From 33145f6fa2a9164ddf1e120ccccf6723cae97122 Mon Sep 17 00:00:00 2001
From: Andreas Hasselberg <andreas.hasselberg@gmail.com>
Date: Mon, 14 Sep 2026 08:28:24 +0200
Subject: [PATCH 1/2] Support [elem, ...] and [...] non-empty list shorthands
 in AbstractCode

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
---
 lib/spectral/abstract_code.ex        | 10 ++++++++
 test/spectral_nonempty_list_test.exs | 35 ++++++++++++++++++++++++++++
 test/support/all_types_module.ex     |  2 ++
 test/support/nonempty_list_module.ex |  7 ++++++
 test/type_info_equivalence_test.exs  |  2 ++
 5 files changed, 56 insertions(+)
 create mode 100644 test/spectral_nonempty_list_test.exs
 create mode 100644 test/support/nonempty_list_module.ex

diff --git a/lib/spectral/abstract_code.ex b/lib/spectral/abstract_code.ex
index 46b02d3..ab69bd7 100644
--- a/lib/spectral/abstract_code.ex
+++ b/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))
diff --git a/test/spectral_nonempty_list_test.exs b/test/spectral_nonempty_list_test.exs
new file mode 100644
index 0000000..175eb5e
--- /dev/null
+++ b/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
diff --git a/test/support/all_types_module.ex b/test/support/all_types_module.ex
index f8ae4bc..7b3e31e 100644
--- a/test/support/all_types_module.ex
+++ b/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()
diff --git a/test/support/nonempty_list_module.ex b/test/support/nonempty_list_module.ex
new file mode 100644
index 0000000..3e16448
--- /dev/null
+++ b/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
diff --git a/test/type_info_equivalence_test.exs b/test/type_info_equivalence_test.exs
index c7a276f..808e39d 100644
--- a/test/type_info_equivalence_test.exs
+++ b/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,

From e1aae80b1b56525b1985859a332de32f67ba5f8d Mon Sep 17 00:00:00 2001
From: Andreas Hasselberg <andreas.hasselberg@gmail.com>
Date: Mon, 14 Sep 2026 10:34:14 +0200
Subject: [PATCH 2/2] Add changelog entry for non-empty list shorthand fix

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
---
 CHANGELOG.md | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index f886566..de3a9b9 100644
--- a/CHANGELOG.md
+++ b/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