test_must_fail git checkout world all
'
+test_expect_success 'check ambiguity in subdir' '
+ mkdir sub &&
+ # not ambiguous because sub/world does not exist
+ git -C sub checkout world ../all &&
+ echo hello >sub/world &&
+ # ambiguous because sub/world does exist
+ test_must_fail git -C sub checkout world ../all
+'
+
test_expect_success 'disambiguate checking out from a tree-ish' '
echo bye > world &&
git checkout world -- world &&