blob: f8795d885d2164c784b69cb1c5125f4b2de53964 [file] [log] [blame]
//! A `MutVisitor` represents an AST modification; it accepts an AST piece and
//! and mutates it in place. So, for instance, macro expansion is a `MutVisitor`
//! that walks over an AST and modifies it.
//!
//! Note: using a `MutVisitor` (other than the `MacroExpander` `MutVisitor`) on
//! an AST before macro expansion is probably a bad idea. For instance,
//! a `MutVisitor` renaming item names in a module will miss all of those
//! that are created by the expansion of a macro.
use crate::ast::*;
use crate::source_map::{Spanned, respan};
use crate::token::{self, Token};
use crate::ptr::P;
use crate::ThinVec;
use crate::tokenstream::*;
use crate::util::map_in_place::MapInPlace;
use smallvec::{smallvec, Array, SmallVec};
use syntax_pos::Span;
use rustc_data_structures::sync::Lrc;
use std::ops::DerefMut;
use std::{panic, process, ptr};
pub trait ExpectOne<A: Array> {
fn expect_one(self, err: &'static str) -> A::Item;
}
impl<A: Array> ExpectOne<A> for SmallVec<A> {
fn expect_one(self, err: &'static str) -> A::Item {
assert!(self.len() == 1, err);
self.into_iter().next().unwrap()
}
}
pub trait MutVisitor: Sized {
// Methods in this trait have one of three forms:
//
// fn visit_t(&mut self, t: &mut T); // common
// fn flat_map_t(&mut self, t: T) -> SmallVec<[T; 1]>; // rare
// fn filter_map_t(&mut self, t: T) -> Option<T>; // rarest
//
// Any additions to this trait should happen in form of a call to a public
// `noop_*` function that only calls out to the visitor again, not other
// `noop_*` functions. This is a necessary API workaround to the problem of
// not being able to call out to the super default method in an overridden
// default method.
//
// When writing these methods, it is better to use destructuring like this:
//
// fn visit_abc(&mut self, ABC { a, b, c: _ }: &mut ABC) {
// visit_a(a);
// visit_b(b);
// }
//
// than to use field access like this:
//
// fn visit_abc(&mut self, abc: &mut ABC) {
// visit_a(&mut abc.a);
// visit_b(&mut abc.b);
// // ignore abc.c
// }
//
// As well as being more concise, the former is explicit about which fields
// are skipped. Furthermore, if a new field is added, the destructuring
// version will cause a compile error, which is good. In comparison, the
// field access version will continue working and it would be easy to
// forget to add handling for it.
fn visit_crate(&mut self, c: &mut Crate) {
noop_visit_crate(c, self)
}
fn visit_meta_list_item(&mut self, list_item: &mut NestedMetaItem) {
noop_visit_meta_list_item(list_item, self);
}
fn visit_meta_item(&mut self, meta_item: &mut MetaItem) {
noop_visit_meta_item(meta_item, self);
}
fn visit_use_tree(&mut self, use_tree: &mut UseTree) {
noop_visit_use_tree(use_tree, self);
}
fn flat_map_foreign_item(&mut self, ni: ForeignItem) -> SmallVec<[ForeignItem; 1]> {
noop_flat_map_foreign_item(ni, self)
}
fn flat_map_item(&mut self, i: P<Item>) -> SmallVec<[P<Item>; 1]> {
noop_flat_map_item(i, self)
}
fn visit_fn_header(&mut self, header: &mut FnHeader) {
noop_visit_fn_header(header, self);
}
fn flat_map_struct_field(&mut self, sf: StructField) -> SmallVec<[StructField; 1]> {
noop_flat_map_struct_field(sf, self)
}
fn visit_item_kind(&mut self, i: &mut ItemKind) {
noop_visit_item_kind(i, self);
}
fn flat_map_trait_item(&mut self, i: TraitItem) -> SmallVec<[TraitItem; 1]> {
noop_flat_map_trait_item(i, self)
}
fn flat_map_impl_item(&mut self, i: ImplItem) -> SmallVec<[ImplItem; 1]> {
noop_flat_map_impl_item(i, self)
}
fn visit_fn_decl(&mut self, d: &mut P<FnDecl>) {
noop_visit_fn_decl(d, self);
}
fn visit_asyncness(&mut self, a: &mut IsAsync) {
noop_visit_asyncness(a, self);
}
fn visit_block(&mut self, b: &mut P<Block>) {
noop_visit_block(b, self);
}
fn flat_map_stmt(&mut self, s: Stmt) -> SmallVec<[Stmt; 1]> {
noop_flat_map_stmt(s, self)
}
fn flat_map_arm(&mut self, arm: Arm) -> SmallVec<[Arm; 1]> {
noop_flat_map_arm(arm, self)
}
fn visit_pat(&mut self, p: &mut P<Pat>) {
noop_visit_pat(p, self);
}
fn visit_anon_const(&mut self, c: &mut AnonConst) {
noop_visit_anon_const(c, self);
}
fn visit_expr(&mut self, e: &mut P<Expr>) {
noop_visit_expr(e, self);
}
fn filter_map_expr(&mut self, e: P<Expr>) -> Option<P<Expr>> {
noop_filter_map_expr(e, self)
}
fn visit_generic_arg(&mut self, arg: &mut GenericArg) {
noop_visit_generic_arg(arg, self);
}
fn visit_ty(&mut self, t: &mut P<Ty>) {
noop_visit_ty(t, self);
}
fn visit_lifetime(&mut self, l: &mut Lifetime) {
noop_visit_lifetime(l, self);
}
fn visit_ty_constraint(&mut self, t: &mut AssocTyConstraint) {
noop_visit_ty_constraint(t, self);
}
fn visit_mod(&mut self, m: &mut Mod) {
noop_visit_mod(m, self);
}
fn visit_foreign_mod(&mut self, nm: &mut ForeignMod) {
noop_visit_foreign_mod(nm, self);
}
fn flat_map_variant(&mut self, v: Variant) -> SmallVec<[Variant; 1]> {
