excess braces ignored: bug or feature ?

[Mike Frysinger]

can't tell if this is a bug or a feature.

FOO= BAR=bar
: ${FOO:=${BAR}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}
echo $FOO

i'd expect an error, or FOO to contain those excess braces.  instead, FOO is 
just "bar".
-mike

signature.asc
Description: This is a digitally signed message part.