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fuchsia / third_party / rust / eda6dc928323fcd0ac1b51cea1aa79ab17e8519d / . / compiler / rustc_expand / src / expand.rs
blob: dbb4a9de9e03aeb06d11d277ebb133aa72e29b54 [file] [log] [blame]
use std::path::PathBuf;
use std::rc::Rc;
use std::sync::Arc;
use std::{iter, mem, slice};
use rustc_ast::mut_visit::*;
use rustc_ast::tokenstream::TokenStream;
use rustc_ast::visit::{self, AssocCtxt, Visitor, VisitorResult, try_visit, walk_list};
use rustc_ast::{
self as ast, AssocItemKind, AstNodeWrapper, AttrArgs, AttrStyle, AttrVec, DUMMY_NODE_ID,
ExprKind, ForeignItemKind, HasAttrs, HasNodeId, Inline, ItemKind, MacStmtStyle, MetaItemInner,
MetaItemKind, ModKind, NodeId, PatKind, StmtKind, TyKind, token,
};
use rustc_ast_pretty::pprust;
use rustc_attr_parsing::{AttributeParser, Early, EvalConfigResult, ShouldEmit, validate_attr};
use rustc_data_structures::flat_map_in_place::FlatMapInPlace;
use rustc_data_structures::stack::ensure_sufficient_stack;
use rustc_errors::PResult;
use rustc_feature::Features;
use rustc_hir::Target;
use rustc_hir::def::MacroKinds;
use rustc_parse::parser::{
AttemptLocalParseRecovery, CommaRecoveryMode, ForceCollect, Parser, RecoverColon, RecoverComma,
token_descr,
};
use rustc_session::lint::BuiltinLintDiag;
use rustc_session::lint::builtin::{UNUSED_ATTRIBUTES, UNUSED_DOC_COMMENTS};
use rustc_session::parse::feature_err;
use rustc_session::{Limit, Session};
use rustc_span::hygiene::SyntaxContext;
use rustc_span::{ErrorGuaranteed, FileName, Ident, LocalExpnId, Span, Symbol, sym};
use smallvec::SmallVec;
use crate::base::*;
use crate::config::{StripUnconfigured, attr_into_trace};
use crate::errors::{
EmptyDelegationMac, GlobDelegationOutsideImpls, GlobDelegationTraitlessQpath, IncompleteParse,
RecursionLimitReached, RemoveExprNotSupported, RemoveNodeNotSupported, UnsupportedKeyValue,
WrongFragmentKind,
};
use crate::fluent_generated;
use crate::mbe::diagnostics::annotate_err_with_kind;
use crate::module::{
DirOwnership, ParsedExternalMod, mod_dir_path, mod_file_path_from_attr, parse_external_mod,
};
use crate::placeholders::{PlaceholderExpander, placeholder};
use crate::stats::*;
macro_rules! ast_fragments {
(
$($Kind:ident($AstTy:ty) {
$kind_name:expr;
$(one
fn $mut_visit_ast:ident;
fn $visit_ast:ident;
fn $ast_to_string:path;
)?
$(many
fn $flat_map_ast_elt:ident;
fn $visit_ast_elt:ident($($args:tt)*);
fn $ast_to_string_elt:path;
)?
fn $make_ast:ident;
})*
) => {
/// A fragment of AST that can be produced by a single macro expansion.
/// Can also serve as an input and intermediate result for macro expansion operations.
pub enum AstFragment {
OptExpr(Option<Box<ast::Expr>>),
MethodReceiverExpr(Box<ast::Expr>),
$($Kind($AstTy),)*
}
/// "Discriminant" of an AST fragment.
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
pub enum AstFragmentKind {
OptExpr,
MethodReceiverExpr,
$($Kind,)*
}
impl AstFragmentKind {
pub fn name(self) -> &'static str {
match self {
AstFragmentKind::OptExpr => "expression",
AstFragmentKind::MethodReceiverExpr => "expression",
$(AstFragmentKind::$Kind => $kind_name,)*
}
}
fn make_from(self, result: Box<dyn MacResult + '_>) -> Option<AstFragment> {
match self {
AstFragmentKind::OptExpr =>
result.make_expr().map(Some).map(AstFragment::OptExpr),
AstFragmentKind::MethodReceiverExpr =>
result.make_expr().map(AstFragment::MethodReceiverExpr),
$(AstFragmentKind::$Kind => result.$make_ast().map(AstFragment::$Kind),)*
}
}
}
impl AstFragment {
fn add_placeholders(&mut self, placeholders: &[NodeId]) {
if placeholders.is_empty() {
return;
}
match self {
$($(AstFragment::$Kind(ast) => ast.extend(placeholders.iter().flat_map(|id| {
${ignore($flat_map_ast_elt)}
placeholder(AstFragmentKind::$Kind, *id, None).$make_ast()
})),)?)*
_ => panic!("unexpected AST fragment kind")
}
}
pub(crate) fn make_opt_expr(self) -> Option<Box<ast::Expr>> {
match self {
AstFragment::OptExpr(expr) => expr,
_ => panic!("AstFragment::make_* called on the wrong kind of fragment"),
}
}
pub(crate) fn make_method_receiver_expr(self) -> Box<ast::Expr> {
match self {
AstFragment::MethodReceiverExpr(expr) => expr,
_ => panic!("AstFragment::make_* called on the wrong kind of fragment"),
}
}
$(pub fn $make_ast(self) -> $AstTy {
match self {
AstFragment::$Kind(ast) => ast,
_ => panic!("AstFragment::make_* called on the wrong kind of fragment"),
}
})*
fn make_ast<T: InvocationCollectorNode>(self) -> T::OutputTy {
T::fragment_to_output(self)
}
pub(crate) fn mut_visit_with(&mut self, vis: &mut impl MutVisitor) {
match self {
AstFragment::OptExpr(opt_expr) => {
if let Some(expr) = opt_expr.take() {
*opt_expr = vis.filter_map_expr(expr)
}
}
AstFragment::MethodReceiverExpr(expr) => vis.visit_method_receiver_expr(expr),
$($(AstFragment::$Kind(ast) => vis.$mut_visit_ast(ast),)?)*
$($(AstFragment::$Kind(ast) =>
ast.flat_map_in_place(|ast| vis.$flat_map_ast_elt(ast, $($args)*)),)?)*
}
}
pub fn visit_with<'a, V: Visitor<'a>>(&'a self, visitor: &mut V) -> V::Result {
match self {
AstFragment::OptExpr(Some(expr)) => try_visit!(visitor.visit_expr(expr)),
AstFragment::OptExpr(None) => {}
AstFragment::MethodReceiverExpr(expr) => try_visit!(visitor.visit_method_receiver_expr(expr)),
$($(AstFragment::$Kind(ast) => try_visit!(visitor.$visit_ast(ast)),)?)*
$($(AstFragment::$Kind(ast) => walk_list!(visitor, $visit_ast_elt, &ast[..], $($args)*),)?)*
}
V::Result::output()
}
pub(crate) fn to_string(&self) -> String {
match self {
AstFragment::OptExpr(Some(expr)) => pprust::expr_to_string(expr),
AstFragment::OptExpr(None) => unreachable!(),
AstFragment::MethodReceiverExpr(expr) => pprust::expr_to_string(expr),
$($(AstFragment::$Kind(ast) => $ast_to_string(ast),)?)*
$($(
AstFragment::$Kind(ast) => {
// The closure unwraps a `P` if present, or does nothing otherwise.
elems_to_string(&*ast, |ast| $ast_to_string_elt(&*ast))
}
)?)*
}
}
}
impl<'a> MacResult for crate::mbe::macro_rules::ParserAnyMacro<'a> {
$(fn $make_ast(self: Box<crate::mbe::macro_rules::ParserAnyMacro<'a>>)
-> Option<$AstTy> {
Some(self.make(AstFragmentKind::$Kind).$make_ast())
})*
}
}
}
ast_fragments! {
Expr(Box<ast::Expr>) {
"expression";
one fn visit_expr; fn visit_expr; fn pprust::expr_to_string;
fn make_expr;
}
Pat(Box<ast::Pat>) {
"pattern";
one fn visit_pat; fn visit_pat; fn pprust::pat_to_string;
fn make_pat;
}
Ty(Box<ast::Ty>) {
"type";
one fn visit_ty; fn visit_ty; fn pprust::ty_to_string;
fn make_ty;
}
Stmts(SmallVec<[ast::Stmt; 1]>) {
"statement";
many fn flat_map_stmt; fn visit_stmt(); fn pprust::stmt_to_string;
fn make_stmts;
}
Items(SmallVec<[Box<ast::Item>; 1]>) {
"item";
many fn flat_map_item; fn visit_item(); fn pprust::item_to_string;
fn make_items;
}
TraitItems(SmallVec<[Box<ast::AssocItem>; 1]>) {
"trait item";
many fn flat_map_assoc_item; fn visit_assoc_item(AssocCtxt::Trait);
fn pprust::assoc_item_to_string;
fn make_trait_items;
}
ImplItems(SmallVec<[Box<ast::AssocItem>; 1]>) {
"impl item";
many fn flat_map_assoc_item; fn visit_assoc_item(AssocCtxt::Impl { of_trait: false });
fn pprust::assoc_item_to_string;
fn make_impl_items;
}
TraitImplItems(SmallVec<[Box<ast::AssocItem>; 1]>) {
"impl item";
many fn flat_map_assoc_item; fn visit_assoc_item(AssocCtxt::Impl { of_trait: true });
fn pprust::assoc_item_to_string;
fn make_trait_impl_items;
}
ForeignItems(SmallVec<[Box<ast::ForeignItem>; 1]>) {
"foreign item";
many fn flat_map_foreign_item; fn visit_foreign_item(); fn pprust::foreign_item_to_string;
fn make_foreign_items;
}
Arms(SmallVec<[ast::Arm; 1]>) {
"match arm";
many fn flat_map_arm; fn visit_arm(); fn unreachable_to_string;
fn make_arms;
}
ExprFields(SmallVec<[ast::ExprField; 1]>) {
"field expression";
many fn flat_map_expr_field; fn visit_expr_field(); fn unreachable_to_string;
fn make_expr_fields;
}
PatFields(SmallVec<[ast::PatField; 1]>) {
"field pattern";
many fn flat_map_pat_field; fn visit_pat_field(); fn unreachable_to_string;
fn make_pat_fields;
}
GenericParams(SmallVec<[ast::GenericParam; 1]>) {
"generic parameter";
many fn flat_map_generic_param; fn visit_generic_param(); fn unreachable_to_string;
fn make_generic_params;
}
Params(SmallVec<[ast::Param; 1]>) {
"function parameter";
many fn flat_map_param; fn visit_param(); fn unreachable_to_string;
fn make_params;
}
FieldDefs(SmallVec<[ast::FieldDef; 1]>) {
"field";
many fn flat_map_field_def; fn visit_field_def(); fn unreachable_to_string;
fn make_field_defs;
}
Variants(SmallVec<[ast::Variant; 1]>) {
"variant"; many fn flat_map_variant; fn visit_variant(); fn unreachable_to_string;
fn make_variants;
}
WherePredicates(SmallVec<[ast::WherePredicate; 1]>) {
"where predicate";
many fn flat_map_where_predicate; fn visit_where_predicate(); fn unreachable_to_string;
fn make_where_predicates;
}
Crate(ast::Crate) {
"crate";
one fn visit_crate; fn visit_crate; fn unreachable_to_string;
fn make_crate;
}
}
pub enum SupportsMacroExpansion {
No,
Yes { supports_inner_attrs: bool },
}
impl AstFragmentKind {
pub(crate) fn dummy(self, span: Span, guar: ErrorGuaranteed) -> AstFragment {
self.make_from(DummyResult::any(span, guar)).expect("couldn't create a dummy AST fragment")
}
pub fn supports_macro_expansion(self) -> SupportsMacroExpansion {
match self {
AstFragmentKind::OptExpr
| AstFragmentKind::Expr
| AstFragmentKind::MethodReceiverExpr
| AstFragmentKind::Stmts
| AstFragmentKind::Ty
| AstFragmentKind::Pat => SupportsMacroExpansion::Yes { supports_inner_attrs: false },
AstFragmentKind::Items
| AstFragmentKind::TraitItems
| AstFragmentKind::ImplItems
| AstFragmentKind::TraitImplItems
| AstFragmentKind::ForeignItems
| AstFragmentKind::Crate => SupportsMacroExpansion::Yes { supports_inner_attrs: true },
AstFragmentKind::Arms
| AstFragmentKind::ExprFields
| AstFragmentKind::PatFields
| AstFragmentKind::GenericParams
| AstFragmentKind::Params
| AstFragmentKind::FieldDefs
