rustc_expand/
build.rs

1use rustc_ast::token::Delimiter;
2use rustc_ast::tokenstream::TokenStream;
3use rustc_ast::util::literal;
4use rustc_ast::{
5    self as ast, AnonConst, AttrItem, AttrVec, BlockCheckMode, Expr, LocalKind, MatchKind, PatKind,
6    UnOp, attr, token, tokenstream,
7};
8use rustc_span::{DUMMY_SP, Ident, Span, Spanned, Symbol, kw, sym};
9use thin_vec::{ThinVec, thin_vec};
10
11use crate::base::ExtCtxt;
12
13impl<'a> ExtCtxt<'a> {
14    pub fn path(&self, span: Span, strs: Vec<Ident>) -> ast::Path {
15        self.path_all(span, false, strs, ::alloc::vec::Vec::new()vec![])
16    }
17    pub fn path_ident(&self, span: Span, id: Ident) -> ast::Path {
18        self.path(span, ::alloc::boxed::box_assume_init_into_vec_unsafe(::alloc::intrinsics::write_box_via_move(::alloc::boxed::Box::new_uninit(),
        [id]))vec![id])
19    }
20    pub fn path_global(&self, span: Span, strs: Vec<Ident>) -> ast::Path {
21        self.path_all(span, true, strs, ::alloc::vec::Vec::new()vec![])
22    }
23    pub fn path_all(
24        &self,
25        span: Span,
26        global: bool,
27        mut idents: Vec<Ident>,
28        args: Vec<ast::GenericArg>,
29    ) -> ast::Path {
30        if !!idents.is_empty() {
    ::core::panicking::panic("assertion failed: !idents.is_empty()")
};assert!(!idents.is_empty());
31        let add_root = global && !idents[0].is_path_segment_keyword();
32        let mut segments = ThinVec::with_capacity(idents.len() + add_root as usize);
33        if add_root {
34            segments.push(ast::PathSegment::path_root(span));
35        }
36        let last_ident = idents.pop().unwrap();
37        segments.extend(
38            idents.into_iter().map(|ident| ast::PathSegment::from_ident(ident.with_span_pos(span))),
39        );
40        let args = if !args.is_empty() {
41            let args = args.into_iter().map(ast::AngleBracketedArg::Arg).collect();
42            Some(ast::AngleBracketedArgs { args, span }.into())
43        } else {
44            None
45        };
46        segments.push(ast::PathSegment {
47            ident: last_ident.with_span_pos(span),
48            id: ast::DUMMY_NODE_ID,
49            args,
50        });
51        ast::Path { span, segments }
52    }
53
54    pub fn macro_call(
55        &self,
56        span: Span,
57        path: ast::Path,
58        delim: Delimiter,
59        tokens: TokenStream,
60    ) -> Box<ast::MacCall> {
61        Box::new(ast::MacCall {
62            path,
63            args: Box::new(ast::DelimArgs {
64                dspan: tokenstream::DelimSpan { open: span, close: span },
65                delim,
66                tokens,
67            }),
68        })
69    }
70
71    pub fn ty_mt(&self, ty: Box<ast::Ty>, mutbl: ast::Mutability) -> ast::MutTy {
72        ast::MutTy { ty, mutbl }
73    }
74
75    pub fn ty(&self, span: Span, kind: ast::TyKind) -> Box<ast::Ty> {
76        Box::new(ast::Ty { id: ast::DUMMY_NODE_ID, span, kind })
77    }
78
79    pub fn ty_infer(&self, span: Span) -> Box<ast::Ty> {
80        self.ty(span, ast::TyKind::Infer)
81    }
82
83    pub fn ty_path(&self, path: ast::Path) -> Box<ast::Ty> {
84        self.ty(path.span, ast::TyKind::Path(None, path))
85    }
86
87    // Might need to take bounds as an argument in the future, if you ever want
88    // to generate a bounded existential trait type.
