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//! HIR walker for walking the contents of nodes.
//!
//! Here are the three available patterns for the visitor strategy,
//! in roughly the order of desirability:
//!
//! 1. **Shallow visit**: Get a simple callback for every item (or item-like thing) in the HIR.
//! - Example: find all items with a `#[foo]` attribute on them.
//! - How: Use the `hir_crate_items` or `hir_module_items` query to traverse over item-like ids
//! (ItemId, TraitItemId, etc.) and use tcx.def_kind and `tcx.hir().item*(id)` to filter and
//! access actual item-like thing, respectively.
//! - Pro: Efficient; just walks the lists of item ids and gives users control whether to access
//! the hir_owners themselves or not.
//! - Con: Don't get information about nesting
//! - Con: Don't have methods for specific bits of HIR, like "on
//! every expr, do this".
//! 2. **Deep visit**: Want to scan for specific kinds of HIR nodes within
//! an item, but don't care about how item-like things are nested
//! within one another.
//! - Example: Examine each expression to look for its type and do some check or other.
//! - How: Implement `intravisit::Visitor` and override the `NestedFilter` type to
//! `nested_filter::OnlyBodies` (and implement `nested_visit_map`), and use
//! `tcx.hir().visit_all_item_likes_in_crate(&mut visitor)`. Within your
//! `intravisit::Visitor` impl, implement methods like `visit_expr()` (don't forget to invoke
//! `intravisit::walk_expr()` to keep walking the subparts).
//! - Pro: Visitor methods for any kind of HIR node, not just item-like things.
//! - Pro: Integrates well into dependency tracking.
//! - Con: Don't get information about nesting between items
//! 3. **Nested visit**: Want to visit the whole HIR and you care about the nesting between
//! item-like things.
//! - Example: Lifetime resolution, which wants to bring lifetimes declared on the
//! impl into scope while visiting the impl-items, and then back out again.
//! - How: Implement `intravisit::Visitor` and override the `NestedFilter` type to
//! `nested_filter::All` (and implement `nested_visit_map`). Walk your crate with
//! `tcx.hir().walk_toplevel_module(visitor)` invoked on `tcx.hir().krate()`.
//! - Pro: Visitor methods for any kind of HIR node, not just item-like things.
//! - Pro: Preserves nesting information
//! - Con: Does not integrate well into dependency tracking.
//!
//! If you have decided to use this visitor, here are some general
//! notes on how to do so:
//!
//! Each overridden visit method has full control over what
//! happens with its node, it can do its own traversal of the node's children,
//! call `intravisit::walk_*` to apply the default traversal algorithm, or prevent
//! deeper traversal by doing nothing.
//!
//! When visiting the HIR, the contents of nested items are NOT visited
//! by default. This is different from the AST visitor, which does a deep walk.
//! Hence this module is called `intravisit`; see the method `visit_nested_item`
//! for more details.
//!
//! Note: it is an important invariant that the default visitor walks
//! the body of a function in "execution order" - more concretely, if
//! we consider the reverse post-order (RPO) of the CFG implied by the HIR,
//! then a pre-order traversal of the HIR is consistent with the CFG RPO
//! on the *initial CFG point* of each HIR node, while a post-order traversal
//! of the HIR is consistent with the CFG RPO on each *final CFG point* of
//! each CFG node.
//!
//! One thing that follows is that if HIR node A always starts/ends executing
//! before HIR node B, then A appears in traversal pre/postorder before B,
//! respectively. (This follows from RPO respecting CFG domination).
//!
//! This order consistency is required in a few places in rustc, for
//! example generator inference, and possibly also HIR borrowck.
use crate::hir::*;
use rustc_ast::walk_list;
use rustc_ast::{Attribute, Label};
use rustc_span::symbol::{Ident, Symbol};
use rustc_span::Span;
pub trait IntoVisitor<'hir> {
type Visitor: Visitor<'hir>;
fn into_visitor(&self) -> Self::Visitor;
}
#[derive(Copy, Clone, Debug)]
pub enum FnKind<'a> {
/// `#[xxx] pub async/const/extern "Abi" fn foo()`
ItemFn(Ident, &'a Generics<'a>, FnHeader),
/// `fn foo(&self)`
Method(Ident, &'a FnSig<'a>),
/// `|x, y| {}`
Closure,
}
impl<'a> FnKind<'a> {
pub fn header(&self) -> Option<&FnHeader> {
match *self {
FnKind::ItemFn(_, _, ref header) => Some(header),
FnKind::Method(_, ref sig) => Some(&sig.header),
FnKind::Closure => None,
}
}
pub fn constness(self) -> Constness {
self.header().map_or(Constness::NotConst, |header| header.constness)
}
pub fn asyncness(self) -> IsAsync {
self.header().map_or(IsAsync::NotAsync, |header| header.asyncness)
}
}
/// An abstract representation of the HIR `rustc_middle::hir::map::Map`.
pub trait Map<'hir> {
/// Retrieves the `Node` corresponding to `id`, returning `None` if cannot be found.
fn find(&self, hir_id: HirId) -> Option<Node<'hir>>;
fn body(&self, id: BodyId) -> &'hir Body<'hir>;
fn item(&self, id: ItemId) -> &'hir Item<'hir>;
fn trait_item(&self, id: TraitItemId) -> &'hir TraitItem<'hir>;
fn impl_item(&self, id: ImplItemId) -> &'hir ImplItem<'hir>;
fn foreign_item(&self, id: ForeignItemId) -> &'hir ForeignItem<'hir>;
}
// Used when no map is actually available, forcing manual implementation of nested visitors.
impl<'hir> Map<'hir> for ! {
fn find(&self, _: HirId) -> Option<Node<'hir>> {
*self;
}
fn body(&self, _: BodyId) -> &'hir Body<'hir> {
*self;
}
fn item(&self, _: ItemId) -> &'hir Item<'hir> {
*self;
}
fn trait_item(&self, _: TraitItemId) -> &'hir TraitItem<'hir> {
*self;
}
fn impl_item(&self, _: ImplItemId) -> &'hir ImplItem<'hir> {
*self;
}
fn foreign_item(&self, _: ForeignItemId) -> &'hir ForeignItem<'hir> {
*self;
}
}
pub mod nested_filter {
use super::Map;
/// Specifies what nested things a visitor wants to visit. By "nested
/// things", 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.
