Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 616 insertions, 0 deletions

diff --git a/compiler/rustc_expand/src/build.rs b/compiler/rustc_expand/src/build.rs
new file mode 100644
index 000000000..fa3e2a4a5
--- /dev/null
+++ b/compiler/rustc_expand/src/build.rs
@@ -0,0 +1,616 @@
+use crate::base::ExtCtxt;
+
+use rustc_ast::attr;
+use rustc_ast::ptr::P;
+use rustc_ast::{self as ast, AttrVec, BlockCheckMode, Expr, LocalKind, PatKind, UnOp};
+use rustc_span::source_map::Spanned;
+use rustc_span::symbol::{kw, sym, Ident, Symbol};
+
+use rustc_span::Span;
+
+impl<'a> ExtCtxt<'a> {
+    pub fn path(&self, span: Span, strs: Vec<Ident>) -> ast::Path {
+        self.path_all(span, false, strs, vec![])
+    }
+    pub fn path_ident(&self, span: Span, id: Ident) -> ast::Path {
+        self.path(span, vec![id])
+    }
+    pub fn path_global(&self, span: Span, strs: Vec<Ident>) -> ast::Path {
+        self.path_all(span, true, strs, vec![])
+    }
+    pub fn path_all(
+        &self,
+        span: Span,
+        global: bool,
+        mut idents: Vec<Ident>,
+        args: Vec<ast::GenericArg>,
+    ) -> ast::Path {
+        assert!(!idents.is_empty());
+        let add_root = global && !idents[0].is_path_segment_keyword();
+        let mut segments = Vec::with_capacity(idents.len() + add_root as usize);
+        if add_root {
+            segments.push(ast::PathSegment::path_root(span));
+        }
+        let last_ident = idents.pop().unwrap();
+        segments.extend(
+            idents.into_iter().map(|ident| ast::PathSegment::from_ident(ident.with_span_pos(span))),
+        );
+        let args = if !args.is_empty() {
+            let args = args.into_iter().map(ast::AngleBracketedArg::Arg).collect();
+            ast::AngleBracketedArgs { args, span }.into()
+        } else {
+            None
+        };
+        segments.push(ast::PathSegment {
+            ident: last_ident.with_span_pos(span),
+            id: ast::DUMMY_NODE_ID,
+            args,
+        });
+        ast::Path { span, segments, tokens: None }
+    }
+
+    pub fn ty_mt(&self, ty: P<ast::Ty>, mutbl: ast::Mutability) -> ast::MutTy {
+        ast::MutTy { ty, mutbl }
+    }
+
+    pub fn ty(&self, span: Span, kind: ast::TyKind) -> P<ast::Ty> {
+        P(ast::Ty { id: ast::DUMMY_NODE_ID, span, kind, tokens: None })
+    }
+
+    pub fn ty_infer(&self, span: Span) -> P<ast::Ty> {
+        self.ty(span, ast::TyKind::Infer)
+    }
+
+    pub fn ty_path(&self, path: ast::Path) -> P<ast::Ty> {
+        self.ty(path.span, ast::TyKind::Path(None, path))
+    }
+
+    // Might need to take bounds as an argument in the future, if you ever want
+    // to generate a bounded existential trait type.
