diff --git a/base/abstractdict.jl b/base/abstractdict.jl
index d9989265e0e0c..2056c55ab9b77 100644
--- a/base/abstractdict.jl
+++ b/base/abstractdict.jl
@@ -533,38 +533,22 @@ mutable struct IdDict{K,V} <: AbstractDict{K,V}
     end
 
     IdDict{K,V}(d::IdDict{K,V}) where {K, V} = new{K,V}(copy(d.ht))
-    function IdDict{K,V}(d::IdDict{K}) where {K, V}
-        d = IdDict{K,V}()
-        sizehint!(d, length(pairs))
-        for (k,v) in pairs; d[k] = v; end
-        d
-    end
 end
-const _IdDict = IdDict{Any,Any} # this is needed to make src/dump.c and src/staticdata.c work
 
 IdDict() = IdDict{Any,Any}()
 IdDict(kv::Tuple{}) = IdDict()
 
-IdDict(ps::Pair{K,V}...)           where {K,V} = IdDict{K,V}(ps)
-IdDict(ps::Pair{K}...)             where {K}   = IdDict{K,Any}(ps)
-IdDict(ps::(Pair{K,V} where K)...) where {V}   = IdDict{Any,V}(ps)
-IdDict(ps::Pair...)                            = IdDict{Any,Any}(ps)
-
-function IdDict(kv)
-    try
-        dict_with_eltype((K, V) -> IdDict{K, V}, kv, eltype(kv))
-    catch e
-        if !applicable(start, kv) || !all(x->isa(x,Union{Tuple,Pair}),kv)
-            throw(ArgumentError(
-                "IdDict(kv): kv needs to be an iterator of tuples or pairs"))
-        else
-            rethrow(e)
-        end
-    end
-end
+IdDict(ps::Pair...) = IdDict{Any,Any}(ps)
+IdDict(itr) = IdDict{Any,Any}(itr)
 
 empty(d::IdDict, ::Type{K}, ::Type{V}) where {K, V} = IdDict{K,V}()
 
+# TODO: this should probably be removed
+function haskey(d::IdDict, k)
+    v = ccall(:jl_eqtable_get, Any, (Any, Any, Any), d.ht, k, secret_table_token)
+    v !== secret_table_token
+end
+
 function rehash!(d::IdDict, newsz = length(d.ht))
     d.ht = ccall(:jl_idtable_rehash, Any, (Any, Csize_t), d.ht, newsz)
     d
@@ -580,7 +564,8 @@ function sizehint!(d::IdDict, newsz)
     rehash!(d, newsz)
 end
 
-function setindex!(d::IdDict{K,V}, v, k::K) where {K, V}
+function setindex!(d::IdDict{K,V}, v, k) where {K, V}
+    !isa(k, K) && throw(KeyError(k))
     v = convert(V, v)
     if d.ndel >= ((3*length(d.ht))>>2)
         rehash!(d, max(length(d.ht)>>1, 32))
@@ -590,19 +575,20 @@ function setindex!(d::IdDict{K,V}, v, k::K) where {K, V}
     return d
 end
 
-function get(d::IdDict{K,V}, key::K, default) where {K, V}
-    v = ccall(:jl_eqtable_get, Any, (Any, Any, Any), d.ht, key, default)
-    v===default ? default : v::V
+function get(d::IdDict{K,V}, @nospecialize(key), @nospecialize(default)) where {K, V}
+    val = ccall(:jl_eqtable_get, Any, (Any, Any, Any), d.ht, key, default)
+    val === default ? default : val::V
 end
-function getindex(d::IdDict{K,V}, key::K) where {K, V}
-    v = get(d, key, secret_table_token)
-    v == secret_table_token ? throw(KeyError(key)) : v::V
+function getindex(d::IdDict{K,V}, key) where {K, V}
+    val = get(d, key, secret_table_token)
+    val === secret_table_token && throw(KeyError(key))
+    return val::V
 end
 
-function pop!(d::IdDict{K,V}, key::K, default) where {K, V}
+function pop!(d::IdDict{K,V}, key, default) where {K, V}
     val = ccall(:jl_eqtable_pop, Any, (Any, Any, Any), d.ht, key, default)
     # TODO: this can underestimate `ndel`
-    if val==default
+    if val === default
         return default
     else
         (d.ndel += 1)
@@ -612,7 +598,8 @@ end
 
 function pop!(d::IdDict{K,V}, key::K) where {K, V}
     val = pop!(d, key, secret_table_token)
-    val !== secret_table_token ? val::V : throw(KeyError(key))
+    val === secret_table_token && throw(KeyError(key))
+    return val::V
 end
 
 function delete!(d::IdDict{K}, key::K) where K
@@ -627,7 +614,7 @@ function empty!(d::IdDict)
     return d
 end
 
-_oidd_nextind(a, i) = reinterpret(Int,ccall(:jl_eqtable_nextind, Csize_t, (Any, Csize_t), a, i))
+_oidd_nextind(a, i) = reinterpret(Int, ccall(:jl_eqtable_nextind, Csize_t, (Any, Csize_t), a, i))
 
 start(d::IdDict) = _oidd_nextind(d.ht, 0)
 done(d::IdDict, i) = (i == -1)
diff --git a/base/codevalidation.jl b/base/codevalidation.jl
index 957a304b9b9d7..a28fda60505b8 100644
--- a/base/codevalidation.jl
+++ b/base/codevalidation.jl
@@ -1,7 +1,7 @@
 # This file is a part of Julia. License is MIT: https://julialang.org/license
 
