When this fails, you get output that looks like:
/home/user/rust/tests/rustdoc-gui/search-result-impl-disambiguation.goml search-result-impl-disambiguation... FAILED
[ERROR] `tests/rustdoc-gui/utils.goml` around line 49
from `tests/rustdoc-gui/search-result-impl-disambiguation.goml` line 25: JS errors occurred: Event: Event
Making the error message more informative requires patching browser-ui-test.