+    pub fn ty_ident(&self, span: Span, ident: Ident) -> P<ast::Ty> {
+        self.ty_path(self.path_ident(span, ident))
+    }
+
+    pub fn anon_const(&self, span: Span, kind: ast::ExprKind) -> ast::AnonConst {
+        ast::AnonConst {
+            id: ast::DUMMY_NODE_ID,
+            value: P(ast::Expr {
+                id: ast::DUMMY_NODE_ID,
+                kind,
+                span,
+                attrs: AttrVec::new(),
+                tokens: None,
+            }),
+        }
+    }
+
+    pub fn const_ident(&self, span: Span, ident: Ident) -> ast::AnonConst {
+        self.anon_const(span, ast::ExprKind::Path(None, self.path_ident(span, ident)))
+    }
+
+    pub fn ty_rptr(
+        &self,
+        span: Span,
+        ty: P<ast::Ty>,
+        lifetime: Option<ast::Lifetime>,
+        mutbl: ast::Mutability,
+    ) -> P<ast::Ty> {
+        self.ty(span, ast::TyKind::Rptr(lifetime, self.ty_mt(ty, mutbl)))
+    }
+
+    pub fn ty_ptr(&self, span: Span, ty: P<ast::Ty>, mutbl: ast::Mutability) -> P<ast::Ty> {
+        self.ty(span, ast::TyKind::Ptr(self.ty_mt(ty, mutbl)))
+    }
+
+    pub fn typaram(
+        &self,
+        span: Span,
+        ident: Ident,
+        attrs: Vec<ast::Attribute>,
+        bounds: ast::GenericBounds,
+        default: Option<P<ast::Ty>>,
+    ) -> ast::GenericParam {
+        ast::GenericParam {
+            ident: ident.with_span_pos(span),
+            id: ast::DUMMY_NODE_ID,
+            attrs: attrs.into(),
+            bounds,
+            kind: ast::GenericParamKind::Type { default },
+            is_placeholder: false,
+            colon_span: None,
+        }
+    }
+
+    pub fn trait_ref(&self, path: ast::Path) -> ast::TraitRef {
+        ast::TraitRef { path, ref_id: ast::DUMMY_NODE_ID }
+    }
+
+    pub fn poly_trait_ref(&self, span: Span, path: ast::Path) -> ast::PolyTraitRef {
+        ast::PolyTraitRef {
+            bound_generic_params: Vec::new(),
+            trait_ref: self.trait_ref(path),
+            span,
+        }
+    }
+
+    pub fn trait_bound(&self, path: ast::Path) -> ast::GenericBound {
+        ast::GenericBound::Trait(
+            self.poly_trait_ref(path.span, path),
+            ast::TraitBoundModifier::None,
+        )
+    }
+
+    pub fn lifetime(&self, span: Span, ident: Ident) -> ast::Lifetime {
+        ast::Lifetime { id: ast::DUMMY_NODE_ID, ident: ident.with_span_pos(span) }
+    }
+
+    pub fn lifetime_static(&self, span: Span) -> ast::Lifetime {
+        self.lifetime(span, Ident::new(kw::StaticLifetime, span))
+    }
+
+    pub fn stmt_expr(&self, expr: P<ast::Expr>) -> ast::Stmt {
+        ast::Stmt { id: ast::DUMMY_NODE_ID, span: expr.span, kind: ast::StmtKind::Expr(expr) }
+    }
+
+    pub fn stmt_let_pat(&self, sp: Span, pat: P<ast::Pat>, ex: P<ast::Expr>) -> ast::Stmt {
+        let local = P(ast::Local {
+            pat,
+            ty: None,
+            id: ast::DUMMY_NODE_ID,
+            kind: LocalKind::Init(ex),
+            span: sp,
+            attrs: AttrVec::new(),
+            tokens: None,
+        });
+        self.stmt_local(local, sp)
+    }
+
+    pub fn stmt_let(&self, sp: Span, mutbl: bool, ident: Ident, ex: P<ast::Expr>) -> ast::Stmt {
+        self.stmt_let_ty(sp, mutbl, ident, None, ex)
+    }
+
+    pub fn stmt_let_ty(
+        &self,
+        sp: Span,
+        mutbl: bool,
+        ident: Ident,
+        ty: Option<P<ast::Ty>>,
+        ex: P<ast::Expr>,
+    ) -> ast::Stmt {
+        let pat = if mutbl {
+            let binding_mode = ast::BindingMode::ByValue(ast::Mutability::Mut);
+            self.pat_ident_binding_mode(sp, ident, binding_mode)
+        } else {
+            self.pat_ident(sp, ident)
+        };
+        let local = P(ast::Local {
+            pat,
+            ty,
+            id: ast::DUMMY_NODE_ID,
+            kind: LocalKind::Init(ex),
+            span: sp,
+            attrs: AttrVec::new(),
+            tokens: None,
+        });
+        self.stmt_local(local, sp)
+    }
+
+    // Generates `let _: Type;`, which is usually used for type assertions.
