I guess this can be considered as a bug as it is breaking my apps.
If version 2.1.0 has breaking changes, why don't set it to 3.0.0? Semantic versioning, right?
Typescript lives and has important role in the nodejs ecosystem, therefore should follow some basic rules.
We can not use the npm's semver features to block only major changes.

TypeScript Version: 2.1.1 / nightly (2.2.0-dev.201xxxxx)

2.1.0
Code

// A *self-contained* demonstration of the problem follows...
No need

Expected behavior:
Follow semantic versioning rules
Actual behavior:
Just follows marketing versioning rules
can be related to #6520 created a year ago and closed without being solved