diff options
Diffstat (limited to 'src/libsyntax/parse/diagnostics.rs')
| -rw-r--r-- | src/libsyntax/parse/diagnostics.rs | 88 |
1 files changed, 49 insertions, 39 deletions
diff --git a/src/libsyntax/parse/diagnostics.rs b/src/libsyntax/parse/diagnostics.rs index d4e661d1a38..b74f2492c35 100644 --- a/src/libsyntax/parse/diagnostics.rs +++ b/src/libsyntax/parse/diagnostics.rs @@ -29,7 +29,14 @@ crate fn dummy_arg(ident: Ident) -> Param { span: ident.span, id: ast::DUMMY_NODE_ID }; - Param { attrs: ThinVec::default(), id: ast::DUMMY_NODE_ID, pat, span: ident.span, ty: P(ty) } + Param { + attrs: ThinVec::default(), + id: ast::DUMMY_NODE_ID, + pat, + span: ident.span, + ty: P(ty), + is_placeholder: false, + } } pub enum Error { @@ -240,7 +247,7 @@ impl<'a> Parser<'a> { ) -> PResult<'a, bool /* recovered */> { fn tokens_to_string(tokens: &[TokenType]) -> String { let mut i = tokens.iter(); - // This might be a sign we need a connect method on Iterator. + // This might be a sign we need a connect method on `Iterator`. let b = i.next() .map_or(String::new(), |t| t.to_string()); i.enumerate().fold(b, |mut b, (i, a)| { @@ -301,7 +308,7 @@ impl<'a> Parser<'a> { ); } let sp = if self.token == token::Eof { - // This is EOF, don't want to point at the following char, but rather the last token + // This is EOF; don't want to point at the following char, but rather the last token. self.prev_span } else { label_sp @@ -317,9 +324,9 @@ impl<'a> Parser<'a> { } let is_semi_suggestable = expected.iter().any(|t| match t { - TokenType::Token(token::Semi) => true, // we expect a `;` here + TokenType::Token(token::Semi) => true, // We expect a `;` here. _ => false, - }) && ( // a `;` would be expected before the current keyword + }) && ( // A `;` would be expected before the current keyword. self.token.is_keyword(kw::Break) || self.token.is_keyword(kw::Continue) || self.token.is_keyword(kw::For) || @@ -541,16 +548,16 @@ impl<'a> Parser<'a> { } } - /// Produce an error if comparison operators are chained (RFC #558). - /// We only need to check lhs, not rhs, because all comparison ops - /// have same precedence and are left-associative - crate fn check_no_chained_comparison(&self, lhs: &Expr, outer_op: &AssocOp) { + /// Produces an error if comparison operators are chained (RFC #558). + /// We only need to check the LHS, not the RHS, because all comparison ops + /// have same precedence and are left-associative. + crate fn check_no_chained_comparison(&self, lhs: &Expr, outer_op: &AssocOp) -> PResult<'a, ()> { debug_assert!(outer_op.is_comparison(), "check_no_chained_comparison: {:?} is not comparison", outer_op); match lhs.node { ExprKind::Binary(op, _, _) if op.node.is_comparison() => { - // respan to include both operators + // Respan to include both operators. let op_span = op.span.to(self.token.span); let mut err = self.struct_span_err( op_span, @@ -563,11 +570,14 @@ impl<'a> Parser<'a> { err.help( "use `::<...>` instead of `<...>` if you meant to specify type arguments"); err.help("or use `(...)` if you meant to specify fn arguments"); + // These cases cause too many knock-down errors, bail out (#61329). + return Err(err); } err.emit(); } _ => {} } + Ok(()) } crate fn maybe_report_ambiguous_plus( @@ -688,9 +698,9 @@ impl<'a> Parser<'a> { Ok(()) } - /// Try to recover from associated item paths like `[T]::AssocItem`/`(T, U)::AssocItem`. - /// Attempt to convert the base expression/pattern/type into a type, parse the `::AssocItem` - /// tail, and combine them into a `<Ty>::AssocItem` expression/pattern/type. + /// Tries to recover from associated item paths like `[T]::AssocItem` / `(T, U)::AssocItem`. + /// Attempts to convert the base expression/pattern/type into a type, parses the `::AssocItem` + /// tail, and combines them into a `<Ty>::AssocItem` expression/pattern/type. crate fn maybe_recover_from_bad_qpath<T: RecoverQPath>( &mut self, base: P<T>, @@ -705,8 +715,8 @@ impl<'a> Parser<'a> { Ok(base) } - /// Given an already parsed `Ty` parse the `::AssocItem` tail and - /// combine them into a `<Ty>::AssocItem` expression/pattern/type. + /// Given an already parsed `Ty`, parses the `::AssocItem` tail and + /// combines them into a `<Ty>::AssocItem` expression/pattern/type. crate fn maybe_recover_from_bad_qpath_stage_2<T: RecoverQPath>( &mut self, ty_span: Span, @@ -727,7 +737,7 @@ impl<'a> Parser<'a> { self.diagnostic() .struct_span_err(path.span, "missing angle brackets in associated item path") .span_suggestion( - // this is a best-effort recovery + // This is a best-effort recovery. path.span, "try", format!