noop_flat_map_variant(v, self)
}
fn visit_ident(&mut self, i: &mut Ident) {
noop_visit_ident(i, self);
}
fn visit_path(&mut self, p: &mut Path) {
noop_visit_path(p, self);
}
fn visit_qself(&mut self, qs: &mut Option<QSelf>) {
noop_visit_qself(qs, self);
}
fn visit_generic_args(&mut self, p: &mut GenericArgs) {
noop_visit_generic_args(p, self);
}
fn visit_angle_bracketed_parameter_data(&mut self, p: &mut AngleBracketedArgs) {
noop_visit_angle_bracketed_parameter_data(p, self);
}
fn visit_parenthesized_parameter_data(&mut self, p: &mut ParenthesizedArgs) {
noop_visit_parenthesized_parameter_data(p, self);
}
fn visit_local(&mut self, l: &mut P<Local>) {
noop_visit_local(l, self);
}
fn visit_mac(&mut self, _mac: &mut Mac) {
panic!("visit_mac disabled by default");
// N.B., see note about macros above. If you really want a visitor that
// works on macros, use this definition in your trait impl:
// mut_visit::noop_visit_mac(_mac, self);
}
fn visit_macro_def(&mut self, def: &mut MacroDef) {
noop_visit_macro_def(def, self);
}
fn visit_label(&mut self, label: &mut Label) {
noop_visit_label(label, self);
}
fn visit_attribute(&mut self, at: &mut Attribute) {
noop_visit_attribute(at, self);
}
fn flat_map_param(&mut self, param: Param) -> SmallVec<[Param; 1]> {
noop_flat_map_param(param, self)
}
fn visit_generics(&mut self, generics: &mut Generics) {
noop_visit_generics(generics, self);
}
fn visit_trait_ref(&mut self, tr: &mut TraitRef) {
noop_visit_trait_ref(tr, self);
}
fn visit_poly_trait_ref(&mut self, p: &mut PolyTraitRef) {
noop_visit_poly_trait_ref(p, self);
}
fn visit_variant_data(&mut self, vdata: &mut VariantData) {
noop_visit_variant_data(vdata, self);
}
fn flat_map_generic_param(&mut self, param: GenericParam) -> SmallVec<[GenericParam; 1]> {
noop_flat_map_generic_param(param, self)
}
fn visit_tt(&mut self, tt: &mut TokenTree) {
noop_visit_tt(tt, self);
}
fn visit_tts(&mut self, tts: &mut TokenStream) {
noop_visit_tts(tts, self);
}
fn visit_token(&mut self, t: &mut Token) {
noop_visit_token(t, self);
}
fn visit_interpolated(&mut self, nt: &mut token::Nonterminal) {
noop_visit_interpolated(nt, self);
}
fn visit_param_bound(&mut self, tpb: &mut GenericBound) {
noop_visit_param_bound(tpb, self);
}
fn visit_mt(&mut self, mt: &mut MutTy) {
noop_visit_mt(mt, self);
}
fn flat_map_field(&mut self, f: Field) -> SmallVec<[Field; 1]> {
noop_flat_map_field(f, self)
}
fn visit_where_clause(&mut self, where_clause: &mut WhereClause) {
noop_visit_where_clause(where_clause, self);
}
fn visit_where_predicate(&mut self, where_predicate: &mut WherePredicate) {
noop_visit_where_predicate(where_predicate, self);
}
fn visit_vis(&mut self, vis: &mut Visibility) {
noop_visit_vis(vis, self);
}
fn visit_id(&mut self, _id: &mut NodeId) {
// Do nothing.
}
fn visit_span(&mut self, _sp: &mut Span) {
// Do nothing.
}
fn flat_map_field_pattern(&mut self, fp: FieldPat) -> SmallVec<[FieldPat; 1]> {
noop_flat_map_field_pattern(fp, self)
}
}
/// Use a map-style function (`FnOnce(T) -> T`) to overwrite a `&mut T`. Useful
/// when using a `flat_map_*` or `filter_map_*` method within a `visit_`
/// method. Abort the program if the closure panics.
//
// No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
pub fn visit_clobber<T, F>(t: &mut T, f: F) where F: FnOnce(T) -> T {
unsafe {
// Safe because `t` is used in a read-only fashion by `read()` before
// being overwritten by `write()`.
let old_t = ptr::read(t);
let new_t = panic::catch_unwind(panic::AssertUnwindSafe(|| f(old_t)))
.unwrap_or_else(|_| process::abort());
ptr::write(t, new_t);
}
}
// No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
#[inline]
pub fn visit_vec<T, F>(elems: &mut Vec<T>, mut visit_elem: F) where F: FnMut(&mut T) {
for elem in elems {
visit_elem(elem);
}
}
// No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
#[inline]
pub fn visit_opt<T, F>(opt: &mut Option<T>, mut visit_elem: F) where F: FnMut(&mut T) {
if let Some(elem) = opt {
visit_elem(elem);
}
}
// No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
pub fn visit_attrs<T: MutVisitor>(attrs: &mut Vec<Attribute>, vis: &mut T) {
visit_vec(attrs, |attr| vis.visit_attribute(attr));
}
// No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
pub fn visit_thin_attrs<T: MutVisitor>(attrs: &mut ThinVec<Attribute>, vis: &mut T) {
for attr in attrs.iter_mut() {
vis.visit_attribute(attr);
}
}
// No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
pub fn visit_exprs<T: MutVisitor>(exprs: &mut Vec<P<Expr>>, vis: &mut T) {
exprs.flat_map_in_place(|expr| vis.filter_map_expr(expr))
}
// No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
pub fn visit_bounds<T: MutVisitor>(bounds: &mut GenericBounds, vis: &mut T) {
visit_vec(bounds, |bound| vis.visit_param_bound(bound));
}
// No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