///
/// The most common choice is `OnlyBodies`, which will cause the visitor to
/// visit fn bodies for fns that it encounters, and closure bodies, but
/// skip over nested item-like things.
///
/// See the comments on `ItemLikeVisitor` for more details on the overall
/// visit strategy.
pub trait NestedFilter<'hir> {
type Map: Map<'hir>;
/// Whether the visitor visits nested "item-like" things.
/// E.g., item, impl-item.
const INTER: bool;
/// Whether the visitor visits "intra item-like" things.
/// E.g., function body, closure, `AnonConst`
const INTRA: bool;
}
/// Do not visit any nested things. When you add a new
/// "non-nested" thing, you will want to audit such uses to see if
/// they remain valid.
///
/// Use this if you are only walking some particular kind of tree
/// (i.e., a type, or fn signature) and you don't want to thread a
/// HIR map around.
pub struct None(());
impl NestedFilter<'_> for None {
type Map = !;
const INTER: bool = false;
const INTRA: bool = false;
}
}
use nested_filter::NestedFilter;
/// Each method of the Visitor trait is a hook to be potentially
/// overridden. Each method's default implementation recursively visits
/// the substructure of the input via the corresponding `walk` method;
/// e.g., the `visit_mod` method by default calls `intravisit::walk_mod`.
///
/// Note that this visitor does NOT visit nested items by default
/// (this is why the module is called `intravisit`, to distinguish it
/// from the AST's `visit` module, which acts differently). If you
/// simply want to visit all items in the crate in some order, you
/// should call `tcx.hir().visit_all_item_likes_in_crate`. Otherwise, see the comment
/// on `visit_nested_item` for details on how to visit nested items.
///
/// If you want to ensure that your code handles every variant
/// explicitly, you need to override each method. (And you also need
/// to monitor future changes to `Visitor` in case a new method with a
/// new default implementation gets introduced.)
pub trait Visitor<'v>: Sized {
// this type should not be overridden, it exists for convenient usage as `Self::Map`
type Map: Map<'v> = <Self::NestedFilter as NestedFilter<'v>>::Map;
///////////////////////////////////////////////////////////////////////////
// Nested items.
/// Override this type to control which nested HIR are visited; see
/// [`NestedFilter`] for details. If you override this type, you
/// must also override [`nested_visit_map`](Self::nested_visit_map).
///
/// **If for some reason you want the nested behavior, but don't
/// have a `Map` at your disposal:** then override the
/// `visit_nested_XXX` methods. If a new `visit_nested_XXX` variant is
/// added in the future, it will cause a panic which can be detected
/// and fixed appropriately.
type NestedFilter: NestedFilter<'v> = nested_filter::None;
/// If `type NestedFilter` is set to visit nested items, this method
/// must also be overridden to provide a map to retrieve nested items.
fn nested_visit_map(&mut self) -> Self::Map {
panic!(
"nested_visit_map must be implemented or consider using \
`type NestedFilter = nested_filter::None` (the default)"
);
}
/// Invoked when a nested item is encountered. By default, when
/// `Self::NestedFilter` is `nested_filter::None`, this method does
/// nothing. **You probably don't want to override this method** --
/// instead, override [`Self::NestedFilter`] 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_item(&mut self, id: ItemId) {
if Self::NestedFilter::INTER {
let item = self.nested_visit_map().item(id);
self.visit_item(item);
}
}
/// Like `visit_nested_item()`, but for trait items. See
/// `visit_nested_item()` for advice on when to override this
/// method.
fn visit_nested_trait_item(&mut self, id: TraitItemId) {
if Self::NestedFilter::INTER {
let item = self.nested_visit_map().trait_item(id);
self.visit_trait_item(item);
}
}
/// Like `visit_nested_item()`, but for impl items. See
/// `visit_nested_item()` for advice on when to override this
/// method.
fn visit_nested_impl_item(&mut self, id: ImplItemId) {
if Self::NestedFilter::INTER {
let item = self.nested_visit_map().impl_item(id);
self.visit_impl_item(item);
}
}
/// Like `visit_nested_item()`, but for foreign items. See
/// `visit_nested_item()` for advice on when to override this
/// method.
fn visit_nested_foreign_item(&mut self, id: ForeignItemId) {
if Self::NestedFilter::INTER {
let item = self.nested_visit_map().foreign_item(id);
self.visit_foreign_item(item);
}
}
/// Invoked to visit the body of a function, method or closure. Like
/// `visit_nested_item`, does nothing by default unless you override
/// `Self::NestedFilter`.
fn visit_nested_body(&mut self, id: BodyId) {
if Self::NestedFilter::INTRA {
let body = self.nested_visit_map().body(id);
self.visit_body(body);
}
}
fn visit_param(&mut self, param: &'v Param<'v>) {
walk_param(self, param)
}
/// Visits the top-level item and (optionally) nested items / impl items. See
/// `visit_nested_item` for details.
fn visit_item(&mut self, i: &'v Item<'v>) {
walk_item(self, i)
}
fn visit_body(&mut self, b: &'v Body<'v>) {
walk_body(self, b);
}
///////////////////////////////////////////////////////////////////////////
fn visit_id(&mut self, _hir_id: HirId) {
// Nothing to do.
}
fn visit_name(&mut self, _name: Symbol) {
// Nothing to do.
