From 0c98e656cf60d4b693376a2013a312039560b95d Mon Sep 17 00:00:00 2001
From: Zach Allaun <zach.allaun@gmail.com>
Date: Sat, 3 Aug 2024 02:46:57 -0700
Subject: [PATCH] Do a runtime check for `Macro.classify_atom/1` (#294)

---
 .../providers/completion/completion_engine.ex | 25 +++++++++----------
 1 file changed, 12 insertions(+), 13 deletions(-)

diff --git a/lib/elixir_sense/providers/completion/completion_engine.ex b/lib/elixir_sense/providers/completion/completion_engine.ex
index 36ed51bd..5d67ccd0 100644
--- a/lib/elixir_sense/providers/completion/completion_engine.ex
+++ b/lib/elixir_sense/providers/completion/completion_engine.ex
@@ -850,19 +850,18 @@ defmodule ElixirSense.Providers.Completion.CompletionEngine do
 
   ## Helpers
 
-  # Version.match? is slow, we need to avoid it in a hot loop
-  if Version.match?(System.version(), ">= 1.14.0-dev") do
-    defp usable_as_unquoted_module?(name) do
-      # Conversion to atom is not a problem because
-      # it is only called with existing modules names.
-      # credo:disable-for-lines:7
-      Macro.classify_atom(String.to_atom(name)) in [:identifier, :unquoted] and
-        not String.starts_with?(name, "Elixir.")
-    end
-  else
-    defp usable_as_unquoted_module?(name) do
-      Code.Identifier.classify(String.to_atom(name)) != :other and
-        not String.starts_with?(name, "Elixir.")
+  defp usable_as_unquoted_module?(name) do
+    unquoted_atom_or_identifier?(String.to_atom(name)) and
+      not String.starts_with?(name, "Elixir.")
+  end
+
+  defp unquoted_atom_or_identifier?(atom) when is_atom(atom) do
+    # Macro.classify_atom/1 was introduced in 1.14.0. If it's not available,
+    # assume we're on an older version and fall back to a private API.
+    if function_exported?(Macro, :classify_atom, 1) do
+      apply(Macro, :classify_atom, [atom]) in [:identifier, :unquoted]
+    else
+      apply(Code.Identifier, :classify, [atom]) != :other
     end
   end