Segfault on missing semicolon

[xzyfer]

Originally reported in sass/node-sass#1316

a {
  display: block

  b {
    c {
      foo: bar;
    }
  }
}

Ruby Sass

Error: Illegal nesting: Only properties may be nested beneath properties.
        on line 5 of test.scss
  Use --trace for backtrace.

LibSass 3.3.2

[1]    64183 segmentation fault  /Users/michael/Projects/Sass/sassc/bin/sassc test.scss

Spec added sass/sass-spec#644