Open source and free software isn't the same thing. Nobody made a claim on Java either, until someone did. I just distinctly remember explicitly not exploring D for that reason. Also this way way before LLVM and I also don't think GNU had a D compiler back then. There was only the (and I really believe it was closed source) Digital Mars compiler.
15 years ago, both LLVM and GNU had a D compiler. gdc (the GNU compiler) was not an official part of the gcc collection, but it was definitely there and 100% open source.
All three compilers shared the open source D front end. The DMD backend source code was available for anyone to use, it just couldn't be redistributed. We were eventually able to fully Boost license it.
The DMD compiler always had source available for free from Digital Mars. I never sold a single copy :-)
