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Commit | Line | Data |
---|---|---|
dfeec247 | 1 | use super::diagnostics::{dummy_arg, ConsumeClosingDelim, Error}; |
fc512014 | 2 | use super::ty::{AllowPlus, RecoverQPath, RecoverReturnSign}; |
6a06907d | 3 | use super::{AttrWrapper, FollowedByType, ForceCollect, Parser, PathStyle, TrailingToken}; |
416331ca | 4 | |
5869c6ff | 5 | use rustc_ast::ast::*; |
74b04a01 | 6 | use rustc_ast::ptr::P; |
ba9703b0 | 7 | use rustc_ast::token::{self, TokenKind}; |
74b04a01 | 8 | use rustc_ast::tokenstream::{DelimSpan, TokenStream, TokenTree}; |
29967ef6 | 9 | use rustc_ast::{self as ast, AttrVec, Attribute, DUMMY_NODE_ID}; |
3dfed10e XL |
10 | use rustc_ast::{Async, Const, Defaultness, IsAuto, Mutability, Unsafe, UseTree, UseTreeKind}; |
11 | use rustc_ast::{BindingMode, Block, FnDecl, FnSig, Param, SelfKind}; | |
6a06907d | 12 | use rustc_ast::{EnumDef, FieldDef, Generics, TraitRef, Ty, TyKind, Variant, VariantData}; |
3dfed10e XL |
13 | use rustc_ast::{FnHeader, ForeignItem, Path, PathSegment, Visibility, VisibilityKind}; |
14 | use rustc_ast::{MacArgs, MacCall, MacDelimiter}; | |
74b04a01 XL |
15 | use rustc_ast_pretty::pprust; |
16 | use rustc_errors::{struct_span_err, Applicability, PResult, StashKey}; | |
5869c6ff | 17 | use rustc_span::edition::{Edition, LATEST_STABLE_EDITION}; |
74b04a01 | 18 | use rustc_span::source_map::{self, Span}; |
f9f354fc | 19 | use rustc_span::symbol::{kw, sym, Ident, Symbol}; |
416331ca | 20 | |
74b04a01 | 21 | use std::convert::TryFrom; |
60c5eb7d | 22 | use std::mem; |
3dfed10e | 23 | use tracing::debug; |
416331ca | 24 | |
ba9703b0 XL |
25 | impl<'a> Parser<'a> { |
26 | /// Parses a source module as a crate. This is the main entry point for the parser. | |
27 | pub fn parse_crate_mod(&mut self) -> PResult<'a, ast::Crate> { | |
6a06907d | 28 | let (attrs, items, span) = self.parse_mod(&token::Eof)?; |
94222f64 | 29 | Ok(ast::Crate { attrs, items, span }) |
ba9703b0 XL |
30 | } |
31 | ||
32 | /// Parses a `mod <foo> { ... }` or `mod <foo>;` item. | |
33 | fn parse_item_mod(&mut self, attrs: &mut Vec<Attribute>) -> PResult<'a, ItemInfo> { | |
1b1a35ee XL |
34 | let unsafety = self.parse_unsafety(); |
35 | self.expect_keyword(kw::Mod)?; | |
ba9703b0 | 36 | let id = self.parse_ident()?; |
6a06907d XL |
37 | let mod_kind = if self.eat(&token::Semi) { |
38 | ModKind::Unloaded | |
ba9703b0 XL |
39 | } else { |
40 | self.expect(&token::OpenDelim(token::Brace))?; | |
6a06907d XL |
41 | let (mut inner_attrs, items, inner_span) = |
42 | self.parse_mod(&token::CloseDelim(token::Brace))?; | |
43 | attrs.append(&mut inner_attrs); | |
44 | ModKind::Loaded(items, Inline::Yes, inner_span) | |
ba9703b0 | 45 | }; |
6a06907d | 46 | Ok((id, ItemKind::Mod(unsafety, mod_kind))) |
ba9703b0 XL |
47 | } |
48 | ||
49 | /// Parses the contents of a module (inner attributes followed by module items). | |
1b1a35ee XL |
50 | pub fn parse_mod( |
51 | &mut self, | |
52 | term: &TokenKind, | |
6a06907d | 53 | ) -> PResult<'a, (Vec<Attribute>, Vec<P<Item>>, Span)> { |
ba9703b0 XL |
54 | let lo = self.token.span; |
55 | let attrs = self.parse_inner_attributes()?; | |
ba9703b0 | 56 | |
ba9703b0 | 57 | let mut items = vec![]; |
5869c6ff | 58 | while let Some(item) = self.parse_item(ForceCollect::No)? { |
ba9703b0 XL |
59 | items.push(item); |
60 | self.maybe_consume_incorrect_semicolon(&items); | |
61 | } | |
62 | ||
63 | if !self.eat(term) { | |
64 | let token_str = super::token_descr(&self.token); | |
65 | if !self.maybe_consume_incorrect_semicolon(&items) { | |
66 | let msg = &format!("expected item, found {}", token_str); | |
67 | let mut err = self.struct_span_err(self.token.span, msg); | |
68 | err.span_label(self.token.span, "expected item"); | |
69 | return Err(err); | |
70 | } | |
71 | } | |
72 | ||
6a06907d | 73 | Ok((attrs, items, lo.to(self.prev_token.span))) |
ba9703b0 XL |
74 | } |
75 | } | |
76 | ||
74b04a01 | 77 | pub(super) type ItemInfo = (Ident, ItemKind); |
416331ca XL |
78 | |
79 | impl<'a> Parser<'a> { | |
5869c6ff XL |
80 | pub fn parse_item(&mut self, force_collect: ForceCollect) -> PResult<'a, Option<P<Item>>> { |
81 | self.parse_item_(|_| true, force_collect).map(|i| i.map(P)) | |
74b04a01 XL |
82 | } |
83 | ||
5869c6ff XL |
84 | fn parse_item_( |
85 | &mut self, | |
86 | req_name: ReqName, | |
87 | force_collect: ForceCollect, | |
88 | ) -> PResult<'a, Option<Item>> { | |
416331ca | 89 | let attrs = self.parse_outer_attributes()?; |
5869c6ff | 90 | self.parse_item_common(attrs, true, false, req_name, force_collect) |
416331ca XL |
91 | } |
92 | ||
74b04a01 | 93 | pub(super) fn parse_item_common( |
416331ca | 94 | &mut self, |
6a06907d | 95 | attrs: AttrWrapper, |
74b04a01 XL |
96 | mac_allowed: bool, |
97 | attrs_allowed: bool, | |
98 | req_name: ReqName, | |
5869c6ff | 99 | force_collect: ForceCollect, |
74b04a01 | 100 | ) -> PResult<'a, Option<Item>> { |
6a06907d XL |
101 | // Don't use `maybe_whole` so that we have precise control |
102 | // over when we bump the parser | |
103 | if let token::Interpolated(nt) = &self.token.kind { | |
104 | if let token::NtItem(item) = &**nt { | |
cdc7bbd5 XL |
105 | let mut item = item.clone(); |
106 | self.bump(); | |
107 | ||
108 | attrs.prepend_to_nt_inner(&mut item.attrs); | |
109 | return Ok(Some(item.into_inner())); | |
6a06907d XL |
110 | } |
111 | }; | |
74b04a01 | 112 | |
416331ca | 113 | let mut unclosed_delims = vec![]; |
6a06907d XL |
114 | let item = |
115 | self.collect_tokens_trailing_token(attrs, force_collect, |this: &mut Self, attrs| { | |
116 | let item = this.parse_item_common_(attrs, mac_allowed, attrs_allowed, req_name); | |
117 | unclosed_delims.append(&mut this.unclosed_delims); | |
118 | Ok((item?, TrailingToken::None)) | |
119 | })?; | |
29967ef6 XL |
120 | |
121 | self.unclosed_delims.append(&mut unclosed_delims); | |
74b04a01 | 122 | Ok(item) |
416331ca XL |
123 | } |
124 | ||
74b04a01 | 125 | fn parse_item_common_( |
416331ca | 126 | &mut self, |
74b04a01 XL |
127 | mut attrs: Vec<Attribute>, |
128 | mac_allowed: bool, | |
129 | attrs_allowed: bool, | |
130 | req_name: ReqName, | |
131 | ) -> PResult<'a, Option<Item>> { | |
416331ca | 132 | let lo = self.token.span; |
60c5eb7d | 133 | let vis = self.parse_visibility(FollowedByType::No)?; |
74b04a01 XL |
134 | let mut def = self.parse_defaultness(); |
135 | let kind = self.parse_item_kind(&mut attrs, mac_allowed, lo, &vis, &mut def, req_name)?; | |
136 | if let Some((ident, kind)) = kind { | |
137 | self.error_on_unconsumed_default(def, &kind); | |
138 | let span = lo.to(self.prev_token.span); | |
139 | let id = DUMMY_NODE_ID; | |
140 | let item = Item { ident, attrs, id, kind, vis, span, tokens: None }; | |
416331ca XL |
141 | return Ok(Some(item)); |
142 | } | |
143 | ||
74b04a01 XL |
144 | // At this point, we have failed to parse an item. |
145 | self.error_on_unmatched_vis(&vis); | |
146 | self.error_on_unmatched_defaultness(def); | |
147 | if !attrs_allowed { | |
148 | self.recover_attrs_no_item(&attrs)?; | |
416331ca | 149 | } |
74b04a01 XL |
150 | Ok(None) |
151 | } | |
416331ca | 152 | |
74b04a01 XL |
153 | /// Error in-case a non-inherited visibility was parsed but no item followed. |
154 | fn error_on_unmatched_vis(&self, vis: &Visibility) { | |
1b1a35ee | 155 | if let VisibilityKind::Inherited = vis.kind { |
74b04a01 | 156 | return; |
416331ca | 157 | } |
74b04a01 XL |
158 | let vs = pprust::vis_to_string(&vis); |
159 | let vs = vs.trim_end(); | |
160 | self.struct_span_err(vis.span, &format!("visibility `{}` is not followed by an item", vs)) | |
161 | .span_label(vis.span, "the visibility") | |
162 | .help(&format!("you likely meant to define an item, e.g., `{} fn foo() {{}}`", vs)) | |
163 | .emit(); | |
164 | } | |
e74abb32 | 165 | |
74b04a01 XL |
166 | /// Error in-case a `default` was parsed but no item followed. |
167 | fn error_on_unmatched_defaultness(&self, def: Defaultness) { | |
168 | if let Defaultness::Default(sp) = def { | |
169 | self.struct_span_err(sp, "`default` is not followed by an item") | |
170 | .span_label(sp, "the `default` qualifier") | |
171 | .note("only `fn`, `const`, `type`, or `impl` items may be prefixed by `default`") | |
172 | .emit(); | |
416331ca | 173 | } |
74b04a01 | 174 | } |
416331ca | 175 | |
74b04a01 XL |
176 | /// Error in-case `default` was parsed in an in-appropriate context. |
177 | fn error_on_unconsumed_default(&self, def: Defaultness, kind: &ItemKind) { | |
178 | if let Defaultness::Default(span) = def { | |
179 | let msg = format!("{} {} cannot be `default`", kind.article(), kind.descr()); | |
180 | self.struct_span_err(span, &msg) | |
181 | .span_label(span, "`default` because of this") | |
182 | .note("only associated `fn`, `const`, and `type` items can be `default`") | |
183 | .emit(); | |
416331ca | 184 | } |
74b04a01 | 185 | } |
e74abb32 | 186 | |
74b04a01 XL |
187 | /// Parses one of the items allowed by the flags. |
188 | fn parse_item_kind( | |
189 | &mut self, | |
190 | attrs: &mut Vec<Attribute>, | |
191 | macros_allowed: bool, | |
192 | lo: Span, | |
193 | vis: &Visibility, | |
194 | def: &mut Defaultness, | |
195 | req_name: ReqName, | |
196 | ) -> PResult<'a, Option<ItemInfo>> { | |
6a06907d | 197 | let def_final = def == &Defaultness::Final; |
74b04a01 | 198 | let mut def = || mem::replace(def, Defaultness::Final); |
e74abb32 | 199 | |
74b04a01 XL |
200 | let info = if self.eat_keyword(kw::Use) { |
201 | // USE ITEM | |
202 | let tree = self.parse_use_tree()?; | |
5869c6ff XL |
203 | |
204 | // If wildcard or glob-like brace syntax doesn't have `;`, | |
205 | // the user may not know `*` or `{}` should be the last. | |
206 | if let Err(mut e) = self.expect_semi() { | |
207 | match tree.kind { | |
208 | UseTreeKind::Glob => { | |
209 | e.note("the wildcard token must be last on the path").emit(); | |
210 | } | |
211 | UseTreeKind::Nested(..) => { | |
212 | e.note("glob-like brace syntax must be last on the path").emit(); | |
213 | } | |
214 | _ => (), | |
215 | } | |
216 | return Err(e); | |
217 | } | |
218 | ||
6a06907d XL |
219 | (Ident::invalid(), ItemKind::Use(tree)) |
220 | } else if self.check_fn_front_matter(def_final) { | |
74b04a01 | 221 | // FUNCTION ITEM |
3dfed10e | 222 | let (ident, sig, generics, body) = self.parse_fn(attrs, req_name, lo)?; |
94222f64 | 223 | (ident, ItemKind::Fn(Box::new(FnKind(def(), sig, generics, body)))) |
74b04a01 XL |
224 | } else if self.eat_keyword(kw::Extern) { |
225 | if self.eat_keyword(kw::Crate) { | |
226 | // EXTERN CRATE | |
227 | self.parse_item_extern_crate()? | |
228 | } else { | |
229 | // EXTERN BLOCK | |
1b1a35ee | 230 | self.parse_item_foreign_mod(attrs, Unsafe::No)? |
74b04a01 | 231 | } |
1b1a35ee XL |
232 | } else if self.is_unsafe_foreign_mod() { |
233 | // EXTERN BLOCK | |
234 | let unsafety = self.parse_unsafety(); | |
235 | self.expect_keyword(kw::Extern)?; | |
236 | self.parse_item_foreign_mod(attrs, unsafety)? | |
74b04a01 XL |
237 | } else if self.is_static_global() { |
238 | // STATIC ITEM | |
239 | self.bump(); // `static` | |
240 | let m = self.parse_mutability(); | |
241 | let (ident, ty, expr) = self.parse_item_global(Some(m))?; | |
242 | (ident, ItemKind::Static(ty, m, expr)) | |
243 | } else if let Const::Yes(const_span) = self.parse_constness() { | |
244 | // CONST ITEM | |
fc512014 XL |
245 | if self.token.is_keyword(kw::Impl) { |
246 | // recover from `const impl`, suggest `impl const` | |
247 | self.recover_const_impl(const_span, attrs, def())? | |
248 | } else { | |
249 | self.recover_const_mut(const_span); | |
250 | let (ident, ty, expr) = self.parse_item_global(None)?; | |
251 | (ident, ItemKind::Const(def(), ty, expr)) | |
252 | } | |
74b04a01 XL |
253 | } else if self.check_keyword(kw::Trait) || self.check_auto_or_unsafe_trait_item() { |
