Skip to content

Fix map difference union optimization #15319

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
josevalim merged 1 commit into from
Apr 28, 2026
Merged

Fix map difference union optimization #15319

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
3 changes: 2 additions & 1 deletion lib/elixir/lib/module/types/descr.ex
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -3062,7 +3062,8 @@ defmodule Module.Types.Descr do
#
# Outside of this particular scenario, the `a_int` optimization has been useful,
# but we haven't measured benefits for `a_union`.
defp map_leaf_difference(bdd_leaf(tag, fields), bdd_leaf(:open, [{key, v2}]), type) do
defp map_leaf_difference(bdd_leaf(tag, fields), bdd_leaf(:open, [{key, v2}]), type)
when type != :union do
{found?, v1} =
case fields_find(key, fields) do
{:ok, value} -> {true, value}
Expand Down
6 changes: 6 additions & 0 deletions lib/elixir/test/elixir/module/types/descr_test.exs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -608,6 +608,12 @@ defmodule Module.Types.DescrTest do
assert difference(closed_map(a: integer()), open_map(b: if_set(integer()))) == none()
end

test "map double negation with redundant empty map" do
type = closed_map(a: atom()) |> union(open_map(a: if_set(integer()))) |> union(empty_map())

assert negation(negation(type)) |> equal?(type)
end

test "map (struct optimizations)" do
# We do direct assertions because we want to check how it works underneath
atom_foo = atom([:foo])
Expand Down
Loading