Struct rustc_passes::region::RegionResolutionVisitor

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>

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.

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.

fn enter_node_scope_with_dtor(&mut self, id: ItemLocalId)

Trait Implementations

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

type Map = ErasedMap<'tcx>

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.

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

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

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

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

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

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

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

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.

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.

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.

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.

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

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.

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.

fn visit_id(&mut self, _hir_id: HirId)

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

fn visit_ident(&mut self, ident: Ident)

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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