254 | // TRAIT ITEM | |
255 | self.parse_item_trait(attrs, lo)? | |
256 | } else if self.check_keyword(kw::Impl) | |
dfeec247 | 257 | || self.check_keyword(kw::Unsafe) && self.is_keyword_ahead(1, &[kw::Impl]) |
e74abb32 | 258 | { |
416331ca | 259 | // IMPL ITEM |
74b04a01 | 260 | self.parse_item_impl(attrs, def())? |
1b1a35ee XL |
261 | } else if self.check_keyword(kw::Mod) |
262 | || self.check_keyword(kw::Unsafe) && self.is_keyword_ahead(1, &[kw::Mod]) | |
263 | { | |
416331ca | 264 | // MODULE ITEM |
74b04a01 XL |
265 | self.parse_item_mod(attrs)? |
266 | } else if self.eat_keyword(kw::Type) { | |
416331ca | 267 | // TYPE ITEM |
74b04a01 XL |
268 | self.parse_type_alias(def())? |
269 | } else if self.eat_keyword(kw::Enum) { | |
416331ca | 270 | // ENUM ITEM |
74b04a01 XL |
271 | self.parse_item_enum()? |
272 | } else if self.eat_keyword(kw::Struct) { | |
416331ca | 273 | // STRUCT ITEM |
74b04a01 XL |
274 | self.parse_item_struct()? |
275 | } else if self.is_kw_followed_by_ident(kw::Union) { | |
416331ca | 276 | // UNION ITEM |
74b04a01 XL |
277 | self.bump(); // `union` |
278 | self.parse_item_union()? | |
279 | } else if self.eat_keyword(kw::Macro) { | |
280 | // MACROS 2.0 ITEM | |
281 | self.parse_item_decl_macro(lo)? | |
282 | } else if self.is_macro_rules_item() { | |
283 | // MACRO_RULES ITEM | |
284 | self.parse_item_macro_rules(vis)? | |
1b1a35ee | 285 | } else if vis.kind.is_pub() && self.isnt_macro_invocation() { |
74b04a01 XL |
286 | self.recover_missing_kw_before_item()?; |
287 | return Ok(None); | |
ba9703b0 | 288 | } else if macros_allowed && self.check_path() { |
74b04a01 | 289 | // MACRO INVOCATION ITEM |
ba9703b0 | 290 | (Ident::invalid(), ItemKind::MacCall(self.parse_item_macro(vis)?)) |
74b04a01 XL |
291 | } else { |
292 | return Ok(None); | |
293 | }; | |
294 | Ok(Some(info)) | |
295 | } | |
e74abb32 | 296 | |
74b04a01 XL |
297 | /// When parsing a statement, would the start of a path be an item? |
298 | pub(super) fn is_path_start_item(&mut self) -> bool { | |
299 | self.is_crate_vis() // no: `crate::b`, yes: `crate $item` | |
300 | || self.is_kw_followed_by_ident(kw::Union) // no: `union::b`, yes: `union U { .. }` | |
301 | || self.check_auto_or_unsafe_trait_item() // no: `auto::b`, yes: `auto trait X { .. }` | |
302 | || self.is_async_fn() // no(2015): `async::b`, yes: `async fn` | |
303 | || self.is_macro_rules_item() // no: `macro_rules::b`, yes: `macro_rules! mac` | |
304 | } | |
305 | ||
306 | /// Are we sure this could not possibly be a macro invocation? | |
307 | fn isnt_macro_invocation(&mut self) -> bool { | |
308 | self.check_ident() && self.look_ahead(1, |t| *t != token::Not && *t != token::ModSep) | |
309 | } | |
310 | ||
311 | /// Recover on encountering a struct or method definition where the user | |
312 | /// forgot to add the `struct` or `fn` keyword after writing `pub`: `pub S {}`. | |
313 | fn recover_missing_kw_before_item(&mut self) -> PResult<'a, ()> { | |
314 | // Space between `pub` keyword and the identifier | |
315 | // | |
316 | // pub S {} | |
317 | // ^^^ `sp` points here | |
318 | let sp = self.prev_token.span.between(self.token.span); | |
319 | let full_sp = self.prev_token.span.to(self.token.span); | |
320 | let ident_sp = self.token.span; | |
321 | if self.look_ahead(1, |t| *t == token::OpenDelim(token::Brace)) { | |
322 | // possible public struct definition where `struct` was forgotten | |
323 | let ident = self.parse_ident().unwrap(); | |
324 | let msg = format!("add `struct` here to parse `{}` as a public struct", ident); | |
325 | let mut err = self.struct_span_err(sp, "missing `struct` for struct definition"); | |
326 | err.span_suggestion_short( | |
327 | sp, | |
328 | &msg, | |
329 | " struct ".into(), | |
330 | Applicability::MaybeIncorrect, // speculative | |
331 | ); | |
ba9703b0 | 332 | Err(err) |
74b04a01 XL |
333 | } else if self.look_ahead(1, |t| *t == token::OpenDelim(token::Paren)) { |
334 | let ident = self.parse_ident().unwrap(); | |
335 | self.bump(); // `(` | |
336 | let kw_name = self.recover_first_param(); | |
337 | self.consume_block(token::Paren, ConsumeClosingDelim::Yes); | |
338 | let (kw, kw_name, ambiguous) = if self.check(&token::RArrow) { | |
339 | self.eat_to_tokens(&[&token::OpenDelim(token::Brace)]); | |
340 | self.bump(); // `{` | |
341 | ("fn", kw_name, false) | |
342 | } else if self.check(&token::OpenDelim(token::Brace)) { | |
343 | self.bump(); // `{` | |
344 | ("fn", kw_name, false) | |
345 | } else if self.check(&token::Colon) { | |
346 | let kw = "struct"; | |
347 | (kw, kw, false) | |
348 | } else { | |
349 | ("fn` or `struct", "function or struct", true) | |
350 | }; | |
416331ca | 351 | |
74b04a01 XL |
352 | let msg = format!("missing `{}` for {} definition", kw, kw_name); |
353 | let mut err = self.struct_span_err(sp, &msg); | |
354 | if !ambiguous { | |
355 | self.consume_block(token::Brace, ConsumeClosingDelim::Yes); | |
356 | let suggestion = | |
357 | format!("add `{}` here to parse `{}` as a public {}", kw, ident, kw_name); | |
416331ca | 358 | err.span_suggestion_short( |
dfeec247 | 359 | sp, |
74b04a01 XL |
360 | &suggestion, |
361 | format!(" {} ", kw), | |
362 | Applicability::MachineApplicable, | |
416331ca | 363 | ); |
29967ef6 XL |
364 | } else if let Ok(snippet) = self.span_to_snippet(ident_sp) { |
365 | err.span_suggestion( | |
366 | full_sp, | |
367 | "if you meant to call a macro, try", | |
368 | format!("{}!", snippet), | |
369 | // this is the `ambiguous` conditional branch | |
370 | Applicability::MaybeIncorrect, | |
371 | ); | |
74b04a01 | 372 | } else { |
29967ef6 XL |
373 | err.help( |
374 | "if you meant to call a macro, remove the `pub` \ | |
375 | and add a trailing `!` after the identifier", | |
376 | ); | |
416331ca | 377 | } |
ba9703b0 | 378 | Err(err) |
74b04a01 XL |
379 | } else if self.look_ahead(1, |t| *t == token::Lt) { |
380 | let ident = self.parse_ident().unwrap(); | |
381 | self.eat_to_tokens(&[&token::Gt]); | |
382 | self.bump(); // `>` | |
383 | let (kw, kw_name, ambiguous) = if self.eat(&token::OpenDelim(token::Paren)) { | |
384 | ("fn", self.recover_first_param(), false) | |
385 | } else if self.check(&token::OpenDelim(token::Brace)) { | |
386 | ("struct", "struct", false) | |
387 | } else { | |
388 | ("fn` or `struct", "function or struct", true) | |
389 | }; | |
390 | let msg = format!("missing `{}` for {} definition", kw, kw_name); | |
391 | let mut err = self.struct_span_err(sp, &msg); | |
392 | if !ambiguous { | |
393 | err.span_suggestion_short( | |
394 | sp, | |
395 | &format!("add `{}` here to parse `{}` as a public {}", kw, ident, kw_name), | |
396 | format!(" {} ", kw), | |
397 | Applicability::MachineApplicable, | |
398 | ); | |
416331ca | 399 | } |
ba9703b0 | 400 | Err(err) |
74b04a01 XL |
401 | } else { |
402 | Ok(()) | |
416331ca | 403 | } |
74b04a01 | 404 | } |
416331ca | 405 | |
74b04a01 | 406 | /// Parses an item macro, e.g., `item!();`. |
ba9703b0 | 407 | fn parse_item_macro(&mut self, vis: &Visibility) -> PResult<'a, MacCall> { |
74b04a01 XL |
408 | let path = self.parse_path(PathStyle::Mod)?; // `foo::bar` |
409 | self.expect(&token::Not)?; // `!` | |
410 | let args = self.parse_mac_args()?; // `( .. )` or `[ .. ]` (followed by `;`), or `{ .. }`. | |
411 | self.eat_semi_for_macro_if_needed(&args); | |
412 | self.complain_if_pub_macro(vis, false); | |
ba9703b0 | 413 | Ok(MacCall { path, args, prior_type_ascription: self.last_type_ascription }) |
416331ca XL |
414 | } |
415 | ||
74b04a01 XL |
416 | /// Recover if we parsed attributes and expected an item but there was none. |
417 | fn recover_attrs_no_item(&mut self, attrs: &[Attribute]) -> PResult<'a, ()> { | |
418 | let (start, end) = match attrs { | |
419 | [] => return Ok(()), | |
ba9703b0 | 420 | [x0 @ xn] | [x0, .., xn] => (x0, xn), |
416331ca | 421 | }; |
74b04a01 XL |
422 | let msg = if end.is_doc_comment() { |
423 | "expected item after doc comment" | |
424 | } else { | |
425 | "expected item after attributes" | |
426 | }; | |
427 | let mut err = self.struct_span_err(end.span, msg); | |
428 | if end.is_doc_comment() { | |
429 | err.span_label(end.span, "this doc comment doesn't document anything"); | |
430 | } | |
431 | if let [.., penultimate, _] = attrs { | |
432 | err.span_label(start.span.to(penultimate.span), "other attributes here"); | |
416331ca XL |
433 | } |
434 | Err(err) | |
435 | } | |
436 | ||
74b04a01 | 437 | fn is_async_fn(&self) -> bool { |
dfeec247 | 438 | self.token.is_keyword(kw::Async) && self.is_keyword_ahead(1, &[kw::Fn]) |
416331ca XL |
439 | } |
440 | ||
ba9703b0 XL |
441 | fn parse_polarity(&mut self) -> ast::ImplPolarity { |
442 | // Disambiguate `impl !Trait for Type { ... }` and `impl ! { ... }` for the never type. | |
443 | if self.check(&token::Not) && self.look_ahead(1, |t| t.can_begin_type()) { | |
444 | self.bump(); // `!` | |
445 | ast::ImplPolarity::Negative(self.prev_token.span) | |
446 | } else { | |
447 | ast::ImplPolarity::Positive | |
448 | } | |
449 | } | |
450 | ||
74b04a01 | 451 | /// Parses an implementation item. |
416331ca | 452 | /// |
74b04a01 XL |
453 | /// ``` |
454 | /// impl<'a, T> TYPE { /* impl items */ } | |
455 | /// impl<'a, T> TRAIT for TYPE { /* impl items */ } | |
456 | /// impl<'a, T> !TRAIT for TYPE { /* impl items */ } | |
457 | /// impl<'a, T> const TRAIT for TYPE { /* impl items */ } | |
458 | /// ``` | |
416331ca XL |
459 | /// |
460 | /// We actually parse slightly more relaxed grammar for better error reporting and recovery. | |
74b04a01 XL |
461 | /// ``` |
462 | /// "impl" GENERICS "const"? "!"? TYPE "for"? (TYPE | "..") ("where" PREDICATES)? "{" BODY "}" | |
463 | /// "impl" GENERICS "const"? "!"? TYPE ("where" PREDICATES)? "{" BODY "}" | |
464 | /// ``` | |
dfeec247 XL |
465 | fn parse_item_impl( |
466 | &mut self, | |
74b04a01 | 467 | attrs: &mut Vec<Attribute>, |
dfeec247 XL |
468 | defaultness: Defaultness, |
469 | ) -> PResult<'a, ItemInfo> { | |
74b04a01 XL |
470 | let unsafety = self.parse_unsafety(); |
471 | self.expect_keyword(kw::Impl)?; | |
472 | ||
416331ca | 473 | // First, parse generic parameters if necessary. |
ba9703b0 | 474 | let mut generics = if self.choose_generics_over_qpath(0) { |
416331ca XL |
475 | self.parse_generics()? |
476 | } else { | |
dfeec247 XL |
477 | let mut generics = Generics::default(); |
478 | // impl A for B {} | |
479 | // /\ this is where `generics.span` should point when there are no type params. | |
74b04a01 | 480 | generics.span = self.prev_token.span.shrink_to_hi(); |
dfeec247 XL |
481 | generics |
482 | }; | |
483 | ||
74b04a01 XL |
484 | let constness = self.parse_constness(); |
485 | if let Const::Yes(span) = constness { | |
dfeec247 | 486 | self.sess.gated_spans.gate(sym::const_trait_impl, span); |
74b04a01 | 487 | } |
416331ca | 488 | |
ba9703b0 | 489 | let polarity = self.parse_polarity(); |
416331ca XL |
490 | |
491 | // Parse both types and traits as a type, then reinterpret if necessary. | |
5869c6ff | 492 | let err_path = |span| ast::Path::from_ident(Ident::new(kw::Empty, span)); |
dfeec247 XL |
493 | let ty_first = if self.token.is_keyword(kw::For) && self.look_ahead(1, |t| t != &token::Lt) |
494 | { | |
74b04a01 | 495 | let span = self.prev_token.span.between(self.token.span); |
c295e0f8 XL |
496 | self.struct_span_err(span, "missing trait in a trait impl") |
497 | .span_suggestion( | |
498 | span, | |
499 | "add a trait here", | |
500 | " Trait ".into(), | |
501 | Applicability::HasPlaceholders, | |
502 | ) | |
503 | .span_suggestion( | |
504 | span.to(self.token.span), | |
505 | "for an inherent impl, drop this `for`", | |
506 | "".into(), | |
507 | Applicability::MaybeIncorrect, | |
508 | ) | |
509 | .emit(); | |
1b1a35ee XL |
510 | P(Ty { |
511 | kind: TyKind::Path(None, err_path(span)), | |