89    pub fn ty_ident(&self, span: Span, ident: Ident) -> Box<ast::Ty> {
90        self.ty_path(self.path_ident(span, ident))
91    }
92
93    pub fn anon_const(&self, span: Span, kind: ast::ExprKind) -> ast::AnonConst {
94        ast::AnonConst {
95            id: ast::DUMMY_NODE_ID,
96            value: Box::new(ast::Expr {
97                id: ast::DUMMY_NODE_ID,
98                kind,
99                span,
100                attrs: AttrVec::new(),
101                tokens: None,
102            }),
103        }
104    }
105
106    pub fn anon_const_block(&self, b: Box<ast::Block>) -> Box<ast::AnonConst> {
107        Box::new(self.anon_const(b.span, ast::ExprKind::Block(b, None)))
108    }
109
110    pub fn const_ident(&self, span: Span, ident: Ident) -> ast::AnonConst {
111        self.anon_const(span, ast::ExprKind::Path(None, self.path_ident(span, ident)))
112    }
113
114    pub fn ty_ref(
115        &self,
116        span: Span,
117        ty: Box<ast::Ty>,
118        lifetime: Option<ast::Lifetime>,
119        mutbl: ast::Mutability,
120    ) -> Box<ast::Ty> {
121        self.ty(span, ast::TyKind::Ref(lifetime, self.ty_mt(ty, mutbl)))
122    }
123
124    pub fn ty_ptr(&self, span: Span, ty: Box<ast::Ty>, mutbl: ast::Mutability) -> Box<ast::Ty> {
125        self.ty(span, ast::TyKind::Ptr(self.ty_mt(ty, mutbl)))
126    }
127
128    pub fn typaram(
129        &self,
130        span: Span,
131        ident: Ident,
132        bounds: ast::GenericBounds,
133        default: Option<Box<ast::Ty>>,
134    ) -> ast::GenericParam {
135        ast::GenericParam {
136            ident: ident.with_span_pos(span),
137            id: ast::DUMMY_NODE_ID,
138            attrs: AttrVec::new(),
139            bounds,
140            kind: ast::GenericParamKind::Type { default },
141            is_placeholder: false,
142            colon_span: None,
143        }
144    }
145
146    pub fn lifetime_param(
147        &self,
148        span: Span,
149        ident: Ident,
150        bounds: ast::GenericBounds,
151    ) -> ast::GenericParam {
152        ast::GenericParam {
153            id: ast::DUMMY_NODE_ID,
154            ident: ident.with_span_pos(span),
155            attrs: AttrVec::new(),
156            bounds,
157            is_placeholder: false,
158            kind: ast::GenericParamKind::Lifetime,
159            colon_span: None,
160        }
161    }
162
163    pub fn const_param(
164        &self,
165        span: Span,
166        ident: Ident,
167        bounds: ast::GenericBounds,
168        ty: Box<ast::Ty>,
169        default: Option<AnonConst>,
170    ) -> ast::GenericParam {
171        ast::GenericParam {
172            id: ast::DUMMY_NODE_ID,
173            ident: ident.with_span_pos(span),
174            attrs: AttrVec::new(),
175            bounds,
176            is_placeholder: false,
177            kind: ast::GenericParamKind::Const { ty, span: DUMMY_SP, default },
178            colon_span: None,
179        }
180    }
181
182    pub fn trait_ref(&self, path: ast::Path) -> ast::TraitRef {
183        ast::TraitRef { path, ref_id: ast::DUMMY_NODE_ID }
184    }
185
186    pub fn poly_trait_ref(&self, span: Span, path: ast::Path, is_const: bool) -> ast::PolyTraitRef {
187        ast::PolyTraitRef {
188            bound_generic_params: ThinVec::new(),
189            modifiers: ast::TraitBoundModifiers {
190                polarity: ast::BoundPolarity::Positive,
191                constness: if is_const {
192                    ast::BoundConstness::Maybe(DUMMY_SP)
193                } else {
194                    ast::BoundConstness::Never
195                },
196                asyncness: ast::BoundAsyncness::Normal,
197            },
198            trait_ref: self.trait_ref(path),
199            span,
