Use triangular dispatch in eltype definition (#11)

Author: martinholters

src/definitions.jl

@@ -8,7 +8,7 @@ import Base: show, summary, size, ndims, length, eltype,
 # DFT plan where the inputs are an array of eltype T
 abstract type Plan{T} end
 
-eltype(::Type{Plan{T}}) where {T} = T
+eltype(::Type{<:Plan{T}}) where {T} = T
 
 # size(p) should return the size of the input array for p
 size(p::Plan, d) = size(p)[d]

test/runtests.jl

@@ -63,6 +63,8 @@ Base.:*(p::InverseTestPlan, x::Vector) = mul!(copy(x), p, x)
 
     fftw_ifft = [Complex{Float64}(i, 0) for i in 1:8]
     @test AbstractFFTs.ifft(x) ≈ fftw_ifft
+
+    @test eltype(plan_fft(collect(1:8))) == Int
 end
 
 @testset "Shift functions" begin