512 | span, | |
513 | id: DUMMY_NODE_ID, | |
514 | tokens: None, | |
515 | }) | |
416331ca XL |
516 | } else { |
517 | self.parse_ty()? | |
518 | }; | |
519 | ||
520 | // If `for` is missing we try to recover. | |
521 | let has_for = self.eat_keyword(kw::For); | |
74b04a01 | 522 | let missing_for_span = self.prev_token.span.between(self.token.span); |
416331ca XL |
523 | |
524 | let ty_second = if self.token == token::DotDot { | |
525 | // We need to report this error after `cfg` expansion for compatibility reasons | |
526 | self.bump(); // `..`, do not add it to expected tokens | |
74b04a01 | 527 | Some(self.mk_ty(self.prev_token.span, TyKind::Err)) |
416331ca XL |
528 | } else if has_for || self.token.can_begin_type() { |
529 | Some(self.parse_ty()?) | |
530 | } else { | |
531 | None | |
532 | }; | |
533 | ||
534 | generics.where_clause = self.parse_where_clause()?; | |
535 | ||
cdc7bbd5 | 536 | let impl_items = self.parse_item_list(attrs, |p| p.parse_impl_item(ForceCollect::No))?; |
416331ca XL |
537 | |
538 | let item_kind = match ty_second { | |
539 | Some(ty_second) => { | |
540 | // impl Trait for Type | |
541 | if !has_for { | |
542 | self.struct_span_err(missing_for_span, "missing `for` in a trait impl") | |
543 | .span_suggestion_short( | |
544 | missing_for_span, | |
545 | "add `for` here", | |
546 | " for ".to_string(), | |
547 | Applicability::MachineApplicable, | |
dfeec247 XL |
548 | ) |
549 | .emit(); | |
416331ca XL |
550 | } |
551 | ||
552 | let ty_first = ty_first.into_inner(); | |
e74abb32 | 553 | let path = match ty_first.kind { |
416331ca XL |
554 | // This notably includes paths passed through `ty` macro fragments (#46438). |
555 | TyKind::Path(None, path) => path, | |
556 | _ => { | |
dfeec247 | 557 | self.struct_span_err(ty_first.span, "expected a trait, found type").emit(); |
416331ca XL |
558 | err_path(ty_first.span) |
559 | } | |
560 | }; | |
561 | let trait_ref = TraitRef { path, ref_id: ty_first.id }; | |
562 | ||
94222f64 | 563 | ItemKind::Impl(Box::new(ImplKind { |
dfeec247 XL |
564 | unsafety, |
565 | polarity, | |
566 | defaultness, | |
567 | constness, | |
568 | generics, | |
569 | of_trait: Some(trait_ref), | |
570 | self_ty: ty_second, | |
571 | items: impl_items, | |
94222f64 | 572 | })) |
416331ca XL |
573 | } |
574 | None => { | |
575 | // impl Type | |
94222f64 | 576 | ItemKind::Impl(Box::new(ImplKind { |
dfeec247 XL |
577 | unsafety, |
578 | polarity, | |
579 | defaultness, | |
580 | constness, | |
581 | generics, | |
582 | of_trait: None, | |
583 | self_ty: ty_first, | |
584 | items: impl_items, | |
94222f64 | 585 | })) |
416331ca XL |
586 | } |
587 | }; | |
588 | ||
74b04a01 | 589 | Ok((Ident::invalid(), item_kind)) |
416331ca XL |
590 | } |
591 | ||
74b04a01 XL |
592 | fn parse_item_list<T>( |
593 | &mut self, | |
594 | attrs: &mut Vec<Attribute>, | |
595 | mut parse_item: impl FnMut(&mut Parser<'a>) -> PResult<'a, Option<Option<T>>>, | |
596 | ) -> PResult<'a, Vec<T>> { | |
597 | let open_brace_span = self.token.span; | |
416331ca | 598 | self.expect(&token::OpenDelim(token::Brace))?; |
74b04a01 | 599 | attrs.append(&mut self.parse_inner_attributes()?); |
416331ca | 600 | |
74b04a01 | 601 | let mut items = Vec::new(); |
416331ca | 602 | while !self.eat(&token::CloseDelim(token::Brace)) { |
74b04a01 XL |
603 | if self.recover_doc_comment_before_brace() { |
604 | continue; | |
605 | } | |
606 | match parse_item(self) { | |
607 | Ok(None) => { | |
608 | // We have to bail or we'll potentially never make progress. | |
609 | let non_item_span = self.token.span; | |
610 | self.consume_block(token::Brace, ConsumeClosingDelim::Yes); | |
611 | self.struct_span_err(non_item_span, "non-item in item list") | |
612 | .span_label(open_brace_span, "item list starts here") | |
613 | .span_label(non_item_span, "non-item starts here") | |
614 | .span_label(self.prev_token.span, "item list ends here") | |
615 | .emit(); | |
616 | break; | |
617 | } | |
618 | Ok(Some(item)) => items.extend(item), | |
416331ca | 619 | Err(mut err) => { |
74b04a01 XL |
620 | self.consume_block(token::Brace, ConsumeClosingDelim::Yes); |
621 | err.span_label(open_brace_span, "while parsing this item list starting here") | |
622 | .span_label(self.prev_token.span, "the item list ends here") | |
623 | .emit(); | |
624 | break; | |
416331ca XL |
625 | } |
626 | } | |
627 | } | |
74b04a01 XL |
628 | Ok(items) |
629 | } | |
630 | ||
631 | /// Recover on a doc comment before `}`. | |
632 | fn recover_doc_comment_before_brace(&mut self) -> bool { | |
3dfed10e | 633 | if let token::DocComment(..) = self.token.kind { |
74b04a01 XL |
634 | if self.look_ahead(1, |tok| tok == &token::CloseDelim(token::Brace)) { |
635 | struct_span_err!( | |
636 | self.diagnostic(), | |
637 | self.token.span, | |
638 | E0584, | |
639 | "found a documentation comment that doesn't document anything", | |
640 | ) | |
641 | .span_label(self.token.span, "this doc comment doesn't document anything") | |
642 | .help( | |
643 | "doc comments must come before what they document, maybe a \ | |
644 | comment was intended with `//`?", | |
645 | ) | |
646 | .emit(); | |
647 | self.bump(); | |
648 | return true; | |
649 | } | |
650 | } | |
651 | false | |
416331ca XL |
652 | } |
653 | ||
416331ca XL |
654 | /// Parses defaultness (i.e., `default` or nothing). |
655 | fn parse_defaultness(&mut self) -> Defaultness { | |
74b04a01 XL |
656 | // We are interested in `default` followed by another identifier. |
657 | // However, we must avoid keywords that occur as binary operators. | |
658 | // Currently, the only applicable keyword is `as` (`default as Ty`). | |
dfeec247 | 659 | if self.check_keyword(kw::Default) |
74b04a01 | 660 | && self.look_ahead(1, |t| t.is_non_raw_ident_where(|i| i.name != kw::As)) |
416331ca XL |
661 | { |
662 | self.bump(); // `default` | |
74b04a01 | 663 | Defaultness::Default(self.prev_token.uninterpolated_span()) |
416331ca XL |
664 | } else { |
665 | Defaultness::Final | |
666 | } | |
667 | } | |
668 | ||
74b04a01 XL |
669 | /// Is this an `(unsafe auto? | auto) trait` item? |
670 | fn check_auto_or_unsafe_trait_item(&mut self) -> bool { | |
671 | // auto trait | |
672 | self.check_keyword(kw::Auto) && self.is_keyword_ahead(1, &[kw::Trait]) | |
673 | // unsafe auto trait | |
674 | || self.check_keyword(kw::Unsafe) && self.is_keyword_ahead(1, &[kw::Trait, kw::Auto]) | |
675 | } | |
676 | ||
677 | /// Parses `unsafe? auto? trait Foo { ... }` or `trait Foo = Bar;`. | |
678 | fn parse_item_trait(&mut self, attrs: &mut Vec<Attribute>, lo: Span) -> PResult<'a, ItemInfo> { | |
679 | let unsafety = self.parse_unsafety(); | |
e74abb32 | 680 | // Parse optional `auto` prefix. |
dfeec247 | 681 | let is_auto = if self.eat_keyword(kw::Auto) { IsAuto::Yes } else { IsAuto::No }; |
416331ca | 682 | |
e74abb32 | 683 | self.expect_keyword(kw::Trait)?; |
416331ca XL |
684 | let ident = self.parse_ident()?; |
685 | let mut tps = self.parse_generics()?; | |
686 | ||
687 | // Parse optional colon and supertrait bounds. | |
e74abb32 | 688 | let had_colon = self.eat(&token::Colon); |
74b04a01 XL |
689 | let span_at_colon = self.prev_token.span; |
690 | let bounds = if had_colon { | |
691 | self.parse_generic_bounds(Some(self.prev_token.span))? | |
692 | } else { | |
693 | Vec::new() | |
694 | }; | |
416331ca | 695 | |
74b04a01 | 696 | let span_before_eq = self.prev_token.span; |
416331ca | 697 | if self.eat(&token::Eq) { |
e1599b0c | 698 | // It's a trait alias. |
e74abb32 XL |
699 | if had_colon { |
700 | let span = span_at_colon.to(span_before_eq); | |
dfeec247 | 701 | self.struct_span_err(span, "bounds are not allowed on trait aliases").emit(); |
e74abb32 XL |
702 | } |
703 | ||
416331ca XL |
704 | let bounds = self.parse_generic_bounds(None)?; |
705 | tps.where_clause = self.parse_where_clause()?; | |
e74abb32 XL |
706 | self.expect_semi()?; |
707 | ||
74b04a01 | 708 | let whole_span = lo.to(self.prev_token.span); |
416331ca XL |
709 | if is_auto == IsAuto::Yes { |
710 | let msg = "trait aliases cannot be `auto`"; | |
dfeec247 | 711 | self.struct_span_err(whole_span, msg).span_label(whole_span, msg).emit(); |
416331ca | 712 | } |
74b04a01 | 713 | if let Unsafe::Yes(_) = unsafety { |
416331ca | 714 | let msg = "trait aliases cannot be `unsafe`"; |
dfeec247 | 715 | self.struct_span_err(whole_span, msg).span_label(whole_span, msg).emit(); |
416331ca | 716 | } |
e74abb32 | 717 | |
60c5eb7d | 718 | self.sess.gated_spans.gate(sym::trait_alias, whole_span); |
e74abb32 | 719 | |
74b04a01 | 720 | Ok((ident, ItemKind::TraitAlias(tps, bounds))) |
416331ca | 721 | } else { |
e1599b0c | 722 | // It's a normal trait. |
416331ca | 723 | tps.where_clause = self.parse_where_clause()?; |
cdc7bbd5 | 724 | let items = self.parse_item_list(attrs, |p| p.parse_trait_item(ForceCollect::No))?; |
94222f64 | 725 | Ok((ident, ItemKind::Trait(Box::new(TraitKind(is_auto, unsafety, tps, bounds, items))))) |
416331ca XL |
726 | } |
727 | } | |
728 | ||
cdc7bbd5 XL |
729 | pub fn parse_impl_item( |
730 | &mut self, | |
731 | force_collect: ForceCollect, | |
732 | ) -> PResult<'a, Option<Option<P<AssocItem>>>> { | |
733 | self.parse_assoc_item(|_| true, force_collect) | |
dfeec247 XL |
734 | } |
735 | ||
cdc7bbd5 XL |
736 | pub fn parse_trait_item( |
737 | &mut self, | |
738 | force_collect: ForceCollect, | |
739 | ) -> PResult<'a, Option<Option<P<AssocItem>>>> { | |
740 | self.parse_assoc_item(|edition| edition >= Edition::Edition2018, force_collect) | |
dfeec247 XL |
741 | } |
742 | ||
743 | /// Parses associated items. | |
cdc7bbd5 XL |
744 | fn parse_assoc_item( |
745 | &mut self, | |
746 | req_name: ReqName, | |
747 | force_collect: ForceCollect, | |
748 | ) -> PResult<'a, Option<Option<P<AssocItem>>>> { | |
749 | Ok(self.parse_item_(req_name, force_collect)?.map( | |
5869c6ff XL |
750 | |Item { attrs, id, span, vis, ident, kind, tokens }| { |
751 | let kind = match AssocItemKind::try_from(kind) { | |
752 | Ok(kind) => kind, | |
753 | Err(kind) => match kind { | |
754 | ItemKind::Static(a, _, b) => { | |
755 | self.struct_span_err(span, "associated `static` items are not allowed") | |
756 | .emit(); | |
757 | AssocItemKind::Const(Defaultness::Final, a, b) | |
758 | } | |
759 | _ => return self.error_bad_item_kind(span, &kind, "`trait`s or `impl`s"), | |
760 | }, | |
761 | }; | |
762 | Some(P(Item { attrs, id, span, vis, ident, kind, tokens })) | |
763 | }, | |
764 | )) | |
e74abb32 XL |
765 | } |
766 | ||
74b04a01 XL |
767 | /// Parses a `type` alias with the following grammar: |
768 | /// ``` | |
769 | /// TypeAlias = "type" Ident Generics {":" GenericBounds}? {"=" Ty}? ";" ; | |
770 | /// ``` | |
771 | /// The `"type"` has already been eaten. | |
772 | fn parse_type_alias(&mut self, def: Defaultness) -> PResult<'a, ItemInfo> { | |
416331ca XL |
773 | let ident = self.parse_ident()?; |
774 | let mut generics = self.parse_generics()?; | |
775 | ||
776 | // Parse optional colon and param bounds. | |
dfeec247 XL |
777 | let bounds = |
778 | if self.eat(&token::Colon) { self.parse_generic_bounds(None)? } else { Vec::new() }; | |
416331ca XL |
779 | generics.where_clause = self.parse_where_clause()?; |
780 | ||
dfeec247 | 781 | let default = if self.eat(&token::Eq) { Some(self.parse_ty()?) } else { None }; |
e74abb32 | 782 | self.expect_semi()?; |
416331ca | 783 | |
94222f64 | 784 | Ok((ident, ItemKind::TyAlias(Box::new(TyAliasKind(def, generics, bounds, default))))) |
416331ca XL |
785 | } |
786 | ||
787 | /// Parses a `UseTree`. | |
788 | /// | |
ba9703b0 | 789 | /// ```text |
416331ca XL |
790 | /// USE_TREE = [`::`] `*` | |
791 | /// [`::`] `{` USE_TREE_LIST `}` | | |
792 | /// PATH `::` `*` | | |
793 | /// PATH `::` `{` USE_TREE_LIST `}` | | |
794 | /// PATH [`as` IDENT] | |
795 | /// ``` | |