200            parens: ast::Parens::No,
201        }
202    }
203
204    pub fn trait_bound(&self, path: ast::Path, is_const: bool) -> ast::GenericBound {
205        ast::GenericBound::Trait(self.poly_trait_ref(path.span, path, is_const))
206    }
207
208    pub fn lifetime(&self, span: Span, ident: Ident) -> ast::Lifetime {
209        ast::Lifetime { id: ast::DUMMY_NODE_ID, ident: ident.with_span_pos(span) }
210    }
211
212    pub fn lifetime_static(&self, span: Span) -> ast::Lifetime {
213        self.lifetime(span, Ident::new(kw::StaticLifetime, span))
214    }
215
216    pub fn stmt_expr(&self, expr: Box<ast::Expr>) -> ast::Stmt {
217        ast::Stmt { id: ast::DUMMY_NODE_ID, span: expr.span, kind: ast::StmtKind::Expr(expr) }
218    }
219
220    pub fn stmt_let(&self, sp: Span, mutbl: bool, ident: Ident, ex: Box<ast::Expr>) -> ast::Stmt {
221        self.stmt_let_ty(sp, mutbl, ident, None, ex)
222    }
223
224    pub fn stmt_let_ty(
225        &self,
226        sp: Span,
227        mutbl: bool,
228        ident: Ident,
229        ty: Option<Box<ast::Ty>>,
230        ex: Box<ast::Expr>,
231    ) -> ast::Stmt {
232        let pat = if mutbl {
233            self.pat_ident_binding_mode(sp, ident, ast::BindingMode::MUT)
234        } else {
235            self.pat_ident(sp, ident)
236        };
237        let local = Box::new(ast::Local {
238            super_: None,
239            pat: Box::new(pat),
240            ty,
241            id: ast::DUMMY_NODE_ID,
242            kind: LocalKind::Init(ex),
243            span: sp,
244            colon_sp: None,
245            attrs: AttrVec::new(),
246            tokens: None,
247        });
248        self.stmt_local(local, sp)
249    }
250
251    /// Generates `let _: Type;`, which is usually used for type assertions.
252    pub fn stmt_let_type_only(&self, span: Span, ty: Box<ast::Ty>) -> ast::Stmt {
253        let local = Box::new(ast::Local {
254            super_: None,
255            pat: Box::new(self.pat_wild(span)),
256            ty: Some(ty),
257            id: ast::DUMMY_NODE_ID,
258            kind: LocalKind::Decl,
259            span,
260            colon_sp: None,
261            attrs: AttrVec::new(),
262            tokens: None,
263        });
264        self.stmt_local(local, span)
265    }
266
267    pub fn stmt_semi(&self, expr: Box<ast::Expr>) -> ast::Stmt {
268        ast::Stmt { id: ast::DUMMY_NODE_ID, span: expr.span, kind: ast::StmtKind::Semi(expr) }
269    }
270
271    pub fn stmt_local(&self, local: Box<ast::Local>, span: Span) -> ast::Stmt {
272        ast::Stmt { id: ast::DUMMY_NODE_ID, kind: ast::StmtKind::Let(local), span }
273    }
274
275    pub fn stmt_item(&self, sp: Span, item: Box<ast::Item>) -> ast::Stmt {
276        ast::Stmt { id: ast::DUMMY_NODE_ID, kind: ast::StmtKind::Item(item), span: sp }
277    }
278
279    pub fn block_expr(&self, expr: Box<ast::Expr>) -> Box<ast::Block> {
280        self.block(
281            expr.span,
282            {
    let len = [()].len();
    let mut vec = ::thin_vec::ThinVec::with_capacity(len);
    vec.push(ast::Stmt {
            id: ast::DUMMY_NODE_ID,
            span: expr.span,
            kind: ast::StmtKind::Expr(expr),
        });
    vec
}thin_vec![ast::Stmt {
283                id: ast::DUMMY_NODE_ID,
284                span: expr.span,
285                kind: ast::StmtKind::Expr(expr),
286            }],
287        )
288    }
289    pub fn block(&self, span: Span, stmts: ThinVec<ast::Stmt>) -> Box<ast::Block> {
290        Box::new(ast::Block { stmts, id: ast::DUMMY_NODE_ID, rules: BlockCheckMode::Default, span })
291    }
292
293    pub fn expr(&self, span: Span, kind: ast::ExprKind) -> Box<ast::Expr> {
294        Box::new(ast::Expr {
295            id: ast::DUMMY_NODE_ID,