| AstFragmentKind::Variants
| AstFragmentKind::WherePredicates => SupportsMacroExpansion::No,
}
}
pub(crate) fn expect_from_annotatables(
self,
items: impl IntoIterator<Item = Annotatable>,
) -> AstFragment {
let mut items = items.into_iter();
match self {
AstFragmentKind::Arms => {
AstFragment::Arms(items.map(Annotatable::expect_arm).collect())
}
AstFragmentKind::ExprFields => {
AstFragment::ExprFields(items.map(Annotatable::expect_expr_field).collect())
}
AstFragmentKind::PatFields => {
AstFragment::PatFields(items.map(Annotatable::expect_pat_field).collect())
}
AstFragmentKind::GenericParams => {
AstFragment::GenericParams(items.map(Annotatable::expect_generic_param).collect())
}
AstFragmentKind::Params => {
AstFragment::Params(items.map(Annotatable::expect_param).collect())
}
AstFragmentKind::FieldDefs => {
AstFragment::FieldDefs(items.map(Annotatable::expect_field_def).collect())
}
AstFragmentKind::Variants => {
AstFragment::Variants(items.map(Annotatable::expect_variant).collect())
}
AstFragmentKind::WherePredicates => AstFragment::WherePredicates(
items.map(Annotatable::expect_where_predicate).collect(),
),
AstFragmentKind::Items => {
AstFragment::Items(items.map(Annotatable::expect_item).collect())
}
AstFragmentKind::ImplItems => {
AstFragment::ImplItems(items.map(Annotatable::expect_impl_item).collect())
}
AstFragmentKind::TraitImplItems => {
AstFragment::TraitImplItems(items.map(Annotatable::expect_impl_item).collect())
}
AstFragmentKind::TraitItems => {
AstFragment::TraitItems(items.map(Annotatable::expect_trait_item).collect())
}
AstFragmentKind::ForeignItems => {
AstFragment::ForeignItems(items.map(Annotatable::expect_foreign_item).collect())
}
AstFragmentKind::Stmts => {
AstFragment::Stmts(items.map(Annotatable::expect_stmt).collect())
}
AstFragmentKind::Expr => AstFragment::Expr(
items.next().expect("expected exactly one expression").expect_expr(),
),
AstFragmentKind::MethodReceiverExpr => AstFragment::MethodReceiverExpr(
items.next().expect("expected exactly one expression").expect_expr(),
),
AstFragmentKind::OptExpr => {
AstFragment::OptExpr(items.next().map(Annotatable::expect_expr))
}
AstFragmentKind::Crate => {
AstFragment::Crate(items.next().expect("expected exactly one crate").expect_crate())
}
AstFragmentKind::Pat | AstFragmentKind::Ty => {
panic!("patterns and types aren't annotatable")
}
}
}
}
pub struct Invocation {
pub kind: InvocationKind,
pub fragment_kind: AstFragmentKind,
pub expansion_data: ExpansionData,
}
pub enum InvocationKind {
Bang {
mac: Box<ast::MacCall>,
span: Span,
},
Attr {
attr: ast::Attribute,
/// Re-insertion position for inert attributes.
pos: usize,
item: Annotatable,
/// Required for resolving derive helper attributes.
derives: Vec<ast::Path>,
},
Derive {
path: ast::Path,
is_const: bool,
item: Annotatable,
},
GlobDelegation {
item: Box<ast::AssocItem>,
/// Whether this is a trait impl or an inherent impl
of_trait: bool,
},
}
impl InvocationKind {
fn placeholder_visibility(&self) -> Option<ast::Visibility> {
// HACK: For unnamed fields placeholders should have the same visibility as the actual
// fields because for tuple structs/variants resolve determines visibilities of their
// constructor using these field visibilities before attributes on them are expanded.
// The assumption is that the attribute expansion cannot change field visibilities,
// and it holds because only inert attributes are supported in this position.
match self {
InvocationKind::Attr { item: Annotatable::FieldDef(field), .. }
| InvocationKind::Derive { item: Annotatable::FieldDef(field), .. }
if field.ident.is_none() =>
{
Some(field.vis.clone())
}
_ => None,
}
}
}
impl Invocation {
pub fn span(&self) -> Span {
match &self.kind {
InvocationKind::Bang { span, .. } => *span,
InvocationKind::Attr { attr, .. } => attr.span,
InvocationKind::Derive { path, .. } => path.span,
InvocationKind::GlobDelegation { item, .. } => item.span,
}
}
fn span_mut(&mut self) -> &mut Span {
match &mut self.kind {
InvocationKind::Bang { span, .. } => span,
InvocationKind::Attr { attr, .. } => &mut attr.span,
InvocationKind::Derive { path, .. } => &mut path.span,
InvocationKind::GlobDelegation { item, .. } => &mut item.span,
}
}
}
pub struct MacroExpander<'a, 'b> {
pub cx: &'a mut ExtCtxt<'b>,
monotonic: bool, // cf. `cx.monotonic_expander()`
}
impl<'a, 'b> MacroExpander<'a, 'b> {
pub fn new(cx: &'a mut ExtCtxt<'b>, monotonic: bool) -> Self {
MacroExpander { cx, monotonic }
}
pub fn expand_crate(&mut self, krate: ast::Crate) -> ast::Crate {
let file_path = match self.cx.source_map().span_to_filename(krate.spans.inner_span) {
FileName::Real(name) => name
.into_local_path()
.expect("attempting to resolve a file path in an external file"),
other => PathBuf::from(other.prefer_local().to_string()),
};
let dir_path = file_path.parent().unwrap_or(&file_path).to_owned();
self.cx.root_path = dir_path.clone();
self.cx.current_expansion.module = Rc::new(ModuleData {
mod_path: vec![Ident::with_dummy_span(self.cx.ecfg.crate_name)],
file_path_stack: vec![file_path],
dir_path,
});
let krate = self.fully_expand_fragment(AstFragment::Crate(krate)).make_crate();
assert_eq!(krate.id, ast::CRATE_NODE_ID);
self.cx.trace_macros_diag();
krate
}
/// Recursively expand all macro invocations in this AST fragment.
pub fn fully_expand_fragment(&mut self, input_fragment: AstFragment) -> AstFragment {
let orig_expansion_data = self.cx.current_expansion.clone();
let orig_force_mode = self.cx.force_mode;
// Collect all macro invocations and replace them with placeholders.
let (mut fragment_with_placeholders, mut invocations) =
self.collect_invocations(input_fragment, &[]);
// Optimization: if we resolve all imports now,
// we'll be able to immediately resolve most of imported macros.
self.resolve_imports();
// Resolve paths in all invocations and produce output expanded fragments for them, but
// do not insert them into our input AST fragment yet, only store in `expanded_fragments`.
// The output fragments also go through expansion recursively until no invocations are left.
// Unresolved macros produce dummy outputs as a recovery measure.
invocations.reverse();
let mut expanded_fragments = Vec::new();
let mut undetermined_invocations = Vec::new();
let (mut progress, mut force) = (false, !self.monotonic);
loop {
let Some((invoc, ext)) = invocations.pop() else {
self.resolve_imports();
if undetermined_invocations.is_empty() {
break;
}
invocations = mem::take(&mut undetermined_invocations);
force = !progress;
progress = false;
if force && self.monotonic {
self.cx.dcx().span_delayed_bug(
invocations.last().unwrap().0.span(),
"expansion entered force mode without producing any errors",
);
}
continue;
};
let ext = match ext {
Some(ext) => ext,
None => {
let eager_expansion_root = if self.monotonic {
invoc.expansion_data.id
} else {
orig_expansion_data.id
};
match self.cx.resolver.resolve_macro_invocation(
&invoc,
eager_expansion_root,
force,
) {
Ok(ext) => ext,
Err(Indeterminate) => {
// Cannot resolve, will retry this invocation later.
undetermined_invocations.push((invoc, None));
continue;
}
}
}
};
let ExpansionData { depth, id: expn_id, .. } = invoc.expansion_data;
let depth = depth - orig_expansion_data.depth;
self.cx.current_expansion = invoc.expansion_data.clone();
self.cx.force_mode = force;
let fragment_kind = invoc.fragment_kind;
match self.expand_invoc(invoc, &ext.kind) {
ExpandResult::Ready(fragment) => {
let mut derive_invocations = Vec::new();
let derive_placeholders = self
.cx
.resolver
.take_derive_resolutions(expn_id)
.map(|derives| {
derive_invocations.reserve(derives.len());
derives
.into_iter()
.map(|DeriveResolution { path, item, exts: _, is_const }| {
// FIXME: Consider using the derive resolutions (`_exts`)
// instead of enqueuing the derives to be resolved again later.
// Note that this can result in duplicate diagnostics.
let expn_id = LocalExpnId::fresh_empty();
derive_invocations.push((
Invocation {
kind: InvocationKind::Derive { path, item, is_const },
fragment_kind,
expansion_data: ExpansionData {
id: expn_id,
..self.cx.current_expansion.clone()
},
},
None,
));
NodeId::placeholder_from_expn_id(expn_id)
})
.collect::<Vec<_>>()
})
.unwrap_or_default();
let (expanded_fragment, collected_invocations) =
self.collect_invocations(fragment, &derive_placeholders);
// We choose to expand any derive invocations associated with this macro
// invocation *before* any macro invocations collected from the output
// fragment.
derive_invocations.extend(collected_invocations);
progress = true;
if expanded_fragments.len() < depth {
expanded_fragments.push(Vec::new());
}
expanded_fragments[depth - 1].push((expn_id, expanded_fragment));
invocations.extend(derive_invocations.into_iter().rev());
}
ExpandResult::Retry(invoc) => {
if force {
self.cx.dcx().span_bug(
invoc.span(),
"expansion entered force mode but is still stuck",
);
} else {
// Cannot expand, will retry this invocation later.
undetermined_invocations.push((invoc, Some(ext)));
}
}
}
}
self.cx.current_expansion = orig_expansion_data;
self.cx.force_mode = orig_force_mode;
// Finally incorporate all the expanded macros into the input AST fragment.
let mut placeholder_expander = PlaceholderExpander::default();
while let Some(expanded_fragments) = expanded_fragments.pop() {
for (expn_id, expanded_fragment) in expanded_fragments.into_iter().rev() {
placeholder_expander
.add(NodeId::placeholder_from_expn_id(expn_id), expanded_fragment);
}
}
fragment_with_placeholders.mut_visit_with(&mut placeholder_expander);
fragment_with_placeholders
}
fn resolve_imports(&mut self) {
if self.monotonic {
self.cx.resolver.resolve_imports();
}
}
/// Collects all macro invocations reachable at this time in this AST fragment, and replace
/// them with "placeholders" - dummy macro invocations with specially crafted `NodeId`s.
