rust/compiler/rustc_expand/src/base.rs
Ralf Jung a0215d8e46 Re-do recursive const stability checks
Fundamentally, we have *three* disjoint categories of functions:
1. const-stable functions
2. private/unstable functions that are meant to be callable from const-stable functions
3. functions that can make use of unstable const features

This PR implements the following system:
- `#[rustc_const_stable]` puts functions in the first category. It may only be applied to `#[stable]` functions.
- `#[rustc_const_unstable]` by default puts functions in the third category. The new attribute `#[rustc_const_stable_indirect]` can be added to such a function to move it into the second category.
- `const fn` without a const stability marker are in the second category if they are still unstable. They automatically inherit the feature gate for regular calls, it can now also be used for const-calls.

Also, several holes in recursive const stability checking are being closed.
There's still one potential hole that is hard to avoid, which is when MIR
building automatically inserts calls to a particular function in stable
functions -- which happens in the panic machinery. Those need to *not* be
`rustc_const_unstable` (or manually get a `rustc_const_stable_indirect`) to be
sure they follow recursive const stability. But that's a fairly rare and special
case so IMO it's fine.

The net effect of this is that a `#[unstable]` or unmarked function can be
constified simply by marking it as `const fn`, and it will then be
const-callable from stable `const fn` and subject to recursive const stability
requirements. If it is publicly reachable (which implies it cannot be unmarked),
it will be const-unstable under the same feature gate. Only if the function ever
becomes `#[stable]` does it need a `#[rustc_const_unstable]` or
`#[rustc_const_stable]` marker to decide if this should also imply
const-stability.

Adding `#[rustc_const_unstable]` is only needed for (a) functions that need to
use unstable const lang features (including intrinsics), or (b) `#[stable]`
functions that are not yet intended to be const-stable. Adding
`#[rustc_const_stable]` is only needed for functions that are actually meant to
be directly callable from stable const code. `#[rustc_const_stable_indirect]` is
used to mark intrinsics as const-callable and for `#[rustc_const_unstable]`
functions that are actually called from other, exposed-on-stable `const fn`. No
other attributes are required.
2024-10-25 20:31:40 +02:00

1440 lines
49 KiB
Rust

use std::default::Default;
use std::iter;
use std::path::Component::Prefix;
use std::path::{Path, PathBuf};
use std::rc::Rc;
use rustc_ast::attr::MarkedAttrs;
use rustc_ast::ptr::P;
use rustc_ast::token::Nonterminal;
use rustc_ast::tokenstream::TokenStream;
use rustc_ast::visit::{AssocCtxt, Visitor};
use rustc_ast::{self as ast, AttrVec, Attribute, HasAttrs, Item, NodeId, PatKind};
use rustc_attr::{self as attr, Deprecation, Stability};
use rustc_data_structures::fx::FxIndexMap;
use rustc_data_structures::sync::{self, Lrc};
use rustc_errors::{DiagCtxtHandle, ErrorGuaranteed, PResult};
use rustc_feature::Features;
use rustc_lint_defs::{BufferedEarlyLint, RegisteredTools};
use rustc_parse::MACRO_ARGUMENTS;
use rustc_parse::parser::Parser;
use rustc_session::config::CollapseMacroDebuginfo;
use rustc_session::parse::ParseSess;
use rustc_session::{Limit, Session};
use rustc_span::def_id::{CrateNum, DefId, LocalDefId};
use rustc_span::edition::Edition;
use rustc_span::hygiene::{AstPass, ExpnData, ExpnKind, LocalExpnId, MacroKind};
use rustc_span::source_map::SourceMap;
use rustc_span::symbol::{Ident, Symbol, kw, sym};
use rustc_span::{DUMMY_SP, FileName, Span};
use smallvec::{SmallVec, smallvec};
use thin_vec::ThinVec;
use crate::base::ast::MetaItemInner;
use crate::errors;
use crate::expand::{self, AstFragment, Invocation};
use crate::module::DirOwnership;
// When adding new variants, make sure to
// adjust the `visit_*` / `flat_map_*` calls in `InvocationCollector`
// to use `assign_id!`
#[derive(Debug, Clone)]
pub enum Annotatable {
Item(P<ast::Item>),
AssocItem(P<ast::AssocItem>, AssocCtxt),
ForeignItem(P<ast::ForeignItem>),
Stmt(P<ast::Stmt>),
Expr(P<ast::Expr>),
Arm(ast::Arm),
ExprField(ast::ExprField),
PatField(ast::PatField),
GenericParam(ast::GenericParam),
Param(ast::Param),
FieldDef(ast::FieldDef),
Variant(ast::Variant),
Crate(ast::Crate),
}
impl Annotatable {
pub fn span(&self) -> Span {
match self {
Annotatable::Item(item) => item.span,
Annotatable::AssocItem(assoc_item, _) => assoc_item.span,
Annotatable::ForeignItem(foreign_item) => foreign_item.span,
Annotatable::Stmt(stmt) => stmt.span,
Annotatable::Expr(expr) => expr.span,
Annotatable::Arm(arm) => arm.span,
Annotatable::ExprField(field) => field.span,
Annotatable::PatField(fp) => fp.pat.span,
Annotatable::GenericParam(gp) => gp.ident.span,
Annotatable::Param(p) => p.span,
Annotatable::FieldDef(sf) => sf.span,
Annotatable::Variant(v) => v.span,
Annotatable::Crate(c) => c.spans.inner_span,
}
}
pub fn visit_attrs(&mut self, f: impl FnOnce(&mut AttrVec)) {
match self {
Annotatable::Item(item) => item.visit_attrs(f),
Annotatable::AssocItem(assoc_item, _) => assoc_item.visit_attrs(f),
Annotatable::ForeignItem(foreign_item) => foreign_item.visit_attrs(f),
Annotatable::Stmt(stmt) => stmt.visit_attrs(f),
Annotatable::Expr(expr) => expr.visit_attrs(f),
Annotatable::Arm(arm) => arm.visit_attrs(f),
Annotatable::ExprField(field) => field.visit_attrs(f),
Annotatable::PatField(fp) => fp.visit_attrs(f),
Annotatable::GenericParam(gp) => gp.visit_attrs(f),
Annotatable::Param(p) => p.visit_attrs(f),
Annotatable::FieldDef(sf) => sf.visit_attrs(f),
Annotatable::Variant(v) => v.visit_attrs(f),
Annotatable::Crate(c) => c.visit_attrs(f),
}
}
pub fn visit_with<'a, V: Visitor<'a>>(&'a self, visitor: &mut V) -> V::Result {
match self {
Annotatable::Item(item) => visitor.visit_item(item),
Annotatable::AssocItem(item, ctxt) => visitor.visit_assoc_item(item, *ctxt),
Annotatable::ForeignItem(foreign_item) => visitor.visit_foreign_item(foreign_item),
Annotatable::Stmt(stmt) => visitor.visit_stmt(stmt),
Annotatable::Expr(expr) => visitor.visit_expr(expr),
Annotatable::Arm(arm) => visitor.visit_arm(arm),
Annotatable::ExprField(field) => visitor.visit_expr_field(field),
Annotatable::PatField(fp) => visitor.visit_pat_field(fp),
Annotatable::GenericParam(gp) => visitor.visit_generic_param(gp),
Annotatable::Param(p) => visitor.visit_param(p),
Annotatable::FieldDef(sf) => visitor.visit_field_def(sf),
Annotatable::Variant(v) => visitor.visit_variant(v),
Annotatable::Crate(c) => visitor.visit_crate(c),
}
}
pub fn to_tokens(&self) -> TokenStream {
match self {
Annotatable::Item(node) => TokenStream::from_ast(node),
Annotatable::AssocItem(node, _) => TokenStream::from_ast(node),
Annotatable::ForeignItem(node) => TokenStream::from_ast(node),
Annotatable::Stmt(node) => {
assert!(!matches!(node.kind, ast::StmtKind::Empty));
TokenStream::from_ast(node)
}
Annotatable::Expr(node) => TokenStream::from_ast(node),
Annotatable::Arm(..)