296            kind,
297            span,
298            attrs: AttrVec::new(),
299            tokens: None,
300        })
301    }
302
303    pub fn expr_path(&self, path: ast::Path) -> Box<ast::Expr> {
304        self.expr(path.span, ast::ExprKind::Path(None, path))
305    }
306
307    pub fn expr_ident(&self, span: Span, id: Ident) -> Box<ast::Expr> {
308        self.expr_path(self.path_ident(span, id))
309    }
310    pub fn expr_self(&self, span: Span) -> Box<ast::Expr> {
311        self.expr_ident(span, Ident::new(kw::SelfLower, span))
312    }
313
314    pub fn expr_macro_call(&self, span: Span, call: Box<ast::MacCall>) -> Box<ast::Expr> {
315        self.expr(span, ast::ExprKind::MacCall(call))
316    }
317
318    pub fn expr_binary(
319        &self,
320        sp: Span,
321        op: ast::BinOpKind,
322        lhs: Box<ast::Expr>,
323        rhs: Box<ast::Expr>,
324    ) -> Box<ast::Expr> {
325        self.expr(sp, ast::ExprKind::Binary(Spanned { node: op, span: sp }, lhs, rhs))
326    }
327
328    pub fn expr_deref(&self, sp: Span, e: Box<ast::Expr>) -> Box<ast::Expr> {
329        self.expr(sp, ast::ExprKind::Unary(UnOp::Deref, e))
330    }
331
332    pub fn expr_addr_of(&self, sp: Span, e: Box<ast::Expr>) -> Box<ast::Expr> {
333        self.expr(sp, ast::ExprKind::AddrOf(ast::BorrowKind::Ref, ast::Mutability::Not, e))
334    }
335
336    pub fn expr_paren(&self, sp: Span, e: Box<ast::Expr>) -> Box<ast::Expr> {
337        self.expr(sp, ast::ExprKind::Paren(e))
338    }
339
340    pub fn expr_method_call(
341        &self,
342        span: Span,
343        expr: Box<ast::Expr>,
344        ident: Ident,
345        args: ThinVec<Box<ast::Expr>>,
346    ) -> Box<ast::Expr> {
347        let seg = ast::PathSegment::from_ident(ident);
348        self.expr(
349            span,
350            ast::ExprKind::MethodCall(Box::new(ast::MethodCall {
351                seg,
352                receiver: expr,
353                args,
354                span,
355            })),
356        )
357    }
358
359    pub fn expr_call(
360        &self,
361        span: Span,
362        expr: Box<ast::Expr>,
363        args: ThinVec<Box<ast::Expr>>,
364    ) -> Box<ast::Expr> {
365        self.expr(span, ast::ExprKind::Call(expr, args))
366    }
367    pub fn expr_loop(&self, sp: Span, block: Box<ast::Block>) -> Box<ast::Expr> {
368        self.expr(sp, ast::ExprKind::Loop(block, None, sp))
369    }
370    pub fn expr_asm(&self, sp: Span, expr: Box<ast::InlineAsm>) -> Box<ast::Expr> {
371        self.expr(sp, ast::ExprKind::InlineAsm(expr))
372    }
373    pub fn expr_call_ident(
374        &self,
375        span: Span,
376        id: Ident,
377        args: ThinVec<Box<ast::Expr>>,
378    ) -> Box<ast::Expr> {
379        self.expr(span, ast::ExprKind::Call(self.expr_ident(span, id), args))
380    }
381    pub fn expr_call_global(
382        &self,
383        sp: Span,
384        fn_path: Vec<Ident>,
385        args: ThinVec<Box<ast::Expr>>,
386    ) -> Box<ast::Expr> {
387        let pathexpr = self.expr_path(self.path_global(sp, fn_path));
388        self.expr_call(sp, pathexpr, args)
389    }
390    pub fn expr_block(&self, b: Box<ast::Block>) -> Box<ast::Expr> {
391        self.expr(b.span, ast::ExprKind::Block(b, None))
392    }
393    pub fn field_imm(&self, span: Span, ident: Ident, e: Box<ast::Expr>) -> ast::ExprField {
394        ast::ExprField {
395            ident: ident.with_span_pos(span),
396            expr: e,
397            span,
398            is_shorthand: false,
399            attrs: AttrVec::new(),
400            id: ast::DUMMY_NODE_ID,
401            is_placeholder: false,
402        }
403    }
404    pub fn expr_struct(
405        &self,
406        span: Span,
407        path: ast::Path,
