I think that determining `this` at the call-site is really awful, and has been the cause of many more bugs than is reasonable

That’s what almost all (more or less) dynamic languages do, except those that don’t have an arbitrary “object” struct. Out of few dynamic languages only python does what you need, at the cost of the enormous GC pressure. It’s okay for python because it was meant to be slow as hell by design.

And even then the solution would be more error-prone than the “issue” itself. Consider this code:

  app.use(sass({
    src: “.”,
    log: console.log,
    log2: function () {…},
  }))

Should the anonymous object overtake console.log()’s “this”? And for log2()? And if you create an object and assign a bunch of functions to it in a literal? Later in the code?

Your frustration is understandable, but I assure you that python’s “bound methods” are really awful to debug as well (been there done that), because the issue is not in functions taking “this” one way or another, but in a mismatch between developer’s expectations and reality.