796 | fn parse_use_tree(&mut self) -> PResult<'a, UseTree> { | |
797 | let lo = self.token.span; | |
798 | ||
1b1a35ee | 799 | let mut prefix = ast::Path { segments: Vec::new(), span: lo.shrink_to_lo(), tokens: None }; |
dfeec247 XL |
800 | let kind = if self.check(&token::OpenDelim(token::Brace)) |
801 | || self.check(&token::BinOp(token::Star)) | |
802 | || self.is_import_coupler() | |
803 | { | |
416331ca XL |
804 | // `use *;` or `use ::*;` or `use {...};` or `use ::{...};` |
805 | let mod_sep_ctxt = self.token.span.ctxt(); | |
806 | if self.eat(&token::ModSep) { | |
dfeec247 XL |
807 | prefix |
808 | .segments | |
809 | .push(PathSegment::path_root(lo.shrink_to_lo().with_ctxt(mod_sep_ctxt))); | |
416331ca XL |
810 | } |
811 | ||
e74abb32 | 812 | self.parse_use_tree_glob_or_nested()? |
416331ca XL |
813 | } else { |
814 | // `use path::*;` or `use path::{...};` or `use path;` or `use path as bar;` | |
815 | prefix = self.parse_path(PathStyle::Mod)?; | |
816 | ||
817 | if self.eat(&token::ModSep) { | |
e74abb32 | 818 | self.parse_use_tree_glob_or_nested()? |
416331ca | 819 | } else { |
e1599b0c | 820 | UseTreeKind::Simple(self.parse_rename()?, DUMMY_NODE_ID, DUMMY_NODE_ID) |
416331ca XL |
821 | } |
822 | }; | |
823 | ||
74b04a01 | 824 | Ok(UseTree { prefix, kind, span: lo.to(self.prev_token.span) }) |
416331ca XL |
825 | } |
826 | ||
e74abb32 XL |
827 | /// Parses `*` or `{...}`. |
828 | fn parse_use_tree_glob_or_nested(&mut self) -> PResult<'a, UseTreeKind> { | |
829 | Ok(if self.eat(&token::BinOp(token::Star)) { | |
830 | UseTreeKind::Glob | |
831 | } else { | |
832 | UseTreeKind::Nested(self.parse_use_tree_list()?) | |
833 | }) | |
834 | } | |
835 | ||
416331ca XL |
836 | /// Parses a `UseTreeKind::Nested(list)`. |
837 | /// | |
ba9703b0 | 838 | /// ```text |
416331ca XL |
839 | /// USE_TREE_LIST = Ø | (USE_TREE `,`)* USE_TREE [`,`] |
840 | /// ``` | |
841 | fn parse_use_tree_list(&mut self) -> PResult<'a, Vec<(UseTree, ast::NodeId)>> { | |
e1599b0c | 842 | self.parse_delim_comma_seq(token::Brace, |p| Ok((p.parse_use_tree()?, DUMMY_NODE_ID))) |
416331ca XL |
843 | .map(|(r, _)| r) |
844 | } | |
845 | ||
846 | fn parse_rename(&mut self) -> PResult<'a, Option<Ident>> { | |
dfeec247 | 847 | if self.eat_keyword(kw::As) { self.parse_ident_or_underscore().map(Some) } else { Ok(None) } |
416331ca XL |
848 | } |
849 | ||
f9f354fc | 850 | fn parse_ident_or_underscore(&mut self) -> PResult<'a, Ident> { |
74b04a01 XL |
851 | match self.token.ident() { |
852 | Some((ident @ Ident { name: kw::Underscore, .. }, false)) => { | |
416331ca | 853 | self.bump(); |
74b04a01 | 854 | Ok(ident) |
416331ca XL |
855 | } |
856 | _ => self.parse_ident(), | |
857 | } | |
858 | } | |
859 | ||
860 | /// Parses `extern crate` links. | |
861 | /// | |
862 | /// # Examples | |
863 | /// | |
864 | /// ``` | |
865 | /// extern crate foo; | |
866 | /// extern crate bar as foo; | |
867 | /// ``` | |
74b04a01 | 868 | fn parse_item_extern_crate(&mut self) -> PResult<'a, ItemInfo> { |
416331ca XL |
869 | // Accept `extern crate name-like-this` for better diagnostics |
870 | let orig_name = self.parse_crate_name_with_dashes()?; | |
871 | let (item_name, orig_name) = if let Some(rename) = self.parse_rename()? { | |
872 | (rename, Some(orig_name.name)) | |
873 | } else { | |
874 | (orig_name, None) | |
875 | }; | |
e74abb32 | 876 | self.expect_semi()?; |
74b04a01 | 877 | Ok((item_name, ItemKind::ExternCrate(orig_name))) |
416331ca XL |
878 | } |
879 | ||
f9f354fc | 880 | fn parse_crate_name_with_dashes(&mut self) -> PResult<'a, Ident> { |
416331ca XL |
881 | let error_msg = "crate name using dashes are not valid in `extern crate` statements"; |
882 | let suggestion_msg = "if the original crate name uses dashes you need to use underscores \ | |
883 | in the code"; | |
884 | let mut ident = if self.token.is_keyword(kw::SelfLower) { | |
885 | self.parse_path_segment_ident() | |
886 | } else { | |
887 | self.parse_ident() | |
888 | }?; | |
889 | let mut idents = vec![]; | |
890 | let mut replacement = vec![]; | |
891 | let mut fixed_crate_name = false; | |
e1599b0c | 892 | // Accept `extern crate name-like-this` for better diagnostics. |
416331ca | 893 | let dash = token::BinOp(token::BinOpToken::Minus); |
dfeec247 XL |
894 | if self.token == dash { |
895 | // Do not include `-` as part of the expected tokens list. | |
416331ca XL |
896 | while self.eat(&dash) { |
897 | fixed_crate_name = true; | |
74b04a01 | 898 | replacement.push((self.prev_token.span, "_".to_string())); |
416331ca XL |
899 | idents.push(self.parse_ident()?); |
900 | } | |
901 | } | |
902 | if fixed_crate_name { | |
903 | let fixed_name_sp = ident.span.to(idents.last().unwrap().span); | |
904 | let mut fixed_name = format!("{}", ident.name); | |
905 | for part in idents { | |
906 | fixed_name.push_str(&format!("_{}", part.name)); | |
907 | } | |
e1599b0c | 908 | ident = Ident::from_str_and_span(&fixed_name, fixed_name_sp); |
416331ca XL |
909 | |
910 | self.struct_span_err(fixed_name_sp, error_msg) | |
911 | .span_label(fixed_name_sp, "dash-separated idents are not valid") | |
912 | .multipart_suggestion(suggestion_msg, replacement, Applicability::MachineApplicable) | |
913 | .emit(); | |
914 | } | |
915 | Ok(ident) | |
916 | } | |
917 | ||
416331ca XL |
918 | /// Parses `extern` for foreign ABIs modules. |
919 | /// | |
74b04a01 | 920 | /// `extern` is expected to have been consumed before calling this method. |
416331ca XL |
921 | /// |
922 | /// # Examples | |
923 | /// | |
924 | /// ```ignore (only-for-syntax-highlight) | |
925 | /// extern "C" {} | |
926 | /// extern {} | |
927 | /// ``` | |
1b1a35ee XL |
928 | fn parse_item_foreign_mod( |
929 | &mut self, | |
930 | attrs: &mut Vec<Attribute>, | |
931 | unsafety: Unsafe, | |
932 | ) -> PResult<'a, ItemInfo> { | |
74b04a01 | 933 | let abi = self.parse_abi(); // ABI? |
cdc7bbd5 | 934 | let items = self.parse_item_list(attrs, |p| p.parse_foreign_item(ForceCollect::No))?; |
1b1a35ee | 935 | let module = ast::ForeignMod { unsafety, abi, items }; |
74b04a01 | 936 | Ok((Ident::invalid(), ItemKind::ForeignMod(module))) |
416331ca XL |
937 | } |
938 | ||
74b04a01 | 939 | /// Parses a foreign item (one in an `extern { ... }` block). |
cdc7bbd5 XL |
940 | pub fn parse_foreign_item( |
941 | &mut self, | |
942 | force_collect: ForceCollect, | |
943 | ) -> PResult<'a, Option<Option<P<ForeignItem>>>> { | |
944 | Ok(self.parse_item_(|_| true, force_collect)?.map( | |
5869c6ff XL |
945 | |Item { attrs, id, span, vis, ident, kind, tokens }| { |
946 | let kind = match ForeignItemKind::try_from(kind) { | |
947 | Ok(kind) => kind, | |
948 | Err(kind) => match kind { | |
949 | ItemKind::Const(_, a, b) => { | |
950 | self.error_on_foreign_const(span, ident); | |
951 | ForeignItemKind::Static(a, Mutability::Not, b) | |
952 | } | |
953 | _ => return self.error_bad_item_kind(span, &kind, "`extern` blocks"), | |
954 | }, | |
955 | }; | |
956 | Some(P(Item { attrs, id, span, vis, ident, kind, tokens })) | |
957 | }, | |
958 | )) | |
416331ca XL |
959 | } |
960 | ||
74b04a01 | 961 | fn error_bad_item_kind<T>(&self, span: Span, kind: &ItemKind, ctx: &str) -> Option<T> { |
ba9703b0 XL |
962 | let span = self.sess.source_map().guess_head_span(span); |
963 | let descr = kind.descr(); | |
964 | self.struct_span_err(span, &format!("{} is not supported in {}", descr, ctx)) | |
965 | .help(&format!("consider moving the {} out to a nearby module scope", descr)) | |
966 | .emit(); | |
967 | None | |
416331ca XL |
968 | } |
969 | ||
74b04a01 XL |
970 | fn error_on_foreign_const(&self, span: Span, ident: Ident) { |
971 | self.struct_span_err(ident.span, "extern items cannot be `const`") | |
972 | .span_suggestion( | |
973 | span.with_hi(ident.span.lo()), | |
974 | "try using a static value", | |
975 | "static ".to_string(), | |
976 | Applicability::MachineApplicable, | |
977 | ) | |
978 | .note("for more information, visit https://doc.rust-lang.org/std/keyword.extern.html") | |
979 | .emit(); | |
416331ca XL |
980 | } |
981 | ||
1b1a35ee XL |
982 | fn is_unsafe_foreign_mod(&self) -> bool { |
983 | self.token.is_keyword(kw::Unsafe) | |
984 | && self.is_keyword_ahead(1, &[kw::Extern]) | |
985 | && self.look_ahead( | |
986 | 2 + self.look_ahead(2, |t| t.can_begin_literal_maybe_minus() as usize), | |
987 | |t| t.kind == token::OpenDelim(token::Brace), | |
988 | ) | |
989 | } | |
990 | ||
416331ca XL |
991 | fn is_static_global(&mut self) -> bool { |
992 | if self.check_keyword(kw::Static) { | |
e1599b0c | 993 | // Check if this could be a closure. |
416331ca XL |
994 | !self.look_ahead(1, |token| { |
995 | if token.is_keyword(kw::Move) { | |
996 | return true; | |
997 | } | |
29967ef6 | 998 | matches!(token.kind, token::BinOp(token::Or) | token::OrOr) |
416331ca XL |
999 | }) |
1000 | } else { | |
1001 | false | |
1002 | } | |
1003 | } | |
1004 | ||
74b04a01 XL |
1005 | /// Recover on `const mut` with `const` already eaten. |
1006 | fn recover_const_mut(&mut self, const_span: Span) { | |
1007 | if self.eat_keyword(kw::Mut) { | |
1008 | let span = self.prev_token.span; | |
1009 | self.struct_span_err(span, "const globals cannot be mutable") | |
1010 | .span_label(span, "cannot be mutable") | |
1011 | .span_suggestion( | |
1012 | const_span, | |
1013 | "you might want to declare a static instead", | |
1014 | "static".to_owned(), | |
1015 | Applicability::MaybeIncorrect, | |
1016 | ) | |
1017 | .emit(); | |
1018 | } | |
1019 | } | |
1020 | ||
fc512014 XL |
1021 | /// Recover on `const impl` with `const` already eaten. |
1022 | fn recover_const_impl( | |
1023 | &mut self, | |
1024 | const_span: Span, | |
1025 | attrs: &mut Vec<Attribute>, | |
1026 | defaultness: Defaultness, | |
1027 | ) -> PResult<'a, ItemInfo> { | |
1028 | let impl_span = self.token.span; | |
1029 | let mut err = self.expected_ident_found(); | |
5869c6ff XL |
1030 | |
1031 | // Only try to recover if this is implementing a trait for a type | |
1032 | let mut impl_info = match self.parse_item_impl(attrs, defaultness) { | |
1033 | Ok(impl_info) => impl_info, | |
1034 | Err(mut recovery_error) => { | |
1035 | // Recovery failed, raise the "expected identifier" error | |
1036 | recovery_error.cancel(); | |
1037 | return Err(err); | |
1038 | } | |
1039 | }; | |
1040 | ||
fc512014 | 1041 | match impl_info.1 { |
5869c6ff XL |
1042 | ItemKind::Impl(box ImplKind { |
1043 | of_trait: Some(ref trai), ref mut constness, .. | |
1044 | }) => { | |
fc512014 XL |
1045 | *constness = Const::Yes(const_span); |
1046 | ||
1047 | let before_trait = trai.path.span.shrink_to_lo(); | |
1048 | let const_up_to_impl = const_span.with_hi(impl_span.lo()); | |
1049 | err.multipart_suggestion( | |
1050 | "you might have meant to write a const trait impl", | |
1051 | vec![(const_up_to_impl, "".to_owned()), (before_trait, "const ".to_owned())], | |
1052 | Applicability::MaybeIncorrect, | |
1053 | ) | |
1054 | .emit(); | |
1055 | } | |
1056 | ItemKind::Impl { .. } => return Err(err), | |
1057 | _ => unreachable!(), | |
1058 | } | |
5869c6ff | 1059 | |
fc512014 XL |
1060 | Ok(impl_info) |
1061 | } | |
1062 | ||
74b04a01 | 1063 | /// Parse `["const" | ("static" "mut"?)] $ident ":" $ty (= $expr)?` with |
e74abb32 XL |
1064 | /// `["const" | ("static" "mut"?)]` already parsed and stored in `m`. |
1065 | /// | |
1066 | /// When `m` is `"const"`, `$ident` may also be `"_"`. | |
74b04a01 XL |
1067 | fn parse_item_global( |
1068 | &mut self, | |
1069 | m: Option<Mutability>, | |
1070 | ) -> PResult<'a, (Ident, P<Ty>, Option<P<ast::Expr>>)> { | |
416331ca | 1071 | let id = if m.is_none() { self.parse_ident_or_underscore() } else { self.parse_ident() }?; |
e74abb32 XL |
1072 | |
1073 | // Parse the type of a `const` or `static mut?` item. | |
1074 | // That is, the `":" $ty` fragment. | |
