diff --git a/rust/Cargo.lock b/rust/Cargo.lock
--- a/rust/Cargo.lock
+++ b/rust/Cargo.lock
@@ -166,7 +166,6 @@
  "libc",
  "num-traits",
  "paste",
- "python27-sys",
  "python3-sys",
 ]
 
@@ -671,16 +670,6 @@
 ]
 
 [[package]]
-name = "python27-sys"
-version = "0.7.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "94670354e264300dde81a5864cbb6bfc9d56ac3dcf3a278c32cb52f816f4dfd1"
-dependencies = [
- "libc",
- "regex",
-]
-
-[[package]]
 name = "python3-sys"
 version = "0.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
diff --git a/rust/hg-cpython/Cargo.toml b/rust/hg-cpython/Cargo.toml
--- a/rust/hg-cpython/Cargo.toml
+++ b/rust/hg-cpython/Cargo.toml
@@ -12,12 +12,10 @@
 default = ["python3"]
 
 # Features to build an extension module:
-python27 = ["cpython/python27-sys", "cpython/extension-module-2-7"]
 python3 = ["cpython/python3-sys", "cpython/extension-module"]
 
-# Enable one of these features to build a test executable linked to libpython:
-# e.g. cargo test --no-default-features --features python27-bin
-python27-bin = ["cpython/python27-sys"]
+# Enable this feature to build a test executable linked to libpython:
+# e.g. cargo test --no-default-features --features python3-bin
 python3-bin = ["cpython/python3-sys"]
 
 [dependencies]
@@ -29,4 +27,3 @@
 env_logger = "0.7.1"
 stable_deref_trait = "1.2.0"
 vcsgraph = "0.2.0"
-
diff --git a/rust/hg-cpython/src/lib.rs b/rust/hg-cpython/src/lib.rs
--- a/rust/hg-cpython/src/lib.rs
+++ b/rust/hg-cpython/src/lib.rs
@@ -62,7 +62,7 @@
     Ok(())
 });
 
-#[cfg(not(any(feature = "python27-bin", feature = "python3-bin")))]
+#[cfg(not(feature = "python3-bin"))]
 #[test]
 #[ignore]
 fn libpython_must_be_linked_to_run_tests() {