/// Then call into resolver that builds a skeleton ("reduced graph") of the fragment and
/// prepares data for resolving paths of macro invocations.
fn collect_invocations(
&mut self,
mut fragment: AstFragment,
extra_placeholders: &[NodeId],
) -> (AstFragment, Vec<(Invocation, Option<Arc<SyntaxExtension>>)>) {
// Resolve `$crate`s in the fragment for pretty-printing.
self.cx.resolver.resolve_dollar_crates();
let mut invocations = {
let mut collector = InvocationCollector {
// Non-derive macro invocations cannot see the results of cfg expansion - they
// will either be removed along with the item, or invoked before the cfg/cfg_attr
// attribute is expanded. Therefore, we don't need to configure the tokens
// Derive macros *can* see the results of cfg-expansion - they are handled
// specially in `fully_expand_fragment`
cx: self.cx,
invocations: Vec::new(),
monotonic: self.monotonic,
};
fragment.mut_visit_with(&mut collector);
fragment.add_placeholders(extra_placeholders);
collector.invocations
};
if self.monotonic {
self.cx
.resolver
.visit_ast_fragment_with_placeholders(self.cx.current_expansion.id, &fragment);
if self.cx.sess.opts.incremental.is_some() {
for (invoc, _) in invocations.iter_mut() {
let expn_id = invoc.expansion_data.id;
let parent_def = self.cx.resolver.invocation_parent(expn_id);
let span = invoc.span_mut();
*span = span.with_parent(Some(parent_def));
}
}
}
(fragment, invocations)
}
fn error_recursion_limit_reached(&mut self) -> ErrorGuaranteed {
let expn_data = self.cx.current_expansion.id.expn_data();
let suggested_limit = match self.cx.ecfg.recursion_limit {
Limit(0) => Limit(2),
limit => limit * 2,
};
let guar = self.cx.dcx().emit_err(RecursionLimitReached {
span: expn_data.call_site,
descr: expn_data.kind.descr(),
suggested_limit,
crate_name: self.cx.ecfg.crate_name,
});
self.cx.macro_error_and_trace_macros_diag();
guar
}
/// A macro's expansion does not fit in this fragment kind.
/// For example, a non-type macro in a type position.
fn error_wrong_fragment_kind(
&mut self,
kind: AstFragmentKind,
mac: &ast::MacCall,
span: Span,
) -> ErrorGuaranteed {
let guar =
self.cx.dcx().emit_err(WrongFragmentKind { span, kind: kind.name(), name: &mac.path });
self.cx.macro_error_and_trace_macros_diag();
guar
}
fn expand_invoc(
&mut self,
invoc: Invocation,
ext: &SyntaxExtensionKind,
) -> ExpandResult<AstFragment, Invocation> {
let recursion_limit = match self.cx.reduced_recursion_limit {
Some((limit, _)) => limit,
None => self.cx.ecfg.recursion_limit,
};
if !recursion_limit.value_within_limit(self.cx.current_expansion.depth) {
let guar = match self.cx.reduced_recursion_limit {
Some((_, guar)) => guar,
None => self.error_recursion_limit_reached(),
};
// Reduce the recursion limit by half each time it triggers.
self.cx.reduced_recursion_limit = Some((recursion_limit / 2, guar));
return ExpandResult::Ready(invoc.fragment_kind.dummy(invoc.span(), guar));
}
let macro_stats = self.cx.sess.opts.unstable_opts.macro_stats;
let (fragment_kind, span) = (invoc.fragment_kind, invoc.span());
ExpandResult::Ready(match invoc.kind {
InvocationKind::Bang { mac, span } => {
if let SyntaxExtensionKind::Bang(expander) = ext {
match expander.expand(self.cx, span, mac.args.tokens.clone()) {
Ok(tok_result) => {
let fragment =
self.parse_ast_fragment(tok_result, fragment_kind, &mac.path, span);
if macro_stats {
update_bang_macro_stats(
self.cx,
fragment_kind,
span,
mac,
&fragment,
);
}
fragment
}
Err(guar) => return ExpandResult::Ready(fragment_kind.dummy(span, guar)),
}
} else if let Some(expander) = ext.as_legacy_bang() {
let tok_result = match expander.expand(self.cx, span, mac.args.tokens.clone()) {
ExpandResult::Ready(tok_result) => tok_result,
ExpandResult::Retry(_) => {
// retry the original
return ExpandResult::Retry(Invocation {
kind: InvocationKind::Bang { mac, span },
..invoc
});
}
};
if let Some(fragment) = fragment_kind.make_from(tok_result) {
if macro_stats {
update_bang_macro_stats(self.cx, fragment_kind, span, mac, &fragment);
}
fragment
} else {
let guar = self.error_wrong_fragment_kind(fragment_kind, &mac, span);
fragment_kind.dummy(span, guar)
}
} else {
unreachable!();
}
}
InvocationKind::Attr { attr, pos, mut item, derives } => {
if let Some(expander) = ext.as_attr() {
self.gate_proc_macro_input(&item);
self.gate_proc_macro_attr_item(span, &item);
let tokens = match &item {
// FIXME: Collect tokens and use them instead of generating
// fake ones. These are unstable, so it needs to be
// fixed prior to stabilization
// Fake tokens when we are invoking an inner attribute, and
// we are invoking it on an out-of-line module or crate.
Annotatable::Crate(krate) => {
rustc_parse::fake_token_stream_for_crate(&self.cx.sess.psess, krate)
}
Annotatable::Item(item_inner)
if matches!(attr.style, AttrStyle::Inner)
&& matches!(
item_inner.kind,
ItemKind::Mod(
_,
_,
ModKind::Unloaded
| ModKind::Loaded(_, Inline::No { .. }, _),
)
) =>
{
rustc_parse::fake_token_stream_for_item(&self.cx.sess.psess, item_inner)
}
_ => item.to_tokens(),
};
let attr_item = attr.get_normal_item();
if let AttrArgs::Eq { .. } = attr_item.args {
self.cx.dcx().emit_err(UnsupportedKeyValue { span });
}
let inner_tokens = attr_item.args.inner_tokens();
match expander.expand(self.cx, span, inner_tokens, tokens) {
Ok(tok_result) => {
let fragment = self.parse_ast_fragment(
tok_result,
fragment_kind,
&attr_item.path,
span,
);
if macro_stats {
update_attr_macro_stats(
self.cx,
fragment_kind,
span,
&attr_item.path,
&attr,
item,
&fragment,
);
}
fragment
}
Err(guar) => return ExpandResult::Ready(fragment_kind.dummy(span, guar)),
}
} else if let SyntaxExtensionKind::LegacyAttr(expander) = ext {
match validate_attr::parse_meta(&self.cx.sess.psess, &attr) {
Ok(meta) => {
let item_clone = macro_stats.then(|| item.clone());
let items = match expander.expand(self.cx, span, &meta, item, false) {
ExpandResult::Ready(items) => items,
ExpandResult::Retry(item) => {
// Reassemble the original invocation for retrying.
return ExpandResult::Retry(Invocation {
kind: InvocationKind::Attr { attr, pos, item, derives },
..invoc
});
}
};
if matches!(
fragment_kind,
AstFragmentKind::Expr | AstFragmentKind::MethodReceiverExpr
) && items.is_empty()
{
let guar = self.cx.dcx().emit_err(RemoveExprNotSupported { span });
fragment_kind.dummy(span, guar)
} else {
let fragment = fragment_kind.expect_from_annotatables(items);
if macro_stats {
update_attr_macro_stats(
self.cx,
fragment_kind,
span,
&meta.path,
&attr,
item_clone.unwrap(),
&fragment,
);
}
fragment
}
}
Err(err) => {
let _guar = err.emit();
fragment_kind.expect_from_annotatables(iter::once(item))
}
}
} else if let SyntaxExtensionKind::NonMacroAttr = ext {
// `-Zmacro-stats` ignores these because they don't do any real expansion.
self.cx.expanded_inert_attrs.mark(&attr);
item.visit_attrs(|attrs| attrs.insert(pos, attr));
fragment_kind.expect_from_annotatables(iter::once(item))
} else {
unreachable!();
}
}
InvocationKind::Derive { path, item, is_const } => match ext {
SyntaxExtensionKind::Derive(expander)
| SyntaxExtensionKind::LegacyDerive(expander) => {
if let SyntaxExtensionKind::Derive(..) = ext {
self.gate_proc_macro_input(&item);
}
// The `MetaItem` representing the trait to derive can't
// have an unsafe around it (as of now).
let meta = ast::MetaItem {
unsafety: ast::Safety::Default,
kind: MetaItemKind::Word,
span,
path,
};
let items = match expander.expand(self.cx, span, &meta, item, is_const) {
ExpandResult::Ready(items) => items,
ExpandResult::Retry(item) => {
// Reassemble the original invocation for retrying.
return ExpandResult::Retry(Invocation {
kind: InvocationKind::Derive { path: meta.path, item, is_const },
..invoc
});
}
};
let fragment = fragment_kind.expect_from_annotatables(items);
if macro_stats {
update_derive_macro_stats(
self.cx,
fragment_kind,
span,
&meta.path,
&fragment,
);
}
fragment
}
SyntaxExtensionKind::MacroRules(expander)
if expander.kinds().contains(MacroKinds::DERIVE) =>
{
if is_const {
let guar = self
.cx
.dcx()
.span_err(span, "macro `derive` does not support const derives");
return ExpandResult::Ready(fragment_kind.dummy(span, guar));
}
let body = item.to_tokens();
match expander.expand_derive(self.cx, span, &body) {
Ok(tok_result) => {
let fragment =
self.parse_ast_fragment(tok_result, fragment_kind, &path, span);
if macro_stats {
update_derive_macro_stats(
self.cx,
fragment_kind,
span,
&path,
&fragment,
);
}
fragment
}
Err(guar) => return ExpandResult::Ready(fragment_kind.dummy(span, guar)),
}
}
_ => unreachable!(),
},
InvocationKind::GlobDelegation { item, of_trait } => {
let AssocItemKind::DelegationMac(deleg) = &item.kind else { unreachable!() };
let suffixes = match ext {
SyntaxExtensionKind::GlobDelegation(expander) => match expander.expand(self.cx)
{
ExpandResult::Ready(suffixes) => suffixes,
ExpandResult::Retry(()) => {
// Reassemble the original invocation for retrying.