}
fn visit_ident(&mut self, ident: Ident) {
walk_ident(self, ident)
}
fn visit_mod(&mut self, m: &'v Mod<'v>, _s: Span, n: HirId) {
walk_mod(self, m, n)
}
fn visit_foreign_item(&mut self, i: &'v ForeignItem<'v>) {
walk_foreign_item(self, i)
}
fn visit_local(&mut self, l: &'v Local<'v>) {
walk_local(self, l)
}
fn visit_block(&mut self, b: &'v Block<'v>) {
walk_block(self, b)
}
fn visit_stmt(&mut self, s: &'v Stmt<'v>) {
walk_stmt(self, s)
}
fn visit_arm(&mut self, a: &'v Arm<'v>) {
walk_arm(self, a)
}
fn visit_pat(&mut self, p: &'v Pat<'v>) {
walk_pat(self, p)
}
fn visit_pat_field(&mut self, f: &'v PatField<'v>) {
walk_pat_field(self, f)
}
fn visit_array_length(&mut self, len: &'v ArrayLen) {
walk_array_len(self, len)
}
fn visit_anon_const(&mut self, c: &'v AnonConst) {
walk_anon_const(self, c)
}
fn visit_expr(&mut self, ex: &'v Expr<'v>) {
walk_expr(self, ex)
}
fn visit_let_expr(&mut self, lex: &'v Let<'v>) {
walk_let_expr(self, lex)
}
fn visit_expr_field(&mut self, field: &'v ExprField<'v>) {
walk_expr_field(self, field)
}
fn visit_ty(&mut self, t: &'v Ty<'v>) {
walk_ty(self, t)
}
fn visit_generic_param(&mut self, p: &'v GenericParam<'v>) {
walk_generic_param(self, p)
}
fn visit_const_param_default(&mut self, _param: HirId, ct: &'v AnonConst) {
walk_const_param_default(self, ct)
}
fn visit_generics(&mut self, g: &'v Generics<'v>) {
walk_generics(self, g)
}
fn visit_where_predicate(&mut self, predicate: &'v WherePredicate<'v>) {
walk_where_predicate(self, predicate)
}
fn visit_fn_decl(&mut self, fd: &'v FnDecl<'v>) {
walk_fn_decl(self, fd)
}
fn visit_fn(&mut self, fk: FnKind<'v>, fd: &'v FnDecl<'v>, b: BodyId, _: Span, id: HirId) {
walk_fn(self, fk, fd, b, id)
}
fn visit_use(&mut self, path: &'v Path<'v>, hir_id: HirId) {
walk_use(self, path, hir_id)
}
fn visit_trait_item(&mut self, ti: &'v TraitItem<'v>) {
walk_trait_item(self, ti)
}
fn visit_trait_item_ref(&mut self, ii: &'v TraitItemRef) {
walk_trait_item_ref(self, ii)
}
fn visit_impl_item(&mut self, ii: &'v ImplItem<'v>) {
walk_impl_item(self, ii)
}
fn visit_foreign_item_ref(&mut self, ii: &'v ForeignItemRef) {
walk_foreign_item_ref(self, ii)
}
fn visit_impl_item_ref(&mut self, ii: &'v ImplItemRef) {
walk_impl_item_ref(self, ii)
}
fn visit_trait_ref(&mut self, t: &'v TraitRef<'v>) {
walk_trait_ref(self, t)
}
fn visit_param_bound(&mut self, bounds: &'v GenericBound<'v>) {
walk_param_bound(self, bounds)
}
fn visit_poly_trait_ref(&mut self, t: &'v PolyTraitRef<'v>) {
walk_poly_trait_ref(self, t)
}
fn visit_variant_data(&mut self, s: &'v VariantData<'v>) {
walk_struct_def(self, s)
}
fn visit_field_def(&mut self, s: &'v FieldDef<'v>) {
walk_field_def(self, s)
}
fn visit_enum_def(&mut self, enum_definition: &'v EnumDef<'v>, item_id: HirId) {
walk_enum_def(self, enum_definition, item_id)
}
fn visit_variant(&mut self, v: &'v Variant<'v>) {
walk_variant(self, v)
}
fn visit_label(&mut self, label: &'v Label) {
walk_label(self, label)
}
fn visit_infer(&mut self, inf: &'v InferArg) {
walk_inf(self, inf);
}
fn visit_generic_arg(&mut self, generic_arg: &'v GenericArg<'v>) {
match generic_arg {
GenericArg::Lifetime(lt) => self.visit_lifetime(lt),
GenericArg::Type(ty) => self.visit_ty(ty),
GenericArg::Const(ct) => self.visit_anon_const(&ct.value),
GenericArg::Infer(inf) => self.visit_infer(inf),
}
}
fn visit_lifetime(&mut self, lifetime: &'v Lifetime) {
walk_lifetime(self, lifetime)
}
// The span is that of the surrounding type/pattern/expr/whatever.
fn visit_qpath(&mut self, qpath: &'v QPath<'v>, id: HirId, _span: Span) {
walk_qpath(self, qpath, id)
}
fn visit_path(&mut self, path: &'v Path<'v>, _id: HirId) {
walk_path(self, path)
}
fn visit_path_segment(&mut self, path_segment: &'v PathSegment<'v>) {
walk_path_segment(self, path_segment)
}
fn visit_generic_args(&mut self, generic_args: &'v GenericArgs<'v>) {
walk_generic_args(self, generic_args)
}
fn visit_assoc_type_binding(&mut self, type_binding: &'v TypeBinding<'v>) {
walk_assoc_type_binding(self, type_binding)
}
fn visit_attribute(&mut self, _attr: &'v Attribute) {}
fn visit_associated_item_kind(&mut self, kind: &'v AssocItemKind) {
walk_associated_item_kind(self, kind);
}
fn visit_defaultness(&mut self, defaultness: &'v Defaultness) {
walk_defaultness(self, defaultness);
}
fn visit_inline_asm(&mut self, asm: &'v InlineAsm<'v>, id: HirId) {
walk_inline_asm(self, asm, id);
}
}
pub fn walk_mod<'v, V: Visitor<'v>>(visitor: &mut V, module: &'v Mod<'v>, mod_hir_id: HirId) {
visitor.visit_id(mod_hir_id);
for &item_id in module.item_ids {
visitor.visit_nested_item(item_id);
}
}
pub fn walk_body<'v, V: Visitor<'v>>(visitor: &mut V, body: &'v Body<'v>) {
walk_list!(visitor, visit_param, body.params);
visitor.visit_expr(&body.value);
}
pub fn walk_local<'v, V: Visitor<'v>>(visitor: &mut V, local: &'v Local<'v>) {
// Intentionally visiting the expr first - the initialization expr
// dominates the local's definition.