+    pub fn stmt_let_type_only(&self, span: Span, ty: P<ast::Ty>) -> ast::Stmt {
+        let local = P(ast::Local {
+            pat: self.pat_wild(span),
+            ty: Some(ty),
+            id: ast::DUMMY_NODE_ID,
+            kind: LocalKind::Decl,
+            span,
+            attrs: AttrVec::new(),
+            tokens: None,
+        });
+        self.stmt_local(local, span)
+    }
+
+    pub fn stmt_local(&self, local: P<ast::Local>, span: Span) -> ast::Stmt {
+        ast::Stmt { id: ast::DUMMY_NODE_ID, kind: ast::StmtKind::Local(local), span }
+    }
+
+    pub fn stmt_item(&self, sp: Span, item: P<ast::Item>) -> ast::Stmt {
+        ast::Stmt { id: ast::DUMMY_NODE_ID, kind: ast::StmtKind::Item(item), span: sp }
+    }
+
+    pub fn block_expr(&self, expr: P<ast::Expr>) -> P<ast::Block> {
+        self.block(
+            expr.span,
+            vec![ast::Stmt {
+                id: ast::DUMMY_NODE_ID,
+                span: expr.span,
+                kind: ast::StmtKind::Expr(expr),
+            }],
+        )
+    }
+    pub fn block(&self, span: Span, stmts: Vec<ast::Stmt>) -> P<ast::Block> {
+        P(ast::Block {
+            stmts,
+            id: ast::DUMMY_NODE_ID,
+            rules: BlockCheckMode::Default,
+            span,
+            tokens: None,
+            could_be_bare_literal: false,
+        })
+    }
+
+    pub fn expr(&self, span: Span, kind: ast::ExprKind) -> P<ast::Expr> {
+        P(ast::Expr { id: ast::DUMMY_NODE_ID, kind, span, attrs: AttrVec::new(), tokens: None })
+    }
+
+    pub fn expr_path(&self, path: ast::Path) -> P<ast::Expr> {
+        self.expr(path.span, ast::ExprKind::Path(None, path))
+    }
+
+    pub fn expr_ident(&self, span: Span, id: Ident) -> P<ast::Expr> {
+        self.expr_path(self.path_ident(span, id))
+    }
+    pub fn expr_self(&self, span: Span) -> P<ast::Expr> {
+        self.expr_ident(span, Ident::with_dummy_span(kw::SelfLower))
+    }
+
+    pub fn expr_binary(
+        &self,
+        sp: Span,
+        op: ast::BinOpKind,
+        lhs: P<ast::Expr>,
+        rhs: P<ast::Expr>,
+    ) -> P<ast::Expr> {
+        self.expr(sp, ast::ExprKind::Binary(Spanned { node: op, span: sp }, lhs, rhs))
+    }
+
+    pub fn expr_deref(&self, sp: Span, e: P<ast::Expr>) -> P<ast::Expr> {
+        self.expr(sp, ast::ExprKind::Unary(UnOp::Deref, e))
+    }
+
+    pub fn expr_addr_of(&self, sp: Span, e: P<ast::Expr>) -> P<ast::Expr> {
+        self.expr(sp, ast::ExprKind::AddrOf(ast::BorrowKind::Ref, ast::Mutability::Not, e))
+    }
+
+    pub fn expr_call(
+        &self,
+        span: Span,
+        expr: P<ast::Expr>,
+        args: Vec<P<ast::Expr>>,
+    ) -> P<ast::Expr> {
+        self.expr(span, ast::ExprKind::Call(expr, args))
+    }
+    pub fn expr_call_ident(&self, span: Span, id: Ident, args: Vec<P<ast::Expr>>) -> P<ast::Expr> {
+        self.expr(span, ast::ExprKind::Call(self.expr_ident(span, id), args))
+    }
+    pub fn expr_call_global(
+        &self,
+        sp: Span,
+        fn_path: Vec<Ident>,
+        args: Vec<P<ast::Expr>>,
+    ) -> P<ast::Expr> {
+        let pathexpr = self.expr_path(self.path_global(sp, fn_path));
+        self.expr_call(sp, pathexpr, args)
+    }
+    pub fn expr_block(&self, b: P<ast::Block>) -> P<ast::Expr> {
+        self.expr(b.span, ast::ExprKind::Block(b, None))
+    }
+    pub fn field_imm(&self, span: Span, ident: Ident, e: P<ast::Expr>) -> ast::ExprField {
+        ast::ExprField {
+            ident: ident.with_span_pos(span),
+            expr: e,
+            span,
+            is_shorthand: false,
+            attrs: AttrVec::new(),
+            id: ast::DUMMY_NODE_ID,
+            is_placeholder: false,
+        }
+    }
+    pub fn expr_struct(
+        &self,
+        span: Span,
+        path: ast::Path,
+        fields: Vec<ast::ExprField>,
+    ) -> P<ast::Expr> {
+        self.expr(