 # Expr head => argument count bounds
-const VALID_EXPR_HEADS = IdDict(
+const VALID_EXPR_HEADS = IdDict{Any,Any}(
     :call => 1:typemax(Int),
     :invoke => 2:typemax(Int),
     :static_parameter => 1:1,
diff --git a/src/dump.c b/src/dump.c
index d36dc422e195b..92b2321e91564 100644
--- a/src/dump.c
+++ b/src/dump.c
@@ -2297,7 +2297,7 @@ JL_DLLEXPORT int jl_save_incremental(const char *fname, jl_array_t *worklist)
     htable_new(&backref_table, 5000);
     ptrhash_put(&backref_table, jl_main_module, (char*)HT_NOTFOUND + 1);
     backref_table_numel = 1;
-    jl_idtable_type = jl_base_module ? jl_get_global(jl_base_module, jl_symbol("_IdDict")) : NULL;
+    jl_idtable_type = jl_base_module ? jl_get_global(jl_base_module, jl_symbol("IdDict")) : NULL;
 
     int en = jl_gc_enable(0); // edges map is not gc-safe
     jl_array_t *lambdas = jl_alloc_vec_any(0);
diff --git a/src/staticdata.c b/src/staticdata.c
index 3a81270bd43c0..64b7ca4cbe48e 100644
--- a/src/staticdata.c
+++ b/src/staticdata.c
@@ -1205,7 +1205,7 @@ static void jl_save_system_image_to_stream(ios_t *f)
         }
     }
 
-    jl_idtable_type = jl_base_module ? jl_get_global(jl_base_module, jl_symbol("_IdDict")) : NULL;
+    jl_idtable_type = jl_base_module ? jl_get_global(jl_base_module, jl_symbol("IdDict")) : NULL;
 
     { // step 1: record values (recursively) that need to go in the image
         jl_serialize_value(&s, jl_core_module);
diff --git a/test/dict.jl b/test/dict.jl
index 6fc268ae62bbc..848f057b72ee5 100644
--- a/test/dict.jl
+++ b/test/dict.jl
@@ -384,14 +384,14 @@ mutable struct T10647{T}; x::T; end
     Base.show(Base.IOContext(IOBuffer(), :limit => true), a)
 end
 
-@testset "Base.ObjectIdDict" begin
-    a = Base.ObjectIdDict()
+@testset "IdDict{Any,Any}" begin
+    a = IdDict{Any,Any}()
     a[1] = a
     a[a] = 2
 
     sa = empty(a)
     @test isempty(sa)
-    @test isa(sa, Base.ObjectIdDict)
+    @test isa(sa, IdDict{Any,Any})
 
     @test length(a) == 2
     @test 1 in keys(a)
@@ -411,16 +411,16 @@ end
     d = Dict('a'=>1, 'b'=>1, 'c'=> 3)
     @test a != d
 
-    @test length(Base.ObjectIdDict(1=>2, 1.0=>3)) == 2
+    @test length(IdDict{Any,Any}(1=>2, 1.0=>3)) == 2
     @test length(Dict(1=>2, 1.0=>3)) == 1
 
-    d = @inferred Base.ObjectIdDict(i=>i for i=1:3)
-    @test isa(d, Base.ObjectIdDict)
-    @test d == Base.ObjectIdDict(1=>1, 2=>2, 3=>3)
+    d = @inferred IdDict{Any,Any}(i=>i for i=1:3)
+    @test isa(d, IdDict{Any,Any})
+    @test d == IdDict{Any,Any}(1=>1, 2=>2, 3=>3)
 
-    d = @inferred Base.ObjectIdDict(Pair(1,1), Pair(2,2), Pair(3,3))
-    @test isa(d, Base.ObjectIdDict)
-    @test d == Base.ObjectIdDict(1=>1, 2=>2, 3=>3)
+    d = @inferred IdDict{Any,Any}(Pair(1,1), Pair(2,2), Pair(3,3))
+    @test isa(d, IdDict{Any,Any})
+    @test d == IdDict{Any,Any}(1=>1, 2=>2, 3=>3)
     @test eltype(d) == Pair{Any,Any}
 end
 
@@ -461,13 +461,23 @@ end
     d = @inferred IdDict(Pair(1,1), Pair(2,2), Pair(3,3))
     @test isa(d, IdDict)
     @test d == IdDict(1=>1, 2=>2, 3=>3)
+    @test eltype(d) == Pair{Any,Any}
+
+    d = @inferred IdDict{Int,Int}(Pair(1,1), Pair(2,2), Pair(3,3))
+    @test d == IdDict{Int,Int}(1=>1, 2=>2, 3=>3)
+    @test d == IdDict{Any,Any}(1=>1, 2=>2, 3=>3)
     @test eltype(d) == Pair{Int,Int}
-    @test_throws MethodError d[:a]
-    @test_throws MethodError d[:a] = 1
+    @test_throws KeyError d[:a]
+    @test_throws KeyError d[:a] = 1
     @test_throws MethodError d[1] = :a
 
+    # copy constructor
+    d = IdDict{Int,Int}(Pair(1,1), Pair(2,2), Pair(3,3))
+    @test collect(values(IdDict{Int,Float64}(d))) == collect(values(d))
+    @test_throws KeyError IdDict{Float64,Int}(d)
+
     # check that returned values are inferred
-    d = @inferred IdDict(Pair(1,1), Pair(2,2), Pair(3,3))
+    d = @inferred IdDict{Int,Int}(Pair(1,1), Pair(2,2), Pair(3,3))
     @test 1 == @inferred d[1]
     @inferred setindex!(d, -1, 10)
     @test d[10] == -1