MRI 2.1.3 parser regression?

example.sh

# chruby-exec 2.1.2 -- ruby y.rb
{:a=>:foo}
# chruby-exec 2.1.3 -- ruby y.rb
y.rb:2: syntax error, unexpected modifier_if
  a: if true; :foo; end
       ^
y.rb:2: syntax error, unexpected keyword_end, expecting end-of-input

y.rb

# not that I'd like this code. But its valid on 2.1.2 and invalid on 2.1.3. Found via mutant.
p(
  a: if true; :foo; end
)