return ExpandResult::Retry(Invocation {
kind: InvocationKind::GlobDelegation { item, of_trait },
..invoc
});
}
},
SyntaxExtensionKind::LegacyBang(..) => {
let msg = "expanded a dummy glob delegation";
let guar = self.cx.dcx().span_delayed_bug(span, msg);
return ExpandResult::Ready(fragment_kind.dummy(span, guar));
}
_ => unreachable!(),
};
type Node = AstNodeWrapper<Box<ast::AssocItem>, ImplItemTag>;
let single_delegations = build_single_delegations::<Node>(
self.cx, deleg, &item, &suffixes, item.span, true,
);
// `-Zmacro-stats` ignores these because they don't seem important.
fragment_kind.expect_from_annotatables(single_delegations.map(|item| {
Annotatable::AssocItem(Box::new(item), AssocCtxt::Impl { of_trait })
}))
}
})
}
#[allow(rustc::untranslatable_diagnostic)] // FIXME: make this translatable
fn gate_proc_macro_attr_item(&self, span: Span, item: &Annotatable) {
let kind = match item {
Annotatable::Item(_)
| Annotatable::AssocItem(..)
| Annotatable::ForeignItem(_)
| Annotatable::Crate(..) => return,
Annotatable::Stmt(stmt) => {
// Attributes are stable on item statements,
// but unstable on all other kinds of statements
if stmt.is_item() {
return;
}
"statements"
}
Annotatable::Expr(_) => "expressions",
Annotatable::Arm(..)
| Annotatable::ExprField(..)
| Annotatable::PatField(..)
| Annotatable::GenericParam(..)
| Annotatable::Param(..)
| Annotatable::FieldDef(..)
| Annotatable::Variant(..)
| Annotatable::WherePredicate(..) => panic!("unexpected annotatable"),
};
if self.cx.ecfg.features.proc_macro_hygiene() {
return;
}
feature_err(
&self.cx.sess,
sym::proc_macro_hygiene,
span,
format!("custom attributes cannot be applied to {kind}"),
)
.emit();
}
fn gate_proc_macro_input(&self, annotatable: &Annotatable) {
struct GateProcMacroInput<'a> {
sess: &'a Session,
}
impl<'ast, 'a> Visitor<'ast> for GateProcMacroInput<'a> {
fn visit_item(&mut self, item: &'ast ast::Item) {
match &item.kind {
ItemKind::Mod(_, _, mod_kind)
if !matches!(mod_kind, ModKind::Loaded(_, Inline::Yes, _)) =>
{
feature_err(
self.sess,
sym::proc_macro_hygiene,
item.span,
fluent_generated::expand_non_inline_modules_in_proc_macro_input_are_unstable,
)
.emit();
}
_ => {}
}
visit::walk_item(self, item);
}
}
if !self.cx.ecfg.features.proc_macro_hygiene() {
annotatable.visit_with(&mut GateProcMacroInput { sess: &self.cx.sess });
}
}
fn parse_ast_fragment(
&mut self,
toks: TokenStream,
kind: AstFragmentKind,
path: &ast::Path,
span: Span,
) -> AstFragment {
let mut parser = self.cx.new_parser_from_tts(toks);
match parse_ast_fragment(&mut parser, kind) {
Ok(fragment) => {
ensure_complete_parse(&parser, path, kind.name(), span);
fragment
}
Err(mut err) => {
if err.span.is_dummy() {
err.span(span);
}
annotate_err_with_kind(&mut err, kind, span);
let guar = err.emit();
self.cx.macro_error_and_trace_macros_diag();
kind.dummy(span, guar)
}
}
}
}
pub fn parse_ast_fragment<'a>(
this: &mut Parser<'a>,
kind: AstFragmentKind,
) -> PResult<'a, AstFragment> {
Ok(match kind {
AstFragmentKind::Items => {
let mut items = SmallVec::new();
while let Some(item) = this.parse_item(ForceCollect::No)? {
items.push(item);
}
AstFragment::Items(items)
}
AstFragmentKind::TraitItems => {
let mut items = SmallVec::new();
while let Some(item) = this.parse_trait_item(ForceCollect::No)? {
items.extend(item);
}
AstFragment::TraitItems(items)
}
AstFragmentKind::ImplItems => {
let mut items = SmallVec::new();
while let Some(item) = this.parse_impl_item(ForceCollect::No)? {
items.extend(item);
}
AstFragment::ImplItems(items)
}
AstFragmentKind::TraitImplItems => {
let mut items = SmallVec::new();
while let Some(item) = this.parse_impl_item(ForceCollect::No)? {
items.extend(item);
}
AstFragment::TraitImplItems(items)
}
AstFragmentKind::ForeignItems => {
let mut items = SmallVec::new();
while let Some(item) = this.parse_foreign_item(ForceCollect::No)? {
items.extend(item);
}
AstFragment::ForeignItems(items)
}
AstFragmentKind::Stmts => {
let mut stmts = SmallVec::new();
// Won't make progress on a `}`.
while this.token != token::Eof && this.token != token::CloseBrace {
if let Some(stmt) = this.parse_full_stmt(AttemptLocalParseRecovery::Yes)? {
stmts.push(stmt);
}
}
AstFragment::Stmts(stmts)
}
AstFragmentKind::Expr => AstFragment::Expr(this.parse_expr()?),
AstFragmentKind::MethodReceiverExpr => AstFragment::MethodReceiverExpr(this.parse_expr()?),
AstFragmentKind::OptExpr => {
if this.token != token::Eof {
AstFragment::OptExpr(Some(this.parse_expr()?))
} else {
AstFragment::OptExpr(None)
}
}
AstFragmentKind::Ty => AstFragment::Ty(this.parse_ty()?),
AstFragmentKind::Pat => AstFragment::Pat(this.parse_pat_allow_top_guard(
None,
RecoverComma::No,
RecoverColon::Yes,
CommaRecoveryMode::LikelyTuple,
)?),
AstFragmentKind::Crate => AstFragment::Crate(this.parse_crate_mod()?),
AstFragmentKind::Arms
| AstFragmentKind::ExprFields
| AstFragmentKind::PatFields
| AstFragmentKind::GenericParams
| AstFragmentKind::Params
| AstFragmentKind::FieldDefs
| AstFragmentKind::Variants
| AstFragmentKind::WherePredicates => panic!("unexpected AST fragment kind"),
})
}
pub(crate) fn ensure_complete_parse<'a>(
parser: &Parser<'a>,
macro_path: &ast::Path,
kind_name: &str,
span: Span,
) {
if parser.token != token::Eof {
let descr = token_descr(&parser.token);
// Avoid emitting backtrace info twice.
let def_site_span = parser.token.span.with_ctxt(SyntaxContext::root());
let semi_span = parser.psess.source_map().next_point(span);
let add_semicolon = match &parser.psess.source_map().span_to_snippet(semi_span) {
Ok(snippet) if &snippet[..] != ";" && kind_name == "expression" => {
Some(span.shrink_to_hi())
}
_ => None,
};
let expands_to_match_arm = kind_name == "pattern" && parser.token == token::FatArrow;
parser.dcx().emit_err(IncompleteParse {
span: def_site_span,
descr,
label_span: span,
macro_path,
kind_name,
expands_to_match_arm,
add_semicolon,
});
}
}
/// Wraps a call to `walk_*` / `walk_flat_map_*`
/// for an AST node that supports attributes
/// (see the `Annotatable` enum)
/// This method assigns a `NodeId`, and sets that `NodeId`
/// as our current 'lint node id'. If a macro call is found
/// inside this AST node, we will use this AST node's `NodeId`
/// to emit lints associated with that macro (allowing
/// `#[allow]` / `#[deny]` to be applied close to
/// the macro invocation).
///
/// Do *not* call this for a macro AST node
/// (e.g. `ExprKind::MacCall`) - we cannot emit lints
/// at these AST nodes, since they are removed and
/// replaced with the result of macro expansion.
///
/// All other `NodeId`s are assigned by `visit_id`.
/// * `self` is the 'self' parameter for the current method,
/// * `id` is a mutable reference to the `NodeId` field
/// of the current AST node.
/// * `closure` is a closure that executes the
/// `walk_*` / `walk_flat_map_*` method
/// for the current AST node.
macro_rules! assign_id {
($self:ident, $id:expr, $closure:expr) => {{
let old_id = $self.cx.current_expansion.lint_node_id;
if $self.monotonic {
debug_assert_eq!(*$id, ast::DUMMY_NODE_ID);
let new_id = $self.cx.resolver.next_node_id();
*$id = new_id;
$self.cx.current_expansion.lint_node_id = new_id;
}
let ret = ($closure)();
$self.cx.current_expansion.lint_node_id = old_id;
ret
}};
}
enum AddSemicolon {
Yes,
No,
}
/// A trait implemented for all `AstFragment` nodes and providing all pieces
/// of functionality used by `InvocationCollector`.
trait InvocationCollectorNode: HasAttrs + HasNodeId + Sized {
type OutputTy = SmallVec<[Self; 1]>;
type ItemKind = ItemKind;
const KIND: AstFragmentKind;
fn to_annotatable(self) -> Annotatable;
fn fragment_to_output(fragment: AstFragment) -> Self::OutputTy;
fn descr() -> &'static str {
unreachable!()
}
fn walk_flat_map(self, _collector: &mut InvocationCollector<'_, '_>) -> Self::OutputTy {
unreachable!()
}
fn walk(&mut self, _collector: &mut InvocationCollector<'_, '_>) {
unreachable!()
}
fn is_mac_call(&self) -> bool {
false
}
fn take_mac_call(self) -> (Box<ast::MacCall>, ast::AttrVec, AddSemicolon) {
unreachable!()
}
fn delegation(&self) -> Option<(&ast::DelegationMac, &ast::Item<Self::ItemKind>)> {
None
}
fn delegation_item_kind(_deleg: Box<ast::Delegation>) -> Self::ItemKind {
unreachable!()
}
fn from_item(_item: ast::Item<Self::ItemKind>) -> Self {
unreachable!()
}
fn flatten_outputs(_outputs: impl Iterator<Item = Self::OutputTy>) -> Self::OutputTy {
unreachable!()
}
fn pre_flat_map_node_collect_attr(_cfg: &StripUnconfigured<'_>, _attr: &ast::Attribute) {}
fn post_flat_map_node_collect_bang(_output: &mut Self::OutputTy, _add_semicolon: AddSemicolon) {
}
fn wrap_flat_map_node_walk_flat_map(
node: Self,
collector: &mut InvocationCollector<'_, '_>,
walk_flat_map: impl FnOnce(Self, &mut InvocationCollector<'_, '_>) -> Self::OutputTy,
) -> Result<Self::OutputTy, Self> {
Ok(walk_flat_map(node, collector))
}
fn expand_cfg_false(
&mut self,
collector: &mut InvocationCollector<'_, '_>,
_pos: usize,
span: Span,
) {
collector.cx.dcx().emit_err(RemoveNodeNotSupported { span, descr: Self::descr() });
}
/// All of the identifiers (items) declared by this node.
