
+@test (+).([[0,2], [1,3]], [1,-1]) == [[1,3], [0,2]]
+@test (+).([[0,2], [1,3]], Ref([1,-1]))::Vector{Vector{Int}} == [[1,1], [2,2]]