diff options
Diffstat (limited to 'src/libsyntax/parse/parser')
| -rw-r--r-- | src/libsyntax/parse/parser/diagnostics.rs | 50 | ||||
| -rw-r--r-- | src/libsyntax/parse/parser/item.rs | 17 |
2 files changed, 52 insertions, 15 deletions
diff --git a/src/libsyntax/parse/parser/diagnostics.rs b/src/libsyntax/parse/parser/diagnostics.rs index ab2b4519cb7..fcf3b4c0aa8 100644 --- a/src/libsyntax/parse/parser/diagnostics.rs +++ b/src/libsyntax/parse/parser/diagnostics.rs @@ -171,6 +171,12 @@ impl RecoverQPath for Expr { } } +/// Control whether the closing delimiter should be consumed when calling `Parser::consume_block`. +crate enum ConsumeClosingDelim { + Yes, + No, +} + impl<'a> Parser<'a> { pub fn fatal(&self, m: &str) -> DiagnosticBuilder<'a> { self.span_fatal(self.token.span, m) @@ -1105,8 +1111,8 @@ impl<'a> Parser<'a> { Ok(x) => x, Err(mut err) => { err.emit(); - // Recover from parse error. - self.consume_block(delim); + // Recover from parse error, callers expect the closing delim to be consumed. + self.consume_block(delim, ConsumeClosingDelim::Yes); self.mk_expr(lo.to(self.prev_span), ExprKind::Err, ThinVec::new()) } } @@ -1135,6 +1141,11 @@ impl<'a> Parser<'a> { // Don't attempt to recover from this unclosed delimiter more than once. let unmatched = self.unclosed_delims.remove(pos); let delim = TokenType::Token(token::CloseDelim(unmatched.expected_delim)); + if unmatched.found_delim.is_none() { + // We encountered `Eof`, set this fact here to avoid complaining about missing + // `fn main()` when we found place to suggest the closing brace. + *self.sess.reached_eof.borrow_mut() = true; + } // We want to suggest the inclusion of the closing delimiter where it makes // the most sense, which is immediately after the last token: @@ -1154,9 +1165,16 @@ impl<'a> Parser<'a> { delim.to_string(), Applicability::MaybeIncorrect, ); - err.emit(); - self.expected_tokens.clear(); // reduce errors - Ok(true) + if unmatched.found_delim.is_none() { + // Encountered `Eof` when lexing blocks. Do not recover here to avoid knockdown + // errors which would be emitted elsewhere in the parser and let other error + // recovery consume the rest of the file. + Err(err) + } else { + err.emit(); + self.expected_tokens.clear(); // Reduce the number of errors. + Ok(true) + } } _ => Err(err), } @@ -1164,7 +1182,12 @@ impl<'a> Parser<'a> { /// Recovers from `pub` keyword in places where it seems _reasonable_ but isn't valid. pub(super) fn eat_bad_pub(&mut self) { - if self.token.is_keyword(kw::Pub) { + // When `unclosed_delims` is populated, it means that the code being parsed is already + // quite malformed, which might mean that, for example, a pub struct definition could be + // parsed as being a trait item, which is invalid and this error would trigger + // unconditionally, resulting in misleading diagnostics. Because of this, we only attempt + // this nice to have recovery for code that is otherwise well formed. + if self.token.is_keyword(kw::Pub) && self.unclosed_delims.is_empty() { match self.parse_visibility(false) { Ok(vis) => { self.diagnostic() @@ -1422,15 +1445,26 @@ impl<'a> Parser<'a> { Ok(param) } - pub(super) fn consume_block(&mut self, delim: token::DelimToken) { + pub(super) fn consume_block( + &mut self, + delim: token::DelimToken, + consume_close: ConsumeClosingDelim, + ) { let mut brace_depth = 0; loop { if self.eat(&token::OpenDelim(delim)) { brace_depth += 1; - } else if self.eat(&token::CloseDelim(delim)) { + } else if self.check(&token::CloseDelim(delim)) { if brace_depth == 0 { + if let ConsumeClosingDelim::Yes = consume_close { + // Some of the callers of this method expect to be able to parse the + // closing delimiter themselves, so we leave it alone. Otherwise we advance + // the parser. + self.bump(); + } return; } else { + self.bump(); brace_depth -= 1; continue; } diff --git a/src/libsyntax/parse/parser/item.rs b/src/libsyntax/parse/parser/item.rs index fe125336190..5b60e7e6dba 100644 --- a/src/libsyntax/parse/parser/item.rs +++ b/src/libsyntax/parse/parser/item.rs @@ -1,5 +1,5 @@ -use super::{Parser, PResult, PathStyle, SemiColonMode, BlockMode}; -use super::diagnostics::{Error, dummy_arg}; +use super::{Parser, PResult, PathStyle}; +use super::diagnostics::{Error, dummy_arg, ConsumeClosingDelim}; use crate::maybe_whole; use crate::ptr::P; @@ -339,7 +339,7 @@ impl<'a> Parser<'a> { let ident = self.parse_ident().unwrap(); self.bump(); // `(` let kw_name = self.recover_first_param(); - self.consume_block(token::Paren); + self.consume_block(token::Paren, ConsumeClosingDelim::Yes); let (kw, kw_name, ambiguous) = if self.check(&token::RArrow) { self.eat_to_tokens(&[&token::OpenDelim(token::Brace)]); self.bump(); // `{` @@ -357,7 +357,7 @@ impl<'a> Parser<'a> { let msg = format!("missing `{}` for {} definition", kw, kw_name); let mut err = self.diagnostic().struct_span_err(sp, &msg); if !ambiguous { - self.consume_block(token::Brace); + self.consume_block(token::Brace, ConsumeClosingDelim::Yes); let suggestion = format!("add `{}` here to parse `{}` as a public {}", kw, ident, @@ -672,7 +672,8 @@ impl<'a> Parser<'a> { Err(mut err) => { err.emit(); if !at_end { - self.recover_stmt_(SemiColonMode::Break, BlockMode::Break); + self.consume_block(token::Brace, ConsumeClosingDelim::Yes); + break; } } } @@ -861,7 +862,8 @@ impl<'a> Parser<'a> { Err(mut e) => { e.emit(); if !at_end { - self.recover_stmt_(SemiColonMode::Break, BlockMode::Break); + self.consume_block(token::Brace, ConsumeClosingDelim::Yes); + break; } } } @@ -1520,7 +1522,7 @@ impl<'a> Parser<'a> { if self.eat(&token::OpenDelim(token::Brace)) { while self.token != token::CloseDelim(token::Brace) { let field = self.parse_struct_decl_field().map_err(|e| { - self.recover_stmt(); + self.consume_block(token::Brace, ConsumeClosingDelim::No); recovered = true; e }); @@ -1528,6 +1530,7 @@ impl<'a> Parser<'a> { Ok(field) => fields.push(field), Err(mut err) => { err.emit(); + break; } } } |