diff --git a/src/frames.jl b/src/frames.jl
index cb66b23..7629661 100644
--- a/src/frames.jl
+++ b/src/frames.jl
@@ -81,7 +81,7 @@ Base.getindex(frames::Frames{T}, i::Integer) where T = Frame{T}(QuatRotation(fra
 
 Base.:(==)(frames1::Frames, frames2::Frames) = all(f1 == f2 for (f1, f2) in zip(frames1, frames2))
 
-function (frames::Frames{T})(coords::AbstractMatrix{T}) where T <: Real
+function (frames::Frames{T})(coords::AbstractMatrix{<:Real}) where T <: Real
     coords = T.(coords)
     coords_centroid = centroid(coords)
     return stack((f -> f(coords, coords_centroid)).(frames))
diff --git a/test/frames.jl b/test/frames.jl
index 0e63ced..88062b5 100644
--- a/test/frames.jl
+++ b/test/frames.jl
@@ -8,7 +8,7 @@ import Rotations: QuatRotation, params
             params(QuatRotation([0 0 1; 1 0 0; 0 1 0])^2);;
             params(QuatRotation([0 0 1; 1 0 0; 0 1 0])^3);;
         ],
-        Float64[
+        [
             0 10 100;
             0 0 0;
             0 0 0;
@@ -23,7 +23,7 @@ import Rotations: QuatRotation, params
     @test size(frames) == (3,)
     @test frames[1] == Frame{Float64}(QuatRotation([0 0 1; 1 0 0; 0 1 0]), [0.0, 0.0, 0.0])
 
-    standard_coords = Float64[3 1 -4; 1 -1 0; 0 0 0]
+    standard_coords = [3 1 -4; 1 -1 0; 0 0 0]
     backbone = Backbone(frames, standard_coords)
 
     @test backbone.coords == [