Code.Fragment handles anonymous function (#12846)

Author: sabiwara

lib/elixir/lib/code/fragment.ex

@@ -78,6 +78,9 @@ defmodule Code.Fragment do
     * `{:local_call, charlist}` - the context is a local (import or local)
       call, such as `hello_world(` and `hello_world `
 
+    * `{:anonymous_call, inside_caller}` - the context is an anonymous
+      call, such as `fun.(` and `@fun.(`.
+
     * `{:module_attribute, charlist}` - the context is a module attribute,
       such as `@hello_wor`
 
@@ -140,6 +143,7 @@ defmodule Code.Fragment do
           | {:local_or_var, charlist}
           | {:local_arity, charlist}
           | {:local_call, charlist}
+          | {:anonymous_call, inside_caller}
           | {:module_attribute, charlist}
           | {:operator, charlist}
           | {:operator_arity, charlist}
@@ -164,7 +168,8 @@ defmodule Code.Fragment do
                | {:alias, inside_alias, charlist}
                | {:local_or_var, charlist}
                | {:module_attribute, charlist}
-               | {:dot, inside_dot, charlist}
+               | {:dot, inside_dot, charlist},
+             inside_caller: {:var, charlist} | {:module_attribute, charlist}
   def cursor_context(fragment, opts \\ [])
 
   def cursor_context(fragment, opts)
@@ -241,6 +246,14 @@ defmodule Code.Fragment do
     end
   end
 
+  defp call_to_cursor_context({[?., h | t], spaces}) when h not in @non_identifier do
+    case identifier_to_cursor_context([h | t], spaces, true) do
+      {{:local_or_var, acc}, count} -> {{:anonymous_call, {:var, acc}}, count + 1}
+      {{:module_attribute, _} = attr, count} -> {{:anonymous_call, attr}, count + 1}
+      {_, _} -> {:none, 0}
+    end
+  end
+
   defp call_to_cursor_context({reverse, spaces}) do
     case identifier_to_cursor_context(reverse, spaces, true) do
       {{:local_or_var, acc}, count} -> {{:local_call, acc}, count}

lib/elixir/test/elixir/code_fragment_test.exs

@@ -124,6 +124,8 @@ defmodule CodeFragmentTest do
       assert CF.cursor_context("hello(\t") == {:local_call, ~c"hello"}
       assert CF.cursor_context("hello(\n") == {:local_call, ~c"hello"}
       assert CF.cursor_context("hello(\r\n") == {:local_call, ~c"hello"}
+      assert CF.cursor_context("...(") == {:local_call, ~c"..."}
+      assert CF.cursor_context("...(\s") == {:local_call, ~c"..."}
     end
 
     test "dot_arity" do
@@ -200,6 +202,16 @@ defmodule CodeFragmentTest do
                {:dot_call, {:alias, {:module_attribute, ~c"foo"}, ~c"Foo"}, ~c"hello"}
     end
 
+    test "anonymous_call" do
+      assert CF.cursor_context("hello.(") == {:anonymous_call, {:var, ~c"hello"}}
+      assert CF.cursor_context("hello.(\s") == {:anonymous_call, {:var, ~c"hello"}}
+      assert CF.cursor_context("hello.(\t") == {:anonymous_call, {:var, ~c"hello"}}
+      assert CF.cursor_context("hello.(\n") == {:anonymous_call, {:var, ~c"hello"}}
+      assert CF.cursor_context("hello.(\r\n") == {:anonymous_call, {:var, ~c"hello"}}
+
+      assert CF.cursor_context("@hello.(") == {:anonymous_call, {:module_attribute, ~c"hello"}}
+    end
+
     test "nested expressions" do
       assert CF.cursor_context("Hello.world()") == :none
       assert CF.cursor_context("hello().") == {:dot, :expr, ~c""}