walk_list!(visitor, visit_expr, &local.init);
visitor.visit_id(local.hir_id);
visitor.visit_pat(&local.pat);
if let Some(els) = local.els {
visitor.visit_block(els);
}
walk_list!(visitor, visit_ty, &local.ty);
}
pub fn walk_ident<'v, V: Visitor<'v>>(visitor: &mut V, ident: Ident) {
visitor.visit_name(ident.name);
}
pub fn walk_label<'v, V: Visitor<'v>>(visitor: &mut V, label: &'v Label) {
visitor.visit_ident(label.ident);
}
pub fn walk_lifetime<'v, V: Visitor<'v>>(visitor: &mut V, lifetime: &'v Lifetime) {
visitor.visit_id(lifetime.hir_id);
match lifetime.name {
LifetimeName::Param(_, ParamName::Plain(ident)) => {
visitor.visit_ident(ident);
}
LifetimeName::Param(_, ParamName::Fresh)
| LifetimeName::Param(_, ParamName::Error)
| LifetimeName::Static
| LifetimeName::Error
| LifetimeName::ImplicitObjectLifetimeDefault
| LifetimeName::Infer => {}
}
}
pub fn walk_poly_trait_ref<'v, V: Visitor<'v>>(visitor: &mut V, trait_ref: &'v PolyTraitRef<'v>) {
walk_list!(visitor, visit_generic_param, trait_ref.bound_generic_params);
visitor.visit_trait_ref(&trait_ref.trait_ref);
}
pub fn walk_trait_ref<'v, V: Visitor<'v>>(visitor: &mut V, trait_ref: &'v TraitRef<'v>) {
visitor.visit_id(trait_ref.hir_ref_id);
visitor.visit_path(&trait_ref.path, trait_ref.hir_ref_id)
}
pub fn walk_param<'v, V: Visitor<'v>>(visitor: &mut V, param: &'v Param<'v>) {
visitor.visit_id(param.hir_id);
visitor.visit_pat(&param.pat);
}
pub fn walk_item<'v, V: Visitor<'v>>(visitor: &mut V, item: &'v Item<'v>) {
visitor.visit_ident(item.ident);
match item.kind {
ItemKind::ExternCrate(orig_name) => {
visitor.visit_id(item.hir_id());
if let Some(orig_name) = orig_name {
visitor.visit_name(orig_name);
}
}
ItemKind::Use(ref path, _) => {
visitor.visit_use(path, item.hir_id());
}
ItemKind::Static(ref typ, _, body) | ItemKind::Const(ref typ, body) => {
visitor.visit_id(item.hir_id());
visitor.visit_ty(typ);
visitor.visit_nested_body(body);
}
ItemKind::Fn(ref sig, ref generics, body_id) => visitor.visit_fn(
FnKind::ItemFn(item.ident, generics, sig.header),
&sig.decl,
body_id,
item.span,
item.hir_id(),
),
ItemKind::Macro(..) => {
visitor.visit_id(item.hir_id());
}
ItemKind::Mod(ref module) => {
// `visit_mod()` takes care of visiting the `Item`'s `HirId`.
visitor.visit_mod(module, item.span, item.hir_id())
}
ItemKind::ForeignMod { abi: _, items } => {
visitor.visit_id(item.hir_id());
walk_list!(visitor, visit_foreign_item_ref, items);
}
ItemKind::GlobalAsm(asm) => {
visitor.visit_id(item.hir_id());
visitor.visit_inline_asm(asm, item.hir_id());
}
ItemKind::TyAlias(ref ty, ref generics) => {
visitor.visit_id(item.hir_id());
visitor.visit_ty(ty);
visitor.visit_generics(generics)
}
ItemKind::OpaqueTy(OpaqueTy { ref generics, bounds, .. }) => {
visitor.visit_id(item.hir_id());
walk_generics(visitor, generics);
walk_list!(visitor, visit_param_bound, bounds);
}
ItemKind::Enum(ref enum_definition, ref generics) => {
visitor.visit_generics(generics);
// `visit_enum_def()` takes care of visiting the `Item`'s `HirId`.
