It doesn't fix bugs (in the language/compiler). It documents exactly what the language is supposed to do, and therefore what the language user can count on. Without a spec, all you can count on is what you can experimentally determine that the language does (and even then, you can't be sure that it will do that in all situations).
This actually reduces bugs in applications, because it means that the app writers now know what the language will actually do, and can write their code accordingly. Without a spec, they will too often have a cargo cult understanding of what the language does, and so their code won't do what they intend it to.
If there's a spec, and the compiler/language doesn't do what the spec says, now you can definitively say that it's a bug in the language. That can still cause bugs in your app. But at least you can now definitively say that the language implementation is at fault, and demand that they fix it, and you can agree with the language authors on what "fixed" means.
You do not have the right to put words in my mouth, or to claim that your twisted version is what I was saying.
A spec is more detailed and more precise than (other) documentation and design documents. ("Other" because the spec is itself part of the documentation, and one of the design documents.) For the safety-critical software itself, you would demand a full, formal spec, not just "documentation". (At least, if you wouldn't, then others would. and they are right to do so.)
But if you demand that for the software, doesn't it make at least some sense to ask it of the compiler? And even if you don't think it makes sense for the compiler, it seems reasonable that the standard libraries of the language should face the same requirements as the subroutines that are part of the safety-critical software.
This actually reduces bugs in applications, because it means that the app writers now know what the language will actually do, and can write their code accordingly. Without a spec, they will too often have a cargo cult understanding of what the language does, and so their code won't do what they intend it to.
If there's a spec, and the compiler/language doesn't do what the spec says, now you can definitively say that it's a bug in the language. That can still cause bugs in your app. But at least you can now definitively say that the language implementation is at fault, and demand that they fix it, and you can agree with the language authors on what "fixed" means.