fix #178 (#343)

* fix #178

* Update FillArraysSparseArraysExt.jl

* try to fix

---------

Co-authored-by: Sheehan Olver <[email protected]>

Author: putianyi889

ext/FillArraysSparseArraysExt.jl

@@ -1,12 +1,14 @@
 module FillArraysSparseArraysExt
 
 using SparseArrays
-using FillArrays
-using FillArrays: RectDiagonalFill, RectOrDiagonalFill, ZerosVector, ZerosMatrix, getindex_value
+using SparseArrays: SparseVectorUnion
 import Base: convert, kron
+using FillArrays
+using FillArrays: RectDiagonalFill, RectOrDiagonalFill, ZerosVector, ZerosMatrix, getindex_value, AbstractFillVector, _fill_dot
 # Specifying the full namespace is necessary because of https://github.com/JuliaLang/julia/issues/48533
 # See https://github.com/JuliaStats/LogExpFunctions.jl/pull/63
 using FillArrays.LinearAlgebra
+import LinearAlgebra: dot, kron, I
 
 ##################
 ## Sparse arrays
@@ -58,4 +60,12 @@ end
 # TODO: remove in v2.0
 @deprecate kron(E1::RectDiagonalFill, E2::RectDiagonalFill) kron(sparse(E1), sparse(E2))
 
+# Ambiguity. see #178
+if VERSION >= v"1.8"
+    dot(x::AbstractFillVector, y::SparseVectorUnion) = _fill_dot(x, y)
+else
+    dot(x::AbstractFillVector{<:Number}, y::SparseVectorUnion{<:Number}) = _fill_dot(x, y)
+end
+
+
 end # module

test/runtests.jl

@@ -1438,9 +1438,14 @@ end
     @test axes(E .+ E) === axes(E)
 end
 
-@testset "Issue #31" begin
-    @test convert(SparseMatrixCSC{Float64,Int64}, Zeros{Float64}(3, 3)) == spzeros(3, 3)
-    @test sparse(Zeros(4, 2)) == spzeros(4, 2)
+@testset "Issues" begin
+    @testset "#31" begin
+        @test convert(SparseMatrixCSC{Float64,Int64}, Zeros{Float64}(3, 3)) == spzeros(3, 3)
+        @test sparse(Zeros(4, 2)) == spzeros(4, 2)
+    end
+    @testset "#178" begin
+        @test Zeros(10)'*spzeros(10) == 0
+    end
 end
 
 @testset "Adjoint/Transpose/permutedims" begin