diff --git a/rust/Cargo.toml b/rust/Cargo.toml
--- a/rust/Cargo.toml
+++ b/rust/Cargo.toml
@@ -1,3 +1,4 @@
 [workspace]
 members = ["hg-core", "hg-cpython", "rhg"]
 exclude = ["chg", "hgcli"]
+resolver = "2"