Encouraging consistency across the language ecosystem doesn't have to conflict with layering. The problem with having what are properly library routines in the

Encouraging consistency across the language ecosystem doesn't have to conflict with layering. The problem with having what are properly library routines in the language core syntax is that it's a layering violation: it makes the language more complex, harder to reason about, and harder to learn because it creates special cases in the grammar and core semantics. (For example, note the inconsistent behavior of indexing a nil map vs. indexing a nil slice.) The way to discourage people from "changing everything" is to make the standard library ubiquitous and to use encapsulation to prevent people from changing its internals. If Go had generic maps in the standard library, and you couldn't get access to their internals, then the effect would be exactly the same as the built-in map that Go has today. You see this in other languages: very few people create custom dictionaries in C#, for example.