74b04a01 | 1075 | let ty = if self.eat(&token::Colon) { |
e74abb32 | 1076 | self.parse_ty()? |
74b04a01 XL |
1077 | } else { |
1078 | self.recover_missing_const_type(id, m) | |
e74abb32 XL |
1079 | }; |
1080 | ||
74b04a01 | 1081 | let expr = if self.eat(&token::Eq) { Some(self.parse_expr()?) } else { None }; |
e74abb32 | 1082 | self.expect_semi()?; |
74b04a01 | 1083 | Ok((id, ty, expr)) |
416331ca XL |
1084 | } |
1085 | ||
74b04a01 | 1086 | /// We were supposed to parse `:` but the `:` was missing. |
e74abb32 XL |
1087 | /// This means that the type is missing. |
1088 | fn recover_missing_const_type(&mut self, id: Ident, m: Option<Mutability>) -> P<Ty> { | |
1089 | // Construct the error and stash it away with the hope | |
1090 | // that typeck will later enrich the error with a type. | |
1091 | let kind = match m { | |
dfeec247 XL |
1092 | Some(Mutability::Mut) => "static mut", |
1093 | Some(Mutability::Not) => "static", | |
e74abb32 XL |
1094 | None => "const", |
1095 | }; | |
1096 | let mut err = self.struct_span_err(id.span, &format!("missing type for `{}` item", kind)); | |
1097 | err.span_suggestion( | |
1098 | id.span, | |
1099 | "provide a type for the item", | |
1100 | format!("{}: <type>", id), | |
1101 | Applicability::HasPlaceholders, | |
1102 | ); | |
1103 | err.stash(id.span, StashKey::ItemNoType); | |
1104 | ||
1105 | // The user intended that the type be inferred, | |
1106 | // so treat this as if the user wrote e.g. `const A: _ = expr;`. | |
1b1a35ee | 1107 | P(Ty { kind: TyKind::Infer, span: id.span, id: ast::DUMMY_NODE_ID, tokens: None }) |
e74abb32 XL |
1108 | } |
1109 | ||
416331ca XL |
1110 | /// Parses an enum declaration. |
1111 | fn parse_item_enum(&mut self) -> PResult<'a, ItemInfo> { | |
1112 | let id = self.parse_ident()?; | |
1113 | let mut generics = self.parse_generics()?; | |
1114 | generics.where_clause = self.parse_where_clause()?; | |
416331ca | 1115 | |
dfeec247 XL |
1116 | let (variants, _) = |
1117 | self.parse_delim_comma_seq(token::Brace, |p| p.parse_enum_variant()).map_err(|e| { | |
1118 | self.recover_stmt(); | |
1119 | e | |
1120 | })?; | |
60c5eb7d | 1121 | |
94222f64 | 1122 | let enum_definition = EnumDef { variants: variants.into_iter().flatten().collect() }; |
74b04a01 | 1123 | Ok((id, ItemKind::Enum(enum_definition, generics))) |
416331ca XL |
1124 | } |
1125 | ||
60c5eb7d XL |
1126 | fn parse_enum_variant(&mut self) -> PResult<'a, Option<Variant>> { |
1127 | let variant_attrs = self.parse_outer_attributes()?; | |
6a06907d XL |
1128 | self.collect_tokens_trailing_token( |
1129 | variant_attrs, | |
1130 | ForceCollect::No, | |
1131 | |this, variant_attrs| { | |
1132 | let vlo = this.token.span; | |
1133 | ||
1134 | let vis = this.parse_visibility(FollowedByType::No)?; | |
1135 | if !this.recover_nested_adt_item(kw::Enum)? { | |
1136 | return Ok((None, TrailingToken::None)); | |
1137 | } | |
17df50a5 | 1138 | let ident = this.parse_field_ident("enum", vlo)?; |
6a06907d XL |
1139 | |
1140 | let struct_def = if this.check(&token::OpenDelim(token::Brace)) { | |
1141 | // Parse a struct variant. | |
17df50a5 | 1142 | let (fields, recovered) = this.parse_record_struct_body("struct")?; |
6a06907d XL |
1143 | VariantData::Struct(fields, recovered) |
1144 | } else if this.check(&token::OpenDelim(token::Paren)) { | |
1145 | VariantData::Tuple(this.parse_tuple_struct_body()?, DUMMY_NODE_ID) | |
1146 | } else { | |
1147 | VariantData::Unit(DUMMY_NODE_ID) | |
1148 | }; | |
416331ca | 1149 | |
6a06907d XL |
1150 | let disr_expr = |
1151 | if this.eat(&token::Eq) { Some(this.parse_anon_const_expr()?) } else { None }; | |
1152 | ||
1153 | let vr = ast::Variant { | |
1154 | ident, | |
1155 | vis, | |
1156 | id: DUMMY_NODE_ID, | |
136023e0 | 1157 | attrs: variant_attrs.into(), |
6a06907d XL |
1158 | data: struct_def, |
1159 | disr_expr, | |
1160 | span: vlo.to(this.prev_token.span), | |
1161 | is_placeholder: false, | |
1162 | }; | |
416331ca | 1163 | |
6a06907d XL |
1164 | Ok((Some(vr), TrailingToken::MaybeComma)) |
1165 | }, | |
1166 | ) | |
416331ca XL |
1167 | } |
1168 | ||
1169 | /// Parses `struct Foo { ... }`. | |
1170 | fn parse_item_struct(&mut self) -> PResult<'a, ItemInfo> { | |
1171 | let class_name = self.parse_ident()?; | |
1172 | ||
1173 | let mut generics = self.parse_generics()?; | |
1174 | ||
1175 | // There is a special case worth noting here, as reported in issue #17904. | |
1176 | // If we are parsing a tuple struct it is the case that the where clause | |
1177 | // should follow the field list. Like so: | |
1178 | // | |
1179 | // struct Foo<T>(T) where T: Copy; | |
1180 | // | |
1181 | // If we are parsing a normal record-style struct it is the case | |
1182 | // that the where clause comes before the body, and after the generics. | |
1183 | // So if we look ahead and see a brace or a where-clause we begin | |
1184 | // parsing a record style struct. | |
1185 | // | |
1186 | // Otherwise if we look ahead and see a paren we parse a tuple-style | |
1187 | // struct. | |
1188 | ||
1189 | let vdata = if self.token.is_keyword(kw::Where) { | |
1190 | generics.where_clause = self.parse_where_clause()?; | |
1191 | if self.eat(&token::Semi) { | |
1192 | // If we see a: `struct Foo<T> where T: Copy;` style decl. | |
e1599b0c | 1193 | VariantData::Unit(DUMMY_NODE_ID) |
416331ca XL |
1194 | } else { |
1195 | // If we see: `struct Foo<T> where T: Copy { ... }` | |
17df50a5 | 1196 | let (fields, recovered) = self.parse_record_struct_body("struct")?; |
416331ca XL |
1197 | VariantData::Struct(fields, recovered) |
1198 | } | |
1199 | // No `where` so: `struct Foo<T>;` | |
1200 | } else if self.eat(&token::Semi) { | |
e1599b0c | 1201 | VariantData::Unit(DUMMY_NODE_ID) |
416331ca XL |
1202 | // Record-style struct definition |
1203 | } else if self.token == token::OpenDelim(token::Brace) { | |
17df50a5 | 1204 | let (fields, recovered) = self.parse_record_struct_body("struct")?; |
416331ca XL |
1205 | VariantData::Struct(fields, recovered) |
1206 | // Tuple-style struct definition with optional where-clause. | |
1207 | } else if self.token == token::OpenDelim(token::Paren) { | |
e1599b0c | 1208 | let body = VariantData::Tuple(self.parse_tuple_struct_body()?, DUMMY_NODE_ID); |
416331ca | 1209 | generics.where_clause = self.parse_where_clause()?; |
e74abb32 | 1210 | self.expect_semi()?; |
416331ca XL |
1211 | body |
1212 | } else { | |
dfeec247 XL |
1213 | let token_str = super::token_descr(&self.token); |
1214 | let msg = &format!( | |
416331ca XL |
1215 | "expected `where`, `{{`, `(`, or `;` after struct name, found {}", |
1216 | token_str | |
dfeec247 XL |
1217 | ); |
1218 | let mut err = self.struct_span_err(self.token.span, msg); | |
416331ca XL |
1219 | err.span_label(self.token.span, "expected `where`, `{`, `(`, or `;` after struct name"); |
1220 | return Err(err); | |
1221 | }; | |
1222 | ||
74b04a01 | 1223 | Ok((class_name, ItemKind::Struct(vdata, generics))) |
416331ca XL |
1224 | } |
1225 | ||
1226 | /// Parses `union Foo { ... }`. | |
1227 | fn parse_item_union(&mut self) -> PResult<'a, ItemInfo> { | |
1228 | let class_name = self.parse_ident()?; | |
1229 | ||
1230 | let mut generics = self.parse_generics()?; | |
1231 | ||
1232 | let vdata = if self.token.is_keyword(kw::Where) { | |
1233 | generics.where_clause = self.parse_where_clause()?; | |
17df50a5 | 1234 | let (fields, recovered) = self.parse_record_struct_body("union")?; |
416331ca XL |
1235 | VariantData::Struct(fields, recovered) |
1236 | } else if self.token == token::OpenDelim(token::Brace) { | |
17df50a5 | 1237 | let (fields, recovered) = self.parse_record_struct_body("union")?; |
416331ca XL |
1238 | VariantData::Struct(fields, recovered) |
1239 | } else { | |
dfeec247 XL |
1240 | let token_str = super::token_descr(&self.token); |
1241 | let msg = &format!("expected `where` or `{{` after union name, found {}", token_str); | |
1242 | let mut err = self.struct_span_err(self.token.span, msg); | |
416331ca XL |
1243 | err.span_label(self.token.span, "expected `where` or `{` after union name"); |
1244 | return Err(err); | |
1245 | }; | |
1246 | ||
74b04a01 | 1247 | Ok((class_name, ItemKind::Union(vdata, generics))) |
416331ca XL |
1248 | } |
1249 | ||
94222f64 | 1250 | fn parse_record_struct_body( |
17df50a5 XL |
1251 | &mut self, |
1252 | adt_ty: &str, | |
1253 | ) -> PResult<'a, (Vec<FieldDef>, /* recovered */ bool)> { | |
416331ca XL |
1254 | let mut fields = Vec::new(); |
1255 | let mut recovered = false; | |
1256 | if self.eat(&token::OpenDelim(token::Brace)) { | |
1257 | while self.token != token::CloseDelim(token::Brace) { | |
17df50a5 | 1258 | let field = self.parse_field_def(adt_ty).map_err(|e| { |
e74abb32 | 1259 | self.consume_block(token::Brace, ConsumeClosingDelim::No); |
416331ca XL |
1260 | recovered = true; |
1261 | e | |
1262 | }); | |
1263 | match field { | |
1264 | Ok(field) => fields.push(field), | |
1265 | Err(mut err) => { | |
1266 | err.emit(); | |
e74abb32 | 1267 | break; |
416331ca XL |
1268 | } |
1269 | } | |
1270 | } | |
1271 | self.eat(&token::CloseDelim(token::Brace)); | |
1272 | } else { | |
dfeec247 XL |
1273 | let token_str = super::token_descr(&self.token); |
1274 | let msg = &format!("expected `where`, or `{{` after struct name, found {}", token_str); | |
1275 | let mut err = self.struct_span_err(self.token.span, msg); | |
416331ca XL |
1276 | err.span_label(self.token.span, "expected `where`, or `{` after struct name"); |
1277 | return Err(err); | |
1278 | } | |
1279 | ||
1280 | Ok((fields, recovered)) | |
1281 | } | |
1282 | ||
6a06907d | 1283 | fn parse_tuple_struct_body(&mut self) -> PResult<'a, Vec<FieldDef>> { |
416331ca XL |
1284 | // This is the case where we find `struct Foo<T>(T) where T: Copy;` |
1285 | // Unit like structs are handled in parse_item_struct function | |
1286 | self.parse_paren_comma_seq(|p| { | |
1287 | let attrs = p.parse_outer_attributes()?; | |
6a06907d XL |
1288 | p.collect_tokens_trailing_token(attrs, ForceCollect::No, |p, attrs| { |
1289 | let lo = p.token.span; | |
1290 | let vis = p.parse_visibility(FollowedByType::Yes)?; | |
1291 | let ty = p.parse_ty()?; | |
1292 | ||
1293 | Ok(( | |
1294 | FieldDef { | |
1295 | span: lo.to(ty.span), | |
1296 | vis, | |
1297 | ident: None, | |
1298 | id: DUMMY_NODE_ID, | |
1299 | ty, | |
136023e0 | 1300 | attrs: attrs.into(), |
6a06907d XL |
1301 | is_placeholder: false, |
1302 | }, | |
1303 | TrailingToken::MaybeComma, | |
1304 | )) | |
416331ca | 1305 | }) |
dfeec247 XL |
1306 | }) |
1307 | .map(|(r, _)| r) | |
416331ca XL |
1308 | } |
1309 | ||
1310 | /// Parses an element of a struct declaration. | |
17df50a5 | 1311 | fn parse_field_def(&mut self, adt_ty: &str) -> PResult<'a, FieldDef> { |
416331ca | 1312 | let attrs = self.parse_outer_attributes()?; |
6a06907d XL |
1313 | self.collect_tokens_trailing_token(attrs, ForceCollect::No, |this, attrs| { |
1314 | let lo = this.token.span; | |
1315 | let vis = this.parse_visibility(FollowedByType::No)?; | |
17df50a5 | 1316 | Ok((this.parse_single_struct_field(adt_ty, lo, vis, attrs)?, TrailingToken::None)) |
6a06907d | 1317 | }) |
416331ca XL |
1318 | } |
1319 | ||
1320 | /// Parses a structure field declaration. | |
dfeec247 XL |
1321 | fn parse_single_struct_field( |
1322 | &mut self, | |
17df50a5 | 1323 | adt_ty: &str, |
dfeec247 XL |
1324 | lo: Span, |
1325 | vis: Visibility, | |
1326 | attrs: Vec<Attribute>, | |
6a06907d | 1327 | ) -> PResult<'a, FieldDef> { |
416331ca | 1328 | let mut seen_comma: bool = false; |
17df50a5 | 1329 | let a_var = self.parse_name_and_ty(adt_ty, lo, vis, attrs)?; |
416331ca XL |
1330 | if self.token == token::Comma { |
1331 | seen_comma = true; | |
1332 | } | |
1333 | match self.token.kind { | |
1334 | token::Comma => { | |
1335 | self.bump(); | |
1336 | } | |
1337 | token::CloseDelim(token::Brace) => {} | |
