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Diffstat (limited to 'compiler/rustc_expand/src/base.rs')
| -rw-r--r-- | compiler/rustc_expand/src/base.rs | 1444 |
1 files changed, 1444 insertions, 0 deletions
diff --git a/compiler/rustc_expand/src/base.rs b/compiler/rustc_expand/src/base.rs new file mode 100644 index 000000000..6e093811f --- /dev/null +++ b/compiler/rustc_expand/src/base.rs @@ -0,0 +1,1444 @@ +use crate::expand::{self, AstFragment, Invocation}; +use crate::module::DirOwnership; + +use rustc_ast::attr::MarkedAttrs; +use rustc_ast::ptr::P; +use rustc_ast::token::{self, Nonterminal}; +use rustc_ast::tokenstream::TokenStream; +use rustc_ast::visit::{AssocCtxt, Visitor}; +use rustc_ast::{self as ast, Attribute, HasAttrs, Item, NodeId, PatKind}; +use rustc_attr::{self as attr, Deprecation, Stability}; +use rustc_data_structures::fx::{FxHashSet, FxIndexMap}; +use rustc_data_structures::sync::{self, Lrc}; +use rustc_errors::{Applicability, DiagnosticBuilder, ErrorGuaranteed, MultiSpan, PResult}; +use rustc_lint_defs::builtin::PROC_MACRO_BACK_COMPAT; +use rustc_lint_defs::{BufferedEarlyLint, BuiltinLintDiagnostics}; +use rustc_parse::{self, parser, MACRO_ARGUMENTS}; +use rustc_session::{parse::ParseSess, Limit, Session, SessionDiagnostic}; +use rustc_span::def_id::{CrateNum, DefId, LocalDefId}; +use rustc_span::edition::Edition; +use rustc_span::hygiene::{AstPass, ExpnData, ExpnKind, LocalExpnId}; +use rustc_span::source_map::SourceMap; +use rustc_span::symbol::{kw, sym, Ident, Symbol}; +use rustc_span::{FileName, Span, DUMMY_SP}; +use smallvec::{smallvec, SmallVec}; + +use std::default::Default; +use std::iter; +use std::path::PathBuf; +use std::rc::Rc; + +pub(crate) use rustc_span::hygiene::MacroKind; + +// 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>), + TraitItem(P<ast::AssocItem>), + ImplItem(P<ast::AssocItem>), + 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(ref item) => item.span, + Annotatable::TraitItem(ref trait_item) => trait_item.span, + Annotatable::ImplItem(ref impl_item) => impl_item.span, + Annotatable::ForeignItem(ref foreign_item) => foreign_item.span, + Annotatable::Stmt(ref stmt) => stmt.span, + Annotatable::Expr(ref expr) => expr.span, + Annotatable::Arm(ref arm) => arm.span, + Annotatable::ExprField(ref field) => field.span, + Annotatable::PatField(ref fp) => fp.pat.span, + Annotatable::GenericParam(ref gp) => gp.ident.span, + Annotatable::Param(ref p) => p.span, + Annotatable::FieldDef(ref sf) => sf.span, + Annotatable::Variant(ref v) => v.span, + Annotatable::Crate(ref c) => c.spans.inner_span, + } + } + + pub fn visit_attrs(&mut self, f: impl FnOnce(&mut Vec<Attribute>)) { + match self { + Annotatable::Item(item) => item.visit_attrs(f), + Annotatable::TraitItem(trait_item) => trait_item.visit_attrs(f), + Annotatable::ImplItem(impl_item) => impl_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) { + match self { + Annotatable::Item(item) => visitor.visit_item(item), + Annotatable::TraitItem(item) => visitor.visit_assoc_item(item, AssocCtxt::Trait), + Annotatable::ImplItem(item) => visitor.visit_assoc_item(item, AssocCtxt::Impl), + 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::TraitItem(node) | Annotatable::ImplItem(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::TraitItem(i) => i, + _ => panic!