| Annotatable::ExprField(..)
| Annotatable::PatField(..)
| Annotatable::GenericParam(..)
| Annotatable::Param(..)
| Annotatable::FieldDef(..)
| Annotatable::Variant(..)
| Annotatable::Crate(..) => panic!("unexpected annotatable"),
}
}
pub fn expect_item(self) -> P<ast::Item> {
match self {
Annotatable::Item(i) => i,
_ => panic!("expected Item"),
}
}
pub fn expect_trait_item(self) -> P<ast::AssocItem> {
match self {
Annotatable::AssocItem(i, AssocCtxt::Trait) => i,
_ => panic!("expected Item"),
}
}
pub fn expect_impl_item(self) -> P<ast::AssocItem> {
match self {
Annotatable::AssocItem(i, AssocCtxt::Impl) => i,
_ => panic!("expected Item"),
}
}
pub fn expect_foreign_item(self) -> P<ast::ForeignItem> {
match self {
Annotatable::ForeignItem(i) => i,
_ => panic!("expected foreign item"),
}
}
pub fn expect_stmt(self) -> ast::Stmt {
match self {
Annotatable::Stmt(stmt) => stmt.into_inner(),
_ => panic!("expected statement"),
}
}
pub fn expect_expr(self) -> P<ast::Expr> {
match self {
Annotatable::Expr(expr) => expr,
_ => panic!("expected expression"),
}
}
pub fn expect_arm(self) -> ast::Arm {
match self {
Annotatable::Arm(arm) => arm,
_ => panic!("expected match arm"),
}
}
pub fn expect_expr_field(self) -> ast::ExprField {
match self {
Annotatable::ExprField(field) => field,
_ => panic!("expected field"),
}
}
pub fn expect_pat_field(self) -> ast::PatField {
match self {
Annotatable::PatField(fp) => fp,
_ => panic!("expected field pattern"),
}
}
pub fn expect_generic_param(self) -> ast::GenericParam {
match self {
Annotatable::GenericParam(gp) => gp,
_ => panic!("expected generic parameter"),
}
}
pub fn expect_param(self) -> ast::Param {
match self {
Annotatable::Param(param) => param,
_ => panic!("expected parameter"),
}
}
pub fn expect_field_def(self) -> ast::FieldDef {
match self {
Annotatable::FieldDef(sf) => sf,
_ => panic!("expected struct field"),
}
}
pub fn expect_variant(self) -> ast::Variant {
match self {
Annotatable::Variant(v) => v,
_ => panic!("expected variant"),
}
}
pub fn expect_crate(self) -> ast::Crate {
match self {
Annotatable::Crate(krate) => krate,
_ => panic!("expected krate"),
}
}
}
/// Result of an expansion that may need to be retried.
/// Consider using this for non-`MultiItemModifier` expanders as well.
pub enum ExpandResult<T, U> {
/// Expansion produced a result (possibly dummy).
Ready(T),
/// Expansion could not produce a result and needs to be retried.
Retry(U),
}
impl<T, U> ExpandResult<T, U> {
pub fn map<E, F: FnOnce(T) -> E>(self, f: F) -> ExpandResult<E, U> {
match self {
ExpandResult::Ready(t) => ExpandResult::Ready(f(t)),
ExpandResult::Retry(u) => ExpandResult::Retry(u),
}
}
}
pub trait MultiItemModifier {
/// `meta_item` is the attribute, and `item` is the item being modified.
fn expand(
&self,
ecx: &mut ExtCtxt<'_>,
span: Span,
meta_item: &ast::MetaItem,
item: Annotatable,
is_derive_const: bool,
) -> ExpandResult<Vec<Annotatable>, Annotatable>;
}
impl<F> MultiItemModifier for F
where
F: Fn(&mut ExtCtxt<'_>, Span, &ast::MetaItem, Annotatable) -> Vec<Annotatable>,
{
fn expand(
&self,
ecx: &mut ExtCtxt<'_>,
span: Span,
meta_item: &ast::MetaItem,
item: Annotatable,
_is_derive_const: bool,
) -> ExpandResult<Vec<Annotatable>, Annotatable> {
ExpandResult::Ready(self(ecx, span, meta_item, item))
}
}
pub trait BangProcMacro {
fn expand<'cx>(
&self,
ecx: &'cx mut ExtCtxt<'_>,
span: Span,
ts: TokenStream,
) -> Result<TokenStream, ErrorGuaranteed>;
}
impl<F> BangProcMacro for F
where
F: Fn(TokenStream) -> TokenStream,
{
fn expand<'cx>(
&self,
_ecx: &'cx mut ExtCtxt<'_>,
_span: Span,
ts: TokenStream,
) -> Result<TokenStream, ErrorGuaranteed> {
// FIXME setup implicit context in TLS before calling self.
