diff --git a/.gitignore b/.gitignore
index 703c136..0a75f1d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,3 +2,4 @@
 *.jl.mem
 docs/build/
 tmp*
+Manifest.toml
diff --git a/Project.toml b/Project.toml
index 8d49409..12a18be 100644
--- a/Project.toml
+++ b/Project.toml
@@ -4,6 +4,7 @@ author = ["Mauro Werder <mauro3@runbox.com>"]
 version = "0.12.0"
 
 [deps]
+ConstructionBase = "187b0558-2788-49d3-abe0-74a17ed4e7c9"
 OrderedCollections = "bac558e1-5e72-5ebc-8fee-abe8a469f55d"
 
 [compat]
diff --git a/src/Parameters.jl b/src/Parameters.jl
index 0e60af0..2e6ea8f 100644
--- a/src/Parameters.jl
+++ b/src/Parameters.jl
@@ -1,5 +1,3 @@
-__precompile__()
-
 """
 This is a package I use to handle numerical-model parameters,
 thus the name. However, it should be useful otherwise too.
@@ -41,10 +39,14 @@ c = BB.c
 ```
 """
 module Parameters
+import ConstructionBase
+using ConstructionBase: setproperties
+
 import Base: @__doc__
 import OrderedCollections: OrderedDict
 
 export @with_kw, @with_kw_noshow, type2dict, reconstruct, @unpack, @pack!, @pack
+export setproperties
 
 ## Parser helpers
 #################
@@ -199,11 +201,7 @@ end
 """
 Make a new instance of a type with the same values as the input type
 except for the fields given in the AbstractDict second argument or as
-keywords.  Works for types, Dicts, and NamedTuples.
-
-Note: this is not very performant.  Check Setfield.jl for a faster &
-nicer implementation.
-
+keywords. Works for types, Dicts, and NamedTuples.
 ```jldoctest
 julia> using Parameters
 
@@ -218,25 +216,29 @@ A(3, 4)
 julia> b = reconstruct(a, b=99)
 A(3, 99)
 ```
+See also [`setproperties`](@ref).
+
+# Overloading
+#
+If you want to overload `reconstruct` consider overloading `setproperties` instead.
+More precisely if you have a dict like type `MyDict <: AbstractDict`, it makes
+sense to overload `reconstruct(o::MyDict, di)`. If you have a record like type,
+you should probably overload `setproperties(o, patch::NamedTuple)` instead.
+
+Formulated differently, if the goal of the reconstruct call is to update:
+* the result of `getindex`, overload `reconstruct`
+* the result of `getproperty` overload `setproperties` instead.
 """
-function reconstruct(pp::T, di) where T
-    di = !isa(di, AbstractDict) ? Dict(di) : copy(di)
-    if pp isa AbstractDict
-        for (k,v) in di
-            !haskey(pp, k) && error("Field $k not in type $T")
-            pp[k] = v
-        end
-        return pp
-    else
-        ns = fieldnames(T)
-        args = []
-        for (i,n) in enumerate(ns)
-            push!(args, pop!(di, n, getfield(pp, n)))
-        end
-        length(di)!=0 && error("Fields $(keys(di)) not in type $T")
-        return pp isa NamedTuple ? T(Tuple(args)) : T(args...)
+function reconstruct(pp::AbstractDict, di)
+    # di = !isa(di, AbstractDict) ? Dict(di) : copy(di)
+    for (k,v) in di
+        !haskey(pp, k) && throw(KeyError(k))
+        pp[k] = v
     end
+    return pp
 end
+reconstruct(obj, patch::NamedTuple) = setproperties(obj, patch)
+reconstruct(obj, patch) = reconstruct(obj, (;patch...))
 reconstruct(pp; kws...) = reconstruct(pp, kws)
 
 
diff --git a/test/runtests.jl b/test/runtests.jl
index 6a2becb..744020a 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -4,11 +4,11 @@ using Parameters, Test, Markdown, REPL
 a8679 = @eval (a=1, b=2)
 ra8679 = @eval (a=1, b=44)
 @test ra8679 == reconstruct(a8679, b=44)
-@test_throws ErrorException reconstruct(a8679, c=44)
+@test_throws ArgumentError reconstruct(a8679, c=44)
 
 a8679 = Dict(:a=>1, :b=>2)
 @test Dict(:a=>1, :b=>44) == reconstruct(a8679, b=44)
-@test_throws ErrorException reconstruct(a8679, c=44)
+@test_throws KeyError reconstruct(a8679, c=44)
 
 struct A8679
     a
@@ -16,7 +16,7 @@ struct A8679
 end
 a8679 = A8679(1, 2)
 @test A8679(1, 44) == reconstruct(a8679, b=44)
-@test_throws ErrorException reconstruct(a8679, c=44)
+@test_throws ArgumentError reconstruct(a8679, c=44)
 
 ##########
 # @with_kw
@@ -36,6 +36,8 @@ end
 # @test "A field Default: sdaf\n" == Markdown.plain(@doc MT1.c)
 @test "Field r Default: 4\n" == Markdown.plain(REPL.fielddoc(MT1, :r))
 @test "A field Default: sdaf\n" == Markdown.plain(REPL.fielddoc(MT1, :c))
+@test setproperties(MT1(), r=12).r === 12
+@test setproperties(MT1(), r=12, c=nothing).c === nothing
 
 abstract type AMT1_2 end
 "Test documentation with type-parameter"
@@ -75,7 +77,8 @@ const TMT1_3 = MT1_3{Int} # Julia bug https://github.com/JuliaLang/julia/issues/
 end
 MT2(r=4, a=5., c=6)
 MT2(r=4, a=5, c="asdf")
-MT2(4, "dsaf", 5)
+obj = MT2(4, "dsaf", 5)
+@test setproperties(obj, (r=42, c=:c)).r === 42
 @test_throws ErrorException MT2(r=4)
 @test_throws ErrorException MT2()
 
@@ -114,6 +117,12 @@ MT3_2(a=5)
 MT3_2(4,5)
 @test_throws ErrorException MT3_2(r=4)
 @test_throws ErrorException MT3_2()
+o = MT3_2(r=4, a=5.0)
+o2 = setproperties(o, r=10, a=20)
+@test o2.r === 10
+@test o2.a === 20.0
+@test o.r === 4
+@test o.a === 5.0
 
 # with type-parameters
 @with_kw struct MT4{R,I}
@@ -130,6 +139,8 @@ mt4=MT4(5.4, 4) # outer positional
 @test_throws ErrorException MT4{Float32, Int}()
 @test_throws InexactError MT4{Float32,Int}(a=5.5)
 @test_throws InexactError MT4{Float32,Int}(5.5, 5.5)
+@test setproperties(MT4(a=1), r=12.0).r === 12.0
+@test setproperties(MT4(a=1), r=12, a=:hello).a === :hello
 
 # with type-parameters 2
 abstract type AMT{R<:Real} end