Struct rustc_passes::region::RegionResolutionVisitor

pub(in region) struct RegionResolutionVisitor<'tcx> {
    tcx: TyCtxt<'tcx>,
    expr_and_pat_count: usize,
    pessimistic_yield: bool,
    fixup_scopes: Vec<Scope>,
    scope_tree: ScopeTree,
    cx: Context,
    terminating_scopes: FxHashSet<ItemLocalId>,
}

Fields

tcx: TyCtxt<'tcx>

expr_and_pat_count: usize

pessimistic_yield: bool

fixup_scopes: Vec<Scope>

scope_tree: ScopeTree

cx: Context

terminating_scopes: FxHashSet<ItemLocalId>

terminating_scopes is a set containing the ids of each statement, or conditional/repeating expression. These scopes are calling "terminating scopes" because, when attempting to find the scope of a temporary, by default we search up the enclosing scopes until we encounter the terminating scope. A conditional/repeating expression is one which is not guaranteed to execute exactly once upon entering the parent scope. This could be because the expression only executes conditionally, such as the expression b in a && b, or because the expression may execute many times, such as a loop body. The reason that we distinguish such expressions is that, upon exiting the parent scope, we cannot statically know how many times the expression executed, and thus if the expression creates temporaries we cannot know statically how many such temporaries we would have to cleanup. Therefore, we ensure that the temporaries never outlast the conditional/repeating expression, preventing the need for dynamic checks and/or arbitrary amounts of stack space. Terminating scopes end up being contained in a DestructionScope that contains the destructor's execution.

Implementations

impl<'tcx> RegionResolutionVisitor<'tcx>

pub(in region) fn record_child_scope(
    &mut self,
    child_scope: Scope
) -> ScopeDepth

Records the current parent (if any) as the parent of child_scope. Returns the depth of child_scope.

pub(in region) fn enter_scope(
    &mut self,
    child_scope: Scope
)

Records the current parent (if any) as the parent of child_scope, and sets child_scope as the new current parent.

pub(in region) fn enter_node_scope_with_dtor(
    &mut self,
    id: ItemLocalId
)

Trait Implementations

impl<'tcx> Visitor<'tcx> for RegionResolutionVisitor<'tcx>

type Map = ErasedMap<'tcx>

pub fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map>

The default versions of the visit_nested_XXX routines invoke this method to get a map to use. By selecting an enum variant, you control which kinds of nested HIR are visited; see NestedVisitorMap for details. By "nested HIR", we are referring to bits of HIR that are not directly embedded within one another but rather indirectly, through a table in the crate. This is done to control dependencies during incremental compilation: the non-inline bits of HIR can be tracked and hashed separately.

pub fn visit_block(&mut self, b: &'tcx Block<'tcx>)

pub fn visit_body(&mut self, body: &'tcx Body<'tcx>)

pub fn visit_arm(&mut self, a: &'tcx Arm<'tcx>)

pub fn visit_pat(&mut self, p: &'tcx Pat<'tcx>)

pub fn visit_stmt(&mut self, s: &'tcx Stmt<'tcx>)

pub fn visit_expr(&mut self, ex: &'tcx Expr<'tcx>)

pub fn visit_local(&mut self, l: &'tcx Local<'tcx>)

pub fn visit_nested_item(&mut self, id: ItemId)

Invoked when a nested item is encountered. By default does nothing unless you override nested_visit_map to return other than None, in which case it will walk the item. You probably don't want to override this method -- instead, override nested_visit_map or use the "shallow" or "deep" visit patterns described on itemlikevisit::ItemLikeVisitor. The only reason to override this method is if you want a nested pattern but cannot supply a Map; see nested_visit_map for advice.

pub fn visit_nested_trait_item(&mut self, id: TraitItemId)

Like visit_nested_item(), but for trait items. See visit_nested_item() for advice on when to override this method.

pub fn visit_nested_impl_item(&mut self, id: ImplItemId)

Like visit_nested_item(), but for impl items. See visit_nested_item() for advice on when to override this method.

pub fn visit_nested_body(&mut self, id: BodyId)

Invoked to visit the body of a function, method or closure. Like visit_nested_item, does nothing by default unless you override nested_visit_map to return other than None, in which case it will walk the body.