Ok(self(ts))
}
}
pub trait AttrProcMacro {
fn expand<'cx>(
&self,
ecx: &'cx mut ExtCtxt<'_>,
span: Span,
annotation: TokenStream,
annotated: TokenStream,
) -> Result<TokenStream, ErrorGuaranteed>;
}
impl<F> AttrProcMacro for F
where
F: Fn(TokenStream, TokenStream) -> TokenStream,
{
fn expand<'cx>(
&self,
_ecx: &'cx mut ExtCtxt<'_>,
_span: Span,
annotation: TokenStream,
annotated: TokenStream,
) -> Result<TokenStream, ErrorGuaranteed> {
// FIXME setup implicit context in TLS before calling self.
Ok(self(annotation, annotated))
}
}
/// Represents a thing that maps token trees to Macro Results
pub trait TTMacroExpander {
fn expand<'cx>(
&self,
ecx: &'cx mut ExtCtxt<'_>,
span: Span,
input: TokenStream,
) -> MacroExpanderResult<'cx>;
}
pub type MacroExpanderResult<'cx> = ExpandResult<Box<dyn MacResult + 'cx>, ()>;
pub type MacroExpanderFn =
for<'cx> fn(&'cx mut ExtCtxt<'_>, Span, TokenStream) -> MacroExpanderResult<'cx>;
impl<F> TTMacroExpander for F
where
F: for<'cx> Fn(&'cx mut ExtCtxt<'_>, Span, TokenStream) -> MacroExpanderResult<'cx>,
{
fn expand<'cx>(
&self,
ecx: &'cx mut ExtCtxt<'_>,
span: Span,
input: TokenStream,
) -> MacroExpanderResult<'cx> {
self(ecx, span, input)
}
}
pub trait GlobDelegationExpander {
fn expand(&self, ecx: &mut ExtCtxt<'_>) -> ExpandResult<Vec<(Ident, Option<Ident>)>, ()>;
}
// Use a macro because forwarding to a simple function has type system issues
macro_rules! make_stmts_default {
($me:expr) => {
$me.make_expr().map(|e| {
smallvec![ast::Stmt {
id: ast::DUMMY_NODE_ID,
span: e.span,
kind: ast::StmtKind::Expr(e),
}]
})
};
}
/// The result of a macro expansion. The return values of the various
/// methods are spliced into the AST at the callsite of the macro.
pub trait MacResult {
/// Creates an expression.
fn make_expr(self: Box<Self>) -> Option<P<ast::Expr>> {
None
}
/// Creates zero or more items.
fn make_items(self: Box<Self>) -> Option<SmallVec<[P<ast::Item>; 1]>> {
None
}
/// Creates zero or more impl items.
fn make_impl_items(self: Box<Self>) -> Option<SmallVec<[P<ast::AssocItem>; 1]>> {
None
}
/// Creates zero or more trait items.
fn make_trait_items(self: Box<Self>) -> Option<SmallVec<[P<ast::AssocItem>; 1]>> {
None
}
/// Creates zero or more items in an `extern {}` block
fn make_foreign_items(self: Box<Self>) -> Option<SmallVec<[P<ast::ForeignItem>; 1]>> {
None
}
/// Creates a pattern.
fn make_pat(self: Box<Self>) -> Option<P<ast::Pat>> {
None
}
/// Creates zero or more statements.
///
/// By default this attempts to create an expression statement,
/// returning None if that fails.
fn make_stmts(self: Box<Self>) -> Option<SmallVec<[ast::Stmt; 1]>> {
make_stmts_default!(self)
}
fn make_ty(self: Box<Self>) -> Option<P<ast::Ty>> {
None
}
fn make_arms(self: Box<Self>) -> Option<SmallVec<[ast::Arm; 1]>> {
None
}
fn make_expr_fields(self: Box<Self>) -> Option<SmallVec<[ast::ExprField; 1]>> {
None
}
fn make_pat_fields(self: Box<Self>) -> Option<SmallVec<[ast::PatField; 1]>> {
None
}
fn make_generic_params(self: Box<Self>) -> Option<SmallVec<[ast::GenericParam; 1]>> {
None
}
fn make_params(self: Box<Self>) -> Option<SmallVec<[ast::Param; 1]>> {
None
}
fn make_field_defs(self: Box<Self>) -> Option<SmallVec<[ast::FieldDef; 1]>> {
None
}
fn make_variants(self: Box<Self>) -> Option<SmallVec<[ast::Variant; 1]>> {
None
}
fn make_crate(self: Box<Self>) -> Option<ast::Crate> {
// Fn-like macros cannot produce a crate.
unreachable!()
}
}
macro_rules! make_MacEager {
( $( $fld:ident: $t:ty, )* ) => {
/// `MacResult` implementation for the common case where you've already
/// built each form of AST that you might return.
#[derive(Default)]
pub struct MacEager {
$(
pub $fld: Option<$t>,
)*
}
impl MacEager {
$(
pub fn $fld(v: $t) -> Box<dyn MacResult> {
Box::new(MacEager {
$fld: Some(v),
..Default::default()
})
}
)*
}
}
}
make_MacEager! {
expr: P<ast::Expr>,
pat: P<ast::Pat>,
items: SmallVec<[P<ast::Item>; 1]>,
impl_items: SmallVec<[P<ast::AssocItem>; 1]>,
trait_items: SmallVec<[P<ast::AssocItem>; 1]>,
foreign_items: SmallVec<[P<ast::ForeignItem>; 1]>,
stmts: SmallVec<[ast::Stmt; 1]>,
ty: P<ast::Ty>,
}
impl MacResult for MacEager {
fn make_expr(self: Box<Self>) -> Option<P<ast::Expr>> {
self.expr
}
fn make_items(self: Box<Self>) -> Option<SmallVec<[P<ast::Item>; 1]>> {
self.items
}
fn make_impl_items(self: Box<Self>) -> Option<SmallVec<[P<ast::AssocItem>; 1]>> {
self.impl_items
}
fn make_trait_items(self: Box<Self>) -> Option<SmallVec<[P<ast::AssocItem>; 1]>> {
self.trait_items
}
fn make_foreign_items(self: Box<Self>) -> Option<SmallVec<[P<ast::ForeignItem>; 1]>> {
self.foreign_items
}
fn make_stmts(self: Box<Self>) -> Option<SmallVec<[ast::Stmt; 1]>> {
match self.stmts.as_ref().map_or(0, |s| s.len()) {
0 => make_stmts_default!(self),
_ => self.stmts,
}
}
fn make_pat(self: Box<Self>) -> Option<P<ast::Pat>> {
if let Some(p) = self.pat {
return Some(p);
}
if let Some(e) = self.expr {
if matches!(e.kind, ast::ExprKind::Lit(_) | ast::ExprKind::IncludedBytes(_)) {
return Some(P(ast::Pat {
id: ast::DUMMY_NODE_ID,
span: e.span,
kind: PatKind::Lit(e),
tokens: None,
}));
}
}
None
}
fn make_ty(self: Box<Self>) -> Option<P<ast::Ty>> {
self.ty
}
}
/// Fill-in macro expansion result, to allow compilation to continue
/// after hitting errors.
