[simias]

They generally sell you an ecosystem though, and are often tied to specific hardware, not "just" a language.

The only examples that come to mind of a "pure" commercial compiler, not tied to a particular environment or piece of hardware are the Comeau C++ compiler (defunct for well over a decade) and arguably the original D compiler (although I don't know if it qualifies as proprietary, just not open source). Swift as well, although it was open sourced relatively quickly.

[mhh__]

The D compiler is now completely open source. It was always source available, but Walter wrote the backend when he was at a different company and he was able to use it but because of copyright it couldn't be open sourced as per se.

Symantec signed off on it a few years ago, it's been Boost licensed ever since.