Fix \ bug introduced in PR#15354 by removing parent of sub.

base/linalg/factorization.jl

@@ -24,16 +24,18 @@ inv{T}(F::Factorization{T}) = A_ldiv_B!(F, eye(T, size(F,1)))
 # With a real lhs and complex rhs with the same precision, we can reinterpret
 # the complex rhs as a real rhs with twice the number of columns
 function (\){T<:BlasReal}(F::Factorization{T}, B::AbstractVector{Complex{T}})
-    c2r = reshape(transpose(reinterpret(T, parent(B), (2, length(B)))), size(B, 1), 2*size(B, 2))
+    c2r = reshape(transpose(reinterpret(T, B, (2, length(B)))), size(B, 1), 2*size(B, 2))
     x = A_ldiv_B!(F, c2r)
     return reinterpret(Complex{T}, transpose(reshape(x, div(length(x), 2), 2)), (size(F,2),))
 end
 function (\){T<:BlasReal}(F::Factorization{T}, B::AbstractMatrix{Complex{T}})
-    c2r = reshape(transpose(reinterpret(T, parent(B), (2, length(B)))), size(B, 1), 2*size(B, 2))
+    c2r = reshape(transpose(reinterpret(T, B, (2, length(B)))), size(B, 1), 2*size(B, 2))
     x = A_ldiv_B!(F, c2r)
     return reinterpret(Complex{T}, transpose(reshape(x, div(length(x), 2), 2)), (size(F,2), size(B,2)))
 end
 
+(\){T<:BlasReal}(F::Factorization{T}, B::SubArray) = F\copy(B)
+
 for (f1, f2) in ((:\, :A_ldiv_B!),
                  (:Ac_ldiv_B, :Ac_ldiv_B!),
                  (:At_ldiv_B, :At_ldiv_B!))

test/linalg/bunchkaufman.jl

@@ -104,3 +104,12 @@ let
         end
     end
 end
+
+# test example due to @timholy in PR 15354
+let
+    A = rand(6,5); A = A'*A
+    F = cholfact(A);
+    v6 = rand(Complex128, 6)
+    v5 = sub(v6, 1:5)
+    @test F\v5 == F\v6[1:5]
+end