3dfed10e | 1338 | token::DocComment(..) => { |
74b04a01 | 1339 | let previous_span = self.prev_token.span; |
17df50a5 | 1340 | let mut err = self.span_err(self.token.span, Error::UselessDocComment); |
416331ca XL |
1341 | self.bump(); // consume the doc comment |
1342 | let comma_after_doc_seen = self.eat(&token::Comma); | |
1343 | // `seen_comma` is always false, because we are inside doc block | |
1344 | // condition is here to make code more readable | |
74b04a01 | 1345 | if !seen_comma && comma_after_doc_seen { |
416331ca XL |
1346 | seen_comma = true; |
1347 | } | |
1348 | if comma_after_doc_seen || self.token == token::CloseDelim(token::Brace) { | |
1349 | err.emit(); | |
1350 | } else { | |
74b04a01 | 1351 | if !seen_comma { |
416331ca XL |
1352 | let sp = self.sess.source_map().next_point(previous_span); |
1353 | err.span_suggestion( | |
1354 | sp, | |
1355 | "missing comma here", | |
1356 | ",".into(), | |
dfeec247 | 1357 | Applicability::MachineApplicable, |
416331ca XL |
1358 | ); |
1359 | } | |
1360 | return Err(err); | |
1361 | } | |
1362 | } | |
1363 | _ => { | |
74b04a01 | 1364 | let sp = self.prev_token.span.shrink_to_hi(); |
dfeec247 XL |
1365 | let mut err = self.struct_span_err( |
1366 | sp, | |
1367 | &format!("expected `,`, or `}}`, found {}", super::token_descr(&self.token)), | |
1368 | ); | |
f035d41b XL |
1369 | |
1370 | // Try to recover extra trailing angle brackets | |
1371 | let mut recovered = false; | |
1372 | if let TyKind::Path(_, Path { segments, .. }) = &a_var.ty.kind { | |
1373 | if let Some(last_segment) = segments.last() { | |
1374 | recovered = self.check_trailing_angle_brackets( | |
1375 | last_segment, | |
1376 | &[&token::Comma, &token::CloseDelim(token::Brace)], | |
1377 | ); | |
1378 | if recovered { | |
1379 | // Handle a case like `Vec<u8>>,` where we can continue parsing fields | |
1380 | // after the comma | |
1381 | self.eat(&token::Comma); | |
1382 | // `check_trailing_angle_brackets` already emitted a nicer error | |
1383 | err.cancel(); | |
1384 | } | |
1385 | } | |
1386 | } | |
1387 | ||
416331ca XL |
1388 | if self.token.is_ident() { |
1389 | // This is likely another field; emit the diagnostic and keep going | |
1390 | err.span_suggestion( | |
1391 | sp, | |
1392 | "try adding a comma", | |
1393 | ",".into(), | |
1394 | Applicability::MachineApplicable, | |
1395 | ); | |
1396 | err.emit(); | |
f035d41b XL |
1397 | recovered = true; |
1398 | } | |
1399 | ||
1400 | if recovered { | |
1401 | // Make sure an error was emitted (either by recovering an angle bracket, | |
1402 | // or by finding an identifier as the next token), since we're | |
1403 | // going to continue parsing | |
1404 | assert!(self.sess.span_diagnostic.has_errors()); | |
416331ca | 1405 | } else { |
dfeec247 | 1406 | return Err(err); |
416331ca XL |
1407 | } |
1408 | } | |
1409 | } | |
1410 | Ok(a_var) | |
1411 | } | |
1412 | ||
17df50a5 XL |
1413 | fn expect_field_ty_separator(&mut self) -> PResult<'a, ()> { |
1414 | if let Err(mut err) = self.expect(&token::Colon) { | |
1415 | let sm = self.sess.source_map(); | |
1416 | let eq_typo = self.token.kind == token::Eq && self.look_ahead(1, |t| t.is_path_start()); | |
1417 | let semi_typo = self.token.kind == token::Semi | |
1418 | && self.look_ahead(1, |t| { | |
1419 | t.is_path_start() | |
1420 | // We check that we are in a situation like `foo; bar` to avoid bad suggestions | |
1421 | // when there's no type and `;` was used instead of a comma. | |
1422 | && match (sm.lookup_line(self.token.span.hi()), sm.lookup_line(t.span.lo())) { | |
1423 | (Ok(l), Ok(r)) => l.line == r.line, | |
1424 | _ => true, | |
1425 | } | |
1426 | }); | |
1427 | if eq_typo || semi_typo { | |
1428 | self.bump(); | |
1429 | // Gracefully handle small typos. | |
1430 | err.span_suggestion_short( | |
1431 | self.prev_token.span, | |
1432 | "field names and their types are separated with `:`", | |
1433 | ":".to_string(), | |
1434 | Applicability::MachineApplicable, | |
1435 | ); | |
1436 | err.emit(); | |
1437 | } else { | |
1438 | return Err(err); | |
1439 | } | |
1440 | } | |
1441 | Ok(()) | |
1442 | } | |
1443 | ||
416331ca XL |
1444 | /// Parses a structure field. |
1445 | fn parse_name_and_ty( | |
1446 | &mut self, | |
17df50a5 | 1447 | adt_ty: &str, |
416331ca XL |
1448 | lo: Span, |
1449 | vis: Visibility, | |
dfeec247 | 1450 | attrs: Vec<Attribute>, |
6a06907d | 1451 | ) -> PResult<'a, FieldDef> { |
17df50a5 XL |
1452 | let name = self.parse_field_ident(adt_ty, lo)?; |
1453 | self.expect_field_ty_separator()?; | |
416331ca | 1454 | let ty = self.parse_ty()?; |
17df50a5 XL |
1455 | if self.token.kind == token::Eq { |
1456 | self.bump(); | |
1457 | let const_expr = self.parse_anon_const_expr()?; | |
1458 | let sp = ty.span.shrink_to_hi().to(const_expr.value.span); | |
1459 | self.struct_span_err(sp, "default values on `struct` fields aren't supported") | |
1460 | .span_suggestion( | |
1461 | sp, | |
1462 | "remove this unsupported default value", | |
1463 | String::new(), | |
1464 | Applicability::MachineApplicable, | |
1465 | ) | |
1466 | .emit(); | |
1467 | } | |
6a06907d | 1468 | Ok(FieldDef { |
74b04a01 | 1469 | span: lo.to(self.prev_token.span), |
416331ca XL |
1470 | ident: Some(name), |
1471 | vis, | |
e1599b0c | 1472 | id: DUMMY_NODE_ID, |
416331ca | 1473 | ty, |
136023e0 | 1474 | attrs: attrs.into(), |
e1599b0c | 1475 | is_placeholder: false, |
416331ca XL |
1476 | }) |
1477 | } | |
1478 | ||
17df50a5 XL |
1479 | /// Parses a field identifier. Specialized version of `parse_ident_common` |
1480 | /// for better diagnostics and suggestions. | |
1481 | fn parse_field_ident(&mut self, adt_ty: &str, lo: Span) -> PResult<'a, Ident> { | |
1482 | let (ident, is_raw) = self.ident_or_err()?; | |
1483 | if !is_raw && ident.is_reserved() { | |
94222f64 XL |
1484 | let err = if self.check_fn_front_matter(false) { |
1485 | // We use `parse_fn` to get a span for the function | |
1486 | if let Err(mut db) = self.parse_fn(&mut Vec::new(), |_| true, lo) { | |
1487 | db.delay_as_bug(); | |
1488 | } | |
1489 | let mut err = self.struct_span_err( | |
1490 | lo.to(self.prev_token.span), | |
1491 | &format!("functions are not allowed in {} definitions", adt_ty), | |
1492 | ); | |
1493 | err.help("unlike in C++, Java, and C#, functions are declared in `impl` blocks"); | |
1494 | err.help("see https://doc.rust-lang.org/book/ch05-03-method-syntax.html for more information"); | |
1495 | err | |
17df50a5 | 1496 | } else { |
94222f64 XL |
1497 | self.expected_ident_found() |
1498 | }; | |
1499 | return Err(err); | |
17df50a5 XL |
1500 | } |
1501 | self.bump(); | |
1502 | Ok(ident) | |
1503 | } | |
1504 | ||
74b04a01 XL |
1505 | /// Parses a declarative macro 2.0 definition. |
1506 | /// The `macro` keyword has already been parsed. | |
1507 | /// ``` | |
1508 | /// MacBody = "{" TOKEN_STREAM "}" ; | |
1509 | /// MacParams = "(" TOKEN_STREAM ")" ; | |
1510 | /// DeclMac = "macro" Ident MacParams? MacBody ; | |
1511 | /// ``` | |
1512 | fn parse_item_decl_macro(&mut self, lo: Span) -> PResult<'a, ItemInfo> { | |
1513 | let ident = self.parse_ident()?; | |
1514 | let body = if self.check(&token::OpenDelim(token::Brace)) { | |
1515 | self.parse_mac_args()? // `MacBody` | |
1516 | } else if self.check(&token::OpenDelim(token::Paren)) { | |
1517 | let params = self.parse_token_tree(); // `MacParams` | |
1518 | let pspan = params.span(); | |
1519 | if !self.check(&token::OpenDelim(token::Brace)) { | |
60c5eb7d | 1520 | return self.unexpected(); |
74b04a01 XL |
1521 | } |
1522 | let body = self.parse_token_tree(); // `MacBody` | |
1523 | // Convert `MacParams MacBody` into `{ MacParams => MacBody }`. | |
1524 | let bspan = body.span(); | |
1525 | let arrow = TokenTree::token(token::FatArrow, pspan.between(bspan)); // `=>` | |
1526 | let tokens = TokenStream::new(vec![params.into(), arrow.into(), body.into()]); | |
1527 | let dspan = DelimSpan::from_pair(pspan.shrink_to_lo(), bspan.shrink_to_hi()); | |
1528 | P(MacArgs::Delimited(dspan, MacDelimiter::Brace, tokens)) | |
1529 | } else { | |
1530 | return self.unexpected(); | |
1531 | }; | |
1532 | ||
1533 | self.sess.gated_spans.gate(sym::decl_macro, lo.to(self.prev_token.span)); | |
ba9703b0 | 1534 | Ok((ident, ItemKind::MacroDef(ast::MacroDef { body, macro_rules: false }))) |
74b04a01 | 1535 | } |
416331ca | 1536 | |
cdc7bbd5 | 1537 | /// Is this unambiguously the start of a `macro_rules! foo` item definition? |
74b04a01 XL |
1538 | fn is_macro_rules_item(&mut self) -> bool { |
1539 | self.check_keyword(kw::MacroRules) | |
dfeec247 XL |
1540 | && self.look_ahead(1, |t| *t == token::Not) |
1541 | && self.look_ahead(2, |t| t.is_ident()) | |
74b04a01 | 1542 | } |
416331ca | 1543 | |
ba9703b0 | 1544 | /// Parses a `macro_rules! foo { ... }` declarative macro. |
74b04a01 XL |
1545 | fn parse_item_macro_rules(&mut self, vis: &Visibility) -> PResult<'a, ItemInfo> { |
1546 | self.expect_keyword(kw::MacroRules)?; // `macro_rules` | |
1547 | self.expect(&token::Not)?; // `!` | |
416331ca | 1548 | |
74b04a01 | 1549 | let ident = self.parse_ident()?; |
c295e0f8 XL |
1550 | |
1551 | if self.eat(&token::Not) { | |
1552 | // Handle macro_rules! foo! | |
1553 | let span = self.prev_token.span; | |
1554 | self.struct_span_err(span, "macro names aren't followed by a `!`") | |
1555 | .span_suggestion( | |
1556 | span, | |
1557 | "remove the `!`", | |
1558 | "".to_owned(), | |
1559 | Applicability::MachineApplicable, | |
1560 | ) | |
1561 | .emit(); | |
1562 | } | |
1563 | ||
74b04a01 XL |
1564 | let body = self.parse_mac_args()?; |
1565 | self.eat_semi_for_macro_if_needed(&body); | |
1566 | self.complain_if_pub_macro(vis, true); | |
e74abb32 | 1567 | |
ba9703b0 | 1568 | Ok((ident, ItemKind::MacroDef(ast::MacroDef { body, macro_rules: true }))) |
74b04a01 XL |
1569 | } |
1570 | ||
1571 | /// Item macro invocations or `macro_rules!` definitions need inherited visibility. | |
1572 | /// If that's not the case, emit an error. | |
1573 | fn complain_if_pub_macro(&self, vis: &Visibility, macro_rules: bool) { | |
1b1a35ee | 1574 | if let VisibilityKind::Inherited = vis.kind { |
74b04a01 | 1575 | return; |
e74abb32 XL |
1576 | } |
1577 | ||
74b04a01 XL |
1578 | let vstr = pprust::vis_to_string(vis); |
1579 | let vstr = vstr.trim_end(); | |
1580 | if macro_rules { | |
cdc7bbd5 XL |
1581 | let msg = format!("can't qualify macro_rules invocation with `{}`", vstr); |
1582 | self.struct_span_err(vis.span, &msg) | |
1583 | .span_suggestion( | |
1584 | vis.span, | |
1585 | "try exporting the macro", | |
1586 | "#[macro_export]".to_owned(), | |
1587 | Applicability::MaybeIncorrect, // speculative | |
1588 | ) | |
1589 | .emit(); | |
74b04a01 XL |
1590 | } else { |
1591 | self.struct_span_err(vis.span, "can't qualify macro invocation with `pub`") | |
1592 | .span_suggestion( | |
1593 | vis.span, | |
1594 | "remove the visibility", | |
1595 | String::new(), | |
1596 | Applicability::MachineApplicable, | |
1597 | ) | |
1598 | .help(&format!("try adjusting the macro to put `{}` inside the invocation", vstr)) | |
1599 | .emit(); | |
1600 | } | |
416331ca XL |
1601 | } |
1602 | ||
74b04a01 XL |
1603 | fn eat_semi_for_macro_if_needed(&mut self, args: &MacArgs) { |
1604 | if args.need_semicolon() && !self.eat(&token::Semi) { | |
1605 | self.report_invalid_macro_expansion_item(args); | |
416331ca XL |
1606 | } |
1607 | } | |
1608 | ||
74b04a01 XL |
1609 | fn report_invalid_macro_expansion_item(&self, args: &MacArgs) { |
1610 | let span = args.span().expect("undelimited macro call"); | |
1611 | let mut err = self.struct_span_err( | |
1612 | span, | |
e74abb32 | 1613 | "macros that expand to items must be delimited with braces or followed by a semicolon", |
74b04a01 XL |
1614 | ); |
1615 | if self.unclosed_delims.is_empty() { | |
