This is a very good talk but I wonder if this alternate compiler design has actually made the TypeScript compiler slower in normal compilation mode. If you really do &quot;helicopter in&quot; to every point in the syntax tree and run IDE queries to implement type checking then that could potentially be much slower if there&#x27;s any overhead at all to doing that.<p>I&#x27;ve been experimenting with programming languages and compilers myself (<a href="https:&#x2F;&#x2F;github.com&#x2F;evanw&#x2F;skew" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;evanw&#x2F;skew</a>) and my compiler appears to be ~2x faster than tsc when run with node even though it&#x27;s also doing constant folding, tree shaking, inlining, and minification while tsc is just removing type annotations (my compiler appears to be ~15x faster when run natively). The slow compilation speed of tsc is my main complaint about the TypeScript ecosystem.