pub fn visit_fn_sig<T: MutVisitor>(FnSig { header, decl }: &mut FnSig, vis: &mut T) {
vis.visit_fn_header(header);
vis.visit_fn_decl(decl);
}
// No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
pub fn visit_mac_args<T: MutVisitor>(args: &mut MacArgs, vis: &mut T) {
match args {
MacArgs::Empty => {}
MacArgs::Delimited(dspan, _delim, tokens) => {
visit_delim_span(dspan, vis);
vis.visit_tts(tokens);
}
MacArgs::Eq(eq_span, tokens) => {
vis.visit_span(eq_span);
vis.visit_tts(tokens);
}
}
}
pub fn visit_delim_span<T: MutVisitor>(dspan: &mut DelimSpan, vis: &mut T) {
vis.visit_span(&mut dspan.open);
vis.visit_span(&mut dspan.close);
}
pub fn noop_flat_map_field_pattern<T: MutVisitor>(
mut fp: FieldPat,
vis: &mut T,
) -> SmallVec<[FieldPat; 1]> {
let FieldPat {
attrs,
id,
ident,
is_placeholder: _,
is_shorthand: _,
pat,
span,
} = &mut fp;
vis.visit_id(id);
vis.visit_ident(ident);
vis.visit_pat(pat);
vis.visit_span(span);
visit_thin_attrs(attrs, vis);
smallvec![fp]
}
pub fn noop_visit_use_tree<T: MutVisitor>(use_tree: &mut UseTree, vis: &mut T) {
let UseTree { prefix, kind, span } = use_tree;
vis.visit_path(prefix);
match kind {
UseTreeKind::Simple(rename, id1, id2) => {
visit_opt(rename, |rename| vis.visit_ident(rename));
vis.visit_id(id1);
vis.visit_id(id2);
}
UseTreeKind::Nested(items) => {
for (tree, id) in items {
vis.visit_use_tree(tree);
vis.visit_id(id);
}
}
UseTreeKind::Glob => {}
}
vis.visit_span(span);
}
pub fn noop_flat_map_arm<T: MutVisitor>(mut arm: Arm, vis: &mut T) -> SmallVec<[Arm; 1]> {
let Arm { attrs, pat, guard, body, span, id, is_placeholder: _ } = &mut arm;
visit_attrs(attrs, vis);
vis.visit_id(id);
vis.visit_pat(pat);
visit_opt(guard, |guard| vis.visit_expr(guard));
vis.visit_expr(body);
vis.visit_span(span);
smallvec![arm]
}
pub fn noop_visit_ty_constraint<T: MutVisitor>(
AssocTyConstraint { id, ident, kind, span }: &mut AssocTyConstraint,
vis: &mut T
) {
vis.visit_id(id);
vis.visit_ident(ident);
match kind {
AssocTyConstraintKind::Equality { ref mut ty } => {
vis.visit_ty(ty);
}
AssocTyConstraintKind::Bound { ref mut bounds } => {
visit_bounds(bounds, vis);
}
}
vis.visit_span(span);
}
pub fn noop_visit_ty<T: MutVisitor>(ty: &mut P<Ty>, vis: &mut T) {
let Ty { id, kind, span } = ty.deref_mut();
vis.visit_id(id);
match kind {
TyKind::Infer | TyKind::ImplicitSelf | TyKind::Err |
TyKind::Never | TyKind::CVarArgs => {}
TyKind::Slice(ty) => vis.visit_ty(ty),
TyKind::Ptr(mt) => vis.visit_mt(mt),
TyKind::Rptr(lt, mt) => {
visit_opt(lt, |lt| noop_visit_lifetime(lt, vis));
vis.visit_mt(mt);
}
TyKind::BareFn(bft) => {
let BareFnTy { unsafety: _, ext: _, generic_params, decl } = bft.deref_mut();
generic_params.flat_map_in_place(|param| vis.flat_map_generic_param(param));
vis.visit_fn_decl(decl);
}
TyKind::Tup(tys) => visit_vec(tys, |ty| vis.visit_ty(ty)),
TyKind::Paren(ty) => vis.visit_ty(ty),
TyKind::Path(qself, path) => {
vis.visit_qself(qself);
vis.visit_path(path);
}
TyKind::Array(ty, length) => {
vis.visit_ty(ty);
vis.visit_anon_const(length);
}
TyKind::Typeof(expr) => vis.visit_anon_const(expr),
TyKind::TraitObject(bounds, _syntax) =>
visit_vec(bounds, |bound| vis.visit_param_bound(bound)),
TyKind::ImplTrait(id, bounds) => {
vis.visit_id(id);
visit_vec(bounds, |bound| vis.visit_param_bound(bound));
}
TyKind::Mac(mac) => vis.visit_mac(mac),
}
vis.visit_span(span);
}
pub fn noop_visit_foreign_mod<T: MutVisitor>(foreign_mod: &mut ForeignMod, vis: &mut T) {
let ForeignMod { abi: _, items} = foreign_mod;
items.flat_map_in_place(|item| vis.flat_map_foreign_item(item));
}
pub fn noop_flat_map_variant<T: MutVisitor>(mut variant: Variant, visitor: &mut T)
-> SmallVec<[Variant; 1]>
{
let Variant { ident, vis, attrs, id, data, disr_expr, span, is_placeholder: _ } = &mut variant;
visitor.visit_ident(ident);
visitor.visit_vis(vis);
visit_attrs(attrs, visitor);
visitor.visit_id(id);
visitor.visit_variant_data(data);
visit_opt(disr_expr, |disr_expr| visitor.visit_anon_const(disr_expr));
visitor.visit_span(span);
smallvec![variant]
}
pub fn noop_visit_ident<T: MutVisitor>(Ident { name: _, span }: &mut Ident, vis: &mut T) {
vis.visit_span(span);
}
pub fn noop_visit_path<T: MutVisitor>(Path { segments, span }: &mut Path, vis: &mut T) {
vis.visit_span(span);
for PathSegment { ident, id, args } in segments {
vis.visit_ident(ident);
vis.visit_id(id);
visit_opt(args, |args| vis.visit_generic_args(args));
}
}
pub fn noop_visit_qself<T: MutVisitor>(qself: &mut Option<QSelf>, vis: &mut T) {
visit_opt(qself, |QSelf { ty, path_span, position: _ }| {
vis.visit_ty(ty);
vis.visit_span(path_span);
})
}
pub fn noop_visit_generic_args<T: MutVisitor>(generic_args: &mut GenericArgs, vis: &mut T) {
match generic_args {
GenericArgs::AngleBracketed(data) => vis.visit_angle_bracketed_parameter_data(data),
GenericArgs::Parenthesized(data) => vis.visit_parenthesized_parameter_data(data),
}
}