1616 | let DelimSpan { open, close } = match args { | |
1617 | MacArgs::Empty | MacArgs::Eq(..) => unreachable!(), | |
1618 | MacArgs::Delimited(dspan, ..) => *dspan, | |
1619 | }; | |
1620 | err.multipart_suggestion( | |
1621 | "change the delimiters to curly braces", | |
1622 | vec![(open, "{".to_string()), (close, '}'.to_string())], | |
1623 | Applicability::MaybeIncorrect, | |
1624 | ); | |
1625 | } else { | |
1626 | err.span_suggestion( | |
1627 | span, | |
1628 | "change the delimiters to curly braces", | |
1629 | " { /* items */ }".to_string(), | |
1630 | Applicability::HasPlaceholders, | |
1631 | ); | |
1632 | } | |
1633 | err.span_suggestion( | |
1634 | span.shrink_to_hi(), | |
e74abb32 XL |
1635 | "add a semicolon", |
1636 | ';'.to_string(), | |
1637 | Applicability::MaybeIncorrect, | |
74b04a01 XL |
1638 | ); |
1639 | err.emit(); | |
e74abb32 XL |
1640 | } |
1641 | ||
60c5eb7d XL |
1642 | /// Checks if current token is one of tokens which cannot be nested like `kw::Enum`. In case |
1643 | /// it is, we try to parse the item and report error about nested types. | |
1644 | fn recover_nested_adt_item(&mut self, keyword: Symbol) -> PResult<'a, bool> { | |
dfeec247 XL |
1645 | if (self.token.is_keyword(kw::Enum) |
1646 | || self.token.is_keyword(kw::Struct) | |
1647 | || self.token.is_keyword(kw::Union)) | |
1648 | && self.look_ahead(1, |t| t.is_ident()) | |
60c5eb7d XL |
1649 | { |
1650 | let kw_token = self.token.clone(); | |
1651 | let kw_str = pprust::token_to_string(&kw_token); | |
5869c6ff | 1652 | let item = self.parse_item(ForceCollect::No)?; |
60c5eb7d XL |
1653 | |
1654 | self.struct_span_err( | |
1655 | kw_token.span, | |
1656 | &format!("`{}` definition cannot be nested inside `{}`", kw_str, keyword), | |
dfeec247 XL |
1657 | ) |
1658 | .span_suggestion( | |
60c5eb7d XL |
1659 | item.unwrap().span, |
1660 | &format!("consider creating a new `{}` definition instead of nesting", kw_str), | |
1661 | String::new(), | |
1662 | Applicability::MaybeIncorrect, | |
dfeec247 XL |
1663 | ) |
1664 | .emit(); | |
60c5eb7d | 1665 | // We successfully parsed the item but we must inform the caller about nested problem. |
dfeec247 | 1666 | return Ok(false); |
60c5eb7d XL |
1667 | } |
1668 | Ok(true) | |
1669 | } | |
416331ca | 1670 | } |
e74abb32 XL |
1671 | |
1672 | /// The parsing configuration used to parse a parameter list (see `parse_fn_params`). | |
74b04a01 XL |
1673 | /// |
1674 | /// The function decides if, per-parameter `p`, `p` must have a pattern or just a type. | |
1675 | type ReqName = fn(Edition) -> bool; | |
e74abb32 XL |
1676 | |
1677 | /// Parsing of functions and methods. | |
1678 | impl<'a> Parser<'a> { | |
74b04a01 XL |
1679 | /// Parse a function starting from the front matter (`const ...`) to the body `{ ... }` or `;`. |
1680 | fn parse_fn( | |
e74abb32 | 1681 | &mut self, |
e74abb32 | 1682 | attrs: &mut Vec<Attribute>, |
74b04a01 | 1683 | req_name: ReqName, |
3dfed10e | 1684 | sig_lo: Span, |
74b04a01 XL |
1685 | ) -> PResult<'a, (Ident, FnSig, Generics, Option<P<Block>>)> { |
1686 | let header = self.parse_fn_front_matter()?; // `const ... fn` | |
1687 | let ident = self.parse_ident()?; // `foo` | |
1688 | let mut generics = self.parse_generics()?; // `<'a, T, ...>` | |
fc512014 | 1689 | let decl = self.parse_fn_decl(req_name, AllowPlus::Yes, RecoverReturnSign::Yes)?; // `(p: u8, ...)` |
74b04a01 | 1690 | generics.where_clause = self.parse_where_clause()?; // `where T: Ord` |
3dfed10e XL |
1691 | |
1692 | let mut sig_hi = self.prev_token.span; | |
29967ef6 | 1693 | let body = self.parse_fn_body(attrs, &ident, &mut sig_hi)?; // `;` or `{ ... }`. |
3dfed10e XL |
1694 | let fn_sig_span = sig_lo.to(sig_hi); |
1695 | Ok((ident, FnSig { header, decl, span: fn_sig_span }, generics, body)) | |
e74abb32 XL |
1696 | } |
1697 | ||
74b04a01 | 1698 | /// Parse the "body" of a function. |
e74abb32 | 1699 | /// This can either be `;` when there's no body, |
74b04a01 | 1700 | /// or e.g. a block when the function is a provided one. |
3dfed10e XL |
1701 | fn parse_fn_body( |
1702 | &mut self, | |
1703 | attrs: &mut Vec<Attribute>, | |
29967ef6 | 1704 | ident: &Ident, |
3dfed10e XL |
1705 | sig_hi: &mut Span, |
1706 | ) -> PResult<'a, Option<P<Block>>> { | |
29967ef6 | 1707 | let (inner_attrs, body) = if self.eat(&token::Semi) { |
3dfed10e | 1708 | // Include the trailing semicolon in the span of the signature |
29967ef6 | 1709 | *sig_hi = self.prev_token.span; |
ba9703b0 XL |
1710 | (Vec::new(), None) |
1711 | } else if self.check(&token::OpenDelim(token::Brace)) || self.token.is_whole_block() { | |
1712 | self.parse_inner_attrs_and_block().map(|(attrs, body)| (attrs, Some(body)))? | |
1713 | } else if self.token.kind == token::Eq { | |
1714 | // Recover `fn foo() = $expr;`. | |
1715 | self.bump(); // `=` | |
1716 | let eq_sp = self.prev_token.span; | |
1717 | let _ = self.parse_expr()?; | |
1718 | self.expect_semi()?; // `;` | |
1719 | let span = eq_sp.to(self.prev_token.span); | |
1720 | self.struct_span_err(span, "function body cannot be `= expression;`") | |
1721 | .multipart_suggestion( | |
1722 | "surround the expression with `{` and `}` instead of `=` and `;`", | |
1723 | vec![(eq_sp, "{".to_string()), (self.prev_token.span, " }".to_string())], | |
1724 | Applicability::MachineApplicable, | |
1725 | ) | |
1726 | .emit(); | |
1727 | (Vec::new(), Some(self.mk_block_err(span))) | |
1728 | } else { | |
29967ef6 XL |
1729 | if let Err(mut err) = |
1730 | self.expected_one_of_not_found(&[], &[token::Semi, token::OpenDelim(token::Brace)]) | |
1731 | { | |
1732 | if self.token.kind == token::CloseDelim(token::Brace) { | |
1733 | // The enclosing `mod`, `trait` or `impl` is being closed, so keep the `fn` in | |
1734 | // the AST for typechecking. | |
1735 | err.span_label(ident.span, "while parsing this `fn`"); | |
1736 | err.emit(); | |
29967ef6 XL |
1737 | } else { |
1738 | return Err(err); | |
1739 | } | |
29967ef6 | 1740 | } |
94222f64 | 1741 | (Vec::new(), None) |
74b04a01 XL |
1742 | }; |
1743 | attrs.extend(inner_attrs); | |
1744 | Ok(body) | |
e74abb32 XL |
1745 | } |
1746 | ||
74b04a01 | 1747 | /// Is the current token the start of an `FnHeader` / not a valid parse? |
6a06907d XL |
1748 | /// |
1749 | /// `check_pub` adds additional `pub` to the checks in case users place it | |
1750 | /// wrongly, can be used to ensure `pub` never comes after `default`. | |
1751 | pub(super) fn check_fn_front_matter(&mut self, check_pub: bool) -> bool { | |
74b04a01 XL |
1752 | // We use an over-approximation here. |
1753 | // `const const`, `fn const` won't parse, but we're not stepping over other syntax either. | |
6a06907d XL |
1754 | // `pub` is added in case users got confused with the ordering like `async pub fn`, |
1755 | // only if it wasn't preceeded by `default` as `default pub` is invalid. | |
1756 | let quals: &[Symbol] = if check_pub { | |
1757 | &[kw::Pub, kw::Const, kw::Async, kw::Unsafe, kw::Extern] | |
1758 | } else { | |
1759 | &[kw::Const, kw::Async, kw::Unsafe, kw::Extern] | |
1760 | }; | |
74b04a01 XL |
1761 | self.check_keyword(kw::Fn) // Definitely an `fn`. |
1762 | // `$qual fn` or `$qual $qual`: | |
6a06907d | 1763 | || quals.iter().any(|&kw| self.check_keyword(kw)) |
74b04a01 | 1764 | && self.look_ahead(1, |t| { |
1b1a35ee | 1765 | // `$qual fn`, e.g. `const fn` or `async fn`. |
74b04a01 | 1766 | t.is_keyword(kw::Fn) |
1b1a35ee | 1767 | // Two qualifiers `$qual $qual` is enough, e.g. `async unsafe`. |
6a06907d | 1768 | || t.is_non_raw_ident_where(|i| quals.contains(&i.name) |
1b1a35ee XL |
1769 | // Rule out 2015 `const async: T = val`. |
1770 | && i.is_reserved() | |
1771 | // Rule out unsafe extern block. | |
1772 | && !self.is_unsafe_foreign_mod()) | |
74b04a01 XL |
1773 | }) |
1774 | // `extern ABI fn` | |
1775 | || self.check_keyword(kw::Extern) | |
1776 | && self.look_ahead(1, |t| t.can_begin_literal_maybe_minus()) | |
1777 | && self.look_ahead(2, |t| t.is_keyword(kw::Fn)) | |
1778 | } | |
1779 | ||
1780 | /// Parses all the "front matter" (or "qualifiers") for a `fn` declaration, | |
1781 | /// up to and including the `fn` keyword. The formal grammar is: | |
e74abb32 | 1782 | /// |
74b04a01 | 1783 | /// ``` |
1b1a35ee | 1784 | /// Extern = "extern" StringLit? ; |
74b04a01 | 1785 | /// FnQual = "const"? "async"? "unsafe"? Extern? ; |
1b1a35ee | 1786 | /// FnFrontMatter = FnQual "fn" ; |
74b04a01 | 1787 | /// ``` |
ba9703b0 | 1788 | pub(super) fn parse_fn_front_matter(&mut self) -> PResult<'a, FnHeader> { |
6a06907d | 1789 | let sp_start = self.token.span; |
74b04a01 | 1790 | let constness = self.parse_constness(); |
94222f64 XL |
1791 | |
1792 | let async_start_sp = self.token.span; | |
e74abb32 | 1793 | let asyncness = self.parse_asyncness(); |
94222f64 XL |
1794 | |
1795 | let unsafe_start_sp = self.token.span; | |
e74abb32 | 1796 | let unsafety = self.parse_unsafety(); |
94222f64 XL |
1797 | |
1798 | let ext_start_sp = self.token.span; | |
6a06907d | 1799 | let ext = self.parse_extern(); |
74b04a01 XL |
1800 | |
1801 | if let Async::Yes { span, .. } = asyncness { | |
1802 | self.ban_async_in_2015(span); | |
1803 | } | |
1804 | ||
e74abb32 XL |
1805 | if !self.eat_keyword(kw::Fn) { |
1806 | // It is possible for `expect_one_of` to recover given the contents of | |
1807 | // `self.expected_tokens`, therefore, do not use `self.unexpected()` which doesn't | |
1808 | // account for this. | |
6a06907d XL |
1809 | match self.expect_one_of(&[], &[]) { |
1810 | Ok(true) => {} | |
1811 | Ok(false) => unreachable!(), | |
1812 | Err(mut err) => { | |
94222f64 XL |
1813 | // Qualifier keywords ordering check |
1814 | ||
1815 | // This will allow the machine fix to directly place the keyword in the correct place | |
1816 | let current_qual_sp = if self.check_keyword(kw::Const) { | |
1817 | Some(async_start_sp) | |
1818 | } else if self.check_keyword(kw::Async) { | |
1819 | Some(unsafe_start_sp) | |
1820 | } else if self.check_keyword(kw::Unsafe) { | |
1821 | Some(ext_start_sp) | |
1822 | } else { | |
1823 | None | |
1824 | }; | |
1825 | ||
1826 | if let Some(current_qual_sp) = current_qual_sp { | |
1827 | let current_qual_sp = current_qual_sp.to(self.prev_token.span); | |
1828 | if let Ok(current_qual) = self.span_to_snippet(current_qual_sp) { | |
1829 | let invalid_qual_sp = self.token.uninterpolated_span(); | |
1830 | let invalid_qual = self.span_to_snippet(invalid_qual_sp).unwrap(); | |
1831 | ||
1832 | err.span_suggestion( | |
1833 | current_qual_sp.to(invalid_qual_sp), | |
1834 | &format!("`{}` must come before `{}`", invalid_qual, current_qual), | |
1835 | format!("{} {}", invalid_qual, current_qual), | |
1836 | Applicability::MachineApplicable, | |
1837 | ).note("keyword order for functions declaration is `default`, `pub`, `const`, `async`, `unsafe`, `extern`"); | |
1838 | } | |
1839 | } | |
6a06907d | 1840 | // Recover incorrect visibility order such as `async pub`. |
94222f64 | 1841 | else if self.check_keyword(kw::Pub) { |
6a06907d XL |
1842 | let sp = sp_start.to(self.prev_token.span); |
1843 | if let Ok(snippet) = self.span_to_snippet(sp) { | |
136023e0 XL |
1844 | let vis = match self.parse_visibility(FollowedByType::No) { |
1845 | Ok(v) => v, | |
1846 | Err(mut d) => { | |
1847 | d.cancel(); | |
1848 | return Err(err); | |
1849 | } | |
1850 | }; | |
6a06907d XL |
1851 | let vs = pprust::vis_to_string(&vis); |
1852 | let vs = vs.trim_end(); | |
1853 | err.span_suggestion( | |
1854 | sp_start.to(self.prev_token.span), | |
1855 | &format!("visibility `{}` must come before `{}`", vs, snippet), | |
1856 | format!("{} {}", vs, snippet), | |
1857 | Applicability::MachineApplicable, | |
1858 | ); | |
1859 | } | |
1860 | } | |
1861 | return Err(err); | |
1862 | } | |
dfeec247 | 1863 | } |
e74abb32 | 1864 | } |
