Do not override signatures of Elixir functions, closes phoenixframewo…

…rk#2222

lib/phoenix_component/declarative.ex

@@ -164,15 +164,31 @@ defmodule Phoenix.Component.Declarative do
     end
   end
 
-  defp annotate_call(_kind, {name, meta, [{:\\, _, _} = arg]}),
-    do: {name, meta, [arg]}
+  defp annotate_call(kind, {name, meta, [{:\\, default_meta, [left, right]}]}),
+    do: {name, meta, [{:\\, default_meta, [annotate_arg(kind, left), right]}]}
 
   defp annotate_call(kind, {name, meta, [arg]}),
-    do: {name, meta, [quote(do: unquote(__MODULE__).__pattern__!(unquote(kind), unquote(arg)))]}
+    do: {name, meta, [annotate_arg(kind, arg)]}
 
   defp annotate_call(_kind, left),
     do: left
 
+  defp annotate_arg(kind, {:=, meta, [{name, _, ctx} = var, arg]}) when is_atom(name) and is_atom(ctx) do
+    {:=, meta, [var, quote(do: unquote(__MODULE__).__pattern__!(unquote(kind), unquote(arg)))]}
+  end
+
+  defp annotate_arg(kind, {:=, meta, [arg, {name, _, ctx} = var]}) when is_atom(name) and is_atom(ctx) do
+    {:=, meta, [quote(do: unquote(__MODULE__).__pattern__!(unquote(kind), unquote(arg))), var]}
+  end
+
+  defp annotate_arg(kind, {name, meta, ctx} = var) when is_atom(name) and is_atom(ctx) do
+    {:=, meta, [quote(do: unquote(__MODULE__).__pattern__!(unquote(kind), _)), var]}
+  end
+
+  defp annotate_arg(kind, arg) do
+    quote(do: unquote(__MODULE__).__pattern__!(unquote(kind), unquote(arg)))
+  end
+
   ## Attrs/slots
 
   @doc false

mix.exs

@@ -10,6 +10,7 @@ defmodule Phoenix.LiveView.MixProject do
       elixir: "~> 1.12",
       start_permanent: Mix.env() == :prod,
       elixirc_paths: elixirc_paths(Mix.env()),
+      test_options: [docs: true],
       package: package(),
       xref: [exclude: [Floki]],
       deps: deps(),

test/phoenix_component/declarative_assigns_test.exs

@@ -920,6 +920,20 @@ defmodule Phoenix.ComponentDeclarativeAssignsTest do
     end
   end
 
+  test "does not override signature of Elixir functions" do
+    {:docs_v1, _, :elixir, "text/markdown", _, _, docs} =
+      Code.fetch_docs(Phoenix.LiveViewTest.FunctionComponentWithAttrs)
+
+    assert {{:function, :identity, 1}, _, ["identity(var)"], _, %{}} =
+             List.keyfind(docs, {:function, :identity, 1}, 0)
+
+    assert {{:function, :map_identity, 1}, _, ["map_identity(map)"], _, %{}} =
+             List.keyfind(docs, {:function, :map_identity, 1}, 0)
+
+    assert Phoenix.LiveViewTest.FunctionComponentWithAttrs.identity(:not_a_map) == :not_a_map
+    assert Phoenix.LiveViewTest.FunctionComponentWithAttrs.identity(%{}) == %{}
+  end
+
   test "raise if attr :doc is not a string" do
     msg = ~r"doc must be a string or false, got: :foo"
 
@@ -1363,23 +1377,19 @@ defmodule Phoenix.ComponentDeclarativeAssignsTest do
   end
 
   test "does not raise if multiple slots with different names share the same attr names" do
-    mod = fn ->
-      defmodule MultipleSlotAttrs do
-        use Phoenix.Component
-
-        slot :foo do
-          attr :attr, :any
-        end
+    defmodule MultipleSlotAttrs do
+      use Phoenix.Component
 
-        slot :bar do
-          attr :attr, :any
-        end
+      slot :foo do
+        attr :attr, :any
+      end
 
-        def func(assigns), do: ~H[]
+      slot :bar do
+        attr :attr, :any
       end
-    end
 
-    assert mod.()
+      def func(assigns), do: ~H[]
+    end
   end
 
   test "raise if slot with name :inner_block has slot attrs" do

test/support/live_views/components.ex

@@ -21,6 +21,9 @@ defmodule Phoenix.LiveViewTest.FunctionComponentWithAttrs do
     defstruct []
   end
 
+  def identity(var), do: var
+  def map_identity(%{} = map), do: map
+
   attr :attr, :any
   def fun_attr_any(assigns), do: ~H[]
 
@@ -196,7 +199,7 @@ defmodule Phoenix.LiveViewTest.StatefulComponent do
     ~H"""
     <div phx-click="transform" id={@id} phx-target={"#" <> @id <> include_parent_id(@parent_id)}>
       <%= @name %> says hi
-      <%= if @dup_name, do: live_component __MODULE__, id: @dup_name, name: @dup_name %>
+      <%= if @dup_name, do: live_component(__MODULE__, id: @dup_name, name: @dup_name) %>
     </div>
     """
   end