408        fields: ThinVec<ast::ExprField>,
409    ) -> Box<ast::Expr> {
410        self.expr(
411            span,
412            ast::ExprKind::Struct(Box::new(ast::StructExpr {
413                qself: None,
414                path,
415                fields,
416                rest: ast::StructRest::None,
417            })),
418        )
419    }
420    pub fn expr_struct_ident(
421        &self,
422        span: Span,
423        id: Ident,
424        fields: ThinVec<ast::ExprField>,
425    ) -> Box<ast::Expr> {
426        self.expr_struct(span, self.path_ident(span, id), fields)
427    }
428
429    pub fn expr_usize(&self, span: Span, n: usize) -> Box<ast::Expr> {
430        let suffix = Some(ast::UintTy::Usize.name());
431        let lit = token::Lit::new(token::Integer, sym::integer(n), suffix);
432        self.expr(span, ast::ExprKind::Lit(lit))
433    }
434
435    pub fn expr_u32(&self, span: Span, n: u32) -> Box<ast::Expr> {
436        let suffix = Some(ast::UintTy::U32.name());
437        let lit = token::Lit::new(token::Integer, sym::integer(n), suffix);
438        self.expr(span, ast::ExprKind::Lit(lit))
439    }
440
441    pub fn expr_bool(&self, span: Span, value: bool) -> Box<ast::Expr> {
442        let lit = token::Lit::new(token::Bool, if value { kw::True } else { kw::False }, None);
443        self.expr(span, ast::ExprKind::Lit(lit))
444    }
445
446    pub fn expr_str(&self, span: Span, s: Symbol) -> Box<ast::Expr> {
447        let lit = token::Lit::new(token::Str, literal::escape_string_symbol(s), None);
448        self.expr(span, ast::ExprKind::Lit(lit))
449    }
450
451    pub fn expr_byte_str(&self, span: Span, bytes: Vec<u8>) -> Box<ast::Expr> {
452        let lit = token::Lit::new(token::ByteStr, literal::escape_byte_str_symbol(&bytes), None);
453        self.expr(span, ast::ExprKind::Lit(lit))
454    }
455
456    /// `[expr1, expr2, ...]`
457    pub fn expr_array(&self, sp: Span, exprs: ThinVec<Box<ast::Expr>>) -> Box<ast::Expr> {
458        self.expr(sp, ast::ExprKind::Array(exprs))
459    }
460
461    /// `&[expr1, expr2, ...]`
462    pub fn expr_array_ref(&self, sp: Span, exprs: ThinVec<Box<ast::Expr>>) -> Box<ast::Expr> {
463        self.expr_addr_of(sp, self.expr_array(sp, exprs))
464    }
465
466    pub fn expr_some(&self, sp: Span, expr: Box<ast::Expr>) -> Box<ast::Expr> {
467        let some = self.std_path(&[sym::option, sym::Option, sym::Some]);
468        self.expr_call_global(sp, some, {
    let len = [()].len();
    let mut vec = ::thin_vec::ThinVec::with_capacity(len);
    vec.push(expr);
    vec
}thin_vec![expr])
469    }
470
471    pub fn expr_none(&self, sp: Span) -> Box<ast::Expr> {
472        let none = self.std_path(&[sym::option, sym::Option, sym::None]);
473        self.expr_path(self.path_global(sp, none))
474    }
475    pub fn expr_tuple(&self, sp: Span, exprs: ThinVec<Box<ast::Expr>>) -> Box<ast::Expr> {
476        self.expr(sp, ast::ExprKind::Tup(exprs))
477    }
478
479    pub fn expr_unreachable(&self, span: Span) -> Box<ast::Expr> {
480        self.expr_macro_call(
481            span,
482            self.macro_call(
483                span,
484                self.path_global(
485                    span,
486                    [sym::std, sym::unreachable].map(|s| Ident::new(s, span)).to_vec(),
487                ),
488                Delimiter::Parenthesis,
489                TokenStream::default(),
490            ),
491        )
492    }
493
494    pub fn expr_ok(&self, sp: Span, expr: Box<ast::Expr>) -> Box<ast::Expr> {
495        let ok = self.std_path(&[sym::result, sym::Result, sym::Ok]);
496        self.expr_call_global(sp, ok, {
    let len = [()].len();
    let mut vec = ::thin_vec::ThinVec::with_capacity(len);
    vec.push(expr);