+            span,
+            ast::ExprKind::Struct(P(ast::StructExpr {
+                qself: None,
+                path,
+                fields,
+                rest: ast::StructRest::None,
+            })),
+        )
+    }
+    pub fn expr_struct_ident(
+        &self,
+        span: Span,
+        id: Ident,
+        fields: Vec<ast::ExprField>,
+    ) -> P<ast::Expr> {
+        self.expr_struct(span, self.path_ident(span, id), fields)
+    }
+
+    pub fn expr_lit(&self, span: Span, lit_kind: ast::LitKind) -> P<ast::Expr> {
+        let lit = ast::Lit::from_lit_kind(lit_kind, span);
+        self.expr(span, ast::ExprKind::Lit(lit))
+    }
+    pub fn expr_usize(&self, span: Span, i: usize) -> P<ast::Expr> {
+        self.expr_lit(
+            span,
+            ast::LitKind::Int(i as u128, ast::LitIntType::Unsigned(ast::UintTy::Usize)),
+        )
+    }
+    pub fn expr_u32(&self, sp: Span, u: u32) -> P<ast::Expr> {
+        self.expr_lit(sp, ast::LitKind::Int(u as u128, ast::LitIntType::Unsigned(ast::UintTy::U32)))
+    }
+    pub fn expr_bool(&self, sp: Span, value: bool) -> P<ast::Expr> {
+        self.expr_lit(sp, ast::LitKind::Bool(value))
+    }
+
+    /// `[expr1, expr2, ...]`
+    pub fn expr_array(&self, sp: Span, exprs: Vec<P<ast::Expr>>) -> P<ast::Expr> {
+        self.expr(sp, ast::ExprKind::Array(exprs))
+    }
+
+    /// `&[expr1, expr2, ...]`
+    pub fn expr_array_ref(&self, sp: Span, exprs: Vec<P<ast::Expr>>) -> P<ast::Expr> {
+        self.expr_addr_of(sp, self.expr_array(sp, exprs))
+    }
+
+    pub fn expr_str(&self, sp: Span, s: Symbol) -> P<ast::Expr> {
+        self.expr_lit(sp, ast::LitKind::Str(s, ast::StrStyle::Cooked))
+    }
+
+    pub fn expr_cast(&self, sp: Span, expr: P<ast::Expr>, ty: P<ast::Ty>) -> P<ast::Expr> {
+        self.expr(sp, ast::ExprKind::Cast(expr, ty))
+    }
+
+    pub fn expr_some(&self, sp: Span, expr: P<ast::Expr>) -> P<ast::Expr> {
+        let some = self.std_path(&[sym::option, sym::Option, sym::Some]);
+        self.expr_call_global(sp, some, vec![expr])
+    }
+
+    pub fn expr_none(&self, sp: Span) -> P<ast::Expr> {
+        let none = self.std_path(&[sym::option, sym::Option, sym::None]);
+        self.expr_path(self.path_global(sp, none))
+    }
+    pub fn expr_tuple(&self, sp: Span, exprs: Vec<P<ast::Expr>>) -> P<ast::Expr> {
+        self.expr(sp, ast::ExprKind::Tup(exprs))
+    }
+
+    pub fn expr_fail(&self, span: Span, msg: Symbol) -> P<ast::Expr> {
+        self.expr_call_global(
+            span,
+            [sym::std, sym::rt, sym::begin_panic].iter().map(|s| Ident::new(*s, span)).collect(),
+            vec![self.expr_str(span, msg)],
+        )
+    }
+
+    pub fn expr_unreachable(&self, span: Span) -> P<ast::Expr> {
+        self.expr_fail(span, Symbol::intern("internal error: entered unreachable code"))
+    }
+
+    pub fn expr_ok(&self, sp: Span, expr: P<ast::Expr>) -> P<ast::Expr> {
+        let ok = self.std_path(&[sym::result, sym::Result, sym::Ok]);
+        self.expr_call_global(sp, ok, vec![expr])
+    }
+
+    pub fn expr_try(&self, sp: Span, head: P<ast::Expr>) -> P<ast::Expr> {
+        let ok = self.std_path(&[sym::result, sym::Result, sym::Ok]);
+        let ok_path = self.path_global(sp, ok);
+        let err = self.std_path(&[sym::result, sym::Result, sym::Err]);
+        let err_path = self.path_global(sp, err);
+
+        let binding_variable = Ident::new(sym::__try_var, sp);
+        let binding_pat = self.pat_ident(sp, binding_variable);
+        let binding_expr = self.expr_ident(sp, binding_variable);
+
+        // `Ok(__try_var)` pattern
+        let ok_pat = self.pat_tuple_struct(sp, ok_path, vec![binding_pat.clone()]);
+
+        // `Err(__try_var)` (pattern and expression respectively)
+        let err_pat = self.pat_tuple_struct(sp, err_path.clone(), vec![binding_pat]);
+        let err_inner_expr =