/// This is an approximation and should only be used for diagnostics.
fn declared_idents(&self) -> Vec<Ident> {
vec![]
}
}
impl InvocationCollectorNode for Box<ast::Item> {
const KIND: AstFragmentKind = AstFragmentKind::Items;
fn to_annotatable(self) -> Annotatable {
Annotatable::Item(self)
}
fn fragment_to_output(fragment: AstFragment) -> Self::OutputTy {
fragment.make_items()
}
fn walk_flat_map(self, collector: &mut InvocationCollector<'_, '_>) -> Self::OutputTy {
walk_flat_map_item(collector, self)
}
fn is_mac_call(&self) -> bool {
matches!(self.kind, ItemKind::MacCall(..))
}
fn take_mac_call(self) -> (Box<ast::MacCall>, ast::AttrVec, AddSemicolon) {
match self.kind {
ItemKind::MacCall(mac) => (mac, self.attrs, AddSemicolon::No),
_ => unreachable!(),
}
}
fn delegation(&self) -> Option<(&ast::DelegationMac, &ast::Item<Self::ItemKind>)> {
match &self.kind {
ItemKind::DelegationMac(deleg) => Some((deleg, self)),
_ => None,
}
}
fn delegation_item_kind(deleg: Box<ast::Delegation>) -> Self::ItemKind {
ItemKind::Delegation(deleg)
}
fn from_item(item: ast::Item<Self::ItemKind>) -> Self {
Box::new(item)
}
fn flatten_outputs(items: impl Iterator<Item = Self::OutputTy>) -> Self::OutputTy {
items.flatten().collect()
}
fn wrap_flat_map_node_walk_flat_map(
mut node: Self,
collector: &mut InvocationCollector<'_, '_>,
walk_flat_map: impl FnOnce(Self, &mut InvocationCollector<'_, '_>) -> Self::OutputTy,
) -> Result<Self::OutputTy, Self> {
if !matches!(node.kind, ItemKind::Mod(..)) {
return Ok(walk_flat_map(node, collector));
}
// Work around borrow checker not seeing through `P`'s deref.
let (span, mut attrs) = (node.span, mem::take(&mut node.attrs));
let ItemKind::Mod(_, ident, ref mut mod_kind) = node.kind else { unreachable!() };
let ecx = &mut collector.cx;
let (file_path, dir_path, dir_ownership) = match mod_kind {
ModKind::Loaded(_, inline, _) => {
// Inline `mod foo { ... }`, but we still need to push directories.
let (dir_path, dir_ownership) = mod_dir_path(
ecx.sess,
ident,
&attrs,
&ecx.current_expansion.module,
ecx.current_expansion.dir_ownership,
*inline,
);
// If the module was parsed from an external file, recover its path.
// This lets `parse_external_mod` catch cycles if it's self-referential.
let file_path = match inline {
Inline::Yes => None,
Inline::No { .. } => mod_file_path_from_attr(ecx.sess, &attrs, &dir_path),
};
node.attrs = attrs;
(file_path, dir_path, dir_ownership)
}
ModKind::Unloaded => {
// We have an outline `mod foo;` so we need to parse the file.
let old_attrs_len = attrs.len();
let ParsedExternalMod {
items,
spans,
file_path,
dir_path,
dir_ownership,
had_parse_error,
} = parse_external_mod(
ecx.sess,
ident,
span,
&ecx.current_expansion.module,
ecx.current_expansion.dir_ownership,
&mut attrs,
);
if let Some(lint_store) = ecx.lint_store {
lint_store.pre_expansion_lint(
ecx.sess,
ecx.ecfg.features,
ecx.resolver.registered_tools(),
ecx.current_expansion.lint_node_id,
&attrs,
&items,
ident.name,
);
}
*mod_kind = ModKind::Loaded(items, Inline::No { had_parse_error }, spans);
node.attrs = attrs;
if node.attrs.len() > old_attrs_len {
// If we loaded an out-of-line module and added some inner attributes,
// then we need to re-configure it and re-collect attributes for
// resolution and expansion.
return Err(node);
}
(Some(file_path), dir_path, dir_ownership)
}
};
// Set the module info before we flat map.
let mut module = ecx.current_expansion.module.with_dir_path(dir_path);
module.mod_path.push(ident);
if let Some(file_path) = file_path {
module.file_path_stack.push(file_path);
}
let orig_module = mem::replace(&mut ecx.current_expansion.module, Rc::new(module));
let orig_dir_ownership =
mem::replace(&mut ecx.current_expansion.dir_ownership, dir_ownership);
let res = Ok(walk_flat_map(node, collector));
collector.cx.current_expansion.dir_ownership = orig_dir_ownership;
collector.cx.current_expansion.module = orig_module;
res
}
fn declared_idents(&self) -> Vec<Ident> {
if let ItemKind::Use(ut) = &self.kind {
fn collect_use_tree_leaves(ut: &ast::UseTree, idents: &mut Vec<Ident>) {
match &ut.kind {
ast::UseTreeKind::Glob => {}
ast::UseTreeKind::Simple(_) => idents.push(ut.ident()),
ast::UseTreeKind::Nested { items, .. } => {
for (ut, _) in items {
collect_use_tree_leaves(ut, idents);
}
}
}
}
let mut idents = Vec::new();
collect_use_tree_leaves(&ut, &mut idents);
idents
} else {
self.kind.ident().into_iter().collect()
}
}
}
struct TraitItemTag;
impl InvocationCollectorNode for AstNodeWrapper<Box<ast::AssocItem>, TraitItemTag> {
type OutputTy = SmallVec<[Box<ast::AssocItem>; 1]>;
type ItemKind = AssocItemKind;
const KIND: AstFragmentKind = AstFragmentKind::TraitItems;
fn to_annotatable(self) -> Annotatable {
Annotatable::AssocItem(self.wrapped, AssocCtxt::Trait)
}
fn fragment_to_output(fragment: AstFragment) -> Self::OutputTy {
fragment.make_trait_items()
}
fn walk_flat_map(self, collector: &mut InvocationCollector<'_, '_>) -> Self::OutputTy {
walk_flat_map_assoc_item(collector, self.wrapped, AssocCtxt::Trait)
}
fn is_mac_call(&self) -> bool {
matches!(self.wrapped.kind, AssocItemKind::MacCall(..))
}
fn take_mac_call(self) -> (Box<ast::MacCall>, ast::AttrVec, AddSemicolon) {
let item = self.wrapped;
match item.kind {
AssocItemKind::MacCall(mac) => (mac, item.attrs, AddSemicolon::No),
_ => unreachable!(),
}
}
fn delegation(&self) -> Option<(&ast::DelegationMac, &ast::Item<Self::ItemKind>)> {
match &self.wrapped.kind {
AssocItemKind::DelegationMac(deleg) => Some((deleg, &self.wrapped)),
_ => None,
}
}
fn delegation_item_kind(deleg: Box<ast::Delegation>) -> Self::ItemKind {
AssocItemKind::Delegation(deleg)
}
fn from_item(item: ast::Item<Self::ItemKind>) -> Self {
AstNodeWrapper::new(Box::new(item), TraitItemTag)
}
fn flatten_outputs(items: impl Iterator<Item = Self::OutputTy>) -> Self::OutputTy {
items.flatten().collect()
}
}
struct ImplItemTag;
impl InvocationCollectorNode for AstNodeWrapper<Box<ast::AssocItem>, ImplItemTag> {
type OutputTy = SmallVec<[Box<ast::AssocItem>; 1]>;
type ItemKind = AssocItemKind;
const KIND: AstFragmentKind = AstFragmentKind::ImplItems;
fn to_annotatable(self) -> Annotatable {
Annotatable::AssocItem(self.wrapped, AssocCtxt::Impl { of_trait: false })
}
fn fragment_to_output(fragment: AstFragment) -> Self::OutputTy {
fragment.make_impl_items()
}
fn walk_flat_map(self, collector: &mut InvocationCollector<'_, '_>) -> Self::OutputTy {
walk_flat_map_assoc_item(collector, self.wrapped, AssocCtxt::Impl { of_trait: false })
}
fn is_mac_call(&self) -> bool {
matches!(self.wrapped.kind, AssocItemKind::MacCall(..))
}
fn take_mac_call(self) -> (Box<ast::MacCall>, ast::AttrVec, AddSemicolon) {
let item = self.wrapped;
match item.kind {
AssocItemKind::MacCall(mac) => (mac, item.attrs, AddSemicolon::No),
_ => unreachable!(),
}
}
fn delegation(&self) -> Option<(&ast::DelegationMac, &ast::Item<Self::ItemKind>)> {
match &self.wrapped.kind {
AssocItemKind::DelegationMac(deleg) => Some((deleg, &self.wrapped)),
_ => None,
}
}
fn delegation_item_kind(deleg: Box<ast::Delegation>) -> Self::ItemKind {
AssocItemKind::Delegation(deleg)
}
fn from_item(item: ast::Item<Self::ItemKind>) -> Self {
AstNodeWrapper::new(Box::new(item), ImplItemTag)
}
fn flatten_outputs(items: impl Iterator<Item = Self::OutputTy>) -> Self::OutputTy {
items.flatten().collect()
}
}
struct TraitImplItemTag;
impl InvocationCollectorNode for AstNodeWrapper<Box<ast::AssocItem>, TraitImplItemTag> {
type OutputTy = SmallVec<[Box<ast::AssocItem>; 1]>;
type ItemKind = AssocItemKind;
const KIND: AstFragmentKind = AstFragmentKind::TraitImplItems;
fn to_annotatable(self) -> Annotatable {
Annotatable::AssocItem(self.wrapped, AssocCtxt::Impl { of_trait: true })
}
fn fragment_to_output(fragment: AstFragment) -> Self::OutputTy {
fragment.make_trait_impl_items()
}
fn walk_flat_map(self, collector: &mut InvocationCollector<'_, '_>) -> Self::OutputTy {
walk_flat_map_assoc_item(collector, self.wrapped, AssocCtxt::Impl { of_trait: true })
}
fn is_mac_call(&self) -> bool {
matches!(self.wrapped.kind, AssocItemKind::MacCall(..))
}
fn take_mac_call(self) -> (Box<ast::MacCall>, ast::AttrVec, AddSemicolon) {
let item = self.wrapped;
match item.kind {
AssocItemKind::MacCall(mac) => (mac, item.attrs, AddSemicolon::No),
_ => unreachable!(),
}
}
fn delegation(&self) -> Option<(&ast::DelegationMac, &ast::Item<Self::ItemKind>)> {
match &self.wrapped.kind {
AssocItemKind::DelegationMac(deleg) => Some((deleg, &self.wrapped)),
_ => None,
}
}
fn delegation_item_kind(deleg: Box<ast::Delegation>) -> Self::ItemKind {
AssocItemKind::Delegation(deleg)
}
fn from_item(item: ast::Item<Self::ItemKind>) -> Self {
AstNodeWrapper::new(Box::new(item), TraitImplItemTag)
}
fn flatten_outputs(items: impl Iterator<Item = Self::OutputTy>) -> Self::OutputTy {
items.flatten().collect()
}
}
impl InvocationCollectorNode for Box<ast::ForeignItem> {
const KIND: AstFragmentKind = AstFragmentKind::ForeignItems;
fn to_annotatable(self) -> Annotatable {
Annotatable::ForeignItem(self)
}
fn fragment_to_output(fragment: AstFragment) -> Self::OutputTy {
fragment.make_foreign_items()
}
fn walk_flat_map(self, collector: &mut InvocationCollector<'_, '_>) -> Self::OutputTy {
walk_flat_map_foreign_item(collector, self)
}
fn is_mac_call(&self) -> bool {
matches!(self.kind, ForeignItemKind::MacCall(..))