pub fn noop_visit_generic_arg<T: MutVisitor>(arg: &mut GenericArg, vis: &mut T) {
match arg {
GenericArg::Lifetime(lt) => vis.visit_lifetime(lt),
GenericArg::Type(ty) => vis.visit_ty(ty),
GenericArg::Const(ct) => vis.visit_anon_const(ct),
}
}
pub fn noop_visit_angle_bracketed_parameter_data<T: MutVisitor>(data: &mut AngleBracketedArgs,
vis: &mut T) {
let AngleBracketedArgs { args, constraints, span } = data;
visit_vec(args, |arg| vis.visit_generic_arg(arg));
visit_vec(constraints, |constraint| vis.visit_ty_constraint(constraint));
vis.visit_span(span);
}
pub fn noop_visit_parenthesized_parameter_data<T: MutVisitor>(args: &mut ParenthesizedArgs,
vis: &mut T) {
let ParenthesizedArgs { inputs, output, span } = args;
visit_vec(inputs, |input| vis.visit_ty(input));
visit_opt(output, |output| vis.visit_ty(output));
vis.visit_span(span);
}
pub fn noop_visit_local<T: MutVisitor>(local: &mut P<Local>, vis: &mut T) {
let Local { id, pat, ty, init, span, attrs } = local.deref_mut();
vis.visit_id(id);
vis.visit_pat(pat);
visit_opt(ty, |ty| vis.visit_ty(ty));
visit_opt(init, |init| vis.visit_expr(init));
vis.visit_span(span);
visit_thin_attrs(attrs, vis);
}
pub fn noop_visit_attribute<T: MutVisitor>(attr: &mut Attribute, vis: &mut T) {
let Attribute { kind, id: _, style: _, span } = attr;
match kind {
AttrKind::Normal(AttrItem { path, args }) => {
vis.visit_path(path);
visit_mac_args(args, vis);
}
AttrKind::DocComment(_) => {}
}
vis.visit_span(span);
}
pub fn noop_visit_mac<T: MutVisitor>(mac: &mut Mac, vis: &mut T) {
let Mac { path, args, prior_type_ascription: _ } = mac;
vis.visit_path(path);
visit_mac_args(args, vis);
}
pub fn noop_visit_macro_def<T: MutVisitor>(macro_def: &mut MacroDef, vis: &mut T) {
let MacroDef { body, legacy: _ } = macro_def;
visit_mac_args(body, vis);
}
pub fn noop_visit_meta_list_item<T: MutVisitor>(li: &mut NestedMetaItem, vis: &mut T) {
match li {
NestedMetaItem::MetaItem(mi) => vis.visit_meta_item(mi),
NestedMetaItem::Literal(_lit) => {}
}
}
pub fn noop_visit_meta_item<T: MutVisitor>(mi: &mut MetaItem, vis: &mut T) {
let MetaItem { path: _, kind, span } = mi;
match kind {
MetaItemKind::Word => {}
MetaItemKind::List(mis) => visit_vec(mis, |mi| vis.visit_meta_list_item(mi)),
MetaItemKind::NameValue(_s) => {}
}
vis.visit_span(span);
}
pub fn noop_flat_map_param<T: MutVisitor>(mut param: Param, vis: &mut T) -> SmallVec<[Param; 1]> {
let Param { attrs, id, pat, span, ty, is_placeholder: _ } = &mut param;
vis.visit_id(id);
visit_thin_attrs(attrs, vis);
vis.visit_pat(pat);
vis.visit_span(span);
vis.visit_ty(ty);
smallvec![param]
}
pub fn noop_visit_tt<T: MutVisitor>(tt: &mut TokenTree, vis: &mut T) {
match tt {
TokenTree::Token(token) => {
vis.visit_token(token);
}
TokenTree::Delimited(DelimSpan { open, close }, _delim, tts) => {
vis.visit_span(open);
vis.visit_span(close);
vis.visit_tts(tts);
}
}
}
pub fn noop_visit_tts<T: MutVisitor>(TokenStream(tts): &mut TokenStream, vis: &mut T) {
let tts = Lrc::make_mut(tts);
visit_vec(tts, |(tree, _is_joint)| vis.visit_tt(tree));
}
// Applies ident visitor if it's an ident; applies other visits to interpolated nodes.
// In practice the ident part is not actually used by specific visitors right now,
// but there's a test below checking that it works.
pub fn noop_visit_token<T: MutVisitor>(t: &mut Token, vis: &mut T) {
let Token { kind, span } = t;
match kind {
token::Ident(name, _) | token::Lifetime(name) => {
let mut ident = Ident::new(*name, *span);
vis.visit_ident(&mut ident);
*name = ident.name;
*span = ident.span;
return; // Avoid visiting the span for the second time.
}
token::Interpolated(nt) => {
let mut nt = Lrc::make_mut(nt);
vis.visit_interpolated(&mut nt);
}
_ => {}
}
vis.visit_span(span);
}
/// Applies the visitor to elements of interpolated nodes.
//
// N.B., this can occur only when applying a visitor to partially expanded
// code, where parsed pieces have gotten implanted ito *other* macro
// invocations. This is relevant for macro hygiene, but possibly not elsewhere.
//
// One problem here occurs because the types for flat_map_item, flat_map_stmt,
// etc., allow the visitor to return *multiple* items; this is a problem for the
// nodes here, because they insist on having exactly one piece. One solution
// would be to mangle the MutVisitor trait to include one-to-many and
// one-to-one versions of these entry points, but that would probably confuse a
// lot of people and help very few. Instead, I'm just going to put in dynamic
// checks. I think the performance impact of this will be pretty much
// nonexistent. The danger is that someone will apply a `MutVisitor` to a
// partially expanded node, and will be confused by the fact that their
// `flat_map_item` or `flat_map_stmt` isn't getting called on `NtItem` or `NtStmt`
// nodes. Hopefully they'll wind up reading this comment, and doing something
// appropriate.