#[derive(Copy, Clone)]
pub struct DummyResult {
guar: Option<ErrorGuaranteed>,
span: Span,
}
impl DummyResult {
/// Creates a default MacResult that can be anything.
///
/// Use this as a return value after hitting any errors and
/// calling `span_err`.
pub fn any(span: Span, guar: ErrorGuaranteed) -> Box<dyn MacResult + 'static> {
Box::new(DummyResult { guar: Some(guar), span })
}
/// Same as `any`, but must be a valid fragment, not error.
pub fn any_valid(span: Span) -> Box<dyn MacResult + 'static> {
Box::new(DummyResult { guar: None, span })
}
/// A plain dummy expression.
pub fn raw_expr(sp: Span, guar: Option<ErrorGuaranteed>) -> P<ast::Expr> {
P(ast::Expr {
id: ast::DUMMY_NODE_ID,
kind: if let Some(guar) = guar {
ast::ExprKind::Err(guar)
} else {
ast::ExprKind::Tup(ThinVec::new())
},
span: sp,
attrs: ast::AttrVec::new(),
tokens: None,
})
}
}
impl MacResult for DummyResult {
fn make_expr(self: Box<DummyResult>) -> Option<P<ast::Expr>> {
Some(DummyResult::raw_expr(self.span, self.guar))
}
fn make_pat(self: Box<DummyResult>) -> Option<P<ast::Pat>> {
Some(P(ast::Pat {
id: ast::DUMMY_NODE_ID,
kind: PatKind::Wild,
span: self.span,
tokens: None,
}))
}
fn make_items(self: Box<DummyResult>) -> Option<SmallVec<[P<ast::Item>; 1]>> {
Some(SmallVec::new())
}
fn make_impl_items(self: Box<DummyResult>) -> Option<SmallVec<[P<ast::AssocItem>; 1]>> {
Some(SmallVec::new())
}
fn make_trait_items(self: Box<DummyResult>) -> Option<SmallVec<[P<ast::AssocItem>; 1]>> {
Some(SmallVec::new())
}
fn make_foreign_items(self: Box<Self>) -> Option<SmallVec<[P<ast::ForeignItem>; 1]>> {
Some(SmallVec::new())
}
fn make_stmts(self: Box<DummyResult>) -> Option<SmallVec<[ast::Stmt; 1]>> {
Some(smallvec![ast::Stmt {
id: ast::DUMMY_NODE_ID,
kind: ast::StmtKind::Expr(DummyResult::raw_expr(self.span, self.guar)),
span: self.span,
}])
}
fn make_ty(self: Box<DummyResult>) -> Option<P<ast::Ty>> {
// FIXME(nnethercote): you might expect `ast::TyKind::Dummy` to be used here, but some
// values produced here end up being lowered to HIR, which `ast::TyKind::Dummy` does not
// support, so we use an empty tuple instead.
Some(P(ast::Ty {
id: ast::DUMMY_NODE_ID,
kind: ast::TyKind::Tup(ThinVec::new()),
span: self.span,
tokens: None,
}))
}
fn make_arms(self: Box<DummyResult>) -> Option<SmallVec<[ast::Arm; 1]>> {
Some(SmallVec::new())
}
fn make_expr_fields(self: Box<DummyResult>) -> Option<SmallVec<[ast::ExprField; 1]>> {
Some(SmallVec::new())
}
fn make_pat_fields(self: Box<DummyResult>) -> Option<SmallVec<[ast::PatField; 1]>> {
Some(SmallVec::new())
}
fn make_generic_params(self: Box<DummyResult>) -> Option<SmallVec<[ast::GenericParam; 1]>> {
Some(SmallVec::new())
}
fn make_params(self: Box<DummyResult>) -> Option<SmallVec<[ast::Param; 1]>> {
Some(SmallVec::new())
}
fn make_field_defs(self: Box<DummyResult>) -> Option<SmallVec<[ast::FieldDef; 1]>> {
Some(SmallVec::new())
}
fn make_variants(self: Box<DummyResult>) -> Option<SmallVec<[ast::Variant; 1]>> {
Some(SmallVec::new())
}
fn make_crate(self: Box<DummyResult>) -> Option<ast::Crate> {
Some(ast::Crate {
attrs: Default::default(),
items: Default::default(),
spans: Default::default(),
id: ast::DUMMY_NODE_ID,
is_placeholder: Default::default(),
})
}
}
/// A syntax extension kind.
pub enum SyntaxExtensionKind {
/// A token-based function-like macro.
Bang(
/// An expander with signature TokenStream -> TokenStream.
Box<dyn BangProcMacro + sync::DynSync + sync::DynSend>,
),
/// An AST-based function-like macro.
LegacyBang(
/// An expander with signature TokenStream -> AST.
Box<dyn TTMacroExpander + sync::DynSync + sync::DynSend>,
),
/// A token-based attribute macro.
Attr(
/// An expander with signature (TokenStream, TokenStream) -> TokenStream.
/// The first TokenStream is the attribute itself, the second is the annotated item.
/// The produced TokenStream replaces the input TokenStream.
Box<dyn AttrProcMacro + sync::DynSync + sync::DynSend>,
),
/// An AST-based attribute macro.
LegacyAttr(
/// An expander with signature (AST, AST) -> AST.
/// The first AST fragment is the attribute itself, the second is the annotated item.
/// The produced AST fragment replaces the input AST fragment.
Box<dyn MultiItemModifier + sync::DynSync + sync::DynSend>,
),
/// A trivial attribute "macro" that does nothing,
/// only keeps the attribute and marks it as inert,
/// thus making it ineligible for further expansion.
NonMacroAttr,
/// A token-based derive macro.
Derive(
/// An expander with signature TokenStream -> TokenStream.
/// The produced TokenStream is appended to the input TokenStream.
///
/// FIXME: The text above describes how this should work. Currently it
/// is handled identically to `LegacyDerive`. It should be migrated to
/// a token-based representation like `Bang` and `Attr`, instead of
/// using `MultiItemModifier`.
Box<dyn MultiItemModifier + sync::DynSync + sync::DynSend>,
),
/// An AST-based derive macro.