visitor.visit_enum_def(enum_definition, item.hir_id())
}
ItemKind::Impl(Impl {
unsafety: _,
defaultness: _,
polarity: _,
constness: _,
defaultness_span: _,
ref generics,
ref of_trait,
ref self_ty,
items,
}) => {
visitor.visit_id(item.hir_id());
visitor.visit_generics(generics);
walk_list!(visitor, visit_trait_ref, of_trait);
visitor.visit_ty(self_ty);
walk_list!(visitor, visit_impl_item_ref, *items);
}
ItemKind::Struct(ref struct_definition, ref generics)
| ItemKind::Union(ref struct_definition, ref generics) => {
visitor.visit_generics(generics);
visitor.visit_id(item.hir_id());
visitor.visit_variant_data(struct_definition);
}
ItemKind::Trait(.., ref generics, bounds, trait_item_refs) => {
visitor.visit_id(item.hir_id());
visitor.visit_generics(generics);
walk_list!(visitor, visit_param_bound, bounds);
walk_list!(visitor, visit_trait_item_ref, trait_item_refs);
}
ItemKind::TraitAlias(ref generics, bounds) => {
visitor.visit_id(item.hir_id());
visitor.visit_generics(generics);
walk_list!(visitor, visit_param_bound, bounds);
}
}
}
pub fn walk_inline_asm<'v, V: Visitor<'v>>(visitor: &mut V, asm: &'v InlineAsm<'v>, id: HirId) {
for (op, op_sp) in asm.operands {
match op {
InlineAsmOperand::In { expr, .. } | InlineAsmOperand::InOut { expr, .. } => {
visitor.visit_expr(expr)
}
InlineAsmOperand::Out { expr, .. } => {
if let Some(expr) = expr {
visitor.visit_expr(expr);
}
}
InlineAsmOperand::SplitInOut { in_expr, out_expr, .. } => {
visitor.visit_expr(in_expr);
if let Some(out_expr) = out_expr {
visitor.visit_expr(out_expr);
}
}
InlineAsmOperand::Const { anon_const, .. }
| InlineAsmOperand::SymFn { anon_const, .. } => visitor.visit_anon_const(anon_const),
InlineAsmOperand::SymStatic { path, .. } => visitor.visit_qpath(path, id, *op_sp),
}
}
}
pub fn walk_use<'v, V: Visitor<'v>>(visitor: &mut V, path: &'v Path<'v>, hir_id: HirId) {
visitor.visit_id(hir_id);
visitor.visit_path(path, hir_id);
}
pub fn walk_enum_def<'v, V: Visitor<'v>>(
visitor: &mut V,
enum_definition: &'v EnumDef<'v>,
item_id: HirId,
) {
visitor.visit_id(item_id);
walk_list!(visitor, visit_variant, enum_definition.variants);
}
pub fn walk_variant<'v, V: Visitor<'v>>(visitor: &mut V, variant: &'v Variant<'v>) {
visitor.visit_ident(variant.ident);
visitor.visit_id(variant.id);
visitor.visit_variant_data(&variant.data);
walk_list!(visitor, visit_anon_const, &variant.disr_expr);
}
pub fn walk_ty<'v, V: Visitor<'v>>(visitor: &mut V, typ: &'v Ty<'v>) {
visitor.visit_id(typ.hir_id);
match typ.kind {
TyKind::Slice(ref ty) => visitor.visit_ty(ty),
TyKind::Ptr(ref mutable_type) => visitor.visit_ty(&mutable_type.ty),
TyKind::Rptr(ref lifetime, ref mutable_type) => {
visitor.visit_lifetime(lifetime);
visitor.visit_ty(&mutable_type.ty)
}
TyKind::Never => {}
TyKind::Tup(tuple_element_types) => {
walk_list!(visitor, visit_ty, tuple_element_types);
}
TyKind::BareFn(ref function_declaration) => {
walk_list!(visitor, visit_generic_param, function_declaration.generic_params);
visitor.visit_fn_decl(&function_declaration.decl);
}
TyKind::Path(ref qpath) => {
visitor.visit_qpath(qpath, typ.hir_id, typ.span);
}
TyKind::OpaqueDef(item_id, lifetimes, _in_trait) => {
visitor.visit_nested_item(item_id);
walk_list!(visitor, visit_generic_arg, lifetimes);
}
TyKind::Array(ref ty, ref length) => {
visitor.visit_ty(ty);
visitor.visit_array_length(length)
}
TyKind::TraitObject(bounds, ref lifetime, _syntax) => {
for bound in bounds {
visitor.visit_poly_trait_ref(bound);
}
visitor.visit_lifetime(lifetime);
}
TyKind::Typeof(ref expression) => visitor.visit_anon_const(expression),
TyKind::Infer | TyKind::Err => {}
}
}
pub fn walk_inf<'v, V: Visitor<'v>>(visitor: &mut V, inf: &'v InferArg) {
visitor.visit_id(inf.hir_id);
}
pub fn walk_qpath<'v, V: Visitor<'v>>(visitor: &mut V, qpath: &'v QPath<'v>, id: HirId) {
match *qpath {
QPath::Resolved(ref maybe_qself, ref path) => {
walk_list!(visitor, visit_ty, maybe_qself);
visitor.visit_path(path, id)
}
QPath::TypeRelative(ref qself, ref segment) => {
visitor.visit_ty(qself);
visitor.visit_path_segment(segment);
}
QPath::LangItem(..) => {}
}
}
pub fn walk_path<'v, V: Visitor<'v>>(visitor: &mut V, path: &'v Path<'v>) {
for segment in path.segments {
visitor.visit_path_segment(segment);
}
}
pub fn walk_path_segment<'v, V: Visitor<'v>>(visitor: &mut V, segment: &'v PathSegment<'v>) {
visitor.visit_ident(segment.ident);
visitor.visit_id(segment.hir_id);
if let Some(ref args) = segment.args {
visitor.visit_generic_args(args);
}
}
pub fn walk_generic_args<'v, V: Visitor<'v>>(visitor: &mut V, generic_args: &'v GenericArgs<'v>) {
walk_list!(visitor, visit_generic_arg, generic_args.args);
walk_list!(visitor, visit_assoc_type_binding, generic_args.bindings);
}
pub fn walk_assoc_type_binding<'v, V: Visitor<'v>>(
visitor: &mut V,
type_binding: &'v TypeBinding<'v>,
) {
visitor.visit_id(type_binding.hir_id);
visitor.visit_ident(type_binding.ident);
visitor.visit_generic_args(type_binding.gen_args);
match type_binding.kind {
TypeBindingKind::Equality { ref term } => match term {
Term::Ty(ref ty) => visitor.visit_ty(ty),
Term::Const(ref c) => visitor.visit_anon_const(c),
},
TypeBindingKind::Constraint { bounds } => walk_list!(visitor, visit_param_bound, bounds),
}
}
