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| -rw-r--r-- | compiler/rustc_hir/src/intravisit.rs | 1232 |
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diff --git a/compiler/rustc_hir/src/intravisit.rs b/compiler/rustc_hir/src/intravisit.rs new file mode 100644 index 000000000..e676acebe --- /dev/null +++ b/compiler/rustc_hir/src/intravisit.rs @@ -0,0 +1,1232 @@ +//! 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, _span: Span, _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_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_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, s: Span, id: HirId) { + walk_fn(self, fk, fd, b, s, 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>, m: TraitBoundModifier) { + walk_poly_trait_ref(self, t, m) + } + fn visit_variant_data( + &mut self, + s: &'v VariantData<'v>, + _: Symbol, + _: &'v Generics<'v>, + _parent_id: HirId, + _: Span, + ) { + 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>, + generics: &'v Generics<'v>, + item_id: HirId, + _: Span, + ) { + walk_enum_def(self, enum_definition, generics, item_id) + } + fn visit_variant(&mut self, v: &'v Variant<'v>, g: &'v Generics<'v>, item_id: HirId) { + walk_variant(self, v, g, item_id) + } + 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) + } + fn visit_qpath(&mut self, qpath: &'v QPath<'v>, id: HirId, span: Span) { + walk_qpath(self, qpath, id, span) + } + fn visit_path(&mut self, path: &'v Path<'v>, _id: HirId) { + walk_path(self, path) + } + fn visit_path_segment(&mut self, path_span: Span, path_segment: &'v PathSegment<'v>) { + walk_path_segment(self, path_span, path_segment) + } + fn visit_generic_args(&mut self, path_span: Span, generic_args: &'v GenericArgs<'v>) { + walk_generic_args(self, path_span, 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.span, 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>, + _modifier: TraitBoundModifier, +) { + 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(¶m.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(item.span, 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, generics, item.hir_id(), item.span) + } + 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, + item.ident.name, + generics, + item.hir_id(), + item.span, + ); + } + 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>, + generics: &'v Generics<'v>, + item_id: HirId, +) { + visitor.visit_id(item_id); + walk_list!(visitor, visit_variant, enum_definition.variants, generics, item_id); +} + +pub fn walk_variant<'v, V: Visitor<'v>>( + visitor: &mut V, + variant: &'v Variant<'v>, + generics: &'v Generics<'v>, + parent_item_id: HirId, +) { + visitor.visit_ident(variant.ident); + visitor.visit_id(variant.id); + visitor.visit_variant_data( + &variant.data, + variant.ident.name, + generics, + parent_item_id, + variant.span, + ); + 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) => { + 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, TraitBoundModifier::None); + } + 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, + span: Span, +) { + 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(span, 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(path.span, segment); + } +} + +pub fn walk_path_segment<'v, V: Visitor<'v>>( + visitor: &mut V, + path_span: Span, + segment: &'v PathSegment<'v>, +) { + visitor.visit_ident(segment.ident); + walk_list!(visitor, visit_id, segment.hir_id); + if let Some(ref args) = segment.args { + visitor.visit_generic_args(path_span, args); + } +} + +pub fn walk_generic_args<'v, V: Visitor<'v>>( + visitor: &mut V, + _path_span: Span, + 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.span, 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); + for field in fields { + visitor.visit_id(field.hir_id); + visitor.visit_ident(field.ident); + visitor.visit_pat(&field.pat) + } + } + 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_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 ¶m_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, modifier); + } + GenericBound::LangItemTrait(_, span, hir_id, args) => { + visitor.visit_id(hir_id); + visitor.visit_generic_args(span, 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 { + ref bounded_ty, + bounds, + bound_generic_params, + .. + }) => { + 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, .. }) => { + visitor.visit_lifetime(lifetime); + walk_list!(visitor, visit_param_bound, bounds); + } + WherePredicate::EqPredicate(WhereEqPredicate { + hir_id, ref lhs_ty, ref rhs_ty, .. + }) => { + visitor.visit_id(hir_id); + 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, + _span: Span, + 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, def_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 ¶m_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 { + def_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::TyAlias(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<'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); + for field in fields { + visitor.visit_id(field.hir_id); + visitor.visit_ident(field.ident); + visitor.visit_expr(&field.expr) + } + 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, arguments, _) => { + visitor.visit_path_segment(expression.span, segment); + 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. +} |