Honestly I think the culture an community surrounding the language has way more influence on quality than actual language features. Take languages like C, C++ or Perl. They they where born during a time where people actually designed software and mostly knew what they where doing. Although Perl is more gung ho than C, but the design is clear, be simple and don't get in my way, I know what I am doing. The average developer is more rigorous, but the language lets you shoot yourself in the foot.
In contrast take languages like Ruby or Python, where you are booed out of the room when you don't have unit tests. This has the perversion where unit tests are written for trivial tasks or in way that is totally ineffective, but YOU CANT'T PROGRAM WITHOUT TESTS. Here the quality comes mostly through process that is indoctrinated in the community. The programmers don't pay much attention to what they are actually doing, if it does not trip a test, all is well.
JavaScript for example a difficult one. JavaScript in the browser is mostly "I can programz, YOLO", like PHP it was born in a community of hobbyists with very little quality control. Their awesome utility made them the center of an industry and as developers from other fields came into the industry the community slowly stated adapting more rigor towards design and quality. Here the quality can be all over the place. In contrast JavaScript in the context of node.js, is totally different. Node.js came to a certain degree from web developers communities, like ruby on rails, they for example took the unit testing rigor with them.
As I noted, the community and culture in which the language is used, is probably the dominant indicator.