The `restriction` group contains many lints which are not about
necessarily “bad” things, but style choices — perhaps even style choices
which contradict conventional Rust style — or are otherwise very
situational. This results in silly wording like “Why is this bad?
It isn't, but ...”, which I’ve seen confuse a newcomer at least once.
To improve this situation, this commit replaces the “Why is this bad?”
section heading with “Why restrict this?”, for most, but not all,
restriction lints. I left alone the ones whose placement in the
restriction group is more incidental.
In order to make this make sense, I had to remove the “It isn't, but”
texts from the contents of the sections. Sometimes further changes
were needed, or there were obvious fixes to make, and I went ahead
and made those changes without attempting to split them into another
commit, even though many of them are not strictly necessary for the
“Why restrict this?” project.
This allows to compute the `BodyOwnerKind` from `DefKind` only, and
removes a direct dependency of some MIR queries onto HIR.
As a side effect, it also simplifies metadata, since we don't need 4
flavours of `EntryKind::*Static` any more.
This renames the variants in HIR UnOp from
enum UnOp {
UnDeref,
UnNot,
UnNeg,
}
to
enum UnOp {
Deref,
Not,
Neg,
}
Motivations:
- This is more consistent with the rest of the code base where most enum
variants don't have a prefix.
- These variants are never used without the `UnOp` prefix so the extra
`Un` prefix doesn't help with readability. E.g. we don't have any
`UnDeref`s in the code, we only have `UnOp::UnDeref`.
- MIR `UnOp` type variants don't have a prefix so this is more
consistent with MIR types.
- "un" prefix reads like "inverse" or "reverse", so as a beginner in
rustc code base when I see "UnDeref" what comes to my mind is
something like "&*" instead of just "*".
