=== scalar document followed by mapping
--- yaml
\--- foo
a: 1
--- error: E_CLASSIFY
=== mapping with double key
--- yaml
foo: 1
foo: 2
--- error: E_DUPKEY
=== scalar document followed by mapping
--- yaml
\--- foo
a: 1
--- error: E_CLASSIFY
=== mapping with double key
--- yaml
foo: 1
foo: 2
--- error: E_DUPKEY