> I think you are misinterpreting when you need a trademark license for > usage a word mark in an implementation of a compiler for a programming > language. Note that gcc used to come with a full implementation of the > Java programming language, compiler, runtime and core library > implementation (for which I was the GNU maintainer). None of that > required a trademark license because the usage of the word java was > just for compatibility with the java programming language.
Was "Java" a trademark for both the language and compiler or just the language? What about "rust"? That would seem to make a difference. If the trademark is just for the language, then when you say you have a "compiler for the XYZ language", you're refering to the trademarked entity (the language) and you can always use a trademark to refer to the trademark owner's product. But if the trademark is also for the compiler and you have a different compiler (even if it differs just by patches), you need the permission of the trademark owner to call you compiler by the trademarked name.