pub fn walk_pat<'v, V: Visitor<'v>>(visitor: &mut V, pattern: &'v Pat<'v>) {
visitor.visit_id(pattern.hir_id);
match pattern.kind {
PatKind::TupleStruct(ref qpath, children, _) => {
visitor.visit_qpath(qpath, pattern.hir_id, pattern.span);
walk_list!(visitor, visit_pat, children);
}
PatKind::Path(ref qpath) => {
visitor.visit_qpath(qpath, pattern.hir_id, pattern.span);
}
PatKind::Struct(ref qpath, fields, _) => {
visitor.visit_qpath(qpath, pattern.hir_id, pattern.span);
walk_list!(visitor, visit_pat_field, fields);
}
PatKind::Or(pats) => walk_list!(visitor, visit_pat, pats),
PatKind::Tuple(tuple_elements, _) => {
walk_list!(visitor, visit_pat, tuple_elements);
}
PatKind::Box(ref subpattern) | PatKind::Ref(ref subpattern, _) => {
visitor.visit_pat(subpattern)
}
PatKind::Binding(_, _hir_id, ident, ref optional_subpattern) => {
visitor.visit_ident(ident);
walk_list!(visitor, visit_pat, optional_subpattern);
}
PatKind::Lit(ref expression) => visitor.visit_expr(expression),
PatKind::Range(ref lower_bound, ref upper_bound, _) => {
walk_list!(visitor, visit_expr, lower_bound);
walk_list!(visitor, visit_expr, upper_bound);
}
PatKind::Wild => (),
PatKind::Slice(prepatterns, ref slice_pattern, postpatterns) => {
walk_list!(visitor, visit_pat, prepatterns);
walk_list!(visitor, visit_pat, slice_pattern);
walk_list!(visitor, visit_pat, postpatterns);
}
}
}
pub fn walk_pat_field<'v, V: Visitor<'v>>(visitor: &mut V, field: &'v PatField<'v>) {
visitor.visit_id(field.hir_id);
visitor.visit_ident(field.ident);
visitor.visit_pat(&field.pat)
}
pub fn walk_foreign_item<'v, V: Visitor<'v>>(visitor: &mut V, foreign_item: &'v ForeignItem<'v>) {
visitor.visit_id(foreign_item.hir_id());
visitor.visit_ident(foreign_item.ident);
match foreign_item.kind {
ForeignItemKind::Fn(ref function_declaration, param_names, ref generics) => {
visitor.visit_generics(generics);
visitor.visit_fn_decl(function_declaration);
for &param_name in param_names {
visitor.visit_ident(param_name);
}
}
ForeignItemKind::Static(ref typ, _) => visitor.visit_ty(typ),
ForeignItemKind::Type => (),
}
}
pub fn walk_param_bound<'v, V: Visitor<'v>>(visitor: &mut V, bound: &'v GenericBound<'v>) {
match *bound {
GenericBound::Trait(ref typ, _modifier) => {
visitor.visit_poly_trait_ref(typ);
}
GenericBound::LangItemTrait(_, _span, hir_id, args) => {
visitor.visit_id(hir_id);
visitor.visit_generic_args(args);
}
GenericBound::Outlives(ref lifetime) => visitor.visit_lifetime(lifetime),
}
}
pub fn walk_generic_param<'v, V: Visitor<'v>>(visitor: &mut V, param: &'v GenericParam<'v>) {
visitor.visit_id(param.hir_id);
match param.name {
ParamName::Plain(ident) => visitor.visit_ident(ident),
ParamName::Error | ParamName::Fresh => {}
}
match param.kind {
GenericParamKind::Lifetime { .. } => {}
GenericParamKind::Type { ref default, .. } => walk_list!(visitor, visit_ty, default),
GenericParamKind::Const { ref ty, ref default } => {
visitor.visit_ty(ty);
if let Some(ref default) = default {
visitor.visit_const_param_default(param.hir_id, default);
}
}
}
}
pub fn walk_const_param_default<'v, V: Visitor<'v>>(visitor: &mut V, ct: &'v AnonConst) {
visitor.visit_anon_const(ct)
}
pub fn walk_generics<'v, V: Visitor<'v>>(visitor: &mut V, generics: &'v Generics<'v>) {
walk_list!(visitor, visit_generic_param, generics.params);
walk_list!(visitor, visit_where_predicate, generics.predicates);
}
pub fn walk_where_predicate<'v, V: Visitor<'v>>(
visitor: &mut V,
predicate: &'v WherePredicate<'v>,
) {
match *predicate {
WherePredicate::BoundPredicate(WhereBoundPredicate {
hir_id,
ref bounded_ty,
bounds,
bound_generic_params,
origin: _,
span: _,
}) => {
visitor.visit_id(hir_id);
visitor.visit_ty(bounded_ty);
walk_list!(visitor, visit_param_bound, bounds);
walk_list!(visitor, visit_generic_param, bound_generic_params);
}
WherePredicate::RegionPredicate(WhereRegionPredicate {
ref lifetime,
bounds,
span: _,
in_where_clause: _,
}) => {
visitor.visit_lifetime(lifetime);
walk_list!(visitor, visit_param_bound, bounds);
}
WherePredicate::EqPredicate(WhereEqPredicate { ref lhs_ty, ref rhs_ty, span: _ }) => {
visitor.visit_ty(lhs_ty);
visitor.visit_ty(rhs_ty);
}
}
}
pub fn walk_fn_ret_ty<'v, V: Visitor<'v>>(visitor: &mut V, ret_ty: &'v FnRetTy<'v>) {
if let FnRetTy::Return(ref output_ty) = *ret_ty {
visitor.visit_ty(output_ty)
}
}
pub fn walk_fn_decl<'v, V: Visitor<'v>>(visitor: &mut V, function_declaration: &'v FnDecl<'v>) {
for ty in function_declaration.inputs {
visitor.visit_ty(ty)
}
walk_fn_ret_ty(visitor, &function_declaration.output)
}
pub fn walk_fn_kind<'v, V: Visitor<'v>>(visitor: &mut V, function_kind: FnKind<'v>) {
match function_kind {
FnKind::ItemFn(_, generics, ..) => {
visitor.visit_generics(generics);
}
FnKind::Closure | FnKind::Method(..) => {}
}
}
pub fn walk_fn<'v, V: Visitor<'v>>(
visitor: &mut V,
function_kind: FnKind<'v>,
function_declaration: &'v FnDecl<'v>,
body_id: BodyId,
id: HirId,
) {
visitor.visit_id(id);
visitor.visit_fn_decl(function_declaration);
walk_fn_kind(visitor, function_kind);
visitor.visit_nested_body(body_id)
}
pub fn walk_trait_item<'v, V: Visitor<'v>>(visitor: &mut V, trait_item: &'v TraitItem<'v>) {
// N.B., deliberately force a compilation error if/when new fields are added.