+            self.expr_call(sp, self.expr_path(err_path), vec![binding_expr.clone()]);
+        // `return Err(__try_var)`
+        let err_expr = self.expr(sp, ast::ExprKind::Ret(Some(err_inner_expr)));
+
+        // `Ok(__try_var) => __try_var`
+        let ok_arm = self.arm(sp, ok_pat, binding_expr);
+        // `Err(__try_var) => return Err(__try_var)`
+        let err_arm = self.arm(sp, err_pat, err_expr);
+
+        // `match head { Ok() => ..., Err() => ... }`
+        self.expr_match(sp, head, vec![ok_arm, err_arm])
+    }
+
+    pub fn pat(&self, span: Span, kind: PatKind) -> P<ast::Pat> {
+        P(ast::Pat { id: ast::DUMMY_NODE_ID, kind, span, tokens: None })
+    }
+    pub fn pat_wild(&self, span: Span) -> P<ast::Pat> {
+        self.pat(span, PatKind::Wild)
+    }
+    pub fn pat_lit(&self, span: Span, expr: P<ast::Expr>) -> P<ast::Pat> {
+        self.pat(span, PatKind::Lit(expr))
+    }
+    pub fn pat_ident(&self, span: Span, ident: Ident) -> P<ast::Pat> {
+        let binding_mode = ast::BindingMode::ByValue(ast::Mutability::Not);
+        self.pat_ident_binding_mode(span, ident, binding_mode)
+    }
+
+    pub fn pat_ident_binding_mode(
+        &self,
+        span: Span,
+        ident: Ident,
+        bm: ast::BindingMode,
+    ) -> P<ast::Pat> {
+        let pat = PatKind::Ident(bm, ident.with_span_pos(span), None);
+        self.pat(span, pat)
+    }
+    pub fn pat_path(&self, span: Span, path: ast::Path) -> P<ast::Pat> {
+        self.pat(span, PatKind::Path(None, path))
+    }
+    pub fn pat_tuple_struct(
+        &self,
+        span: Span,
+        path: ast::Path,
+        subpats: Vec<P<ast::Pat>>,
+    ) -> P<ast::Pat> {
+        self.pat(span, PatKind::TupleStruct(None, path, subpats))
+    }
+    pub fn pat_struct(
+        &self,
+        span: Span,
+        path: ast::Path,
+        field_pats: Vec<ast::PatField>,
+    ) -> P<ast::Pat> {
+        self.pat(span, PatKind::Struct(None, path, field_pats, false))
+    }
+    pub fn pat_tuple(&self, span: Span, pats: Vec<P<ast::Pat>>) -> P<ast::Pat> {
+        self.pat(span, PatKind::Tuple(pats))
+    }
+
+    pub fn pat_some(&self, span: Span, pat: P<ast::Pat>) -> P<ast::Pat> {
+        let some = self.std_path(&[sym::option, sym::Option, sym::Some]);
+        let path = self.path_global(span, some);
+        self.pat_tuple_struct(span, path, vec![pat])
+    }
+
+    pub fn arm(&self, span: Span, pat: P<ast::Pat>, expr: P<ast::Expr>) -> ast::Arm {
+        ast::Arm {
+            attrs: AttrVec::new(),
+            pat,
+            guard: None,
+            body: expr,
+            span,
+            id: ast::DUMMY_NODE_ID,
+            is_placeholder: false,
+        }
+    }
+
+    pub fn arm_unreachable(&self, span: Span) -> ast::Arm {
+        self.arm(span, self.pat_wild(span), self.expr_unreachable(span))
+    }
+
+    pub fn expr_match(&self, span: Span, arg: P<ast::Expr>, arms: Vec<ast::Arm>) -> P<Expr> {
+        self.expr(span, ast::ExprKind::Match(arg, arms))
+    }
+
+    pub fn expr_if(
+        &self,
+        span: Span,
+        cond: P<ast::Expr>,
+        then: P<ast::Expr>,
+        els: Option<P<ast::Expr>>,
+    ) -> P<ast::Expr> {
+        let els = els.map(|x| self.expr_block(self.block_expr(x)));
+        self.expr(span, ast::ExprKind::If(cond, self.block_expr(then), els))
+    }
+
+    pub fn lambda(&self, span: Span, ids: Vec<Ident>, body: P<ast::Expr>) -> P<ast::Expr> {
+        let fn_decl = self.fn_decl(
+            ids.iter().map(|id| self.param(span, *id, self.ty(span, ast::TyKind::Infer))).collect(),
+            ast::FnRetTy::Default(span),
+        );
+
+        // FIXME -- We are using `span` as the span of the `|...|`
+        // part of the lambda, but it probably (maybe?) corresponds to
+        // the entire lambda body. Probably we should extend the API
+        // here, but that's not entirely clear.