//
// BTW, design choice: I considered just changing the type of, e.g., `NtItem` to
// contain multiple items, but decided against it when I looked at
// `parse_item_or_view_item` and tried to figure out what I would do with
// multiple items there....
pub fn noop_visit_interpolated<T: MutVisitor>(nt: &mut token::Nonterminal, vis: &mut T) {
match nt {
token::NtItem(item) =>
visit_clobber(item, |item| {
// This is probably okay, because the only visitors likely to
// peek inside interpolated nodes will be renamings/markings,
// which map single items to single items.
vis.flat_map_item(item).expect_one("expected visitor to produce exactly one item")
}),
token::NtBlock(block) => vis.visit_block(block),
token::NtStmt(stmt) =>
visit_clobber(stmt, |stmt| {
// See reasoning above.
vis.flat_map_stmt(stmt).expect_one("expected visitor to produce exactly one item")
}),
token::NtPat(pat) => vis.visit_pat(pat),
token::NtExpr(expr) => vis.visit_expr(expr),
token::NtTy(ty) => vis.visit_ty(ty),
token::NtIdent(ident, _is_raw) => vis.visit_ident(ident),
token::NtLifetime(ident) => vis.visit_ident(ident),
token::NtLiteral(expr) => vis.visit_expr(expr),
token::NtMeta(AttrItem { path, args }) => {
vis.visit_path(path);
visit_mac_args(args, vis);
}
token::NtPath(path) => vis.visit_path(path),
token::NtTT(tt) => vis.visit_tt(tt),
token::NtImplItem(item) =>
visit_clobber(item, |item| {
// See reasoning above.
vis.flat_map_impl_item(item)
.expect_one("expected visitor to produce exactly one item")
}),
token::NtTraitItem(item) =>
visit_clobber(item, |item| {
// See reasoning above.
vis.flat_map_trait_item(item)
.expect_one("expected visitor to produce exactly one item")
}),
token::NtVis(visib) => vis.visit_vis(visib),
token::NtForeignItem(item) =>
visit_clobber(item, |item| {
// See reasoning above.
vis.flat_map_foreign_item(item)
.expect_one("expected visitor to produce exactly one item")
}),
}
}
pub fn noop_visit_asyncness<T: MutVisitor>(asyncness: &mut IsAsync, vis: &mut T) {
match asyncness {
IsAsync::Async { closure_id, return_impl_trait_id } => {
vis.visit_id(closure_id);
vis.visit_id(return_impl_trait_id);
}
IsAsync::NotAsync => {}
}
}
pub fn noop_visit_fn_decl<T: MutVisitor>(decl: &mut P<FnDecl>, vis: &mut T) {
let FnDecl { inputs, output } = decl.deref_mut();
inputs.flat_map_in_place(|param| vis.flat_map_param(param));
match output {
FunctionRetTy::Default(span) => vis.visit_span(span),
FunctionRetTy::Ty(ty) => vis.visit_ty(ty),
}
}
pub fn noop_visit_param_bound<T: MutVisitor>(pb: &mut GenericBound, vis: &mut T) {
match pb {
GenericBound::Trait(ty, _modifier) => vis.visit_poly_trait_ref(ty),
GenericBound::Outlives(lifetime) => noop_visit_lifetime(lifetime, vis),
}
}
pub fn noop_flat_map_generic_param<T: MutVisitor>(
mut param: GenericParam,
vis: &mut T
) -> SmallVec<[GenericParam; 1]>
{
let GenericParam { id, ident, attrs, bounds, kind, is_placeholder: _ } = &mut param;
vis.visit_id(id);
vis.visit_ident(ident);
visit_thin_attrs(attrs, vis);
visit_vec(bounds, |bound| noop_visit_param_bound(bound, vis));
match kind {
GenericParamKind::Lifetime => {}
GenericParamKind::Type { default } => {
visit_opt(default, |default| vis.visit_ty(default));
}
GenericParamKind::Const { ty } => {
vis.visit_ty(ty);
}
}
smallvec![param]
}
pub fn noop_visit_label<T: MutVisitor>(Label { ident }: &mut Label, vis: &mut T) {
vis.visit_ident(ident);
}
fn noop_visit_lifetime<T: MutVisitor>(Lifetime { id, ident }: &mut Lifetime, vis: &mut T) {
vis.visit_id(id);
vis.visit_ident(ident);
}
pub fn noop_visit_generics<T: MutVisitor>(generics: &mut Generics, vis: &mut T) {
let Generics { params, where_clause, span } = generics;
params.flat_map_in_place(|param| vis.flat_map_generic_param(param));
vis.visit_where_clause(where_clause);
vis.visit_span(span);
}
pub fn noop_visit_where_clause<T: MutVisitor>(wc: &mut WhereClause, vis: &mut T) {
let WhereClause { predicates, span } = wc;
visit_vec(predicates, |predicate| vis.visit_where_predicate(predicate));
vis.visit_span(span);
}
pub fn noop_visit_where_predicate<T: MutVisitor>(pred: &mut WherePredicate, vis: &mut T) {
match pred {
WherePredicate::BoundPredicate(bp) => {
let WhereBoundPredicate { span, bound_generic_params, bounded_ty, bounds } = bp;
vis.visit_span(span);
bound_generic_params.flat_map_in_place(|param| vis.flat_map_generic_param(param));
vis.visit_ty(bounded_ty);
visit_vec(bounds, |bound| vis.visit_param_bound(bound));
}
WherePredicate::RegionPredicate(rp) => {
let WhereRegionPredicate { span, lifetime, bounds } = rp;
vis.visit_span(span);
noop_visit_lifetime(lifetime, vis);
visit_vec(bounds, |bound| noop_visit_param_bound(bound, vis));
}
WherePredicate::EqPredicate(ep) => {
let WhereEqPredicate { id, span, lhs_ty, rhs_ty } = ep;
vis.visit_id(id);
vis.visit_span(span);
vis.visit_ty(lhs_ty);
vis.visit_ty(rhs_ty);
}
}
}
pub fn noop_visit_variant_data<T: MutVisitor>(vdata: &mut VariantData, vis: &mut T) {
match vdata {
VariantData::Struct(fields, ..) => {
fields.flat_map_in_place(|field| vis.flat_map_struct_field(field));
},
VariantData::Tuple(fields, id) => {
fields.flat_map_in_place(|field| vis.flat_map_struct_field(field));
vis.visit_id(id);
},
VariantData::Unit(id) => vis.visit_id(id),
}
}
pub fn noop_visit_trait_ref<T: MutVisitor>(TraitRef { path, ref_id }: &mut TraitRef, vis: &mut T) {
vis.visit_path(path);
vis.visit_id(ref_id);
}
pub fn noop_visit_poly_trait_ref<T: MutVisitor>(p: &mut PolyTraitRef, vis: &mut T) {
let PolyTraitRef { bound_generic_params, trait_ref, span } = p;
