Support [elem, ...] non-empty list shorthand in AbstractCode

CHANGELOG.md

@@ -7,6 +7,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Fixed
+- `Spectral.AbstractCode` now handles the Elixir non-empty list shorthand, `[elem_type, ...]` (and bare `[...]`), matching the existing `nonempty_list(elem_type)` support. Previously these types failed to compile with `unsupported type AST`.
+
 ## [0.13.0] - 2026-05-07
 
 ### Added

lib/spectral/abstract_code.ex

@@ -256,6 +256,16 @@ defmodule Spectral.AbstractCode do
     sp_function(args: args, return: return)
   end
 
+  # Shorthand non-empty list type  [...]  — means nonempty_list()
+  defp convert_type([{:..., _meta, _}]) do
+    sp_nonempty_list(type: sp_simple_type(type: :term))
+  end
+
+  # Shorthand non-empty list type  [elem_type, ...]  — means nonempty_list(elem_type)
+  defp convert_type([elem_ast, {:..., _meta, _}]) do
+    sp_nonempty_list(type: convert_type(elem_ast))
+  end
+
   # Shorthand list type  [elem_type]  — means list(elem_type), i.e. possibly empty
   defp convert_type([elem_ast]) do
     sp_list(type: convert_type(elem_ast))

test/spectral_nonempty_list_test.exs

@@ -0,0 +1,35 @@
+defmodule SpectralNonemptyListTest do
+  use ExUnit.Case, async: true
+
+  describe "[elem, ...] shorthand" do
+    test "encode/decode round-trips a non-empty list" do
+      data = %{tags: ["a", "b"]}
+
+      assert {:ok, encoded} =
+               Spectral.encode(data, NonemptyListModule, :shorthand, :json, [:pre_encoded])
+
+      assert {:ok, ^data} =
+               Spectral.decode(encoded, NonemptyListModule, :shorthand, :json, [:pre_decoded])
+    end
+
+    test "encode rejects an empty list" do
+      assert {:error, [%Spectral.Error{}]} =
+               Spectral.encode(%{tags: []}, NonemptyListModule, :shorthand, :json, [:pre_encoded])
+    end
+
+    test "decode rejects an empty list" do
+      assert {:error, [%Spectral.Error{}]} =
+               Spectral.decode(%{"tags" => []}, NonemptyListModule, :shorthand, :json, [
+                 :pre_decoded
+               ])
+    end
+
+    test "schema has minItems 1, matching nonempty_list(elem)" do
+      shorthand = Spectral.schema(NonemptyListModule, :shorthand, :json_schema, [:pre_encoded])
+      longhand = Spectral.schema(NonemptyListModule, :longhand, :json_schema, [:pre_encoded])
+
+      assert shorthand[:properties]["tags"][:minItems] == 1
+      assert shorthand == longhand
+    end
+  end
+end

test/support/all_types_module.ex

@@ -56,6 +56,8 @@ defmodule AllTypesModule do
   @type t_list_shorthand :: [atom()]
   @type t_nonempty_list :: nonempty_list(integer())
   @type t_nonempty_list_any :: nonempty_list()
+  @type t_nonempty_list_shorthand :: [integer(), ...]
+  @type t_nonempty_list_shorthand_any :: [...]
 
   # Tuple types
   @type t_tuple_any :: tuple()

test/support/nonempty_list_module.ex

@@ -0,0 +1,7 @@
+defmodule NonemptyListModule do
+  @moduledoc false
+  use Spectral
+
+  @type shorthand :: %{tags: [String.t(), ...]}
+  @type longhand :: %{tags: nonempty_list(String.t())}
+end

test/type_info_equivalence_test.exs

@@ -206,6 +206,8 @@ defmodule TypeInfoEquivalenceTest do
       :t_list_typed,
       :t_list_shorthand,
       :t_nonempty_list,
+      :t_nonempty_list_shorthand,
+      :t_nonempty_list_shorthand_any,
       :t_tuple_any,
       :t_tuple2,
       :t_tuple3,