("expected Item"), + } + } + + pub fn expect_impl_item(self) -> P<ast::AssocItem> { + match self { + Annotatable::ImplItem(i) => 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), +} + +// `meta_item` is the attribute, and `item` is the item being modified. +pub trait MultiItemModifier { + fn expand( + &self, + ecx: &mut ExtCtxt<'_>, + span: Span, + meta_item: &ast::MetaItem, + item: Annotatable, + ) -> 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, + ) -> 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, + ) -> Box<dyn MacResult + 'cx>; +} + +pub type MacroExpanderFn = + for<'cx> fn(&'cx mut ExtCtxt<'_>, Span, TokenStream) -> Box<dyn MacResult + 'cx>; + +impl<F> TTMacroExpander for F +where + F: for<'cx> Fn(&'cx mut ExtCtxt<'_>, Span, TokenStream) -> Box<dyn MacResult + 'cx>, +{ + fn expand<'cx>( + &self, + ecx: &'cx mut ExtCtxt<'_>, + span: Span, + input: TokenStream, + ) -> Box<dyn MacResult + 'cx> { + self(ecx, span, input) + } +} + +// 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 let ast::ExprKind::Lit(_) = e.kind { + 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 { + is_error: bool, + 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) -> Box<dyn MacResult + 'static> { + Box::new(DummyResult { is_error: true, 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 { is_error: false, span }) + } + + /// A plain dummy expression. + pub fn raw_expr(sp: Span, is_error: bool) -> P<ast::Expr> { + P(ast::Expr { + id: ast::DUMMY_NODE_ID, + kind: if is_error { ast::ExprKind::Err } else { ast::ExprKind::Tup(Vec::new()) }, + span: sp, + attrs: ast::AttrVec::new(), + tokens: None, + }) + } + + /// A plain dummy pattern. + pub fn raw_pat(sp: Span) -> ast::Pat { + ast::Pat { id: ast::DUMMY_NODE_ID, kind: PatKind::Wild, span: sp, tokens: None } + } + + /// A plain dummy type. + pub fn raw_ty(sp: Span, is_error: bool) -> P<ast::Ty> { + P(ast::Ty { + id: ast::DUMMY_NODE_ID, + kind: if is_error { ast::TyKind::Err } else { ast::TyKind::Tup(Vec::new()) }, + span: sp, + tokens: None, + }) + } +} + +impl MacResult for DummyResult { + fn make_expr(self: Box<DummyResult>) -> Option<P<ast::Expr>> { + Some(DummyResult::raw_expr(self.span, self.is_error)) + } + + fn make_pat(self: Box<DummyResult>) -> Option<P<ast::Pat>> { + Some(P(DummyResult::raw_pat(self.span))) + } + + 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.is_error)), + span: self.span, + }]) + } + + fn make_ty(self: Box<DummyResult>) -> Option<P<ast::Ty>> { + Some(DummyResult::raw_ty(self.span, self.is_error)) + } + + 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()) + } +} + +/// A syntax extension kind. +pub enum SyntaxExtensionKind { + /// A token-based function-like macro. + Bang( + /// An expander with signature TokenStream -> TokenStream. + Box<dyn BangProcMacro + sync::Sync + sync::Send>, + ), + + /// An AST-based function-like macro. + LegacyBang( + /// An expander with signature TokenStream -> AST. + Box<dyn TTMacroExpander + sync::Sync + sync::Send>, + ), + + /// A token-based attribute macro. + Attr( + /// An expander with signature (TokenStream, TokenStream) -> TokenStream. + /// The first TokenSteam is the attribute itself, the second is the annotated item. + /// The produced TokenSteam replaces the input TokenSteam. + Box<dyn AttrProcMacro + sync::Sync + sync::Send>, + ), + + /// 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::Sync + sync::Send>, + ), + + /// 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 (not yet). + /// The produced TokenSteam is appended to the input TokenSteam. + Box<dyn MultiItemModifier + sync::Sync + sync::Send>, + ), + + /// 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::Sync + sync::Send>, + ), +} + +/// 