}
fn take_mac_call(self) -> (Box<ast::MacCall>, ast::AttrVec, AddSemicolon) {
match self.kind {
ForeignItemKind::MacCall(mac) => (mac, self.attrs, AddSemicolon::No),
_ => unreachable!(),
}
}
}
impl InvocationCollectorNode for ast::Variant {
const KIND: AstFragmentKind = AstFragmentKind::Variants;
fn to_annotatable(self) -> Annotatable {
Annotatable::Variant(self)
}
fn fragment_to_output(fragment: AstFragment) -> Self::OutputTy {
fragment.make_variants()
}
fn walk_flat_map(self, collector: &mut InvocationCollector<'_, '_>) -> Self::OutputTy {
walk_flat_map_variant(collector, self)
}
}
impl InvocationCollectorNode for ast::WherePredicate {
const KIND: AstFragmentKind = AstFragmentKind::WherePredicates;
fn to_annotatable(self) -> Annotatable {
Annotatable::WherePredicate(self)
}
fn fragment_to_output(fragment: AstFragment) -> Self::OutputTy {
fragment.make_where_predicates()
}
fn walk_flat_map(self, collector: &mut InvocationCollector<'_, '_>) -> Self::OutputTy {
walk_flat_map_where_predicate(collector, self)
}
}
impl InvocationCollectorNode for ast::FieldDef {
const KIND: AstFragmentKind = AstFragmentKind::FieldDefs;
fn to_annotatable(self) -> Annotatable {
Annotatable::FieldDef(self)
}
fn fragment_to_output(fragment: AstFragment) -> Self::OutputTy {
fragment.make_field_defs()
}
fn walk_flat_map(self, collector: &mut InvocationCollector<'_, '_>) -> Self::OutputTy {
walk_flat_map_field_def(collector, self)
}
}
impl InvocationCollectorNode for ast::PatField {
const KIND: AstFragmentKind = AstFragmentKind::PatFields;
fn to_annotatable(self) -> Annotatable {
Annotatable::PatField(self)
}
fn fragment_to_output(fragment: AstFragment) -> Self::OutputTy {
fragment.make_pat_fields()
}
fn walk_flat_map(self, collector: &mut InvocationCollector<'_, '_>) -> Self::OutputTy {
walk_flat_map_pat_field(collector, self)
}
}
impl InvocationCollectorNode for ast::ExprField {
const KIND: AstFragmentKind = AstFragmentKind::ExprFields;
fn to_annotatable(self) -> Annotatable {
Annotatable::ExprField(self)
}
fn fragment_to_output(fragment: AstFragment) -> Self::OutputTy {
fragment.make_expr_fields()
}
fn walk_flat_map(self, collector: &mut InvocationCollector<'_, '_>) -> Self::OutputTy {
walk_flat_map_expr_field(collector, self)
}
}
impl InvocationCollectorNode for ast::Param {
const KIND: AstFragmentKind = AstFragmentKind::Params;
fn to_annotatable(self) -> Annotatable {
Annotatable::Param(self)
}
fn fragment_to_output(fragment: AstFragment) -> Self::OutputTy {
fragment.make_params()
}
fn walk_flat_map(self, collector: &mut InvocationCollector<'_, '_>) -> Self::OutputTy {
walk_flat_map_param(collector, self)
}
}
impl InvocationCollectorNode for ast::GenericParam {
const KIND: AstFragmentKind = AstFragmentKind::GenericParams;
fn to_annotatable(self) -> Annotatable {
Annotatable::GenericParam(self)
}
fn fragment_to_output(fragment: AstFragment) -> Self::OutputTy {
fragment.make_generic_params()
}
fn walk_flat_map(self, collector: &mut InvocationCollector<'_, '_>) -> Self::OutputTy {
walk_flat_map_generic_param(collector, self)
}
}
impl InvocationCollectorNode for ast::Arm {
const KIND: AstFragmentKind = AstFragmentKind::Arms;
fn to_annotatable(self) -> Annotatable {
Annotatable::Arm(self)
}
fn fragment_to_output(fragment: AstFragment) -> Self::OutputTy {
fragment.make_arms()
}
fn walk_flat_map(self, collector: &mut InvocationCollector<'_, '_>) -> Self::OutputTy {
walk_flat_map_arm(collector, self)
}
}
impl InvocationCollectorNode for ast::Stmt {
const KIND: AstFragmentKind = AstFragmentKind::Stmts;
fn to_annotatable(self) -> Annotatable {
Annotatable::Stmt(Box::new(self))
}
fn fragment_to_output(fragment: AstFragment) -> Self::OutputTy {
fragment.make_stmts()
}
fn walk_flat_map(self, collector: &mut InvocationCollector<'_, '_>) -> Self::OutputTy {
walk_flat_map_stmt(collector, self)
}
fn is_mac_call(&self) -> bool {
match &self.kind {
StmtKind::MacCall(..) => true,
StmtKind::Item(item) => matches!(item.kind, ItemKind::MacCall(..)),
StmtKind::Semi(expr) => matches!(expr.kind, ExprKind::MacCall(..)),
StmtKind::Expr(..) => unreachable!(),
StmtKind::Let(..) | StmtKind::Empty => false,
}
}
fn take_mac_call(self) -> (Box<ast::MacCall>, ast::AttrVec, AddSemicolon) {
// We pull macro invocations (both attributes and fn-like macro calls) out of their
// `StmtKind`s and treat them as statement macro invocations, not as items or expressions.
let (add_semicolon, mac, attrs) = match self.kind {
StmtKind::MacCall(mac) => {
let ast::MacCallStmt { mac, style, attrs, .. } = *mac;
(style == MacStmtStyle::Semicolon, mac, attrs)
}
StmtKind::Item(item) => match *item {
ast::Item { kind: ItemKind::MacCall(mac), attrs, .. } => {
(mac.args.need_semicolon(), mac, attrs)
}
_ => unreachable!(),
},
StmtKind::Semi(expr) => match *expr {
ast::Expr { kind: ExprKind::MacCall(mac), attrs, .. } => {
(mac.args.need_semicolon(), mac, attrs)
}
_ => unreachable!(),
},
_ => unreachable!(),
};
(mac, attrs, if add_semicolon { AddSemicolon::Yes } else { AddSemicolon::No })
}
fn delegation(&self) -> Option<(&ast::DelegationMac, &ast::Item<Self::ItemKind>)> {
match &self.kind {
StmtKind::Item(item) => match &item.kind {
ItemKind::DelegationMac(deleg) => Some((deleg, item)),
_ => None,
},
_ => None,
}
}
fn delegation_item_kind(deleg: Box<ast::Delegation>) -> Self::ItemKind {
ItemKind::Delegation(deleg)
}
fn from_item(item: ast::Item<Self::ItemKind>) -> Self {
ast::Stmt { id: ast::DUMMY_NODE_ID, span: item.span, kind: StmtKind::Item(Box::new(item)) }
}
fn flatten_outputs(items: impl Iterator<Item = Self::OutputTy>) -> Self::OutputTy {
items.flatten().collect()
}
fn post_flat_map_node_collect_bang(stmts: &mut Self::OutputTy, add_semicolon: AddSemicolon) {
// If this is a macro invocation with a semicolon, then apply that
// semicolon to the final statement produced by expansion.
if matches!(add_semicolon, AddSemicolon::Yes) {
if let Some(stmt) = stmts.pop() {
stmts.push(stmt.add_trailing_semicolon());
}
}
}
}
impl InvocationCollectorNode for ast::Crate {
type OutputTy = ast::Crate;
const KIND: AstFragmentKind = AstFragmentKind::Crate;
fn to_annotatable(self) -> Annotatable {
Annotatable::Crate(self)
}
fn fragment_to_output(fragment: AstFragment) -> Self::OutputTy {
fragment.make_crate()
}
fn walk(&mut self, collector: &mut InvocationCollector<'_, '_>) {
walk_crate(collector, self)
}
fn expand_cfg_false(
&mut self,
collector: &mut InvocationCollector<'_, '_>,
pos: usize,
_span: Span,
) {
// Attributes above `cfg(FALSE)` are left in place, because we may want to configure
// some global crate properties even on fully unconfigured crates.
self.attrs.truncate(pos);
// Standard prelude imports are left in the crate for backward compatibility.
self.items.truncate(collector.cx.num_standard_library_imports);
}
}
impl InvocationCollectorNode for ast::Ty {
type OutputTy = Box<ast::Ty>;
const KIND: AstFragmentKind = AstFragmentKind::Ty;
fn to_annotatable(self) -> Annotatable {
unreachable!()
}
fn fragment_to_output(fragment: AstFragment) -> Self::OutputTy {
fragment.make_ty()
}
fn walk(&mut self, collector: &mut InvocationCollector<'_, '_>) {
// Save the pre-expanded name of this `ImplTrait`, so that later when defining
// an APIT we use a name that doesn't have any placeholder fragments in it.
if let ast::TyKind::ImplTrait(..) = self.kind {
// HACK: pprust breaks strings with newlines when the type
// gets too long. We don't want these to show up in compiler
// output or built artifacts, so replace them here...
// Perhaps we should instead format APITs more robustly.
let name = Symbol::intern(&pprust::ty_to_string(self).replace('\n', " "));
collector.cx.resolver.insert_impl_trait_name(self.id, name);
}
walk_ty(collector, self)
}
fn is_mac_call(&self) -> bool {
matches!(self.kind, ast::TyKind::MacCall(..))
}
fn take_mac_call(self) -> (Box<ast::MacCall>, ast::AttrVec, AddSemicolon) {
match self.kind {
TyKind::MacCall(mac) => (mac, AttrVec::new(), AddSemicolon::No),
_ => unreachable!(),
}
}
}
impl InvocationCollectorNode for ast::Pat {
type OutputTy = Box<ast::Pat>;
const KIND: AstFragmentKind = AstFragmentKind::Pat;
fn to_annotatable(self) -> Annotatable {
unreachable!()
}
fn fragment_to_output(fragment: AstFragment) -> Self::OutputTy {
fragment.make_pat()
}
fn walk(&mut self, collector: &mut InvocationCollector<'_, '_>) {
walk_pat(collector, self)
}
fn is_mac_call(&self) -> bool {
matches!(self.kind, PatKind::MacCall(..))
}
fn take_mac_call(self) -> (Box<ast::MacCall>, ast::AttrVec, AddSemicolon) {
match self.kind {
PatKind::MacCall(mac) => (mac, AttrVec::new(), AddSemicolon::No),
_ => unreachable!(),
}
}
}
impl InvocationCollectorNode for ast::Expr {
type OutputTy = Box<ast::Expr>;
const KIND: AstFragmentKind = AstFragmentKind::Expr;
fn to_annotatable(self) -> Annotatable {
Annotatable::Expr(Box::new(self))
}
fn fragment_to_output(fragment: AstFragment) -> Self::OutputTy {
fragment.make_expr()
}
fn descr() -> &'static str {
"an expression"
}
fn walk(&mut self, collector: &mut InvocationCollector<'_, '_>) {
walk_expr(collector, self)
}
fn is_mac_call(&self) -> bool {
matches!(self.kind, ExprKind::MacCall(..))