    vec
}thin_vec![expr])
497    }
498
499    pub fn expr_try(&self, sp: Span, head: Box<ast::Expr>) -> Box<ast::Expr> {
500        let ok = self.std_path(&[sym::result, sym::Result, sym::Ok]);
501        let ok_path = self.path_global(sp, ok);
502        let err = self.std_path(&[sym::result, sym::Result, sym::Err]);
503        let err_path = self.path_global(sp, err);
504
505        let binding_variable = Ident::new(sym::__try_var, sp);
506        let binding_pat = self.pat_ident(sp, binding_variable);
507        let binding_expr = self.expr_ident(sp, binding_variable);
508
509        // `Ok(__try_var)` pattern
510        let ok_pat = self.pat_tuple_struct(sp, ok_path, {
    let len = [()].len();
    let mut vec = ::thin_vec::ThinVec::with_capacity(len);
    vec.push(binding_pat.clone());
    vec
}thin_vec![binding_pat.clone()]);
511
512        // `Err(__try_var)` (pattern and expression respectively)
513        let err_pat = self.pat_tuple_struct(sp, err_path.clone(), {
    let len = [()].len();
    let mut vec = ::thin_vec::ThinVec::with_capacity(len);
    vec.push(binding_pat);
    vec
}thin_vec![binding_pat]);
514        let err_inner_expr =
515            self.expr_call(sp, self.expr_path(err_path), {
    let len = [()].len();
    let mut vec = ::thin_vec::ThinVec::with_capacity(len);
    vec.push(binding_expr.clone());
    vec
}thin_vec![binding_expr.clone()]);
516        // `return Err(__try_var)`
517        let err_expr = self.expr(sp, ast::ExprKind::Ret(Some(err_inner_expr)));
518
519        // `Ok(__try_var) => __try_var`
520        let ok_arm = self.arm(sp, ok_pat, binding_expr);
521        // `Err(__try_var) => return Err(__try_var)`
522        let err_arm = self.arm(sp, err_pat, err_expr);
523
524        // `match head { Ok() => ..., Err() => ... }`
525        self.expr_match(sp, head, {
    let len = [(), ()].len();
    let mut vec = ::thin_vec::ThinVec::with_capacity(len);
    vec.push(ok_arm);
    vec.push(err_arm);
    vec
}thin_vec![ok_arm, err_arm])
526    }
527
528    pub fn pat(&self, span: Span, kind: PatKind) -> ast::Pat {
529        ast::Pat { id: ast::DUMMY_NODE_ID, kind, span }
530    }
531    pub fn pat_wild(&self, span: Span) -> ast::Pat {
532        self.pat(span, PatKind::Wild)
533    }
534    pub fn pat_lit(&self, span: Span, expr: Box<ast::Expr>) -> ast::Pat {
535        self.pat(span, PatKind::Expr(expr))
536    }
537    pub fn pat_ident(&self, span: Span, ident: Ident) -> ast::Pat {
538        self.pat_ident_binding_mode(span, ident, ast::BindingMode::NONE)
539    }
540
541    pub fn pat_ident_binding_mode(
542        &self,
543        span: Span,
544        ident: Ident,
545        ann: ast::BindingMode,
546    ) -> ast::Pat {
547        let pat = PatKind::Ident(ann, ident.with_span_pos(span), None);
548        self.pat(span, pat)
549    }
550    pub fn pat_path(&self, span: Span, path: ast::Path) -> ast::Pat {
551        self.pat(span, PatKind::Path(None, path))
552    }
553    pub fn pat_tuple_struct(
554        &self,
555        span: Span,
556        path: ast::Path,
557        subpats: ThinVec<ast::Pat>,
558    ) -> ast::Pat {
559        self.pat(span, PatKind::TupleStruct(None, path, subpats))
560    }
561    pub fn pat_struct(
562        &self,
563        span: Span,
564        path: ast::Path,
565        field_pats: ThinVec<ast::PatField>,
566    ) -> ast::Pat {
567        self.pat(span, PatKind::Struct(None, path, field_pats, ast::PatFieldsRest::None))
568    }
569    pub fn pat_tuple(&self, span: Span, pats: ThinVec<ast::Pat>) -> ast::Pat {
570        self.pat(span, PatKind::Tuple(pats))
571    }
572
573    pub fn pat_some(&self, span: Span, pat: ast::Pat) -> ast::Pat {
574        let some = self.std_path(&[sym::option, sym::Option, sym::Some]);