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]>>, + /// 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, + /// 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>, +} + +impl SyntaxExtension { + /// Returns which kind of macro calls this syntax extension. + pub fn macro_kind(&self) -> MacroKind { + match self.kind { + SyntaxExtensionKind::Bang(..) | SyntaxExtensionKind::LegacyBang(..) => 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, + allow_internal_unsafe: false, + local_inner_macros: false, + stability: None, + deprecation: None, + helper_attrs: Vec::new(), + edition, + builtin_name: None, + kind, + } + } + + /// Constructs a syntax extension with the given properties + /// and other properties converted from attributes. + pub fn new( + sess: &Session, + kind: SyntaxExtensionKind, + span: Span, + helper_attrs: Vec<Symbol>, + edition: Edition, + name: Symbol, + attrs: &[ast::Attribute], + ) -> SyntaxExtension { + let allow_internal_unstable = + attr::allow_internal_unstable(sess, &attrs).collect::<Vec<Symbol>>(); + + let mut local_inner_macros = false; + if let Some(macro_export) = sess.find_by_name(attrs, sym::macro_export) { + if let Some(l) = macro_export.meta_item_list() { + local_inner_macros = attr::list_contains_name(&l, sym::local_inner_macros); + } + } + + let (builtin_name, helper_attrs) = sess + .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.diagnostic(), 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, const_stability) = attr::find_stability(&sess, attrs, span); + if let Some((_, sp)) = const_stability { + sess.parse_sess + .span_diagnostic + .struct_span_err(sp, "macros cannot have const stability attributes") + .span_label(sp, "invalid const stability attribute") + .span_label( + sess.source_map().guess_head_span(span), + "const stability attribute affects this macro", + ) + .emit(); + } + + SyntaxExtension { + kind, + span, + allow_internal_unstable: (!allow_internal_unstable.is_empty()) + .then(|| allow_internal_unstable.into()), + allow_internal_unsafe: sess.contains_name(attrs, sym::allow_internal_unsafe), + local_inner_macros, + stability: stability.map(|(s, _)| s), + deprecation: attr::find_deprecation(&sess, attrs).map(|(d, _)| d), + helper_attrs, + edition, + builtin_name, + } + } + + pub fn dummy_bang(edition: Edition) -> SyntaxExtension { + fn expander<'cx>( + _: &'cx mut ExtCtxt<'_>, + span: Span, + _: TokenStream, + ) -> Box<dyn MacResult + 'cx> { + DummyResult::any(span) + } + SyntaxExtension::default(SyntaxExtensionKind::LegacyBang(Box::new(expander)), edition) + } + + 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 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.allow_internal_unsafe, + self.local_inner_macros, + self.edition, + macro_def_id, + parent_module, + ) + } +} + +/// Error type that denotes indeterminacy. +pub struct Indeterminate; + +pub type DeriveResolutions = Vec<(ast::Path, Annotatable, Option<Lrc<SyntaxExtension>>)>; + +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() -> DeriveResolutions, + ) -> 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<DeriveResolutions>; + /// Path resolution logic for `#[cfg_accessible(path)]`. + fn cfg_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); + + /// Tools registered with `#![register_tool]` and used by tool attributes and lints. + fn registered_tools(&self) -> &FxHashSet<Ident>; +} + +pub trait LintStoreExpand { + fn pre_expansion_lint( + &self, + sess: &Session, + registered_tools: &FxHashSet<Ident>, + node_id: NodeId, + attrs: &[Attribute], + items: &[P<Item>], + name: &str, + ); +} + +type LintStoreExpandDyn<'a> = Option<&'a (dyn LintStoreExpand + 'a)>; + +#[derive(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, + pub prior_type_ascription: Option<(Span, bool)>, + /// 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 reduced_recursion_limit: Option<Limit>, + 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, + 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 }, + prior_type_ascription: 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![], + } + } + + /// 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::Parser<'a> { + rustc_parse::stream_to_parser(&self.sess.parse_sess, stream, MACRO_ARGUMENTS) + } + pub fn source_map(&self) -> &'a SourceMap { + self.sess.parse_sess.source_map() + } + pub fn parse_sess(&self) -> &'a ParseSess { + &self.sess.parse_sess + } + 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() + } + + #[rustc_lint_diagnostics] + pub fn struct_span_err<S: Into<MultiSpan>>( + &self, + sp: S, + msg: &str, + ) -> DiagnosticBuilder<'a, ErrorGuaranteed> { + self.sess.parse_sess.span_diagnostic.struct_span_err(sp, msg) + } + + pub fn create_err( + &self, + err: impl SessionDiagnostic<'a>, + ) -> DiagnosticBuilder<'a, ErrorGuaranteed> { + self.sess.create_err(err) + } + + pub fn emit_err(&self, err: impl SessionDiagnostic<'a>) -> ErrorGuaranteed { + self.sess.emit_err(err) + } + + /// Emit `msg` attached to `sp`, without immediately stopping + /// compilation. + /// + /// Compilation will be stopped in the near future (at the end of + /// the macro expansion phase). + #[rustc_lint_diagnostics] + pub fn span_err<S: Into<MultiSpan>>(&self, sp: S, msg: &str) { + self.sess.parse_sess.span_diagnostic.span_err(sp, msg); + } + #[rustc_lint_diagnostics] + pub fn span_warn<S: Into<MultiSpan>>(&self, sp: S, msg: &str) { + self.sess.parse_sess.span_diagnostic.span_warn(sp, msg); + } + pub fn span_bug<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> ! { + self.sess.parse_sess.span_diagnostic.span_bug(sp, msg); + } + pub fn trace_macros_diag(&mut self) { + for (sp, notes) in self.expansions.iter() { + let mut db = self.sess.parse_sess.span_diagnostic.span_note_diag(*sp, "trace_macro"); + for note in notes { + db.note(note); + } + db.emit(); + } + // Fixme: does this result in errors? + self.expansions.clear(); + } + pub fn bug(&self, msg: &str) -> ! { + self.sess.parse_sess.span_diagnostic.bug(msg); + } + 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( + parse_sess: &ParseSess, + 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 mut result = match parse_sess.source_map().span_to_filename(callsite) { + FileName::Real(name) => name + .into_local_path() + .expect("attempting to resolve a file path in an external file"), + FileName::DocTest(path, _) => path, + other => { + return Err(parse_sess.span_diagnostic.struct_span_err( + span, + &format!( + "cannot resolve relative path in non-file source `{}`", + parse_sess.source_map().filename_for_diagnostics(&other) + ), + )); + } + }; + result.pop(); + result.push(path); + Ok(result) + } else { + Ok(path) + } +} + +/// Extracts a string literal from the macro expanded version of `expr`, +/// returning a diagnostic error of `err_msg` if `expr` is not a string literal. +/// The returned bool indicates whether an applicable suggestion has already been +/// added to the diagnostic to avoid emitting multiple suggestions. `Err(None)` +/// indicates that an ast error was encountered. +pub fn expr_to_spanned_string<'a>( + cx: &'a mut ExtCtxt<'_>, + expr: P<ast::Expr>, + err_msg: &str, +) -> Result<(Symbol, ast::StrStyle, Span), Option<(DiagnosticBuilder<'a, ErrorGuaranteed>, bool)>> { + // Perform eager expansion on the expression. + // We want to be able to handle e.g., `concat!