let TraitItem { ident, generics, ref defaultness, ref kind, span, owner_id: _ } = *trait_item;
let hir_id = trait_item.hir_id();
visitor.visit_ident(ident);
visitor.visit_generics(&generics);
visitor.visit_defaultness(&defaultness);
match *kind {
TraitItemKind::Const(ref ty, default) => {
visitor.visit_id(hir_id);
visitor.visit_ty(ty);
walk_list!(visitor, visit_nested_body, default);
}
TraitItemKind::Fn(ref sig, TraitFn::Required(param_names)) => {
visitor.visit_id(hir_id);
visitor.visit_fn_decl(&sig.decl);
for &param_name in param_names {
visitor.visit_ident(param_name);
}
}
TraitItemKind::Fn(ref sig, TraitFn::Provided(body_id)) => {
visitor.visit_fn(FnKind::Method(ident, sig), &sig.decl, body_id, span, hir_id);
}
TraitItemKind::Type(bounds, ref default) => {
visitor.visit_id(hir_id);
walk_list!(visitor, visit_param_bound, bounds);
walk_list!(visitor, visit_ty, default);
}
}
}
pub fn walk_trait_item_ref<'v, V: Visitor<'v>>(visitor: &mut V, trait_item_ref: &'v TraitItemRef) {
// N.B., deliberately force a compilation error if/when new fields are added.
let TraitItemRef { id, ident, ref kind, span: _ } = *trait_item_ref;
visitor.visit_nested_trait_item(id);
visitor.visit_ident(ident);
visitor.visit_associated_item_kind(kind);
}
pub fn walk_impl_item<'v, V: Visitor<'v>>(visitor: &mut V, impl_item: &'v ImplItem<'v>) {
// N.B., deliberately force a compilation error if/when new fields are added.
let ImplItem {
owner_id: _,
ident,
ref generics,
ref kind,
ref defaultness,
span: _,
vis_span: _,
} = *impl_item;
visitor.visit_ident(ident);
visitor.visit_generics(generics);
visitor.visit_defaultness(defaultness);
match *kind {
ImplItemKind::Const(ref ty, body) => {
visitor.visit_id(impl_item.hir_id());
visitor.visit_ty(ty);
visitor.visit_nested_body(body);
}
ImplItemKind::Fn(ref sig, body_id) => {
visitor.visit_fn(
FnKind::Method(impl_item.ident, sig),
&sig.decl,
body_id,
impl_item.span,
impl_item.hir_id(),
);
}
ImplItemKind::Type(ref ty) => {
visitor.visit_id(impl_item.hir_id());
visitor.visit_ty(ty);
}
}
}
pub fn walk_foreign_item_ref<'v, V: Visitor<'v>>(
visitor: &mut V,
foreign_item_ref: &'v ForeignItemRef,
) {
// N.B., deliberately force a compilation error if/when new fields are added.
let ForeignItemRef { id, ident, span: _ } = *foreign_item_ref;
visitor.visit_nested_foreign_item(id);
visitor.visit_ident(ident);
}
pub fn walk_impl_item_ref<'v, V: Visitor<'v>>(visitor: &mut V, impl_item_ref: &'v ImplItemRef) {
// N.B., deliberately force a compilation error if/when new fields are added.
let ImplItemRef { id, ident, ref kind, span: _, trait_item_def_id: _ } = *impl_item_ref;
visitor.visit_nested_impl_item(id);
visitor.visit_ident(ident);
visitor.visit_associated_item_kind(kind);
}
pub fn walk_struct_def<'v, V: Visitor<'v>>(
visitor: &mut V,
struct_definition: &'v VariantData<'v>,
) {
walk_list!(visitor, visit_id, struct_definition.ctor_hir_id());
walk_list!(visitor, visit_field_def, struct_definition.fields());
}
pub fn walk_field_def<'v, V: Visitor<'v>>(visitor: &mut V, field: &'v FieldDef<'v>) {
visitor.visit_id(field.hir_id);
visitor.visit_ident(field.ident);
visitor.visit_ty(&field.ty);
}
pub fn walk_block<'v, V: Visitor<'v>>(visitor: &mut V, block: &'v Block<'v>) {
visitor.visit_id(block.hir_id);
walk_list!(visitor, visit_stmt, block.stmts);
walk_list!(visitor, visit_expr, &block.expr);
}
pub fn walk_stmt<'v, V: Visitor<'v>>(visitor: &mut V, statement: &'v Stmt<'v>) {
visitor.visit_id(statement.hir_id);
match statement.kind {
StmtKind::Local(ref local) => visitor.visit_local(local),
StmtKind::Item(item) => visitor.visit_nested_item(item),
StmtKind::Expr(ref expression) | StmtKind::Semi(ref expression) => {
visitor.visit_expr(expression)
}
}
}
pub fn walk_array_len<'v, V: Visitor<'v>>(visitor: &mut V, len: &'v ArrayLen) {
match len {
&ArrayLen::Infer(hir_id, _span) => visitor.visit_id(hir_id),
ArrayLen::Body(c) => visitor.visit_anon_const(c),
}
}
pub fn walk_anon_const<'v, V: Visitor<'v>>(visitor: &mut V, constant: &'v AnonConst) {
visitor.visit_id(constant.hir_id);
visitor.visit_nested_body(constant.body);
}
pub fn walk_let_expr<'v, V: Visitor<'v>>(visitor: &mut V, let_expr: &'v Let<'v>) {
// match the visit order in walk_local
visitor.visit_expr(let_expr.init);
visitor.visit_id(let_expr.hir_id);
visitor.visit_pat(let_expr.pat);
walk_list!(visitor, visit_ty, let_expr.ty);
}
pub fn walk_expr_field<'v, V: Visitor<'v>>(visitor: &mut V, field: &'v ExprField<'v>) {
visitor.visit_id(field.hir_id);