575        let path = self.path_global(span, some);
576        self.pat_tuple_struct(span, path, {
    let len = [()].len();
    let mut vec = ::thin_vec::ThinVec::with_capacity(len);
    vec.push(pat);
    vec
}thin_vec![pat])
577    }
578
579    pub fn arm(&self, span: Span, pat: ast::Pat, expr: Box<ast::Expr>) -> ast::Arm {
580        ast::Arm {
581            attrs: AttrVec::new(),
582            pat: Box::new(pat),
583            guard: None,
584            body: Some(expr),
585            span,
586            id: ast::DUMMY_NODE_ID,
587            is_placeholder: false,
588        }
589    }
590
591    pub fn arm_unreachable(&self, span: Span) -> ast::Arm {
592        self.arm(span, self.pat_wild(span), self.expr_unreachable(span))
593    }
594
595    pub fn expr_match(
596        &self,
597        span: Span,
598        arg: Box<ast::Expr>,
599        arms: ThinVec<ast::Arm>,
600    ) -> Box<Expr> {
601        self.expr(span, ast::ExprKind::Match(arg, arms, MatchKind::Prefix))
602    }
603
604    pub fn expr_if(
605        &self,
606        span: Span,
607        cond: Box<ast::Expr>,
608        then: Box<ast::Expr>,
609        els: Option<Box<ast::Expr>>,
610    ) -> Box<ast::Expr> {
611        let els = els.map(|x| self.expr_block(self.block_expr(x)));
612        self.expr(span, ast::ExprKind::If(cond, self.block_expr(then), els))
613    }
614
615    pub fn lambda(&self, span: Span, ids: Vec<Ident>, body: Box<ast::Expr>) -> Box<ast::Expr> {
616        let fn_decl = self.fn_decl(
617            ids.iter().map(|id| self.param(span, *id, self.ty(span, ast::TyKind::Infer))).collect(),
618            ast::FnRetTy::Default(span),
619        );
620
621        // FIXME -- We are using `span` as the span of the `|...|`
622        // part of the lambda, but it probably (maybe?) corresponds to
623        // the entire lambda body. Probably we should extend the API
624        // here, but that's not entirely clear.
625        self.expr(
626            span,
627            ast::ExprKind::Closure(Box::new(ast::Closure {
628                binder: ast::ClosureBinder::NotPresent,
629                capture_clause: ast::CaptureBy::Ref,
630                constness: ast::Const::No,
631                coroutine_kind: None,
632                movability: ast::Movability::Movable,
633                fn_decl,
634                body,
635                fn_decl_span: span,
636                // FIXME(SarthakSingh31): This points to the start of the declaration block and
637                // not the span of the argument block.
638                fn_arg_span: span,
639            })),
640        )
641    }
642
643    pub fn lambda0(&self, span: Span, body: Box<ast::Expr>) -> Box<ast::Expr> {
644        self.lambda(span, Vec::new(), body)
645    }
646
647    pub fn lambda1(&self, span: Span, body: Box<ast::Expr>, ident: Ident) -> Box<ast::Expr> {
648        self.lambda(span, ::alloc::boxed::box_assume_init_into_vec_unsafe(::alloc::intrinsics::write_box_via_move(::alloc::boxed::Box::new_uninit(),
        [ident]))vec![ident], body)
649    }
650
651    pub fn lambda_stmts_1(
652        &self,
653        span: Span,
654        stmts: ThinVec<ast::Stmt>,
655        ident: Ident,
656    ) -> Box<ast::Expr> {
657        self.lambda1(span, self.expr_block(self.block(span, stmts)), ident)
658    }
659
660    pub fn param(&self, span: Span, ident: Ident, ty: Box<ast::Ty>) -> ast::Param {
661        let pat = Box::new(self.pat_ident(span, ident));
662        ast::Param {
663            attrs: AttrVec::default(),
664            id: ast::DUMMY_NODE_ID,
665            pat,
666            span,
667            ty,
668            is_placeholder: false,
669        }
670    }
671
672    // `self` is unused but keep it as method for the convenience use.