}
fn take_mac_call(self) -> (Box<ast::MacCall>, ast::AttrVec, AddSemicolon) {
match self.kind {
ExprKind::MacCall(mac) => (mac, self.attrs, AddSemicolon::No),
_ => unreachable!(),
}
}
}
struct OptExprTag;
impl InvocationCollectorNode for AstNodeWrapper<Box<ast::Expr>, OptExprTag> {
type OutputTy = Option<Box<ast::Expr>>;
const KIND: AstFragmentKind = AstFragmentKind::OptExpr;
fn to_annotatable(self) -> Annotatable {
Annotatable::Expr(self.wrapped)
}
fn fragment_to_output(fragment: AstFragment) -> Self::OutputTy {
fragment.make_opt_expr()
}
fn walk_flat_map(mut self, collector: &mut InvocationCollector<'_, '_>) -> Self::OutputTy {
walk_expr(collector, &mut self.wrapped);
Some(self.wrapped)
}
fn is_mac_call(&self) -> bool {
matches!(self.wrapped.kind, ast::ExprKind::MacCall(..))
}
fn take_mac_call(self) -> (Box<ast::MacCall>, ast::AttrVec, AddSemicolon) {
let node = self.wrapped;
match node.kind {
ExprKind::MacCall(mac) => (mac, node.attrs, AddSemicolon::No),
_ => unreachable!(),
}
}
fn pre_flat_map_node_collect_attr(cfg: &StripUnconfigured<'_>, attr: &ast::Attribute) {
cfg.maybe_emit_expr_attr_err(attr);
}
}
/// This struct is a hack to workaround unstable of `stmt_expr_attributes`.
/// It can be removed once that feature is stabilized.
struct MethodReceiverTag;
impl InvocationCollectorNode for AstNodeWrapper<ast::Expr, MethodReceiverTag> {
type OutputTy = AstNodeWrapper<Box<ast::Expr>, MethodReceiverTag>;
const KIND: AstFragmentKind = AstFragmentKind::MethodReceiverExpr;
fn descr() -> &'static str {
"an expression"
}
fn to_annotatable(self) -> Annotatable {
Annotatable::Expr(Box::new(self.wrapped))
}
fn fragment_to_output(fragment: AstFragment) -> Self::OutputTy {
AstNodeWrapper::new(fragment.make_method_receiver_expr(), MethodReceiverTag)
}
fn walk(&mut self, collector: &mut InvocationCollector<'_, '_>) {
walk_expr(collector, &mut self.wrapped)
}
fn is_mac_call(&self) -> bool {
matches!(self.wrapped.kind, ast::ExprKind::MacCall(..))
}
fn take_mac_call(self) -> (Box<ast::MacCall>, ast::AttrVec, AddSemicolon) {
let node = self.wrapped;
match node.kind {
ExprKind::MacCall(mac) => (mac, node.attrs, AddSemicolon::No),
_ => unreachable!(),
}
}
}
fn build_single_delegations<'a, Node: InvocationCollectorNode>(
ecx: &ExtCtxt<'_>,
deleg: &'a ast::DelegationMac,
item: &'a ast::Item<Node::ItemKind>,
suffixes: &'a [(Ident, Option<Ident>)],
item_span: Span,
from_glob: bool,
) -> impl Iterator<Item = ast::Item<Node::ItemKind>> + 'a {
if suffixes.is_empty() {
// Report an error for now, to avoid keeping stem for resolution and
// stability checks.
let kind = String::from(if from_glob { "glob" } else { "list" });
ecx.dcx().emit_err(EmptyDelegationMac { span: item.span, kind });
}
suffixes.iter().map(move |&(ident, rename)| {
let mut path = deleg.prefix.clone();
path.segments.push(ast::PathSegment { ident, id: ast::DUMMY_NODE_ID, args: None });
ast::Item {
attrs: item.attrs.clone(),
id: ast::DUMMY_NODE_ID,
span: if from_glob { item_span } else { ident.span },
vis: item.vis.clone(),
kind: Node::delegation_item_kind(Box::new(ast::Delegation {
id: ast::DUMMY_NODE_ID,
qself: deleg.qself.clone(),
path,
ident: rename.unwrap_or(ident),
rename,
body: deleg.body.clone(),
from_glob,
})),
tokens: None,
}
})
}
/// Required for `visit_node` obtained an owned `Node` from `&mut Node`.
trait DummyAstNode {
fn dummy() -> Self;
}
impl DummyAstNode for ast::Crate {
fn dummy() -> Self {
ast::Crate {
attrs: Default::default(),
items: Default::default(),
spans: Default::default(),
id: DUMMY_NODE_ID,
is_placeholder: Default::default(),
}
}
}
impl DummyAstNode for ast::Ty {
fn dummy() -> Self {
ast::Ty {
id: DUMMY_NODE_ID,
kind: TyKind::Dummy,
span: Default::default(),
tokens: Default::default(),
}
}
}
impl DummyAstNode for ast::Pat {
fn dummy() -> Self {
ast::Pat {
id: DUMMY_NODE_ID,
kind: PatKind::Wild,
span: Default::default(),
tokens: Default::default(),
}
}
}
impl DummyAstNode for ast::Expr {
fn dummy() -> Self {
ast::Expr::dummy()
}
}
impl DummyAstNode for AstNodeWrapper<ast::Expr, MethodReceiverTag> {
fn dummy() -> Self {
AstNodeWrapper::new(ast::Expr::dummy(), MethodReceiverTag)
}
}
struct InvocationCollector<'a, 'b> {
cx: &'a mut ExtCtxt<'b>,
invocations: Vec<(Invocation, Option<Arc<SyntaxExtension>>)>,
monotonic: bool,
}
impl<'a, 'b> InvocationCollector<'a, 'b> {
fn cfg(&self) -> StripUnconfigured<'_> {
StripUnconfigured {
sess: self.cx.sess,
features: Some(self.cx.ecfg.features),
config_tokens: false,
lint_node_id: self.cx.current_expansion.lint_node_id,
}
}
fn collect(&mut self, fragment_kind: AstFragmentKind, kind: InvocationKind) -> AstFragment {
let expn_id = LocalExpnId::fresh_empty();
if matches!(kind, InvocationKind::GlobDelegation { .. }) {
// In resolver we need to know which invocation ids are delegations early,
// before their `ExpnData` is filled.
self.cx.resolver.register_glob_delegation(expn_id);
}
let vis = kind.placeholder_visibility();
self.invocations.push((
Invocation {
kind,
fragment_kind,
expansion_data: ExpansionData {
id: expn_id,
depth: self.cx.current_expansion.depth + 1,
..self.cx.current_expansion.clone()
},
},
None,
));
placeholder(fragment_kind, NodeId::placeholder_from_expn_id(expn_id), vis)
}
fn collect_bang(&mut self, mac: Box<ast::MacCall>, kind: AstFragmentKind) -> AstFragment {
// cache the macro call span so that it can be
// easily adjusted for incremental compilation
let span = mac.span();
self.collect(kind, InvocationKind::Bang { mac, span })
}
fn collect_attr(
&mut self,
(attr, pos, derives): (ast::Attribute, usize, Vec<ast::Path>),
item: Annotatable,
kind: AstFragmentKind,
) -> AstFragment {
self.collect(kind, InvocationKind::Attr { attr, pos, item, derives })
}
fn collect_glob_delegation(
&mut self,
item: Box<ast::AssocItem>,
of_trait: bool,
kind: AstFragmentKind,
) -> AstFragment {
self.collect(kind, InvocationKind::GlobDelegation { item, of_trait })
}
/// If `item` is an attribute invocation, remove the attribute and return it together with
/// its position and derives following it. We have to collect the derives in order to resolve
/// legacy derive helpers (helpers written before derives that introduce them).
fn take_first_attr(
&self,
item: &mut impl HasAttrs,
) -> Option<(ast::Attribute, usize, Vec<ast::Path>)> {
let mut attr = None;
let mut cfg_pos = None;
let mut attr_pos = None;
for (pos, attr) in item.attrs().iter().enumerate() {
if !attr.is_doc_comment() && !self.cx.expanded_inert_attrs.is_marked(attr) {
let name = attr.ident().map(|ident| ident.name);
if name == Some(sym::cfg) || name == Some(sym::cfg_attr) {
cfg_pos = Some(pos); // a cfg attr found, no need to search anymore
break;
} else if attr_pos.is_none()
&& !name.is_some_and(rustc_feature::is_builtin_attr_name)
{
attr_pos = Some(pos); // a non-cfg attr found, still may find a cfg attr
}
}
}
item.visit_attrs(|attrs| {
attr = Some(match (cfg_pos, attr_pos) {
(Some(pos), _) => (attrs.remove(pos), pos, Vec::new()),
(_, Some(pos)) => {
let attr = attrs.remove(pos);
let following_derives = attrs[pos..]
.iter()
.filter(|a| a.has_name(sym::derive))
.flat_map(|a| a.meta_item_list().unwrap_or_default())
.filter_map(|meta_item_inner| match meta_item_inner {
MetaItemInner::MetaItem(ast::MetaItem {
kind: MetaItemKind::Word,
path,
..
}) => Some(path),
_ => None,
})
.collect();
(attr, pos, following_derives)
}
_ => return,
});
});
attr
}
// Detect use of feature-gated or invalid attributes on macro invocations
// since they will not be detected after macro expansion.
fn check_attributes(&self, attrs: &[ast::Attribute], call: &ast::MacCall) {
let features = self.cx.ecfg.features;
let mut attrs = attrs.iter().peekable();
let mut span: Option<Span> = None;
while let Some(attr) = attrs.next() {
rustc_ast_passes::feature_gate::check_attribute(attr, self.cx.sess, features);
validate_attr::check_attr(
&self.cx.sess.psess,
attr,
self.cx.current_expansion.lint_node_id,
);
AttributeParser::parse_limited_all(
self.cx.sess,
slice::from_ref(attr),
None,
Target::MacroCall,
call.span(),
self.cx.current_expansion.lint_node_id,
Some(self.cx.ecfg.features),
ShouldEmit::ErrorsAndLints,
);
let current_span = if let Some(sp) = span { sp.to(attr.span) } else { attr.span };
span = Some(current_span);
if attrs.peek().is_some_and(|next_attr| next_attr.doc_str().is_some()) {
continue;
}
if attr.is_doc_comment() {
self.cx.sess.psess.buffer_lint(
UNUSED_DOC_COMMENTS,
current_span,
self.cx.current_expansion.lint_node_id,
BuiltinLintDiag::UnusedDocComment(attr.span),
);
} else if rustc_attr_parsing::is_builtin_attr(attr)
&& !AttributeParser::<Early>::is_parsed_attribute(&attr.path())
{
let attr_name = attr.ident().unwrap().name;
// `#[cfg]` and `#[cfg_attr]` are special - they are
// eagerly evaluated.
if attr_name != sym::cfg_trace && attr_name != sym::cfg_attr_trace {
self.cx.sess.psess.buffer_lint(
UNUSED_ATTRIBUTES,
attr.span,
self.cx.current_expansion.lint_node_id,
BuiltinLintDiag::UnusedBuiltinAttribute {
attr_name,
macro_name: pprust::path_to_string(&call.path),
invoc_span: call.path.span,
attr_span: attr.span,
},
);
}
}
}
}
fn expand_cfg_true(
&mut self,
node: &mut (impl HasAttrs + HasNodeId),
attr: ast::Attribute,
pos: usize,
) -> EvalConfigResult {
let res = self.cfg().cfg_true(&attr, node.node_id(), ShouldEmit::ErrorsAndLints);
if res.as_bool() {
// A trace attribute left in AST in place of the original `cfg` attribute.
