diff --git a/REQUIRE b/REQUIRE
index 2845359..d2f6cd5 100644
--- a/REQUIRE
+++ b/REQUIRE
@@ -1,2 +1,2 @@
 julia 0.6
-Compat 0.30 # @nospecialize
+Compat 0.33 # Compat.Test
diff --git a/src/utilities.jl b/src/utilities.jl
index d7f934c..3c86219 100644
--- a/src/utilities.jl
+++ b/src/utilities.jl
@@ -105,7 +105,7 @@ $(:SIGNATURES)
 
 Is the type `t` a `bitstype`?
 """
-isbitstype(@nospecialize(t)) = isleaftype(t) && sizeof(t) > 0 && isbits(t)
+isbitstype(@nospecialize(t)) = isconcrete(t) && sizeof(t) > 0 && isbits(t)
 
 """
 $(:SIGNATURES)
@@ -249,7 +249,7 @@ function keywords(func, m::Method)
             filter!(arg -> !contains(string(arg), "#"), kwargs)
             # Keywords *may* not be sorted correctly. We move the vararg one to the end.
             local index = findfirst(arg -> endswith(string(arg), "..."), kwargs)
-            if index > 0
+            if index != nothing && index > 0 # TODO: use Compat.findfirst later on
                 kwargs[index], kwargs[end] = kwargs[end], kwargs[index]
             end
             return kwargs
diff --git a/test/runtests.jl b/test/runtests.jl
index 883d055..56e1c5d 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -1,5 +1,5 @@
 using DocStringExtensions
-using Base.Test
+using Compat.Test
 
 include("tests.jl")
 
diff --git a/test/tests.jl b/test/tests.jl
index 617f4e4..c37b535 100644
--- a/test/tests.jl
+++ b/test/tests.jl
@@ -93,7 +93,7 @@ end
     end
     @testset "format" begin
         # Setup.
-        doc = Docs.DocStr(Core.svec(), Nullable(), Dict())
+        doc = Docs.DocStr(Core.svec(), nothing, Dict())
         buf = IOBuffer()
 
         # Errors.
@@ -378,7 +378,11 @@ end
             @test DSE.alltypesigs(Union{}) == Any[]
             @test DSE.alltypesigs(Union{Tuple{}}) == Any[Tuple{}]
             @test DSE.alltypesigs(Tuple{}) == Any[Tuple{}]
-            @test DSE.alltypesigs(Type{T} where {T}) == Any[Type{T} where T]
+
+            # TODO: Clean me up
+            T = Type{T} where {T}
+            @test DSE.alltypesigs(T) ==
+                Base.rewrap_unionall.(DSE.uniontypes(Base.unwrap_unionall(T)), T)
         end
         @testset "groupby" begin
             let groups = DSE.groupby(Int, Vector{Int}, collect(1:10)) do each