visitor.visit_ident(field.ident);
visitor.visit_expr(&field.expr)
}
pub fn walk_expr<'v, V: Visitor<'v>>(visitor: &mut V, expression: &'v Expr<'v>) {
visitor.visit_id(expression.hir_id);
match expression.kind {
ExprKind::Box(ref subexpression) => visitor.visit_expr(subexpression),
ExprKind::Array(subexpressions) => {
walk_list!(visitor, visit_expr, subexpressions);
}
ExprKind::ConstBlock(ref anon_const) => visitor.visit_anon_const(anon_const),
ExprKind::Repeat(ref element, ref count) => {
visitor.visit_expr(element);
visitor.visit_array_length(count)
}
ExprKind::Struct(ref qpath, fields, ref optional_base) => {
visitor.visit_qpath(qpath, expression.hir_id, expression.span);
walk_list!(visitor, visit_expr_field, fields);
walk_list!(visitor, visit_expr, optional_base);
}
ExprKind::Tup(subexpressions) => {
walk_list!(visitor, visit_expr, subexpressions);
}
ExprKind::Call(ref callee_expression, arguments) => {
visitor.visit_expr(callee_expression);
walk_list!(visitor, visit_expr, arguments);
}
ExprKind::MethodCall(ref segment, receiver, arguments, _) => {
visitor.visit_path_segment(segment);
visitor.visit_expr(receiver);
walk_list!(visitor, visit_expr, arguments);
}
ExprKind::Binary(_, ref left_expression, ref right_expression) => {
visitor.visit_expr(left_expression);
visitor.visit_expr(right_expression)
}
ExprKind::AddrOf(_, _, ref subexpression) | ExprKind::Unary(_, ref subexpression) => {
visitor.visit_expr(subexpression)
}
ExprKind::Cast(ref subexpression, ref typ) | ExprKind::Type(ref subexpression, ref typ) => {
visitor.visit_expr(subexpression);
visitor.visit_ty(typ)
}
ExprKind::DropTemps(ref subexpression) => {
visitor.visit_expr(subexpression);
}
ExprKind::Let(ref let_expr) => visitor.visit_let_expr(let_expr),
ExprKind::If(ref cond, ref then, ref else_opt) => {
visitor.visit_expr(cond);
visitor.visit_expr(then);
walk_list!(visitor, visit_expr, else_opt);
}
ExprKind::Loop(ref block, ref opt_label, _, _) => {
walk_list!(visitor, visit_label, opt_label);
visitor.visit_block(block);
}
ExprKind::Match(ref subexpression, arms, _) => {
visitor.visit_expr(subexpression);
walk_list!(visitor, visit_arm, arms);
}
ExprKind::Closure(&Closure {
binder: _,
bound_generic_params,
fn_decl,
body,
capture_clause: _,
fn_decl_span: _,
movability: _,
}) => {
walk_list!(visitor, visit_generic_param, bound_generic_params);
visitor.visit_fn(FnKind::Closure, fn_decl, body, expression.span, expression.hir_id)
}
ExprKind::Block(ref block, ref opt_label) => {
walk_list!(visitor, visit_label, opt_label);
visitor.visit_block(block);
}
ExprKind::Assign(ref lhs, ref rhs, _) => {
visitor.visit_expr(rhs);
visitor.visit_expr(lhs)
}
ExprKind::AssignOp(_, ref left_expression, ref right_expression) => {
visitor.visit_expr(right_expression);
visitor.visit_expr(left_expression);
}
ExprKind::Field(ref subexpression, ident) => {
visitor.visit_expr(subexpression);
visitor.visit_ident(ident);
}
ExprKind::Index(ref main_expression, ref index_expression) => {
visitor.visit_expr(main_expression);
visitor.visit_expr(index_expression)
}
ExprKind::Path(ref qpath) => {
visitor.visit_qpath(qpath, expression.hir_id, expression.span);
}
ExprKind::Break(ref destination, ref opt_expr) => {
walk_list!(visitor, visit_label, &destination.label);
walk_list!(visitor, visit_expr, opt_expr);
}
ExprKind::Continue(ref destination) => {
walk_list!(visitor, visit_label, &destination.label);
}
ExprKind::Ret(ref optional_expression) => {
walk_list!(visitor, visit_expr, optional_expression);
}
ExprKind::InlineAsm(ref asm) => {
visitor.visit_inline_asm(asm, expression.hir_id);
}
ExprKind::Yield(ref subexpression, _) => {
visitor.visit_expr(subexpression);
}
ExprKind::Lit(_) | ExprKind::Err => {}
}
}
pub fn walk_arm<'v, V: Visitor<'v>>(visitor: &mut V, arm: &'v Arm<'v>) {
visitor.visit_id(arm.hir_id);
visitor.visit_pat(&arm.pat);
if let Some(ref g) = arm.guard {
match g {
Guard::If(ref e) => visitor.visit_expr(e),
Guard::IfLet(ref l) => {
visitor.visit_let_expr(l);
}
}
}
visitor.visit_expr(&arm.body);
}
pub fn walk_associated_item_kind<'v, V: Visitor<'v>>(_: &mut V, _: &'v AssocItemKind) {
// No visitable content here: this fn exists so you can call it if
// the right thing to do, should content be added in the future,
// would be to walk it.
}
pub fn walk_defaultness<'v, V: Visitor<'v>>(_: &mut V, _: &'v Defaultness) {
// No visitable content here: this fn exists so you can call it if
// the right thing to do, should content be added in the future,
// would be to walk it.
}