LegacyDerive(
/// An expander with signature AST -> AST.
/// The produced AST fragment is appended to the input AST fragment.
Box<dyn MultiItemModifier + sync::DynSync + sync::DynSend>,
),
/// A glob delegation.
GlobDelegation(Box<dyn GlobDelegationExpander + sync::DynSync + sync::DynSend>),
}
/// A struct representing a macro definition in "lowered" form ready for expansion.
pub struct SyntaxExtension {
/// A syntax extension kind.
pub kind: SyntaxExtensionKind,
/// Span of the macro definition.
pub span: Span,
/// List of unstable features that are treated as stable inside this macro.
pub allow_internal_unstable: Option<Lrc<[Symbol]>>,
/// The macro's stability info.
pub stability: Option<Stability>,
/// The macro's deprecation info.
pub deprecation: Option<Deprecation>,
/// Names of helper attributes registered by this macro.
pub helper_attrs: Vec<Symbol>,
/// Edition of the crate in which this macro is defined.
pub edition: Edition,
/// Built-in macros have a couple of special properties like availability
/// in `#[no_implicit_prelude]` modules, so we have to keep this flag.
pub builtin_name: Option<Symbol>,
/// Suppresses the `unsafe_code` lint for code produced by this macro.
pub allow_internal_unsafe: bool,
/// Enables the macro helper hack (`ident!(...)` -> `$crate::ident!(...)`) for this macro.
pub local_inner_macros: bool,
/// Should debuginfo for the macro be collapsed to the outermost expansion site (in other
/// words, was the macro definition annotated with `#[collapse_debuginfo]`)?
pub collapse_debuginfo: bool,
}
impl SyntaxExtension {
/// Returns which kind of macro calls this syntax extension.
pub fn macro_kind(&self) -> MacroKind {
match self.kind {
SyntaxExtensionKind::Bang(..)
| SyntaxExtensionKind::LegacyBang(..)
| SyntaxExtensionKind::GlobDelegation(..) => MacroKind::Bang,
SyntaxExtensionKind::Attr(..)
| SyntaxExtensionKind::LegacyAttr(..)
| SyntaxExtensionKind::NonMacroAttr => MacroKind::Attr,
SyntaxExtensionKind::Derive(..) | SyntaxExtensionKind::LegacyDerive(..) => {
MacroKind::Derive
}
}
}
/// Constructs a syntax extension with default properties.
pub fn default(kind: SyntaxExtensionKind, edition: Edition) -> SyntaxExtension {
SyntaxExtension {
span: DUMMY_SP,
allow_internal_unstable: None,
stability: None,
deprecation: None,
helper_attrs: Vec::new(),
edition,
builtin_name: None,
kind,
allow_internal_unsafe: false,
local_inner_macros: false,
collapse_debuginfo: false,
}
}
fn collapse_debuginfo_by_name(attr: &Attribute) -> Result<CollapseMacroDebuginfo, Span> {
let list = attr.meta_item_list();
let Some([MetaItemInner::MetaItem(item)]) = list.as_deref() else {
return Err(attr.span);
};
if !item.is_word() {
return Err(item.span);
}
match item.name_or_empty() {
sym::no => Ok(CollapseMacroDebuginfo::No),
sym::external => Ok(CollapseMacroDebuginfo::External),
sym::yes => Ok(CollapseMacroDebuginfo::Yes),
_ => Err(item.path.span),
}
}
/// if-ext - if macro from different crate (related to callsite code)
/// | cmd \ attr | no | (unspecified) | external | yes |
/// | no | no | no | no | no |
/// | (unspecified) | no | if-ext | if-ext | yes |
/// | external | no | if-ext | if-ext | yes |
/// | yes | yes | yes | yes | yes |
fn get_collapse_debuginfo(sess: &Session, attrs: &[ast::Attribute], ext: bool) -> bool {
let flag = sess.opts.cg.collapse_macro_debuginfo;
let attr = attr::find_by_name(attrs, sym::collapse_debuginfo)
.and_then(|attr| {
Self::collapse_debuginfo_by_name(attr)
.map_err(|span| {
sess.dcx().emit_err(errors::CollapseMacroDebuginfoIllegal { span })
})
.ok()
})
.unwrap_or_else(|| {
if attr::contains_name(attrs, sym::rustc_builtin_macro) {
CollapseMacroDebuginfo::Yes
} else {
CollapseMacroDebuginfo::Unspecified
}
});
#[rustfmt::skip]
let collapse_table = [
[false, false, false, false],
[false, ext, ext, true],
[false, ext, ext, true],
[true, true, true, true],
];
collapse_table[flag as usize][attr as usize]
}
/// Constructs a syntax extension with the given properties
/// and other properties converted from attributes.
pub fn new(
sess: &Session,
features: &Features,
kind: SyntaxExtensionKind,
span: Span,
helper_attrs: Vec<Symbol>,
edition: Edition,
name: Symbol,
attrs: &[ast::Attribute],
is_local: bool,
) -> SyntaxExtension {
let allow_internal_unstable =
attr::allow_internal_unstable(sess, attrs).collect::<Vec<Symbol>>();
let allow_internal_unsafe = attr::contains_name(attrs, sym::allow_internal_unsafe);
let local_inner_macros = attr::find_by_name(attrs, sym::macro_export)
.and_then(|macro_export| macro_export.meta_item_list())
.is_some_and(|l| attr::list_contains_name(&l, sym::local_inner_macros));
let collapse_debuginfo = Self::get_collapse_debuginfo(sess, attrs, !is_local);
tracing::debug!(?name, ?local_inner_macros, ?collapse_debuginfo, ?allow_internal_unsafe);
let (builtin_name, helper_attrs) = attr::find_by_name(attrs, sym::rustc_builtin_macro)
.map(|attr| {
// Override `helper_attrs` passed above if it's a built-in macro,
// marking `proc_macro_derive` macros as built-in is not a realistic use case.
parse_macro_name_and_helper_attrs(sess.dcx(), attr, "built-in").map_or_else(
|| (Some(name), Vec::new()),
|(name, helper_attrs)| (Some(name), helper_attrs),
)
})
.unwrap_or_else(|| (None, helper_attrs));
let stability = attr::find_stability(sess, attrs, span);
// We set `is_const_fn` false to avoid getting any implicit const stability.
