diff options
Diffstat (limited to 'compiler')
| -rw-r--r-- | compiler/rustc_lint/src/unused.rs | 2 | ||||
| -rw-r--r-- | compiler/rustc_parse/src/parser/item.rs | 5 | ||||
| -rw-r--r-- | compiler/rustc_parse/src/parser/pat.rs | 184 | ||||
| -rw-r--r-- | compiler/rustc_parse/src/parser/stmt.rs | 8 |
4 files changed, 131 insertions, 68 deletions
diff --git a/compiler/rustc_lint/src/unused.rs b/compiler/rustc_lint/src/unused.rs index e222f82f20a..997b9136320 100644 --- a/compiler/rustc_lint/src/unused.rs +++ b/compiler/rustc_lint/src/unused.rs @@ -872,7 +872,7 @@ impl EarlyLintPass for UnusedParens { fn check_stmt(&mut self, cx: &EarlyContext<'_>, s: &ast::Stmt) { if let StmtKind::Local(ref local) = s.kind { - self.check_unused_parens_pat(cx, &local.pat, false, false); + self.check_unused_parens_pat(cx, &local.pat, true, false); } <Self as UnusedDelimLint>::check_stmt(self, cx, s) diff --git a/compiler/rustc_parse/src/parser/item.rs b/compiler/rustc_parse/src/parser/item.rs index 9668a24bf8a..a28595e6fae 100644 --- a/compiler/rustc_parse/src/parser/item.rs +++ b/compiler/rustc_parse/src/parser/item.rs @@ -1757,8 +1757,9 @@ impl<'a> Parser<'a> { let (pat, ty) = if is_name_required || this.is_named_param() { debug!("parse_param_general parse_pat (is_name_required:{})", is_name_required); - let pat = this.parse_fn_param_pat()?; - if let Err(mut err) = this.expect(&token::Colon) { + let (pat, colon) = this.parse_fn_param_pat_colon()?; + if !colon { + let mut err = this.unexpected::<()>().unwrap_err(); return if let Some(ident) = this.parameter_without_type(&mut err, pat, is_name_required, first_param) { diff --git a/compiler/rustc_parse/src/parser/pat.rs b/compiler/rustc_parse/src/parser/pat.rs index 9e2e7359ca9..5a68afdfa59 100644 --- a/compiler/rustc_parse/src/parser/pat.rs +++ b/compiler/rustc_parse/src/parser/pat.rs @@ -31,6 +31,18 @@ pub enum RecoverComma { No, } +/// The result of `eat_or_separator`. We want to distinguish which case we are in to avoid +/// emitting duplicate diagnostics. +#[derive(Debug, Clone, Copy)] +enum EatOrResult { + /// We recovered from a trailing vert. + TrailingVert, + /// We ate an `|` (or `||` and recovered). + AteOr, + /// We did not eat anything (i.e. the current token is not `|` or `||`). + None, +} + impl<'a> Parser<'a> { /// Parses a pattern. /// @@ -55,9 +67,26 @@ impl<'a> Parser<'a> { gate_or: GateOr, rc: RecoverComma, ) -> PResult<'a, P<Pat>> { + self.parse_pat_allow_top_alt_inner(expected, gate_or, rc).map(|(pat, _)| pat) + } + + /// Returns the pattern and a bool indicating whether we recovered from a trailing vert (true = + /// recovered). + fn parse_pat_allow_top_alt_inner( + &mut self, + expected: Expected, + gate_or: GateOr, + rc: RecoverComma, + ) -> PResult<'a, (P<Pat>, bool)> { + // Keep track of whether we recovered from a trailing vert so that we can avoid duplicated + // suggestions (which bothers rustfix). + // // Allow a '|' before the pats (RFCs 1925, 2530, and 2535). - let leading_vert_span = - if self.eat_or_separator(None) { Some(self.prev_token.span) } else { None }; + let (leading_vert_span, mut trailing_vert) = match self.eat_or_separator(None) { + EatOrResult::AteOr => (Some(self.prev_token.span), false), + EatOrResult::TrailingVert => (None, true), + EatOrResult::None => (None, false), + }; // Parse the first pattern (`p_0`). let first_pat = self.parse_pat_no_top_alt(expected)?; @@ -77,16 +106,24 @@ impl<'a> Parser<'a> { // If there was a leading vert, treat this as an or-pattern. This improves // diagnostics. let span = leading_vert_span.to(self.prev_token.span); - return Ok(self.mk_pat(span, PatKind::Or(vec![first_pat]))); + return Ok((self.mk_pat(span, PatKind::Or(vec![first_pat])), trailing_vert)); } - return Ok(first_pat); + return Ok((first_pat, trailing_vert)); } // Parse the patterns `p_1 | ... | p_n` where `n > 0`. let lo = leading_vert_span.unwrap_or(first_pat.span); let mut pats = vec![first_pat]; - while self.eat_or_separator(Some(lo)) { + loop { + match self.eat_or_separator(Some(lo)) { + EatOrResult::AteOr => {} + EatOrResult::None => break, + EatOrResult::TrailingVert => { + trailing_vert = true; + break; + } + } let pat = self.parse_pat_no_top_alt(expected).map_err(|mut err| { err.span_label(lo, WHILE_PARSING_OR_MSG); err @@ -101,15 +138,63 @@ impl<'a> Parser<'a> { self.sess.gated_spans.gate(sym::or_patterns, or_pattern_span); } - Ok(self.mk_pat(or_pattern_span, PatKind::Or(pats))) + Ok((self.mk_pat(or_pattern_span, PatKind::Or(pats)), trailing_vert)) } - /// Parse the pattern for a function or function pointer parameter. - pub(super) fn parse_fn_param_pat(&mut self) -> PResult<'a, P<Pat>> { - // We actually do _not_ allow top-level or-patterns in function params, but we use - // `parse_pat_allow_top_alt` anyway so that we can detect when a user tries to use it. This - // allows us to print a better error message. - // + /// Parse a pattern and (maybe) a `Colon` in positions where a pattern may be followed by a + /// type annotation (e.g. for `let` bindings or `fn` params). + /// + /// Generally, this corresponds to `pat_no_top_alt` followed by an optional `Colon`. It will + /// eat the `Colon` token if one is present. + /// + /// The return value represents the parsed pattern and `true` if a `Colon` was parsed (`false` + /// otherwise). + pub(super) fn parse_pat_before_ty( + &mut self, + expected: Expected, + gate_or: GateOr, + rc: RecoverComma, + syntax_loc: &str, + ) -> PResult<'a, (P<Pat>, bool)> { + // We use `parse_pat_allow_top_alt` regardless of whether we actually want top-level + // or-patterns so that we can detect when a user tries to use it. This allows us to print a + // better error message. + let (pat, trailing_vert) = self.parse_pat_allow_top_alt_inner(expected, gate_or, rc)?; + let colon = self.eat(&token::Colon); + + if let PatKind::Or(pats) = &pat.kind { + let msg = format!("top-level or-patterns are not allowed in {}", syntax_loc); + let (help, fix) = if pats.len() == 1 { + // If all we have is a leading vert, then print a special message. This is the case + // if `parse_pat_allow_top_alt` returns an or-pattern with one variant. + let msg = "remove the `|`"; + let fix = pprust::pat_to_string(&pat); + (msg, fix) + } else { + let msg = "wrap the pattern in parentheses"; + let fix = format!("({})", pprust::pat_to_string(&pat)); + (msg, fix) + }; + + if trailing_vert { + // We already emitted an error and suggestion to remove the trailing vert. Don't + // emit again. + self.sess.span_diagnostic.delay_span_bug(pat.span, &msg); + } else { + self.struct_span_err(pat.span, &msg) + .span_suggestion(pat.span, help, fix, Applicability::MachineApplicable) + .emit(); + } + } + + Ok((pat, colon)) + } + + /// Parse the pattern for a function or function pointer parameter, followed by a colon. + /// + /// The return value represents the parsed pattern and `true` if a `Colon` was parsed (`false` + /// otherwise). + pub(super) fn parse_fn_param_pat_colon(&mut self) -> PResult<'a, (P<Pat>, bool)> { // In order to get good UX, we first recover in the case of a leading vert for an illegal // top-level or-pat. Normally, this means recovering both `|` and `||`, but in this case, // a leading `||` probably doesn't indicate an or-pattern attempt, so we handle that @@ -128,53 +213,28 @@ impl<'a> Parser<'a> { self.bump(); } - let pat = self.parse_pat_allow_top_alt(PARAM_EXPECTED, GateOr::No, RecoverComma::No)?; - - if let PatKind::Or(..) = &pat.kind { - self.ban_illegal_fn_param_or_pat(&pat); - } - - Ok(pat) - } - - /// Ban `A | B` immediately in a parameter pattern and suggest wrapping in parens. - fn ban_illegal_fn_param_or_pat(&self, pat: &Pat) { - // If all we have a leading vert, then print a special message. This is the case if - // `parse_pat_allow_top_alt` returns an or-pattern with one variant. - let (msg, fix) = match &pat.kind { - PatKind::Or(pats) if pats.len() == 1 => { - let msg = "remove the leading `|`"; - let fix = pprust::pat_to_string(pat); - (msg, fix) - } - - _ => { - let msg = "wrap the pattern in parentheses"; - let fix = format!