Generator results into a fatal error in 2.13.9 (newest not tested)

[Viatorus]

Describe the bug

The following code results in a fatal error.

TEST_CASE("Generator test") {
  SECTION("a") {
    SECTION("aa") {}
    SECTION("ab") {}
  }
  SECTION("b") {}

  GENERATE(true, false);
}

Expected behavior

No error at all.

Reproduction steps

Build and run the example above

Platform information:

• OS: Linux
• Compiler+version: GCC v11.3
• Catch version: v2.13.9

Additional context
Add any other context about the problem here.

[horenmar]

For the record, adding an empty section should work as a workaround for now.