let const_stability =
attr::find_const_stability(sess, attrs, span, /* is_const_fn */ false);
let body_stability = attr::find_body_stability(sess, attrs);
if let Some((_, sp)) = const_stability {
sess.dcx().emit_err(errors::MacroConstStability {
span: sp,
head_span: sess.source_map().guess_head_span(span),
});
}
if let Some((_, sp)) = body_stability {
sess.dcx().emit_err(errors::MacroBodyStability {
span: sp,
head_span: sess.source_map().guess_head_span(span),
});
}
SyntaxExtension {
kind,
span,
allow_internal_unstable: (!allow_internal_unstable.is_empty())
.then(|| allow_internal_unstable.into()),
stability: stability.map(|(s, _)| s),
deprecation: attr::find_deprecation(sess, features, attrs).map(|(d, _)| d),
helper_attrs,
edition,
builtin_name,
allow_internal_unsafe,
local_inner_macros,
collapse_debuginfo,
}
}
/// A dummy bang macro `foo!()`.
pub fn dummy_bang(edition: Edition) -> SyntaxExtension {
fn expander<'cx>(
cx: &'cx mut ExtCtxt<'_>,
span: Span,
_: TokenStream,
) -> MacroExpanderResult<'cx> {
ExpandResult::Ready(DummyResult::any(
span,
cx.dcx().span_delayed_bug(span, "expanded a dummy bang macro"),
))
}
SyntaxExtension::default(SyntaxExtensionKind::LegacyBang(Box::new(expander)), edition)
}
/// A dummy derive macro `#[derive(Foo)]`.
pub fn dummy_derive(edition: Edition) -> SyntaxExtension {
fn expander(
_: &mut ExtCtxt<'_>,
_: Span,
_: &ast::MetaItem,
_: Annotatable,
) -> Vec<Annotatable> {
Vec::new()
}
SyntaxExtension::default(SyntaxExtensionKind::Derive(Box::new(expander)), edition)
}
pub fn non_macro_attr(edition: Edition) -> SyntaxExtension {
SyntaxExtension::default(SyntaxExtensionKind::NonMacroAttr, edition)
}
pub fn glob_delegation(
trait_def_id: DefId,
impl_def_id: LocalDefId,
edition: Edition,
) -> SyntaxExtension {
struct GlobDelegationExpanderImpl {
trait_def_id: DefId,
impl_def_id: LocalDefId,
}
impl GlobDelegationExpander for GlobDelegationExpanderImpl {
fn expand(
&self,
ecx: &mut ExtCtxt<'_>,
) -> ExpandResult<Vec<(Ident, Option<Ident>)>, ()> {
match ecx.resolver.glob_delegation_suffixes(self.trait_def_id, self.impl_def_id) {
Ok(suffixes) => ExpandResult::Ready(suffixes),
Err(Indeterminate) if ecx.force_mode => ExpandResult::Ready(Vec::new()),
Err(Indeterminate) => ExpandResult::Retry(()),
}
}
}
let expander = GlobDelegationExpanderImpl { trait_def_id, impl_def_id };
SyntaxExtension::default(SyntaxExtensionKind::GlobDelegation(Box::new(expander)), edition)
}
pub fn expn_data(
&self,
parent: LocalExpnId,
call_site: Span,
descr: Symbol,
macro_def_id: Option<DefId>,
parent_module: Option<DefId>,
) -> ExpnData {
ExpnData::new(
ExpnKind::Macro(self.macro_kind(), descr),
parent.to_expn_id(),
call_site,
self.span,
self.allow_internal_unstable.clone(),
self.edition,
macro_def_id,
parent_module,
self.allow_internal_unsafe,
self.local_inner_macros,
self.collapse_debuginfo,
)
}
}
/// Error type that denotes indeterminacy.
pub struct Indeterminate;
pub struct DeriveResolution {
pub path: ast::Path,
pub item: Annotatable,
pub exts: Option<Lrc<SyntaxExtension>>,
pub is_const: bool,
}
pub trait ResolverExpand {
fn next_node_id(&mut self) -> NodeId;
fn invocation_parent(&self, id: LocalExpnId) -> LocalDefId;
fn resolve_dollar_crates(&mut self);
fn visit_ast_fragment_with_placeholders(
&mut self,
expn_id: LocalExpnId,
fragment: &AstFragment,
);
fn register_builtin_macro(&mut self, name: Symbol, ext: SyntaxExtensionKind);
fn expansion_for_ast_pass(
&mut self,
call_site: Span,
pass: AstPass,
features: &[Symbol],
parent_module_id: Option<NodeId>,
) -> LocalExpnId;
fn resolve_imports(&mut self);
fn resolve_macro_invocation(
&mut self,
invoc: &Invocation,
eager_expansion_root: LocalExpnId,
force: bool,
) -> Result<Lrc<SyntaxExtension>, Indeterminate>;
fn record_macro_rule_usage(&mut self, mac_id: NodeId, rule_index: usize);
fn check_unused_macros(&mut self);
// Resolver interfaces for specific built-in macros.
/// Does `#[derive(...)]` attribute with the given `ExpnId` have built-in `Copy` inside it?
fn has_derive_copy(&self, expn_id: LocalExpnId) -> bool;
/// Resolve paths inside the `#[derive(...)]` attribute with the given `ExpnId`.
fn resolve_derives(
&mut self,
expn_id: LocalExpnId,
force: bool,
derive_paths: &dyn Fn() -> Vec<DeriveResolution>,
) -> Result<(), Indeterminate>;
/// Take resolutions for paths inside the `#[derive(...)]` attribute with the given `ExpnId`
/// back from resolver.
fn take_derive_resolutions(&mut self, expn_id: LocalExpnId) -> Option<Vec<DeriveResolution>>;
/// Path resolution logic for `#[cfg_accessible(path)]`.
fn cfg_accessible(
&mut self,
expn_id: LocalExpnId,
path: &ast::Path,
) -> Result<bool, Indeterminate>;
fn macro_accessible(
&mut self,
expn_id: LocalExpnId,
path: &ast::Path,
) -> Result<bool, Indeterminate>;
/// Decodes the proc-macro quoted span in the specified crate, with the specified id.
