diff --git a/src/Parameters.jl b/src/Parameters.jl
index 15b9f9e..12800b2 100644
--- a/src/Parameters.jl
+++ b/src/Parameters.jl
@@ -262,7 +262,8 @@ function _pack_new(T, fields)
     Expr(:call, T, fields...)
 end
 
-const macro_hidden_nargs = length(:(@m).args) - 1 # ==1 on Julia 0.6, ==2 on Julia 0.7
+"The symbol to use to indicate that `typeof(default_value)` is used."
+const TYPEOF=:typeof
 
 """
 This function is called by the `@with_kw` macro and does the syntax
@@ -341,10 +342,10 @@ function with_kw(typedef, mod::Module, withshow=true)
     l, i = next(lns, start(lns))
     if l isa Expr && l.head == :macrocall && l.args[1] == Symbol("@deftype")
         has_deftyp = true
-        if length(l.args) != (2 + macro_hidden_nargs)
+        if length(l.args) != 3
             error("Malformed `@deftype` line $l")
         end
-        deftyp = l.args[2 + macro_hidden_nargs]
+        deftyp = l.args[3]
         if done(lns, i)
             error("@with_kw only supported for types which have at least one field.")
         end
@@ -385,7 +386,7 @@ function with_kw(typedef, mod::Module, withshow=true)
     unpack_vars = Any[]
     # the type def
     fielddefs = quote end # holds r::R etc
-    fielddefs.args = Any[] # in julia 0.5 this is [:( # /home/mauro/.julia/v0.5/Parameters/src/Parameters.jl, line 228:)]
+    fielddefs.args = Any[]
     kws = OrderedDict{Any, Any}()
     # assertions in the body
     asserts = Any[]
@@ -395,7 +396,7 @@ function with_kw(typedef, mod::Module, withshow=true)
             continue
         end
         if l isa Symbol  # no default value and no type annotation
-            if has_deftyp
+            if has_deftyp && deftyp!=TYPEOF # doesn't work to do ::typeof(default_value) here
                 push!(fielddefs.args, :($l::$deftyp))
             else
                 push!(fielddefs.args, l)
@@ -407,16 +408,22 @@ function with_kw(typedef, mod::Module, withshow=true)
             push!(unpack_vars, sym)
         elseif l isa String # doc-string
             push!(fielddefs.args, l)
-        elseif l.head==:(=)  # default value and with or without type annotation
+        elseif l.head==:(=)
             if l.args[1] isa Expr && (l.args[1].head==:call || # inner constructor
                                         l.args[1].head==:where && l.args[1].args[1].head==:call) # inner constructor with `where`
                 check_inner_constructor(l)
                 push!(inner_constructors, l)
-            else
+            else # default value and with or without type annotation
                 fld = l.args[1]
                 if fld isa Symbol && has_deftyp # no type annotation
                     fld = :($fld::$deftyp)
                 end
+                # process TYPEOF
+                if !(fld isa Symbol) && fld.args[2]==TYPEOF
+                    # replace with typeof(default_value)
+                    fld.args[2] = :(typeof($(l.args[2])))
+                end
+
                 # add field doc-strings
                 docstring = string("Default: ", l.args[2])
                 if i > 1 && lns[i-1] isa String
@@ -426,6 +433,7 @@ function with_kw(typedef, mod::Module, withshow=true)
                     # otherwise add a new line
                     push!(fielddefs.args, docstring)
                 end
+                # add to output
                 push!(fielddefs.args, fld)
                 kws[decolon2(fld)] = l.args[2]
                 # unwrap-macro
@@ -440,6 +448,7 @@ function with_kw(typedef, mod::Module, withshow=true)
         elseif l.head==:block
             error("No nested begin-end allowed in type defintion")
         else # no default value but with type annotation
+            l.args[2]==TYPEOF && error("Cannot infer type from default if there is no default.")
             push!(fielddefs.args, l)
             sym = decolon2(l.args[1])
             syms = string(sym)
@@ -523,6 +532,20 @@ function with_kw(typedef, mod::Module, withshow=true)
     # constructors are to allow both calls:
     #   `MT4(r=4, a=5.0)` (outer kwarg-constructor) and
     #   `MT4{Float32, Int}(r=4, a=5.)` (inner kwarg constructor).
+    #
+    # NOTE to above NOTE: this is probably not the case (anymore?),
+    # as Base.@kwdef does not define inner constructors:
+    # julia> Base.@kwdef struct MT4_{R,I}
+    #            r::R=5
+    #            a::I
+    #        end
+    #
+    # julia> MT4_(r=4, a=5.0)
+    # MT4_{Int64,Float64}(4, 5.0)
+    #
+    # julia> MT4_{Float32, Int}(r=4, a=5.)
+    # MT4_{Float32,Int64}(4.0f0, 5)
+
 
     ## outer copy constructor
     ###