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Auto merge of #90986 - camsteffen:nested-filter, r=cjgillot

Replace `NestedVisitorMap` with generic `NestedFilter`

This is an attempt to make the `intravisit::Visitor` API simpler and "more const" with regard to nested visiting.

With this change, `intravisit::Visitor` does not visit nested things by default, unless you specify `type NestedFilter = nested_filter::OnlyBodies` (or `All`). `nested_visit_map` returns `Self::Map` instead of `NestedVisitorMap<Self::Map>`. It panics by default (unreachable if `type NestedFilter` is omitted).

One somewhat trixty thing here is that `nested_filter::{OnlyBodies, All}` live in `rustc_middle` so that they may have `type Map = map::Map` and so that `impl Visitor`s never need to specify `type Map` - it has a default of `Self::NestedFilter::Map`.
This commit is contained in:
bors 2022-01-17 14:50:50 +00:00
commit ee5d8d37ba
110 changed files with 388 additions and 947 deletions

View file

@ -10,7 +10,7 @@ use rustc_errors::{error_code, struct_span_err, Applicability, DiagnosticBuilder
use rustc_hir as hir;
use rustc_hir::def::*;
use rustc_hir::def_id::DefId;
use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor};
use rustc_hir::intravisit::{self, Visitor};
use rustc_hir::{HirId, Pat};
use rustc_middle::ty::{self, AdtDef, Ty, TyCtxt};
use rustc_session::lint::builtin::{
@ -54,12 +54,6 @@ struct MatchVisitor<'a, 'p, 'tcx> {
}
impl<'tcx> Visitor<'tcx> for MatchVisitor<'_, '_, 'tcx> {
type Map = intravisit::ErasedMap<'tcx>;
fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
NestedVisitorMap::None
}
fn visit_expr(&mut self, ex: &'tcx hir::Expr<'tcx>) {
intravisit::walk_expr(self, ex);
match &ex.kind {