+        self.expr(
+            span,
+            ast::ExprKind::Closure(
+                ast::ClosureBinder::NotPresent,
+                ast::CaptureBy::Ref,
+                ast::Async::No,
+                ast::Movability::Movable,
+                fn_decl,
+                body,
+                span,
+            ),
+        )
+    }
+
+    pub fn lambda0(&self, span: Span, body: P<ast::Expr>) -> P<ast::Expr> {
+        self.lambda(span, Vec::new(), body)
+    }
+
+    pub fn lambda1(&self, span: Span, body: P<ast::Expr>, ident: Ident) -> P<ast::Expr> {
+        self.lambda(span, vec![ident], body)
+    }
+
+    pub fn lambda_stmts_1(&self, span: Span, stmts: Vec<ast::Stmt>, ident: Ident) -> P<ast::Expr> {
+        self.lambda1(span, self.expr_block(self.block(span, stmts)), ident)
+    }
+
+    pub fn param(&self, span: Span, ident: Ident, ty: P<ast::Ty>) -> ast::Param {
+        let arg_pat = self.pat_ident(span, ident);
+        ast::Param {
+            attrs: AttrVec::default(),
+            id: ast::DUMMY_NODE_ID,
+            pat: arg_pat,
+            span,
+            ty,
+            is_placeholder: false,
+        }
+    }
+
+    // `self` is unused but keep it as method for the convenience use.
+    pub fn fn_decl(&self, inputs: Vec<ast::Param>, output: ast::FnRetTy) -> P<ast::FnDecl> {
+        P(ast::FnDecl { inputs, output })
+    }
+
+    pub fn item(
+        &self,
+        span: Span,
+        name: Ident,
+        attrs: Vec<ast::Attribute>,
+        kind: ast::ItemKind,
+    ) -> P<ast::Item> {
+        // FIXME: Would be nice if our generated code didn't violate
+        // Rust coding conventions
+        P(ast::Item {
+            ident: name,
+            attrs,
+            id: ast::DUMMY_NODE_ID,
+            kind,
+            vis: ast::Visibility {
+                span: span.shrink_to_lo(),
+                kind: ast::VisibilityKind::Inherited,
+                tokens: None,
+            },
+            span,
+            tokens: None,
+        })
+    }
+
+    pub fn item_static(
+        &self,
+        span: Span,
+        name: Ident,
+        ty: P<ast::Ty>,
+        mutbl: ast::Mutability,
+        expr: P<ast::Expr>,
+    ) -> P<ast::Item> {
+        self.item(span, name, Vec::new(), ast::ItemKind::Static(ty, mutbl, Some(expr)))
+    }
+
+    pub fn item_const(
+        &self,
+        span: Span,
+        name: Ident,
+        ty: P<ast::Ty>,
+        expr: P<ast::Expr>,
+    ) -> P<ast::Item> {
+        let def = ast::Defaultness::Final;
+        self.item(span, name, Vec::new(), ast::ItemKind::Const(def, ty, Some(expr)))
+    }
+
+    pub fn attribute(&self, mi: ast::MetaItem) -> ast::Attribute {
+        attr::mk_attr_outer(mi)
+    }
+
+    pub fn meta_word(&self, sp: Span, w: Symbol) -> ast::MetaItem {
+        attr::mk_word_item(Ident::new(w, sp))
+    }
+}