diff --git a/test/dimensionful.jl b/test/dimensionful.jl
index e9dbd04664429..58c3b12142ae4 100644
--- a/test/dimensionful.jl
+++ b/test/dimensionful.jl
@@ -5,8 +5,8 @@
 # represents a quantity in furlongs^p
 immutable Furlong{p,T<:Number} <: Number
     val::T
-    Furlong(v::Number) = new(v)
-    Furlong(x::Furlong{p}) = new(x.val)
+    Furlong{p,T}(v::Number) where {p,T} = new(v)
+    Furlong{p,T}(x::Furlong{p}) where {p,T} = new(x.val)
 end
 Furlong{T<:Number}(x::T) = Furlong{1,T}(x)
 (::Type{T}){p,T}(x::Furlong{p,T}) = x.val