diff --git a/src/expint.jl b/src/expint.jl
index 50dd6f07..a0acd81d 100644
--- a/src/expint.jl
+++ b/src/expint.jl
@@ -207,7 +207,7 @@ En_safe_gamma_term(ν::Integer, z::Real) = (z ≥ 0 || isodd(ν) ? 1 : -1) * exp
 # https://functions.wolfram.com/GammaBetaErf/ExpIntegralE/10/0005/
 # returns the two terms from the above equation separately
 function En_cf_gamma(ν::Number, z::Number, n::Int=1000)
-    A, z = map(float, promote(float(1 - ν), z))
+    A, z = map(float, promote(1 - ν, z))
     B = oneunit(A)
     Bprev = zero(B)
     Aprev = oneunit(A)
diff --git a/test/expint.jl b/test/expint.jl
index afc7cd49..ea59db82 100644
--- a/test/expint.jl
+++ b/test/expint.jl
@@ -160,6 +160,9 @@ using Base.MathConstants
             end
             # type stability
             @inferred SpecialFunctions.En_cf_gamma(1, 1.0 + 2.1im, 1000)
+            @test SpecialFunctions.En_cf_gamma(1, 1.0 + 2.1im, 1000) isa Tuple{ComplexF64,ComplexF64,Int}
+            @inferred SpecialFunctions.En_cf_gamma(1, 1.0f0, 1000)
+            @test SpecialFunctions.En_cf_gamma(1, 1.0f0, 1000) isa Tuple{Float32,Float32,Int}
         end
         @testset "En_expand_origin" begin
             for (x, y) in zip(xs, ys)