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