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Why is the Rust compiler so slow?

(sharnoff.io)
302 points Bogdanp | 1 comments | 26 Jun 25 19:29 UTC | HN request time: 0.258s | source
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adastra22 ◴[26 Jun 25 20:10 UTC] No.44390813[source]▶
As a former C++ developer, claims that rust compilation is slow leave me scratching my head.
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MobiusHorizons ◴[26 Jun 25 20:47 UTC] No.44391177[source]▶
Things can still be slow in absolute terms without being as slow as C++. The issues with compiling C++ are incredibly well understood and documented. It is one of the worst languages on earth for compile times. Rust doesn’t share those language level issues, so the expectations are understandably higher.
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1. int_19h ◴[26 Jun 25 22:52 UTC] No.44392236[source]▶
But it does share some of those issues. Specifically, while Rust generics aren't as unstructured as C++ templates, the main burden is actually from compiling all those tiny instantiations, and Rust monomorphization has the same exact problem responsible for the bulk of its compile times.