("foo", "bar")`. + let expr = cx.expander().fully_expand_fragment(AstFragment::Expr(expr)).make_expr(); + + Err(match expr.kind { + ast::ExprKind::Lit(ref l) => match l.kind { + ast::LitKind::Str(s, style) => return Ok((s, style, expr.span)), + ast::LitKind::ByteStr(_) => { + let mut err = cx.struct_span_err(l.span, err_msg); + err.span_suggestion( + expr.span.shrink_to_lo(), + "consider removing the leading `b`", + "", + Applicability::MaybeIncorrect, + ); + Some((err, true)) + } + ast::LitKind::Err(_) => None, + _ => Some((cx.struct_span_err(l.span, err_msg), false)), + }, + ast::ExprKind::Err => None, + _ => Some((cx.struct_span_err(expr.span, err_msg), false)), + }) +} + +/// Extracts a string literal from the macro expanded version of `expr`, +/// emitting `err_msg` if `expr` is not a string literal. This does not stop +/// compilation on error, merely emits a non-fatal error and returns `None`. +pub fn expr_to_string( + cx: &mut ExtCtxt<'_>, + expr: P<ast::Expr>, + err_msg: &str, +) -> Option<(Symbol, ast::StrStyle)> { + expr_to_spanned_string(cx, expr, err_msg) + .map_err(|err| { + err.map(|(mut err, _)| { + err.emit(); + }) + }) + .ok() + .map(|(symbol, style, _)| (symbol, style)) +} + +/// Non-fatally assert that `tts` is empty. Note that this function +/// returns even when `tts` is non-empty, macros that *need* to stop +/// compilation should call +/// `cx.parse_sess.span_diagnostic.abort_if_errors()` (this should be +/// done as rarely as possible). +pub fn check_zero_tts(cx: &ExtCtxt<'_>, sp: Span, tts: TokenStream, name: &str) { + if !tts.is_empty() { + cx.span_err(sp, &format!("{} takes no arguments", name)); + } +} + +/// Parse an expression. On error, emit it, advancing to `Eof`, and return `None`. +pub fn parse_expr(p: &mut parser::Parser<'_>) -> Option<P<ast::Expr>> { + match p.parse_expr() { + Ok(e) => return Some(e), + Err(mut err) => { + err.emit(); + } + } + while p.token != token::Eof { + p.bump(); + } + None +} + +/// Interpreting `tts` as a comma-separated sequence of expressions, +/// expect exactly one string literal, or emit an error and return `None`. +pub fn get_single_str_from_tts( + cx: &mut ExtCtxt<'_>, + sp: Span, + tts: TokenStream, + name: &str, +) -> Option<Symbol> { + let mut p = cx.new_parser_from_tts(tts); + if p.token == token::Eof { + cx.span_err(sp, &format!("{} takes 1 argument", name)); + return None; + } + let ret = parse_expr(&mut p)?; + let _ = p.eat(&token::Comma); + + if p.token != token::Eof { + cx.span_err(sp, &format!("{} takes 1 argument", name)); + } + expr_to_string(cx, ret, "argument must be a string literal").map(|(s, _)| s) +} + +/// Extracts comma-separated expressions from `tts`. +/// On error, emit it, and return `None`. +pub fn get_exprs_from_tts( + cx: &mut ExtCtxt<'_>, + sp: Span, + tts: TokenStream, +) -> Option<Vec<P<ast::Expr>>> { + let mut p = cx.new_parser_from_tts(tts); + let mut es = Vec::new(); + while p.token != token::Eof { + let expr = parse_expr(&mut p)?; + + // Perform eager expansion on the expression. + // We want to be able to handle e.g., `concat!