Points 1 and 2 are about introspection, which are hugely language- and implementation-dependent. IME, the languages with great tooling and error messages didn't achieve it by integrating every possible feature into the compiler. (Usually, it's closer to the opposite.) Even different compilers for exactly the same language differ greatly in their ability to extract intention, and present it to users in a comprehensible way.
Point 3 is simply that programmers aren't sharing interfaces, which is indeed a shame, but that's independent of whether you choose to put the interface in the language or the library. Didn't TensorFlow fork the Swift compiler?
Point 3 is simply that programmers aren't sharing interfaces, which is indeed a shame, but that's independent of whether you choose to put the interface in the language or the library. Didn't TensorFlow fork the Swift compiler?
https://github.com/apple/swift/tree/tensorflow
Forking the compiler is hardly my idea of getting all programmers on the same page.