673    pub fn fn_decl(&self, inputs: ThinVec<ast::Param>, output: ast::FnRetTy) -> Box<ast::FnDecl> {
674        Box::new(ast::FnDecl { inputs, output })
675    }
676
677    pub fn item(&self, span: Span, attrs: ast::AttrVec, kind: ast::ItemKind) -> Box<ast::Item> {
678        Box::new(ast::Item {
679            attrs,
680            id: ast::DUMMY_NODE_ID,
681            kind,
682            vis: ast::Visibility {
683                span: span.shrink_to_lo(),
684                kind: ast::VisibilityKind::Inherited,
685            },
686            span,
687            tokens: None,
688        })
689    }
690
691    pub fn item_static(
692        &self,
693        span: Span,
694        ident: Ident,
695        ty: Box<ast::Ty>,
696        mutability: ast::Mutability,
697        expr: Box<ast::Expr>,
698    ) -> Box<ast::Item> {
699        self.item(
700            span,
701            AttrVec::new(),
702            ast::ItemKind::Static(
703                ast::StaticItem {
704                    ident,
705                    ty,
706                    safety: ast::Safety::Default,
707                    mutability,
708                    expr: Some(expr),
709                    define_opaque: None,
710                    eii_impls: Default::default(),
711                }
712                .into(),
713            ),
714        )
715    }
716
717    pub fn item_const(
718        &self,
719        span: Span,
720        ident: Ident,
721        ty: Box<ast::Ty>,
722        rhs_kind: ast::ConstItemRhsKind,
723    ) -> Box<ast::Item> {
724        let defaultness = ast::Defaultness::Implicit;
725        self.item(
726            span,
727            AttrVec::new(),
728            ast::ItemKind::Const(
729                ast::ConstItem {
730                    defaultness,
731                    ident,
732                    // FIXME(generic_const_items): Pass the generics as a parameter.
733                    generics: ast::Generics::default(),
734                    ty,
735                    rhs_kind,
736                    define_opaque: None,
737                }
738                .into(),
739            ),
740        )
741    }
742
743    // Builds `#[name]`.
744    pub fn attr_word(&self, name: Symbol, span: Span) -> ast::Attribute {
745        let g = &self.sess.psess.attr_id_generator;
746        attr::mk_attr_word(g, ast::AttrStyle::Outer, ast::Safety::Default, name, span)
747    }
748
749    // Builds `#[name = val]`.
750    //
751    // Note: `span` is used for both the identifier and the value.
752    pub fn attr_name_value_str(&self, name: Symbol, val: Symbol, span: Span) -> ast::Attribute {
753        let g = &self.sess.psess.attr_id_generator;
754        attr::mk_attr_name_value_str(
755            g,
756            ast::AttrStyle::Outer,
757            ast::Safety::Default,
758            name,
759            val,
760            span,
761        )
762    }
763
764    // Builds `#[outer(inner)]`.
765    pub fn attr_nested_word(&self, outer: Symbol, inner: Symbol, span: Span) -> ast::Attribute {
766        let g = &self.sess.psess.attr_id_generator;
767        attr::mk_attr_nested_word(
768            g,
769            ast::AttrStyle::Outer,
770            ast::Safety::Default,
771            outer,
772            inner,
773            span,
774        )
775    }
776
777    // Builds an attribute fully manually.
778    pub fn attr_nested(&self, inner: AttrItem, span: Span) -> ast::Attribute {
779        let g = &self.sess.psess.attr_id_generator;
780        attr::mk_attr_from_item(g, inner, None, ast::AttrStyle::Outer, span)
781    }
782}
rustc_expand/build.rs

rustc_expand/
build.rs