pub fn visit_param(&mut self, param: &'v Param<'v>)

pub fn visit_item(&mut self, i: &'v Item<'v>)

Visits the top-level item and (optionally) nested items / impl items. See visit_nested_item for details.

pub fn as_deep_visitor(&mut self) -> DeepVisitor<'_, Self>

When invoking visit_all_item_likes(), you need to supply an item-like visitor. This method converts a "intra-visit" visitor into an item-like visitor that walks the entire tree. If you use this, you probably don't want to process the contents of nested item-like things, since the outer loop will visit them as well.

pub fn visit_id(&mut self, _hir_id: HirId)

pub fn visit_name(&mut self, _span: Span, _name: Symbol)

pub fn visit_ident(&mut self, ident: Ident)

pub fn visit_mod(&mut self, m: &'v Mod<'v>, _s: Span, n: HirId)

pub fn visit_foreign_item(&mut self, i: &'v ForeignItem<'v>)

pub fn visit_anon_const(&mut self, c: &'v AnonConst)

pub fn visit_ty(&mut self, t: &'v Ty<'v>)

pub fn visit_generic_param(&mut self, p: &'v GenericParam<'v>)

pub fn visit_generics(&mut self, g: &'v Generics<'v>)

pub fn visit_where_predicate(&mut self, predicate: &'v WherePredicate<'v>)

pub fn visit_fn_decl(&mut self, fd: &'v FnDecl<'v>)

pub fn visit_fn(
    &mut self,
    fk: FnKind<'v>,
    fd: &'v FnDecl<'v>,
    b: BodyId,
    s: Span,
    id: HirId
)

pub fn visit_use(&mut self, path: &'v Path<'v>, hir_id: HirId)

pub fn visit_trait_item(&mut self, ti: &'v TraitItem<'v>)

pub fn visit_trait_item_ref(&mut self, ii: &'v TraitItemRef)

pub fn visit_impl_item(&mut self, ii: &'v ImplItem<'v>)

pub fn visit_impl_item_ref(&mut self, ii: &'v ImplItemRef<'v>)

pub fn visit_trait_ref(&mut self, t: &'v TraitRef<'v>)

pub fn visit_param_bound(&mut self, bounds: &'v GenericBound<'v>)

pub fn visit_poly_trait_ref(
    &mut self,
    t: &'v PolyTraitRef<'v>,
    m: TraitBoundModifier
)

pub fn visit_variant_data(
    &mut self,
    s: &'v VariantData<'v>,
    Symbol,
    &'v Generics<'v>,
    _parent_id: HirId,
    Span
)

pub fn visit_struct_field(&mut self, s: &'v StructField<'v>)

pub fn visit_enum_def(
    &mut self,
    enum_definition: &'v EnumDef<'v>,
    generics: &'v Generics<'v>,
    item_id: HirId,
    Span
)

pub fn visit_variant(
    &mut self,
    v: &'v Variant<'v>,
    g: &'v Generics<'v>,
    item_id: HirId
)

pub fn visit_label(&mut self, label: &'v Label)

pub fn visit_generic_arg(&mut self, generic_arg: &'v GenericArg<'v>)

pub fn visit_lifetime(&mut self, lifetime: &'v Lifetime)

pub fn visit_qpath(&mut self, qpath: &'v QPath<'v>, id: HirId, span: Span)

pub fn visit_path(&mut self, path: &'v Path<'v>, _id: HirId)

pub fn visit_path_segment(
    &mut self,
    path_span: Span,
    path_segment: &'v PathSegment<'v>
)

pub fn visit_generic_args(
    &mut self,
    path_span: Span,
    generic_args: &'v GenericArgs<'v>
)

pub fn visit_assoc_type_binding(&mut self, type_binding: &'v TypeBinding<'v>)

pub fn visit_attribute(&mut self, _attr: &'v Attribute)

pub fn visit_macro_def(&mut self, macro_def: &'v MacroDef<'v>)

pub fn visit_vis(&mut self, vis: &'v Spanned<VisibilityKind<'v>>)

pub fn visit_associated_item_kind(&mut self, kind: &'v AssocItemKind)

pub fn visit_defaultness(&mut self, defaultness: &'v Defaultness)