Mixed and lower case Constant names are allowed.

[metaprem]

Documentation says "Constant names must be capitalized."
This code with mixed/lower case constant names runs in playground.
version 0.0.10 ( though v playground does not show lang version )
`
const (
A = 1
B = 2
S = 'upper S'
SSsSS = 'upper with lower'
S_many = 'upper S_many'
s = 'lower s'
s1 = 'lower s1'
)

fn main() {
println('A = $A')
println('B = $B')
println('S = $S')
println('SSsSS = $SSsSS')
println('S_many = $S_many')
println('s = $s')
println('s1 = $s1')
}
`

[medvednikov]

V playground shows the version before you run anything. I'll make it more visible.

Fixed, const capitalization is now enforced.

[metaprem]

Mixed case constant names are allowed

Don't know how to reopen a closed issue so submitting a new one