bound_generic_params.flat_map_in_place(|param| vis.flat_map_generic_param(param));
vis.visit_trait_ref(trait_ref);
vis.visit_span(span);
}
pub fn noop_flat_map_struct_field<T: MutVisitor>(mut sf: StructField, visitor: &mut T)
-> SmallVec<[StructField; 1]>
{
let StructField { span, ident, vis, id, ty, attrs, is_placeholder: _ } = &mut sf;
visitor.visit_span(span);
visit_opt(ident, |ident| visitor.visit_ident(ident));
visitor.visit_vis(vis);
visitor.visit_id(id);
visitor.visit_ty(ty);
visit_attrs(attrs, visitor);
smallvec![sf]
}
pub fn noop_flat_map_field<T: MutVisitor>(mut f: Field, vis: &mut T) -> SmallVec<[Field; 1]> {
let Field { ident, expr, span, is_shorthand: _, attrs, id, is_placeholder: _ } = &mut f;
vis.visit_ident(ident);
vis.visit_expr(expr);
vis.visit_id(id);
vis.visit_span(span);
visit_thin_attrs(attrs, vis);
smallvec![f]
}
pub fn noop_visit_mt<T: MutVisitor>(MutTy { ty, mutbl: _ }: &mut MutTy, vis: &mut T) {
vis.visit_ty(ty);
}
pub fn noop_visit_block<T: MutVisitor>(block: &mut P<Block>, vis: &mut T) {
let Block { id, stmts, rules: _, span } = block.deref_mut();
vis.visit_id(id);
stmts.flat_map_in_place(|stmt| vis.flat_map_stmt(stmt));
vis.visit_span(span);
}
pub fn noop_visit_item_kind<T: MutVisitor>(kind: &mut ItemKind, vis: &mut T) {
match kind {
ItemKind::ExternCrate(_orig_name) => {}
ItemKind::Use(use_tree) => vis.visit_use_tree(use_tree),
ItemKind::Static(ty, _mut, expr) => {
vis.visit_ty(ty);
vis.visit_expr(expr);
}
ItemKind::Const(ty, expr) => {
vis.visit_ty(ty);
vis.visit_expr(expr);
}
ItemKind::Fn(sig, generics, body) => {
visit_fn_sig(sig, vis);
vis.visit_generics(generics);
vis.visit_block(body);
}
ItemKind::Mod(m) => vis.visit_mod(m),
ItemKind::ForeignMod(nm) => vis.visit_foreign_mod(nm),
ItemKind::GlobalAsm(_ga) => {}
ItemKind::TyAlias(ty, generics) => {
vis.visit_ty(ty);
vis.visit_generics(generics);
}
ItemKind::Enum(EnumDef { variants }, generics) => {
variants.flat_map_in_place(|variant| vis.flat_map_variant(variant));
vis.visit_generics(generics);
}
ItemKind::Struct(variant_data, generics) |
ItemKind::Union(variant_data, generics) => {
vis.visit_variant_data(variant_data);
vis.visit_generics(generics);
}
ItemKind::Impl(_unsafety, _polarity, _defaultness, generics, trait_ref, ty, items) => {
vis.visit_generics(generics);
visit_opt(trait_ref, |trait_ref| vis.visit_trait_ref(trait_ref));
vis.visit_ty(ty);
items.flat_map_in_place(|item| vis.flat_map_impl_item(item));
}
ItemKind::Trait(_is_auto, _unsafety, generics, bounds, items) => {
vis.visit_generics(generics);
visit_bounds(bounds, vis);
items.flat_map_in_place(|item| vis.flat_map_trait_item(item));
}
ItemKind::TraitAlias(generics, bounds) => {
vis.visit_generics(generics);
visit_bounds(bounds, vis);
}
ItemKind::Mac(m) => vis.visit_mac(m),
ItemKind::MacroDef(def) => vis.visit_macro_def(def),
}
}
pub fn noop_flat_map_trait_item<T: MutVisitor>(mut item: TraitItem, visitor: &mut T)
-> SmallVec<[TraitItem; 1]>
{
let TraitItem { id, ident, vis, attrs, generics, kind, span, tokens: _ } = &mut item;
visitor.visit_id(id);
visitor.visit_ident(ident);
visitor.visit_vis(vis);
visit_attrs(attrs, visitor);
visitor.visit_generics(generics);
match kind {
TraitItemKind::Const(ty, default) => {
visitor.visit_ty(ty);
visit_opt(default, |default| visitor.visit_expr(default));
}
TraitItemKind::Method(sig, body) => {
visit_fn_sig(sig, visitor);
visit_opt(body, |body| visitor.visit_block(body));
}
TraitItemKind::Type(bounds, default) => {
visit_bounds(bounds, visitor);
visit_opt(default, |default| visitor.visit_ty(default));
}
TraitItemKind::Macro(mac) => {
visitor.visit_mac(mac);
}
}
visitor.visit_span(span);
smallvec![item]
}
pub fn noop_flat_map_impl_item<T: MutVisitor>(mut item: ImplItem, visitor: &mut T)
-> SmallVec<[ImplItem; 1]>
{
let ImplItem { id, ident, vis, defaultness: _, attrs, generics, kind, span, tokens: _ } =
&mut item;
visitor.visit_id(id);
visitor.visit_ident(ident);
visitor.visit_vis(vis);
visit_attrs(attrs, visitor);
visitor.visit_generics(generics);
match kind {
ImplItemKind::Const(ty, expr) => {
visitor.visit_ty(ty);
visitor.visit_expr(expr);
}
ImplItemKind::Method(sig, body) => {
visit_fn_sig(sig, visitor);
visitor.visit_block(body);
}
ImplItemKind::TyAlias(ty) => visitor.visit_ty(ty),
ImplItemKind::Macro(mac) => visitor.visit_mac(mac),
}
visitor.visit_span(span);
smallvec![item]
}
pub fn noop_visit_fn_header<T: MutVisitor>(header: &mut FnHeader, vis: &mut T) {
let FnHeader { unsafety: _, asyncness, constness: _, ext: _ } = header;
vis.visit_asyncness(&mut asyncness.node);
}
pub fn noop_visit_mod<T: MutVisitor>(Mod { inner, items, inline: _ }: &mut Mod, vis: &mut T) {
vis.visit_span(inner);
items.flat_map_in_place(|item| vis.flat_map_item(item));
}
pub fn noop_visit_crate<T: MutVisitor>(krate: &mut Crate, vis: &mut T) {
visit_clobber(krate, |Crate { module, attrs, span }| {
let item = P(Item {
ident: Ident::invalid(),
attrs,
id: DUMMY_NODE_ID,
vis: respan(span.shrink_to_lo(), VisibilityKind::Public),
span,
kind: ItemKind::Mod(module),
tokens: None,
});
let items = vis.flat_map_item(item);
let len = items.len();
if len == 0 {
let module = Mod { inner: span, items: vec![], inline: true };
Crate { module, attrs: vec![], span }
} else if len == 1 {
let Item { attrs, span, kind, .. } = items.into_iter().next().unwrap().into_inner();
match kind {
ItemKind::Mod(module) => Crate { module, attrs, span },
_ => panic!("visitor converted a module to not a module"),
}
} else {
panic!("a crate cannot expand to more than one item");
}
});
}
// Mutates one item into possibly many items.