// It can later be used by lints or other diagnostics.
let trace_attr = attr_into_trace(attr, sym::cfg_trace);
node.visit_attrs(|attrs| attrs.insert(pos, trace_attr));
}
res
}
fn expand_cfg_attr(&self, node: &mut impl HasAttrs, attr: &ast::Attribute, pos: usize) {
node.visit_attrs(|attrs| {
// Repeated `insert` calls is inefficient, but the number of
// insertions is almost always 0 or 1 in practice.
for cfg in self.cfg().expand_cfg_attr(attr, false).into_iter().rev() {
attrs.insert(pos, cfg)
}
});
}
fn flat_map_node<Node: InvocationCollectorNode<OutputTy: Default>>(
&mut self,
mut node: Node,
) -> Node::OutputTy {
loop {
return match self.take_first_attr(&mut node) {
Some((attr, pos, derives)) => match attr.name() {
Some(sym::cfg) => {
let res = self.expand_cfg_true(&mut node, attr, pos);
match res {
EvalConfigResult::True => continue,
EvalConfigResult::False { reason, reason_span } => {
for ident in node.declared_idents() {
self.cx.resolver.append_stripped_cfg_item(
self.cx.current_expansion.lint_node_id,
ident,
reason.clone(),
reason_span,
)
}
}
}
Default::default()
}
Some(sym::cfg_attr) => {
self.expand_cfg_attr(&mut node, &attr, pos);
continue;
}
_ => {
Node::pre_flat_map_node_collect_attr(&self.cfg(), &attr);
self.collect_attr((attr, pos, derives), node.to_annotatable(), Node::KIND)
.make_ast::<Node>()
}
},
None if node.is_mac_call() => {
let (mac, attrs, add_semicolon) = node.take_mac_call();
self.check_attributes(&attrs, &mac);
let mut res = self.collect_bang(mac, Node::KIND).make_ast::<Node>();
Node::post_flat_map_node_collect_bang(&mut res, add_semicolon);
res
}
None if let Some((deleg, item)) = node.delegation() => {
let Some(suffixes) = &deleg.suffixes else {
let traitless_qself =
matches!(&deleg.qself, Some(qself) if qself.position == 0);
let (item, of_trait) = match node.to_annotatable() {
Annotatable::AssocItem(item, AssocCtxt::Impl { of_trait }) => {
(item, of_trait)
}
ann @ (Annotatable::Item(_)
| Annotatable::AssocItem(..)
| Annotatable::Stmt(_)) => {
let span = ann.span();
self.cx.dcx().emit_err(GlobDelegationOutsideImpls { span });
return Default::default();
}
_ => unreachable!(),
};
if traitless_qself {
let span = item.span;
self.cx.dcx().emit_err(GlobDelegationTraitlessQpath { span });
return Default::default();
}
return self
.collect_glob_delegation(item, of_trait, Node::KIND)
.make_ast::<Node>();
};
let single_delegations = build_single_delegations::<Node>(
self.cx, deleg, item, suffixes, item.span, false,
);
Node::flatten_outputs(single_delegations.map(|item| {
let mut item = Node::from_item(item);
assign_id!(self, item.node_id_mut(), || item.walk_flat_map(self))
}))
}
None => {
match Node::wrap_flat_map_node_walk_flat_map(node, self, |mut node, this| {
assign_id!(this, node.node_id_mut(), || node.walk_flat_map(this))
}) {
Ok(output) => output,
Err(returned_node) => {
node = returned_node;
continue;
}
}
}
};
}
}
fn visit_node<Node: InvocationCollectorNode<OutputTy: Into<Node>> + DummyAstNode>(
&mut self,
node: &mut Node,
) {
loop {
return match self.take_first_attr(node) {
Some((attr, pos, derives)) => match attr.name() {
Some(sym::cfg) => {
let span = attr.span;
if self.expand_cfg_true(node, attr, pos).as_bool() {
continue;
}
node.expand_cfg_false(self, pos, span);
continue;
}
Some(sym::cfg_attr) => {
self.expand_cfg_attr(node, &attr, pos);
continue;
}
_ => {
let n = mem::replace(node, Node::dummy());
*node = self
.collect_attr((attr, pos, derives), n.to_annotatable(), Node::KIND)
.make_ast::<Node>()
.into()
}
},
None if node.is_mac_call() => {
let n = mem::replace(node, Node::dummy());
let (mac, attrs, _) = n.take_mac_call();
self.check_attributes(&attrs, &mac);
*node = self.collect_bang(mac, Node::KIND).make_ast::<Node>().into()
}
None if node.delegation().is_some() => unreachable!(),
None => {
assign_id!(self, node.node_id_mut(), || node.walk(self))
}
};
}
}
}
impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
fn flat_map_item(&mut self, node: Box<ast::Item>) -> SmallVec<[Box<ast::Item>; 1]> {
self.flat_map_node(node)
}
fn flat_map_assoc_item(
&mut self,
node: Box<ast::AssocItem>,
ctxt: AssocCtxt,
) -> SmallVec<[Box<ast::AssocItem>; 1]> {
match ctxt {
AssocCtxt::Trait => self.flat_map_node(AstNodeWrapper::new(node, TraitItemTag)),
AssocCtxt::Impl { of_trait: false } => {
self.flat_map_node(AstNodeWrapper::new(node, ImplItemTag))
}
AssocCtxt::Impl { of_trait: true } => {
self.flat_map_node(AstNodeWrapper::new(node, TraitImplItemTag))
}
}
}
fn flat_map_foreign_item(
&mut self,
node: Box<ast::ForeignItem>,
) -> SmallVec<[Box<ast::ForeignItem>; 1]> {
self.flat_map_node(node)
}
fn flat_map_variant(&mut self, node: ast::Variant) -> SmallVec<[ast::Variant; 1]> {
self.flat_map_node(node)
}
fn flat_map_where_predicate(
&mut self,
node: ast::WherePredicate,
) -> SmallVec<[ast::WherePredicate; 1]> {
self.flat_map_node(node)
}
fn flat_map_field_def(&mut self, node: ast::FieldDef) -> SmallVec<[ast::FieldDef; 1]> {
self.flat_map_node(node)
}
fn flat_map_pat_field(&mut self, node: ast::PatField) -> SmallVec<[ast::PatField; 1]> {
self.flat_map_node(node)
}
fn flat_map_expr_field(&mut self, node: ast::ExprField) -> SmallVec<[ast::ExprField; 1]> {
self.flat_map_node(node)
}
fn flat_map_param(&mut self, node: ast::Param) -> SmallVec<[ast::Param; 1]> {
self.flat_map_node(node)
}
fn flat_map_generic_param(
&mut self,
node: ast::GenericParam,
) -> SmallVec<[ast::GenericParam; 1]> {
self.flat_map_node(node)
}
fn flat_map_arm(&mut self, node: ast::Arm) -> SmallVec<[ast::Arm; 1]> {
self.flat_map_node(node)
}
fn flat_map_stmt(&mut self, node: ast::Stmt) -> SmallVec<[ast::Stmt; 1]> {
// FIXME: invocations in semicolon-less expressions positions are expanded as expressions,
// changing that requires some compatibility measures.
if node.is_expr() {
// The only way that we can end up with a `MacCall` expression statement,
// (as opposed to a `StmtKind::MacCall`) is if we have a macro as the
// trailing expression in a block (e.g. `fn foo() { my_macro!() }`).
// Record this information, so that we can report a more specific
// `SEMICOLON_IN_EXPRESSIONS_FROM_MACROS` lint if needed.
// See #78991 for an investigation of treating macros in this position
// as statements, rather than expressions, during parsing.
return match &node.kind {
StmtKind::Expr(expr)
if matches!(**expr, ast::Expr { kind: ExprKind::MacCall(..), .. }) =>
{
self.cx.current_expansion.is_trailing_mac = true;
// Don't use `assign_id` for this statement - it may get removed
// entirely due to a `#[cfg]` on the contained expression
let res = walk_flat_map_stmt(self, node);
self.cx.current_expansion.is_trailing_mac = false;
res
}
_ => walk_flat_map_stmt(self, node),
};
}
self.flat_map_node(node)
}
fn visit_crate(&mut self, node: &mut ast::Crate) {
self.visit_node(node)
}
fn visit_ty(&mut self, node: &mut ast::Ty) {
self.visit_node(node)
}
fn visit_pat(&mut self, node: &mut ast::Pat) {
self.visit_node(node)
}
fn visit_expr(&mut self, node: &mut ast::Expr) {
// FIXME: Feature gating is performed inconsistently between `Expr` and `OptExpr`.
if let Some(attr) = node.attrs.first() {
self.cfg().maybe_emit_expr_attr_err(attr);
}
ensure_sufficient_stack(|| self.visit_node(node))
}
fn visit_method_receiver_expr(&mut self, node: &mut ast::Expr) {
self.visit_node(AstNodeWrapper::from_mut(node, MethodReceiverTag))
}
fn filter_map_expr(&mut self, node: Box<ast::Expr>) -> Option<Box<ast::Expr>> {
self.flat_map_node(AstNodeWrapper::new(node, OptExprTag))
}
fn visit_block(&mut self, node: &mut ast::Block) {
let orig_dir_ownership = mem::replace(
&mut self.cx.current_expansion.dir_ownership,
DirOwnership::UnownedViaBlock,
);
walk_block(self, node);
self.cx.current_expansion.dir_ownership = orig_dir_ownership;
}
fn visit_id(&mut self, id: &mut NodeId) {
// We may have already assigned a `NodeId`
// by calling `assign_id`
if self.monotonic && *id == ast::DUMMY_NODE_ID {
*id = self.cx.resolver.next_node_id();
}
}
}
pub struct ExpansionConfig<'feat> {
pub crate_name: Symbol,
pub features: &'feat Features,
pub recursion_limit: Limit,
pub trace_mac: bool,
/// If false, strip `#[test]` nodes
pub should_test: bool,
/// If true, use verbose debugging for `proc_macro::Span`
pub span_debug: bool,
/// If true, show backtraces for proc-macro panics
pub proc_macro_backtrace: bool,
}
impl ExpansionConfig<'_> {
pub fn default(crate_name: Symbol, features: &Features) -> ExpansionConfig<'_> {
ExpansionConfig {
crate_name,
features,
recursion_limit: Limit::new(1024),
trace_mac: false,
should_test: false,
span_debug: false,
proc_macro_backtrace: false,
}
}
}