fix: nested calling rule using raise

lib/credo/check/readability/nested_function_calls.ex

@@ -252,6 +252,13 @@ defmodule Credo.Check.Readability.NestedFunctionCalls do
         ),
         do: true
 
+    # Kernel.to_string() in a string interpolation
+    def cannot_be_in_pipeline?(
+          {{:., _, [Kernel, :to_string]}, meta, _} = ast,
+          _excluded_functions,
+          _excluded_argument_types
+        ), do: meta[:from_interpolation]
+
     # Elixir <= 1.8.0
     # '__#{val}__' are compiled to String.to_charlist("__#{val}__")
     # we want to consider these charlists a valid pipe chain start

test/credo/check/readability/nested_function_calls_test.exs

@@ -190,4 +190,28 @@ defmodule Credo.Check.Readability.NestedFunctionCallsTest do
     |> run_check(NestedFunctionCalls)
     |> assert_issue()
   end
+
+  test "it should NOT report any issues when Kernel.to_string() is called inside a string interpolation" do
+    ~S"""
+    defmodule FeatureFlag.Adapters.Test do
+      def get(flag, context, fallback) do
+        args = {flag, context, fallback}
+        case :ets.lookup(@table, flag) do
+          [] ->
+            raise "No stubs found for #{inspect(args)}"
+
+          stubs ->
+            attempt_stubs(args, Enum.reverse(stubs))
+        end
+      end
+
+      defp attempt_stubs(args, []) do
+        raise "No stub found for args: #{inspect(args)}"
+      end
+    end
+    """
+    |> to_source_file()
+    |> run_check(NestedFunctionCalls)
+    |> refute_issues()
+  end
 end