/// No caching is performed.
fn get_proc_macro_quoted_span(&self, krate: CrateNum, id: usize) -> Span;
/// The order of items in the HIR is unrelated to the order of
/// items in the AST. However, we generate proc macro harnesses
/// based on the AST order, and later refer to these harnesses
/// from the HIR. This field keeps track of the order in which
/// we generated proc macros harnesses, so that we can map
/// HIR proc macros items back to their harness items.
fn declare_proc_macro(&mut self, id: NodeId);
fn append_stripped_cfg_item(&mut self, parent_node: NodeId, name: Ident, cfg: ast::MetaItem);
/// Tools registered with `#![register_tool]` and used by tool attributes and lints.
fn registered_tools(&self) -> &RegisteredTools;
/// Mark this invocation id as a glob delegation.
fn register_glob_delegation(&mut self, invoc_id: LocalExpnId);
/// Names of specific methods to which glob delegation expands.
fn glob_delegation_suffixes(
&mut self,
trait_def_id: DefId,
impl_def_id: LocalDefId,
) -> Result<Vec<(Ident, Option<Ident>)>, Indeterminate>;
}
pub trait LintStoreExpand {
fn pre_expansion_lint(
&self,
sess: &Session,
features: &Features,
registered_tools: &RegisteredTools,
node_id: NodeId,
attrs: &[Attribute],
items: &[P<Item>],
name: Symbol,
);
}
type LintStoreExpandDyn<'a> = Option<&'a (dyn LintStoreExpand + 'a)>;
#[derive(Debug, Clone, Default)]
pub struct ModuleData {
/// Path to the module starting from the crate name, like `my_crate::foo::bar`.
pub mod_path: Vec<Ident>,
/// Stack of paths to files loaded by out-of-line module items,
/// used to detect and report recursive module inclusions.
pub file_path_stack: Vec<PathBuf>,
/// Directory to search child module files in,
/// often (but not necessarily) the parent of the top file path on the `file_path_stack`.
pub dir_path: PathBuf,
}
impl ModuleData {
pub fn with_dir_path(&self, dir_path: PathBuf) -> ModuleData {
ModuleData {
mod_path: self.mod_path.clone(),
file_path_stack: self.file_path_stack.clone(),
dir_path,
}
}
}
#[derive(Clone)]
pub struct ExpansionData {
pub id: LocalExpnId,
pub depth: usize,
pub module: Rc<ModuleData>,
pub dir_ownership: DirOwnership,
/// Some parent node that is close to this macro call
pub lint_node_id: NodeId,
pub is_trailing_mac: bool,
}
/// One of these is made during expansion and incrementally updated as we go;
/// when a macro expansion occurs, the resulting nodes have the `backtrace()
/// -> expn_data` of their expansion context stored into their span.
pub struct ExtCtxt<'a> {
pub sess: &'a Session,
pub ecfg: expand::ExpansionConfig<'a>,
pub num_standard_library_imports: usize,
pub reduced_recursion_limit: Option<(Limit, ErrorGuaranteed)>,
pub root_path: PathBuf,
pub resolver: &'a mut dyn ResolverExpand,
pub current_expansion: ExpansionData,
/// Error recovery mode entered when expansion is stuck
/// (or during eager expansion, but that's a hack).
pub force_mode: bool,
pub expansions: FxIndexMap<Span, Vec<String>>,
/// Used for running pre-expansion lints on freshly loaded modules.
pub(super) lint_store: LintStoreExpandDyn<'a>,
/// Used for storing lints generated during expansion, like `NAMED_ARGUMENTS_USED_POSITIONALLY`
pub buffered_early_lint: Vec<BufferedEarlyLint>,
/// When we 'expand' an inert attribute, we leave it
/// in the AST, but insert it here so that we know
/// not to expand it again.
pub(super) expanded_inert_attrs: MarkedAttrs,
}
impl<'a> ExtCtxt<'a> {
pub fn new(
sess: &'a Session,
ecfg: expand::ExpansionConfig<'a>,
resolver: &'a mut dyn ResolverExpand,
lint_store: LintStoreExpandDyn<'a>,
) -> ExtCtxt<'a> {
ExtCtxt {
sess,
ecfg,
num_standard_library_imports: 0,
reduced_recursion_limit: None,
resolver,
lint_store,
root_path: PathBuf::new(),
current_expansion: ExpansionData {
id: LocalExpnId::ROOT,
depth: 0,
module: Default::default(),
dir_ownership: DirOwnership::Owned { relative: None },
lint_node_id: ast::CRATE_NODE_ID,
is_trailing_mac: false,
},
force_mode: false,
expansions: FxIndexMap::default(),
expanded_inert_attrs: MarkedAttrs::new(),
buffered_early_lint: vec![],
}
}
pub fn dcx(&self) -> DiagCtxtHandle<'a> {
self.sess.dcx()
}
/// Returns a `Folder` for deeply expanding all macros in an AST node.
pub fn expander<'b>(&'b mut self) -> expand::MacroExpander<'b, 'a> {
expand::MacroExpander::new(self, false)
}
/// Returns a `Folder` that deeply expands all macros and assigns all `NodeId`s in an AST node.
/// Once `NodeId`s are assigned, the node may not be expanded, removed, or otherwise modified.
pub fn monotonic_expander<'b>(&'b mut self) -> expand::MacroExpander<'b, 'a> {
expand::MacroExpander::new(self, true)
}
pub fn new_parser_from_tts(&self, stream: TokenStream) -> Parser<'a> {
Parser::new(&self.sess.psess, stream, MACRO_ARGUMENTS)
}
pub fn source_map(&self) -> &'a SourceMap {
self.sess.psess.source_map()
}
pub fn psess(&self) -> &'a ParseSess {
&self.sess.psess
}
pub fn call_site(&self) -> Span {
self.current_expansion.id.expn_data().call_site
}
/// Returns the current expansion kind's description.
pub(crate) fn expansion_descr(&self) -> String {
let expn_data = self.current_expansion.id.expn_data();
expn_data.kind.descr()
}
/// Equivalent of `Span::def_site` from the proc macro API,
/// except that the location is taken from the span passed as an argument.
pub fn with_def_site_ctxt(&self, span: Span) -> Span {
span.with_def_site_ctxt(self.current_expansion.id.to_expn_id())
}
/// Equivalent of `Span::call_site` from the proc macro API,
/// except that the location is taken from the span passed as an argument.
pub fn with_call_site_ctxt(&self, span: Span) -> Span {
span.with_call_site_ctxt(self.current_expansion.id.to_expn_id())
}
/// Equivalent of `Span::mixed_site` from the proc macro API,
/// except that the location is taken from the span passed as an argument.
pub fn with_mixed_site_ctxt(&self, span: Span) -> Span {
span.with_mixed_site_ctxt(self.current_expansion.id.to_expn_id())
}
/// Returns span for the macro which originally caused the current expansion to happen.
