diff --git a/Project.toml b/Project.toml
index 7d93d67..12320aa 100644
--- a/Project.toml
+++ b/Project.toml
@@ -4,11 +4,13 @@ version = "0.5.3"
 
 [deps]
 DataStructures = "864edb3b-99cc-5e75-8d2d-829cb0a9cfe8"
+ExprTools = "e2ba6199-217a-4e67-a87a-7c52f15ade04"
 Markdown = "d6f4376e-aef5-505a-96c1-9c027394607a"
 Random = "9a3f8284-a2c9-5f02-9a11-845980a1fd5c"
 
 [compat]
 DataStructures = "0.17"
+ExprTools = "0.1"
 julia = "1"
 
 [extras]
diff --git a/src/MacroTools.jl b/src/MacroTools.jl
index fc089e7..a7ce2b0 100644
--- a/src/MacroTools.jl
+++ b/src/MacroTools.jl
@@ -1,7 +1,9 @@
 module MacroTools
 
 using DataStructures, Markdown, Random
-export @match, @capture
+using ExprTools: splitdef, combinedef
+
+export @match, @capture, splitdef
 
 include("match/match.jl")
 include("match/types.jl")
diff --git a/src/utils.jl b/src/utils.jl
index 5d7a690..9fd0e29 100644
--- a/src/utils.jl
+++ b/src/utils.jl
@@ -1,5 +1,5 @@
 export @esc, isexpr, isline, iscall, rmlines, unblock, block, inexpr, namify, isdef,
-  longdef, shortdef, @expand, makeif, prettify, splitdef, splitarg
+  longdef, shortdef, @expand, makeif, prettify, splitarg
 
 """
     assoc!(d, k, v)
@@ -261,89 +261,6 @@ function gatherwheres(ex)
   end
 end
 
-"""    splitdef(fdef)
-
-Match any function definition
-
-```julia
-function name{params}(args; kwargs)::rtype where {whereparams}
-   body
-end
-```
-
-and return `Dict(:name=>..., :args=>..., etc.)`. The definition can be rebuilt by
-calling `MacroTools.combinedef(dict)`, or explicitly with
-
-```
-rtype = get(dict, :rtype, :Any)
-all_params = [get(dict, :params, [])..., get(dict, :whereparams, [])...]
-:(function \$(dict[:name]){\$(all_params...)}(\$(dict[:args]...);
-                                            \$(dict[:kwargs]...))::\$rtype
-      \$(dict[:body])
-  end)
-```
-"""
-function splitdef(fdef)
-  error_msg = "Not a function definition: $(repr(fdef))"
-  @assert(@capture(longdef1(fdef),
-                   function (fcall_ | fcall_) body_ end),
-          "Not a function definition: $fdef")
-  fcall_nowhere, whereparams = gatherwheres(fcall)
-  @assert(@capture(fcall_nowhere, ((func_(args__; kwargs__)) |
-                                   (func_(args__; kwargs__)::rtype_) |
-                                   (func_(args__)) |
-                                   (func_(args__)::rtype_))),
-          error_msg)
-  @assert(@capture(func, (fname_{params__} | fname_)), error_msg)
-  di = Dict(:name=>fname, :args=>args,
-            :kwargs=>(kwargs===nothing ? [] : kwargs), :body=>body)
-  if rtype !== nothing; di[:rtype] = rtype end
-  if whereparams !== nothing; di[:whereparams] = whereparams end
-  if params !== nothing; di[:params] = params end
-  di
-end
-
-"""
-    combinedef(dict::Dict)
-
-`combinedef` is the inverse of `splitdef`. It takes a splitdef-like Dict
-and returns a function definition. """
-function combinedef(dict::Dict)
-  rtype = get(dict, :rtype, nothing)
-  params = get(dict, :params, [])
-  wparams = get(dict, :whereparams, [])
-  body = block(dict[:body])
-  name = dict[:name]
-  name_param = isempty(params) ? name : :($name{$(params...)})
-  # We need the `if` to handle parametric inner/outer constructors like
-  # SomeType{X}(x::X) where X = SomeType{X}(x, x+2)
-  if isempty(wparams)
-    if rtype==nothing
-      @q(function $name_param($(dict[:args]...);
-                              $(dict[:kwargs]...))
-        $(body.args...)
-        end)
-    else
-      @q(function $name_param($(dict[:args]...);
-                              $(dict[:kwargs]...))::$rtype
-        $(body.args...)
-        end)
-    end
-  else
-    if rtype==nothing
-      @q(function $name_param($(dict[:args]...);
-                              $(dict[:kwargs]...)) where {$(wparams...)}
-        $(body.args...)
-        end)
-    else
-      @q(function $name_param($(dict[:args]...);
-                              $(dict[:kwargs]...))::$rtype where {$(wparams...)}
-        $(body.args...)
-        end)
-    end
-  end
-end
-
 """
     combinearg(arg_name, arg_type, is_splat, default)
 