("({})", pprust::pat_to_string(pat)); - (msg, fix) - } - }; - - self.struct_span_err(pat.span, "an or-pattern parameter must be wrapped in parentheses") - .span_suggestion(pat.span, msg, fix, Applicability::MachineApplicable) - .emit(); + self.parse_pat_before_ty( + PARAM_EXPECTED, + GateOr::No, + RecoverComma::No, + "function parameters", + ) } /// Eat the or-pattern `|` separator. /// If instead a `||` token is encountered, recover and pretend we parsed `|`. - fn eat_or_separator(&mut self, lo: Option<Span>) -> bool { + fn eat_or_separator(&mut self, lo: Option<Span>) -> EatOrResult { if self.recover_trailing_vert(lo) { - return false; - } - - match self.token.kind { - token::OrOr => { - // Found `||`; Recover and pretend we parsed `|`. - self.ban_unexpected_or_or(lo); - self.bump(); - true - } - _ => self.eat(&token::BinOp(token::Or)), + EatOrResult::TrailingVert + } else if matches!(self.token.kind, token::OrOr) { + // Found `||`; Recover and pretend we parsed `|`. + self.ban_unexpected_or_or(lo); + self.bump(); + EatOrResult::AteOr + } else if self.eat(&token::BinOp(token::Or)) { + EatOrResult::AteOr + } else { + EatOrResult::None } } @@ -190,14 +250,14 @@ impl<'a> Parser<'a> { matches!( &token.uninterpolate().kind, token::FatArrow // e.g. `a | => 0,`. - | token::Ident(kw::If, false) // e.g. `a | if expr`. - | token::Eq // e.g. `let a | = 0`. - | token::Semi // e.g. `let a |;`. - | token::Colon // e.g. `let a | :`. - | token::Comma // e.g. `let (a |,)`. - | token::CloseDelim(token::Bracket) // e.g. `let [a | ]`. - | token::CloseDelim(token::Paren) // e.g. `let (a | )`. - | token::CloseDelim(token::Brace) // e.g. `let A { f: a | }`. + | token::Ident(kw::If, false) // e.g. `a | if expr`. + | token::Eq // e.g. `let a | = 0`. + | token::Semi // e.g. `let a |;`. + | token::Colon // e.g. `let a | :`. + | token::Comma // e.g. `let (a |,)`. + | token::CloseDelim(token::Bracket) // e.g. `let [a | ]`. + | token::CloseDelim(token::Paren) // e.g. `let (a | )`. + | token::CloseDelim(token::Brace) // e.g. `let A { f: a | }`. ) }); match (is_end_ahead, &self.token.kind) { diff --git a/compiler/rustc_parse/src/parser/stmt.rs b/compiler/rustc_parse/src/parser/stmt.rs index a0f9616f72a..f6599927c6e 100644 --- a/compiler/rustc_parse/src/parser/stmt.rs +++ b/compiler/rustc_parse/src/parser/stmt.rs @@ -13,7 +13,8 @@ use rustc_ast::token::{self, TokenKind}; use rustc_ast::util::classify; use rustc_ast::AstLike; use rustc_ast::{AttrStyle, AttrVec, Attribute, MacCall, MacCallStmt, MacStmtStyle}; -use rustc_ast::{Block, BlockCheckMode, Expr, ExprKind, Local, Stmt, StmtKind, DUMMY_NODE_ID}; +use rustc_ast::{Block, BlockCheckMode, Expr, ExprKind, Local, Stmt}; +use rustc_ast::{StmtKind, DUMMY_NODE_ID}; use rustc_errors::{Applicability, PResult}; use rustc_span::source_map::{BytePos, Span}; use rustc_span::symbol::{kw, sym}; @@ -220,9 +221,10 @@ impl<'a> Parser<'a> { /// Parses a local variable declaration. fn parse_local(&mut self, attrs: AttrVec) -> PResult<'a, P<Local>> { let lo = self.prev_token.span; - let pat = self.parse_pat_allow_top_alt(None, GateOr::Yes, RecoverComma::Yes)?; + let (pat, colon) = + self.parse_pat_before_ty(None, GateOr::Yes, RecoverComma::Yes, "`let` bindings")?; - let (err, ty) = if self.eat(&token::Colon) { + let (err, ty) = if colon { // Save the state of the parser before parsing type normally, in case there is a `:` // instead of an `=` typo. let parser_snapshot_before_type = self.clone(); |