("foo", "bar")`. + let expr = cx.expander().fully_expand_fragment(AstFragment::Expr(expr)).make_expr(); + + es.push(expr); + if p.eat(&token::Comma) { + continue; + } + if p.token != token::Eof { + cx.span_err(sp, "expected token: `,`"); + return None; + } + } + Some(es) +} + +pub fn parse_macro_name_and_helper_attrs( + diag: &rustc_errors::Handler, + attr: &Attribute, + descr: &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()?; + if list.len() != 1 && list.len() != 2 { + diag.span_err(attr.span, "attribute must have either one or two arguments"); + return None; + } + let Some(trait_attr) = list[0].meta_item() else { + diag.span_err(list[0].span(), "not a meta item"); + return None; + }; + let trait_ident = match trait_attr.ident() { + Some(trait_ident) if trait_attr.is_word() => trait_ident, + _ => { + diag.span_err(trait_attr.span, "must only be one word"); + return None; + } + }; + + if !trait_ident.name.can_be_raw() { + diag.span_err( + trait_attr.span, + &format!("`{}` cannot be a name of {} macro", trait_ident, descr), + ); + } + + let attributes_attr = list.get(1); + let proc_attrs: Vec<_> = if let Some(attr) = attributes_attr { + if !attr.has_name(sym::attributes) { + diag.span_err(attr.span(), "second argument must be `attributes`"); + } + attr.meta_item_list() + .unwrap_or_else(|| { + diag.span_err(attr.span(), "attribute must be of form: `attributes(foo, bar)`"); + &[] + }) + .iter() + .filter_map(|attr| { + let Some(attr) = attr.meta_item() else { + diag.span_err(attr.span(), "not a meta item"); + return None; + }; + + let ident = match attr.ident() { + Some(ident) if attr.is_word() => ident, + _ => { + diag.span_err(attr.span, "must only be one word"); + return None; + } + }; + if !ident.name.can_be_raw() { + diag.span_err( + attr.span, + &format!("`{}` cannot be a name of derive helper attribute", ident), + ); + } + + Some(ident.name) + }) + .collect() + } else { + Vec::new() + }; + + Some((trait_ident.name, proc_attrs)) +} + +/// This nonterminal looks like some specific enums from +/// `proc-macro-hack` and `procedural-masquerade` crates. +/// We need to maintain some special pretty-printing behavior for them due to incorrect +/// asserts in old versions of those crates and their wide use in the ecosystem. +/// See issue #73345 for more details. +/// FIXME(#73933): Remove this eventually. +fn pretty_printing_compatibility_hack(item: &Item, sess: &ParseSess) -> bool { + let name = item.ident.name; + if name == sym::ProceduralMasqueradeDummyType { + if let ast::ItemKind::Enum(enum_def, _) = &item.kind { + if let [variant] = &*enum_def.variants { + if variant.ident.name == sym::Input { + sess.buffer_lint_with_diagnostic( + &PROC_MACRO_BACK_COMPAT, + item.ident.span, + ast::CRATE_NODE_ID, + "using `procedural-masquerade` crate", + BuiltinLintDiagnostics::ProcMacroBackCompat( + "The `procedural-masquerade` crate has been unnecessary since Rust 1.30.0. \ + Versions of this crate below 0.1.7 will eventually stop compiling.".to_string()) + ); + return true; + } + } + } + } + false +} + +pub(crate) fn ann_pretty_printing_compatibility_hack(ann: &Annotatable, sess: &ParseSess) -> bool { + let item = match ann { + Annotatable::Item(item) => item, + Annotatable::Stmt(stmt) => match &stmt.kind { + ast::StmtKind::Item(item) => item, + _ => return false, + }, + _ => return false, + }; + pretty_printing_compatibility_hack(item, sess) +} + +pub(crate) fn nt_pretty_printing_compatibility_hack(nt: &Nonterminal, sess: &ParseSess) -> bool { + let item = match nt { + Nonterminal::NtItem(item) => item, + Nonterminal::NtStmt(stmt) => match &stmt.kind { + ast::StmtKind::Item(item) => item, + _ => return false, + }, + _ => return false, + }; + pretty_printing_compatibility_hack(item, sess) +} |