diff --git a/test/split.jl b/test/split.jl
index 52540e0..2496919 100644
--- a/test/split.jl
+++ b/test/split.jl
@@ -1,61 +1,8 @@
 using MacroTools: splitstructdef, combinestructdef
 
-macro nothing_macro()
-end
+macro nothing_macro() end
 @test @expand(@nothing_macro) === nothing
 
-macro splitcombine(fundef) # should be a no-op
-    dict = splitdef(fundef)
-    esc(MacroTools.combinedef(dict))
-end
-
-# Macros for testing that splitcombine doesn't break
-# macrocalls in bodies
-macro zeroarg()
-   :(1)
-end
-macro onearg(x)
-   :(1+$(esc(x)))
-end
-
-let
-    # Ideally we'd compare the result against :(function f(x)::Int 10 end),
-    # but it fails because of :line and :block differences
-    @test longdef(:(f(x)::Int = 10)).head == :function
-    @test longdef(:(f(x::T) where U where T = 2)).head == :function
-    @test shortdef(:(function f(x)::Int 10 end)).head != :function
-    @test map(splitarg, (:(f(a=2, x::Int=nothing, y, args...))).args[2:end]) ==
-        [(:a, :Any, false, 2), (:x, :Int, false, :nothing),
-         (:y, :Any, false, nothing), (:args, :Any, true, nothing)]
-    @test splitarg(:(::Int)) == (nothing, :Int, false, nothing)
-
-    @splitcombine foo(x) = x+2
-    @test foo(10) == 12
-    @splitcombine add(a, b=2; c=3, d=4)::Float64 = a+b+c+d
-    @test add(1; d=10) === 16.0
-    @splitcombine fparam(a::T) where {T} = T
-    @test fparam([]) == Vector{Any}
-    struct Orange end
-    @splitcombine (::Orange)(x) = x+2
-    @test Orange()(10) == 12
-    @splitcombine fwhere(a::T) where T = T
-    @test fwhere(10) == Int
-    @splitcombine manywhere(x::T, y::Vector{U}) where T <: U where U = (T, U)
-    @test manywhere(1, Number[2.0]) == (Int, Number)
-    @splitcombine fmacro0() = @zeroarg
-    @test fmacro0() == 1
-    @splitcombine fmacro1() = @onearg 1
-    @test fmacro1() == 2
-
-    struct Foo{A, B}
-        a::A
-        b::B
-    end
-    # Parametric outer constructor
-    @splitcombine Foo{A}(a::A) where A = Foo{A, A}(a,a)
-    @test Foo{Int}(2) == Foo{Int, Int}(2, 2)
-end
-
 @testset "combinestructdef, splitstructdef" begin
     ex = :(struct S end)
     @test ex |> splitstructdef |> combinestructdef |> Base.remove_linenums! ==