diff --git a/src/build.er b/src/build.er
index c3cd513..aff45ca 100644
--- a/src/build.er
+++ b/src/build.er
@@ -11,7 +11,7 @@ ac = import "ansicolor"
 {load_package_er_as_json!;} = import "metadata"
 
 .compile_command! vers: Versions! =
-    cmd as Array!(Str, _) = !["erg", "compile"]
+    cmd as List!(Str, _) = !["erg", "compile"]
     metadata = load_package_er_as_json!()
     if! metadata.get("py_command") isnot! None, do!:
         cmd.push! "--py-command"
diff --git a/src/cfg.er b/src/cfg.er
index 7d1abf0..1349d5c 100644
--- a/src/cfg.er
+++ b/src/cfg.er
@@ -12,7 +12,7 @@ sys = pyimport "sys"
     .allow_dirty = Bool;
     .certified = Bool;
     .pip_check = Bool;
-    .args = Array(Str);
+    .args = List(Str);
 }
 .Config.
     parse!(): Self =
diff --git a/src/download.er b/src/download.er
index 2fc8a24..36c68b0 100644
--- a/src/download.er
+++ b/src/download.er
@@ -101,7 +101,7 @@ Package = Class {
 Package.
     new as_name, version, path, type, used_in := "run" =
         Package { .as_name; .version; .path; .type; .used_in }
-.Versions! = Class Dict! { .PackageName: Array!(Package) }
+.Versions! = Class Dict! { .PackageName: List!(Package) }
 .Versions!|<: Show|.
     __str__ ref self = "\{self::base}"
 .Versions!|<: Eq|.
@@ -205,7 +205,7 @@ Package.
         if! not(os.path.exists! "package.lock.er"), do!:
             .Versions!.from_package_lock_er!::return None
         data = load_er_as_json! "package.lock.er"
-        assert data["packages"] in Array { Str: Str }
+        assert data["packages"] in List { Str: Str }
         .Versions!.from_packages! data["packages"]
     install_if_not_exists!(ref self, pip_check: Bool) =
         for! self::base.items(), ((pkg, vers),) =>
diff --git a/src/publish.er b/src/publish.er
index c7a294f..15a04ee 100644
--- a/src/publish.er
+++ b/src/publish.er
@@ -29,7 +29,7 @@ check_commit!(cfg: Config) =
         panic """\{ac.RED}Error\{ac.RESET}: There are uncommitted changes in the current branch.
 If you want to publish anyway, use the `--allow-dirty` flag."""
 
-validate_package_er(metadata: {Str: Str or Array(Str) or Record}) =
+validate_package_er(metadata: {Str: Str or List(Str) or Record}) =
     if metadata.get("name") == None:
         do panic "\{ac.RED}Error\{ac.RESET} in package.er: `name` is missing"
         do assert metadata["name"] in Str, "\{ac.RED}Error\{ac.RESET} in package.er: `name` must be a string"
@@ -52,7 +52,7 @@ validate_package_er(metadata: {Str: Str or Array(Str) or Record}) =
                 "\{ac.RED}Error\{ac.RESET} in package.er: `type` must be \"app\", \"lib\", \"hybrid\" or \"decl\""
     if metadata.get("authors") == None:
         do panic "\{ac.RED}Error\{ac.RESET} in package.er: `authors` is missing"
-        do assert metadata["authors"] in Array(Str):
+        do assert metadata["authors"] in List(Str):
             "\{ac.RED}Error\{ac.RESET} in package.er: `authors` must be a list of strings"
 
 create_pr! cfg: Config, user_name, metadata =
@@ -82,7 +82,7 @@ create_pr! cfg: Config, user_name, metadata =
     discard download_dependencies_on_demand! cfg
     check_commit! cfg
     metadata = load_package_er_as_json!()
-    assert metadata in {Str: Str or Array(Str) or Record}
+    assert metadata in {Str: Str or List(Str) or Record}
     validate_package_er metadata
     if! not(cfg.no_verify), do!:
         check!(cfg)