74b04a01 | 1865 | |
60c5eb7d | 1866 | Ok(FnHeader { constness, unsafety, asyncness, ext }) |
e74abb32 XL |
1867 | } |
1868 | ||
74b04a01 XL |
1869 | /// We are parsing `async fn`. If we are on Rust 2015, emit an error. |
1870 | fn ban_async_in_2015(&self, span: Span) { | |
1871 | if span.rust_2015() { | |
1872 | let diag = self.diagnostic(); | |
5869c6ff XL |
1873 | struct_span_err!(diag, span, E0670, "`async fn` is not permitted in Rust 2015") |
1874 | .span_label(span, "to use `async fn`, switch to Rust 2018 or later") | |
1875 | .help(&format!("set `edition = \"{}\"` in `Cargo.toml`", LATEST_STABLE_EDITION)) | |
74b04a01 XL |
1876 | .note("for more on editions, read https://doc.rust-lang.org/edition-guide") |
1877 | .emit(); | |
1878 | } | |
e74abb32 XL |
1879 | } |
1880 | ||
1881 | /// Parses the parameter list and result type of a function declaration. | |
1882 | pub(super) fn parse_fn_decl( | |
1883 | &mut self, | |
74b04a01 XL |
1884 | req_name: ReqName, |
1885 | ret_allow_plus: AllowPlus, | |
fc512014 | 1886 | recover_return_sign: RecoverReturnSign, |
e74abb32 XL |
1887 | ) -> PResult<'a, P<FnDecl>> { |
1888 | Ok(P(FnDecl { | |
74b04a01 | 1889 | inputs: self.parse_fn_params(req_name)?, |
fc512014 | 1890 | output: self.parse_ret_ty(ret_allow_plus, RecoverQPath::Yes, recover_return_sign)?, |
e74abb32 XL |
1891 | })) |
1892 | } | |
1893 | ||
1894 | /// Parses the parameter list of a function, including the `(` and `)` delimiters. | |
74b04a01 XL |
1895 | fn parse_fn_params(&mut self, req_name: ReqName) -> PResult<'a, Vec<Param>> { |
1896 | let mut first_param = true; | |
1897 | // Parse the arguments, starting out with `self` being allowed... | |
dfeec247 | 1898 | let (mut params, _) = self.parse_paren_comma_seq(|p| { |
74b04a01 | 1899 | let param = p.parse_param_general(req_name, first_param).or_else(|mut e| { |
dfeec247 | 1900 | e.emit(); |
74b04a01 | 1901 | let lo = p.prev_token.span; |
dfeec247 XL |
1902 | // Skip every token until next possible arg or end. |
1903 | p.eat_to_tokens(&[&token::Comma, &token::CloseDelim(token::Paren)]); | |
1904 | // Create a placeholder argument for proper arg count (issue #34264). | |
5869c6ff | 1905 | Ok(dummy_arg(Ident::new(kw::Empty, lo.to(p.prev_token.span)))) |
dfeec247 | 1906 | }); |
e74abb32 | 1907 | // ...now that we've parsed the first argument, `self` is no longer allowed. |
74b04a01 | 1908 | first_param = false; |
dfeec247 | 1909 | param |
e74abb32 | 1910 | })?; |
60c5eb7d | 1911 | // Replace duplicated recovered params with `_` pattern to avoid unnecessary errors. |
e74abb32 | 1912 | self.deduplicate_recovered_params_names(&mut params); |
e74abb32 XL |
1913 | Ok(params) |
1914 | } | |
1915 | ||
74b04a01 XL |
1916 | /// Parses a single function parameter. |
1917 | /// | |
1918 | /// - `self` is syntactically allowed when `first_param` holds. | |
1919 | fn parse_param_general(&mut self, req_name: ReqName, first_param: bool) -> PResult<'a, Param> { | |
e74abb32 XL |
1920 | let lo = self.token.span; |
1921 | let attrs = self.parse_outer_attributes()?; | |
6a06907d XL |
1922 | self.collect_tokens_trailing_token(attrs, ForceCollect::No, |this, attrs| { |
1923 | // Possibly parse `self`. Recover if we parsed it and it wasn't allowed here. | |
1924 | if let Some(mut param) = this.parse_self_param()? { | |
1925 | param.attrs = attrs.into(); | |
1926 | let res = if first_param { Ok(param) } else { this.recover_bad_self_param(param) }; | |
1927 | return Ok((res?, TrailingToken::None)); | |
1928 | } | |
e74abb32 | 1929 | |
6a06907d XL |
1930 | let is_name_required = match this.token.kind { |
1931 | token::DotDotDot => false, | |
1932 | _ => req_name(this.token.span.edition()), | |
1933 | }; | |
1934 | let (pat, ty) = if is_name_required || this.is_named_param() { | |
1935 | debug!("parse_param_general parse_pat (is_name_required:{})", is_name_required); | |
1936 | ||
1937 | let (pat, colon) = this.parse_fn_param_pat_colon()?; | |
1938 | if !colon { | |
1939 | let mut err = this.unexpected::<()>().unwrap_err(); | |
1940 | return if let Some(ident) = | |
1941 | this.parameter_without_type(&mut err, pat, is_name_required, first_param) | |
1942 | { | |
1943 | err.emit(); | |
1944 | Ok((dummy_arg(ident), TrailingToken::None)) | |
1945 | } else { | |
1946 | Err(err) | |
1947 | }; | |
1948 | } | |
e74abb32 | 1949 | |
6a06907d XL |
1950 | this.eat_incorrect_doc_comment_for_param_type(); |
1951 | (pat, this.parse_ty_for_param()?) | |
1952 | } else { | |
1953 | debug!("parse_param_general ident_to_pat"); | |
1954 | let parser_snapshot_before_ty = this.clone(); | |
1955 | this.eat_incorrect_doc_comment_for_param_type(); | |
1956 | let mut ty = this.parse_ty_for_param(); | |
1957 | if ty.is_ok() | |
1958 | && this.token != token::Comma | |
1959 | && this.token != token::CloseDelim(token::Paren) | |
74b04a01 | 1960 | { |
6a06907d XL |
1961 | // This wasn't actually a type, but a pattern looking like a type, |
1962 | // so we are going to rollback and re-parse for recovery. | |
1963 | ty = this.unexpected(); | |
e74abb32 | 1964 | } |
6a06907d XL |
1965 | match ty { |
1966 | Ok(ty) => { | |
1967 | let ident = Ident::new(kw::Empty, this.prev_token.span); | |
1968 | let bm = BindingMode::ByValue(Mutability::Not); | |
1969 | let pat = this.mk_pat_ident(ty.span, bm, ident); | |
1970 | (pat, ty) | |
1971 | } | |
1972 | // If this is a C-variadic argument and we hit an error, return the error. | |
1973 | Err(err) if this.token == token::DotDotDot => return Err(err), | |
1974 | // Recover from attempting to parse the argument as a type without pattern. | |
1975 | Err(mut err) => { | |
1976 | err.cancel(); | |
1977 | *this = parser_snapshot_before_ty; | |
1978 | this.recover_arg_parse()? | |
1979 | } | |
e74abb32 | 1980 | } |
6a06907d | 1981 | }; |
e74abb32 | 1982 | |
6a06907d XL |
1983 | let span = lo.until(this.token.span); |
1984 | ||
1985 | Ok(( | |
1986 | Param { | |
1987 | attrs: attrs.into(), | |
1988 | id: ast::DUMMY_NODE_ID, | |
1989 | is_placeholder: false, | |
1990 | pat, | |
1991 | span, | |
1992 | ty, | |
1993 | }, | |
1994 | TrailingToken::None, | |
1995 | )) | |
e74abb32 XL |
1996 | }) |
1997 | } | |
1998 | ||
1999 | /// Returns the parsed optional self parameter and whether a self shortcut was used. | |
e74abb32 XL |
2000 | fn parse_self_param(&mut self) -> PResult<'a, Option<Param>> { |
2001 | // Extract an identifier *after* having confirmed that the token is one. | |
74b04a01 XL |
2002 | let expect_self_ident = |this: &mut Self| match this.token.ident() { |
2003 | Some((ident, false)) => { | |
2004 | this.bump(); | |
2005 | ident | |
e74abb32 | 2006 | } |
74b04a01 | 2007 | _ => unreachable!(), |
e74abb32 XL |
2008 | }; |
2009 | // Is `self` `n` tokens ahead? | |
2010 | let is_isolated_self = |this: &Self, n| { | |
2011 | this.is_keyword_ahead(n, &[kw::SelfLower]) | |
dfeec247 | 2012 | && this.look_ahead(n + 1, |t| t != &token::ModSep) |
e74abb32 XL |
2013 | }; |
2014 | // Is `mut self` `n` tokens ahead? | |
dfeec247 XL |
2015 | let is_isolated_mut_self = |
2016 | |this: &Self, n| this.is_keyword_ahead(n, &[kw::Mut]) && is_isolated_self(this, n + 1); | |
e74abb32 XL |
2017 | // Parse `self` or `self: TYPE`. We already know the current token is `self`. |
2018 | let parse_self_possibly_typed = |this: &mut Self, m| { | |
2019 | let eself_ident = expect_self_ident(this); | |
74b04a01 | 2020 | let eself_hi = this.prev_token.span; |
e74abb32 XL |
2021 | let eself = if this.eat(&token::Colon) { |
2022 | SelfKind::Explicit(this.parse_ty()?, m) | |
2023 | } else { | |
2024 | SelfKind::Value(m) | |
2025 | }; | |
2026 | Ok((eself, eself_ident, eself_hi)) | |
2027 | }; | |
2028 | // Recover for the grammar `*self`, `*const self`, and `*mut self`. | |
2029 | let recover_self_ptr = |this: &mut Self| { | |
2030 | let msg = "cannot pass `self` by raw pointer"; | |
2031 | let span = this.token.span; | |
dfeec247 | 2032 | this.struct_span_err(span, msg).span_label(span, msg).emit(); |
e74abb32 | 2033 | |
74b04a01 | 2034 | Ok((SelfKind::Value(Mutability::Not), expect_self_ident(this), this.prev_token.span)) |
e74abb32 XL |
2035 | }; |
2036 | ||
2037 | // Parse optional `self` parameter of a method. | |
2038 | // Only a limited set of initial token sequences is considered `self` parameters; anything | |
2039 | // else is parsed as a normal function parameter list, so some lookahead is required. | |
2040 | let eself_lo = self.token.span; | |
74b04a01 | 2041 | let (eself, eself_ident, eself_hi) = match self.token.uninterpolate().kind { |
e74abb32 XL |
2042 | token::BinOp(token::And) => { |
2043 | let eself = if is_isolated_self(self, 1) { | |
2044 | // `&self` | |
2045 | self.bump(); | |
dfeec247 | 2046 | SelfKind::Region(None, Mutability::Not) |
e74abb32 XL |
2047 | } else if is_isolated_mut_self(self, 1) { |
2048 | // `&mut self` | |
2049 | self.bump(); | |
2050 | self.bump(); | |
dfeec247 | 2051 | SelfKind::Region(None, Mutability::Mut) |
e74abb32 XL |
2052 | } else if self.look_ahead(1, |t| t.is_lifetime()) && is_isolated_self(self, 2) { |
2053 | // `&'lt self` | |
2054 | self.bump(); | |
2055 | let lt = self.expect_lifetime(); | |
dfeec247 | 2056 | SelfKind::Region(Some(lt), Mutability::Not) |
e74abb32 XL |
2057 | } else if self.look_ahead(1, |t| t.is_lifetime()) && is_isolated_mut_self(self, 2) { |
2058 | // `&'lt mut self` | |
2059 | self.bump(); | |
2060 | let lt = self.expect_lifetime(); | |
2061 | self.bump(); | |
dfeec247 | 2062 | SelfKind::Region(Some(lt), Mutability::Mut) |
e74abb32 XL |
2063 | } else { |
2064 | // `¬_self` | |
2065 | return Ok(None); | |
2066 | }; | |
74b04a01 | 2067 | (eself, expect_self_ident(self), self.prev_token.span) |
e74abb32 XL |
2068 | } |
2069 | // `*self` | |
2070 | token::BinOp(token::Star) if is_isolated_self(self, 1) => { | |
2071 | self.bump(); | |
2072 | recover_self_ptr(self)? | |
2073 | } | |
2074 | // `*mut self` and `*const self` | |
dfeec247 XL |
2075 | token::BinOp(token::Star) |
2076 | if self.look_ahead(1, |t| t.is_mutability()) && is_isolated_self(self, 2) => | |
e74abb32 XL |
2077 | { |
2078 | self.bump(); | |
2079 | self.bump(); | |
2080 | recover_self_ptr(self)? | |
2081 | } | |
2082 | // `self` and `self: TYPE` | |
2083 | token::Ident(..) if is_isolated_self(self, 0) => { | |
dfeec247 | 2084 | parse_self_possibly_typed(self, Mutability::Not)? |
e74abb32 XL |
2085 | } |
2086 | // `mut self` and `mut self: TYPE` | |
2087 | token::Ident(..) if is_isolated_mut_self(self, 0) => { | |
2088 | self.bump(); | |
dfeec247 | 2089 | parse_self_possibly_typed(self, Mutability::Mut)? |
e74abb32 XL |
2090 | } |
2091 | _ => return Ok(None), | |
2092 | }; | |
2093 | ||
2094 | let eself = source_map::respan(eself_lo.to(eself_hi), eself); | |
dfeec247 | 2095 | Ok(Some(Param::from_self(AttrVec::default(), eself, eself_ident))) |
e74abb32 XL |
2096 | } |
2097 | ||
2098 | fn is_named_param(&self) -> bool { | |
2099 | let offset = match self.token.kind { | |
2100 | token::Interpolated(ref nt) => match **nt { | |
2101 | token::NtPat(..) => return self.look_ahead(1, |t| t == &token::Colon), | |
2102 | _ => 0, | |
dfeec247 | 2103 | }, |
e74abb32 XL |
2104 | token::BinOp(token::And) | token::AndAnd => 1, |
2105 | _ if self.token.is_keyword(kw::Mut) => 1, | |
2106 | _ => 0, | |
2107 | }; | |
2108 | ||
dfeec247 XL |
2109 | self.look_ahead(offset, |t| t.is_ident()) |
2110 | && self.look_ahead(offset + 1, |t| t == &token::Colon) | |
e74abb32 XL |
2111 | } |
2112 | ||
2113 | fn recover_first_param(&mut self) -> &'static str { | |
dfeec247 XL |
2114 | match self |
2115 | .parse_outer_attributes() | |
e74abb32 XL |
2116 | .and_then(|_| self.parse_self_param()) |
2117 | .map_err(|mut e| e.cancel()) | |
2118 | { | |
2119 | Ok(Some(_)) => "method", | |
2120 | _ => "function", | |
2121 | } | |
2122 | } | |
2123 | } |