pub fn noop_flat_map_item<T: MutVisitor>(mut item: P<Item>, visitor: &mut T)
-> SmallVec<[P<Item>; 1]> {
let Item { ident, attrs, id, kind, vis, span, tokens: _ } = item.deref_mut();
visitor.visit_ident(ident);
visit_attrs(attrs, visitor);
visitor.visit_id(id);
visitor.visit_item_kind(kind);
visitor.visit_vis(vis);
visitor.visit_span(span);
// FIXME: if `tokens` is modified with a call to `vis.visit_tts` it causes
// an ICE during resolve... odd!
smallvec![item]
}
pub fn noop_flat_map_foreign_item<T: MutVisitor>(mut item: ForeignItem, visitor: &mut T)
-> SmallVec<[ForeignItem; 1]>
{
let ForeignItem { ident, attrs, id, kind, vis, span, tokens: _ } = &mut item;
visitor.visit_ident(ident);
visit_attrs(attrs, visitor);
match kind {
ForeignItemKind::Fn(fdec, generics) => {
visitor.visit_fn_decl(fdec);
visitor.visit_generics(generics);
}
ForeignItemKind::Static(t, _m) => visitor.visit_ty(t),
ForeignItemKind::Ty => {}
ForeignItemKind::Macro(mac) => visitor.visit_mac(mac),
}
visitor.visit_id(id);
visitor.visit_span(span);
visitor.visit_vis(vis);
smallvec![item]
}
pub fn noop_visit_pat<T: MutVisitor>(pat: &mut P<Pat>, vis: &mut T) {
let Pat { id, kind, span } = pat.deref_mut();
vis.visit_id(id);
match kind {
PatKind::Wild | PatKind::Rest => {}
PatKind::Ident(_binding_mode, ident, sub) => {
vis.visit_ident(ident);
visit_opt(sub, |sub| vis.visit_pat(sub));
}
PatKind::Lit(e) => vis.visit_expr(e),
PatKind::TupleStruct(path, elems) => {
vis.visit_path(path);
visit_vec(elems, |elem| vis.visit_pat(elem));
}
PatKind::Path(qself, path) => {
vis.visit_qself(qself);
vis.visit_path(path);
}
PatKind::Struct(path, fields, _etc) => {
vis.visit_path(path);
fields.flat_map_in_place(|field| vis.flat_map_field_pattern(field));
}
PatKind::Box(inner) => vis.visit_pat(inner),
PatKind::Ref(inner, _mutbl) => vis.visit_pat(inner),
PatKind::Range(e1, e2, Spanned { span: _, node: _ }) => {
vis.visit_expr(e1);
vis.visit_expr(e2);
vis.visit_span(span);
}
PatKind::Tuple(elems)
| PatKind::Slice(elems)
| PatKind::Or(elems) => visit_vec(elems, |elem| vis.visit_pat(elem)),
PatKind::Paren(inner) => vis.visit_pat(inner),
PatKind::Mac(mac) => vis.visit_mac(mac),
}
vis.visit_span(span);
}
pub fn noop_visit_anon_const<T: MutVisitor>(AnonConst { id, value }: &mut AnonConst, vis: &mut T) {
vis.visit_id(id);
vis.visit_expr(value);
}
pub fn noop_visit_expr<T: MutVisitor>(Expr { kind, id, span, attrs }: &mut Expr, vis: &mut T) {
match kind {
ExprKind::Box(expr) => vis.visit_expr(expr),
ExprKind::Array(exprs) => visit_exprs(exprs, vis),
ExprKind::Repeat(expr, count) => {
vis.visit_expr(expr);
vis.visit_anon_const(count);
}
ExprKind::Tup(exprs) => visit_exprs(exprs, vis),
ExprKind::Call(f, args) => {
vis.visit_expr(f);
visit_exprs(args, vis);
}
ExprKind::MethodCall(PathSegment { ident, id, args }, exprs) => {
vis.visit_ident(ident);
vis.visit_id(id);
visit_opt(args, |args| vis.visit_generic_args(args));
visit_exprs(exprs, vis);
}
ExprKind::Binary(_binop, lhs, rhs) => {
vis.visit_expr(lhs);
vis.visit_expr(rhs);
}
ExprKind::Unary(_unop, ohs) => vis.visit_expr(ohs),
ExprKind::Cast(expr, ty) => {
vis.visit_expr(expr);
vis.visit_ty(ty);
}
ExprKind::Type(expr, ty) => {
vis.visit_expr(expr);
vis.visit_ty(ty);
}
ExprKind::AddrOf(_, _, ohs) => vis.visit_expr(ohs),
ExprKind::Let(pat, scrutinee) => {
vis.visit_pat(pat);
vis.visit_expr(scrutinee);
}
ExprKind::If(cond, tr, fl) => {
vis.visit_expr(cond);
vis.visit_block(tr);
visit_opt(fl, |fl| vis.visit_expr(fl));
}
ExprKind::While(cond, body, label) => {
vis.visit_expr(cond);
vis.visit_block(body);
visit_opt(label, |label| vis.visit_label(label));
}
ExprKind::ForLoop(pat, iter, body, label) => {
vis.visit_pat(pat);
vis.visit_expr(iter);
vis.visit_block(body);
visit_opt(label, |label| vis.visit_label(label));
}
ExprKind::Loop(body, label) => {
