Syntax error when using substitution to prepend to an array

[ragnaroh]

If you have the following config you get a syntax error on the second line saying "no viable alternative at input '['".

foo: [1, 2]
bar: ${foo} [3]

[mkurz]

Can you use equals? Like:

foo = [1, 2]
bar = ${foo} [3]

[ragnaroh]

Same error message, I'm afraid.

[ragnaroh]

I can add that I'm using Eclipse Oxygen.2 Release (4.7.2)