///
/// Stops backtracing at include! boundary.
pub fn expansion_cause(&self) -> Option<Span> {
self.current_expansion.id.expansion_cause()
}
pub fn trace_macros_diag(&mut self) {
for (span, notes) in self.expansions.iter() {
let mut db = self.dcx().create_note(errors::TraceMacro { span: *span });
for note in notes {
// FIXME: make this translatable
#[allow(rustc::untranslatable_diagnostic)]
db.note(note.clone());
}
db.emit();
}
// Fixme: does this result in errors?
self.expansions.clear();
}
pub fn trace_macros(&self) -> bool {
self.ecfg.trace_mac
}
pub fn set_trace_macros(&mut self, x: bool) {
self.ecfg.trace_mac = x
}
pub fn std_path(&self, components: &[Symbol]) -> Vec<Ident> {
let def_site = self.with_def_site_ctxt(DUMMY_SP);
iter::once(Ident::new(kw::DollarCrate, def_site))
.chain(components.iter().map(|&s| Ident::with_dummy_span(s)))
.collect()
}
pub fn def_site_path(&self, components: &[Symbol]) -> Vec<Ident> {
let def_site = self.with_def_site_ctxt(DUMMY_SP);
components.iter().map(|&s| Ident::new(s, def_site)).collect()
}
pub fn check_unused_macros(&mut self) {
self.resolver.check_unused_macros();
}
}
/// Resolves a `path` mentioned inside Rust code, returning an absolute path.
///
/// This unifies the logic used for resolving `include_X!`.
pub fn resolve_path(sess: &Session, path: impl Into<PathBuf>, span: Span) -> PResult<'_, PathBuf> {
let path = path.into();
// Relative paths are resolved relative to the file in which they are found
// after macro expansion (that is, they are unhygienic).
if !path.is_absolute() {
let callsite = span.source_callsite();
let source_map = sess.source_map();
let Some(mut base_path) = source_map.span_to_filename(callsite).into_local_path() else {
return Err(sess.dcx().create_err(errors::ResolveRelativePath {
span,
path: source_map
.filename_for_diagnostics(&source_map.span_to_filename(callsite))
.to_string(),
}));
};
base_path.pop();
base_path.push(path);
Ok(base_path)
} else {
// This ensures that Windows verbatim paths are fixed if mixed path separators are used,
// which can happen when `concat!` is used to join paths.
match path.components().next() {
Some(Prefix(prefix)) if prefix.kind().is_verbatim() => Ok(path.components().collect()),
_ => Ok(path),
}
}
}
pub fn parse_macro_name_and_helper_attrs(
dcx: DiagCtxtHandle<'_>,
attr: &Attribute,
macro_type: &str,
) -> Option<(Symbol, Vec<Symbol>)> {
// Once we've located the `#[proc_macro_derive]` attribute, verify
// that it's of the form `#[proc_macro_derive(Foo)]` or
// `#[proc_macro_derive(Foo, attributes(A, ..))]`
let list = attr.meta_item_list()?;
let ([trait_attr] | [trait_attr, _]) = list.as_slice() else {
dcx.emit_err(errors::AttrNoArguments { span: attr.span });
return None;
};
let Some(trait_attr) = trait_attr.meta_item() else {
dcx.emit_err(errors::NotAMetaItem { span: trait_attr.span() });
return None;
};
let trait_ident = match trait_attr.ident() {
Some(trait_ident) if trait_attr.is_word() => trait_ident,
_ => {
dcx.emit_err(errors::OnlyOneWord { span: trait_attr.span });
return None;
}
};
if !trait_ident.name.can_be_raw() {
dcx.emit_err(errors::CannotBeNameOfMacro {
span: trait_attr.span,
trait_ident,
macro_type,
});
}
let attributes_attr = list.get(1);
let proc_attrs: Vec<_> = if let Some(attr) = attributes_attr {
if !attr.has_name(sym::attributes) {
dcx.emit_err(errors::ArgumentNotAttributes { span: attr.span() });
}
attr.meta_item_list()
.unwrap_or_else(|| {
dcx.emit_err(errors::AttributesWrongForm { span: attr.span() });
&[]
})
.iter()
.filter_map(|attr| {
let Some(attr) = attr.meta_item() else {
dcx.emit_err(errors::AttributeMetaItem { span: attr.span() });
return None;
};
let ident = match attr.ident() {
Some(ident) if attr.is_word() => ident,
_ => {
dcx.emit_err(errors::AttributeSingleWord { span: attr.span });
return None;
}
};
if !ident.name.can_be_raw() {
dcx.emit_err(errors::HelperAttributeNameInvalid {
span: attr.span,
name: ident,
});
}
Some(ident.name)
})
.collect()
} else {
Vec::new()
};
Some((trait_ident.name, proc_attrs))
}
/// If this item looks like a specific enums from `rental`, emit a fatal error.
/// See #73345 and #83125 for more details.
/// FIXME(#73933): Remove this eventually.
fn pretty_printing_compatibility_hack(item: &Item, sess: &Session) {
let name = item.ident.name;
if name == sym::ProceduralMasqueradeDummyType
&& let ast::ItemKind::Enum(enum_def, _) = &item.kind
&& let [variant] = &*enum_def.variants
&& variant.ident.name == sym::Input
&& let FileName::Real(real) = sess.source_map().span_to_filename(item.ident.span)
&& let Some(c) = real
.local_path()
.unwrap_or(Path::new(""))
.components()
.flat_map(|c| c.as_os_str().to_str())
.find(|c| c.starts_with("rental") || c.starts_with("allsorts-rental"))
{
let crate_matches = if c.starts_with("allsorts-rental") {
true
} else {
let mut version = c.trim_start_matches("rental-").split('.');
version.next() == Some("0")
&& version.next() == Some("5")
&& version.next().and_then(|c| c.parse::<u32>().ok()).is_some_and(|v| v < 6)
};
if crate_matches {
sess.dcx().emit_fatal(errors::ProcMacroBackCompat {
crate_name: "rental".to_string(),
fixed_version: "0.5.6".to_string(),
});
}
}
}
pub(crate) fn ann_pretty_printing_compatibility_hack(ann: &Annotatable, sess: &Session) {
let item = match ann {
Annotatable::Item(item) => item,
Annotatable::Stmt(stmt) => match &stmt.kind {
ast::StmtKind::Item(item) => item,
_ => return,
},
_ => return,
};
pretty_printing_compatibility_hack(item, sess)
}
pub(crate) fn nt_pretty_printing_compatibility_hack(nt: &Nonterminal, sess: &Session) {
let item = match nt {
Nonterminal::NtItem(item) => item,
Nonterminal::NtStmt(stmt) => match &stmt.kind {
ast::StmtKind::Item(item) => item,
_ => return,
},
_ => return,
};
pretty_printing_compatibility_hack(item, sess)
}