vis.visit_block(body);
visit_opt(label, |label| vis.visit_label(label));
}
ExprKind::Match(expr, arms) => {
vis.visit_expr(expr);
arms.flat_map_in_place(|arm| vis.flat_map_arm(arm));
}
ExprKind::Closure(_capture_by, asyncness, _movability, decl, body, span) => {
vis.visit_asyncness(asyncness);
vis.visit_fn_decl(decl);
vis.visit_expr(body);
vis.visit_span(span);
}
ExprKind::Block(blk, label) => {
vis.visit_block(blk);
visit_opt(label, |label| vis.visit_label(label));
}
ExprKind::Async(_capture_by, node_id, body) => {
vis.visit_id(node_id);
vis.visit_block(body);
}
ExprKind::Await(expr) => vis.visit_expr(expr),
ExprKind::Assign(el, er) => {
vis.visit_expr(el);
vis.visit_expr(er);
}
ExprKind::AssignOp(_op, el, er) => {
vis.visit_expr(el);
vis.visit_expr(er);
}
ExprKind::Field(el, ident) => {
vis.visit_expr(el);
vis.visit_ident(ident);
}
ExprKind::Index(el, er) => {
vis.visit_expr(el);
vis.visit_expr(er);
}
ExprKind::Range(e1, e2, _lim) => {
visit_opt(e1, |e1| vis.visit_expr(e1));
visit_opt(e2, |e2| vis.visit_expr(e2));
}
ExprKind::Path(qself, path) => {
vis.visit_qself(qself);
vis.visit_path(path);
}
ExprKind::Break(label, expr) => {
visit_opt(label, |label| vis.visit_label(label));
visit_opt(expr, |expr| vis.visit_expr(expr));
}
ExprKind::Continue(label) => {
visit_opt(label, |label| vis.visit_label(label));
}
ExprKind::Ret(expr) => {
visit_opt(expr, |expr| vis.visit_expr(expr));
}
ExprKind::InlineAsm(asm) => {
let InlineAsm { asm: _, asm_str_style: _, outputs, inputs, clobbers: _, volatile: _,
alignstack: _, dialect: _ } = asm.deref_mut();
for out in outputs {
let InlineAsmOutput { constraint: _, expr, is_rw: _, is_indirect: _ } = out;
vis.visit_expr(expr);
}
visit_vec(inputs, |(_c, expr)| vis.visit_expr(expr));
}
ExprKind::Mac(mac) => vis.visit_mac(mac),
ExprKind::Struct(path, fields, expr) => {
vis.visit_path(path);
fields.flat_map_in_place(|field| vis.flat_map_field(field));
visit_opt(expr, |expr| vis.visit_expr(expr));
},
ExprKind::Paren(expr) => {
vis.visit_expr(expr);
// Nodes that are equal modulo `Paren` sugar no-ops should have the same IDs.
*id = expr.id;
vis.visit_span(span);
visit_thin_attrs(attrs, vis);
return;
}
ExprKind::Yield(expr) => {
visit_opt(expr, |expr| vis.visit_expr(expr));
}
ExprKind::Try(expr) => vis.visit_expr(expr),
ExprKind::TryBlock(body) => vis.visit_block(body),
ExprKind::Lit(_) | ExprKind::Err => {}
}
vis.visit_id(id);
vis.visit_span(span);
visit_thin_attrs(attrs, vis);
}
pub fn noop_filter_map_expr<T: MutVisitor>(mut e: P<Expr>, vis: &mut T) -> Option<P<Expr>> {
Some({ vis.visit_expr(&mut e); e })
}
pub fn noop_flat_map_stmt<T: MutVisitor>(Stmt { kind, mut span, mut id }: Stmt, vis: &mut T)
-> SmallVec<[Stmt; 1]>
{
vis.visit_id(&mut id);
vis.visit_span(&mut span);
noop_flat_map_stmt_kind(kind, vis).into_iter().map(|kind| {
Stmt { id, kind, span }
}).collect()
}
pub fn noop_flat_map_stmt_kind<T: MutVisitor>(kind: StmtKind, vis: &mut T)
-> SmallVec<[StmtKind; 1]> {
match kind {
StmtKind::Local(mut local) =>
smallvec![StmtKind::Local({ vis.visit_local(&mut local); local })],
StmtKind::Item(item) => vis.flat_map_item(item).into_iter().map(StmtKind::Item).collect(),
StmtKind::Expr(expr) => {
vis.filter_map_expr(expr).into_iter().map(StmtKind::Expr).collect()
}
StmtKind::Semi(expr) => {
vis.filter_map_expr(expr).into_iter().map(StmtKind::Semi).collect()
}
StmtKind::Mac(mut mac) => {
let (mac_, _semi, attrs) = mac.deref_mut();
vis.visit_mac(mac_);
visit_thin_attrs(attrs, vis);
smallvec![StmtKind::Mac(mac)]
}
}
}
pub fn noop_visit_vis<T: MutVisitor>(Spanned { node, span }: &mut Visibility, vis: &mut T) {
match node {
VisibilityKind::Public | VisibilityKind::Crate(_) | VisibilityKind::Inherited => {}
VisibilityKind::Restricted { path, id } => {
vis.visit_path(path);
vis.visit_id(id);
}
}
vis.visit_span(span);
}