("<{}>::{}", ty_str, path), @@ -735,7 +745,7 @@ impl<'a> Parser<'a> { ) .emit(); - let path_span = ty_span.shrink_to_hi(); // use an empty path since `position` == 0 + let path_span = ty_span.shrink_to_hi(); // Use an empty path since `position == 0`. Ok(P(T::recovered( Some(QSelf { ty, @@ -758,8 +768,8 @@ impl<'a> Parser<'a> { if !items.is_empty() { let previous_item = &items[items.len() - 1]; let previous_item_kind_name = match previous_item.node { - // say "braced struct" because tuple-structs and - // braceless-empty-struct declarations do take a semicolon + // Say "braced struct" because tuple-structs and + // braceless-empty-struct declarations do take a semicolon. ItemKind::Struct(..) => Some("braced struct"), ItemKind::Enum(..) => Some("enum"), ItemKind::Trait(..) => Some("trait"), @@ -780,7 +790,7 @@ impl<'a> Parser<'a> { } } - /// Create a `DiagnosticBuilder` for an unexpected token `t` and try to recover if it is a + /// Creates a `DiagnosticBuilder` for an unexpected token `t` and tries to recover if it is a /// closing delimiter. pub fn unexpected_try_recover( &mut self, @@ -838,7 +848,7 @@ impl<'a> Parser<'a> { extern_sp: Span, ) -> PResult<'a, ()> { if self.token != token::Semi { - // this might be an incorrect fn definition (#62109) + // This might be an incorrect fn definition (#62109). let parser_snapshot = self.clone(); match self.parse_inner_attrs_and_block() { Ok((_, body)) => { @@ -868,7 +878,7 @@ impl<'a> Parser<'a> { Ok(()) } - /// Consume alternative await syntaxes like `await!(<expr>)`, `await <expr>`, + /// Consumes alternative await syntaxes like `await!(<expr>)`, `await <expr>`, /// `await? <expr>`, `await(<expr>)`, and `await { <expr> }`. crate fn parse_incorrect_await_syntax( &mut self, @@ -921,7 +931,7 @@ impl<'a> Parser<'a> { sp } - /// If encountering `future.await()`, consume and emit error. + /// If encountering `future.await()`, consumes and emits an error. crate fn recover_from_await_method_call(&mut self) { if self.token == token::OpenDelim(token::Paren) && self.look_ahead(1, |t| t == &token::CloseDelim(token::Paren)) @@ -941,7 +951,7 @@ impl<'a> Parser<'a> { } } - /// Recover a situation like `for ( $pat in $expr )` + /// Recovers a situation like `for ( $pat in $expr )` /// and suggest writing `for $pat in $expr` instead. /// /// This should be called before parsing the `$block`. @@ -1007,7 +1017,7 @@ impl<'a> Parser<'a> { Ok(x) => x, Err(mut err) => { err.emit(); - // recover from parse error + // Recover from parse error. self.consume_block(delim); self.mk_expr(lo.to(self.prev_span), ExprKind::Err, ThinVec::new()) } @@ -1020,7 +1030,7 @@ impl<'a> Parser<'a> { mut err: DiagnosticBuilder<'a>, ) -> PResult<'a, bool> { let mut pos = None; - // we want to use the last closing delim that would apply + // We want to use the last closing delim that would apply. for (i, unmatched) in self.unclosed_delims.iter().enumerate().rev() { if tokens.contains(&token::CloseDelim(unmatched.expected_delim)) && Some(self.token.span) > unmatched.unclosed_span @@ -1038,7 +1048,7 @@ impl<'a> Parser<'a> { let unmatched = self.unclosed_delims.remove(pos); let delim = TokenType::Token(token::CloseDelim(unmatched.expected_delim)); - // We want to suggest the inclusion of the closing delimiter where it makes + // We want to suggest the inclusion of the closing delimiter where it makes // the most sense, which is immediately after the last token: // // {foo(bar {}} @@ -1064,7 +1074,7 @@ impl<'a> Parser<'a> { } } - /// Recover from `pub` keyword in places where it seems _reasonable_ but isn't valid. + /// Recovers from `pub` keyword in places where it seems _reasonable_ but isn't valid. crate fn eat_bad_pub(&mut self) { if self.token.is_keyword(kw::Pub) { match self.parse_visibility(false) { @@ -1079,21 +1089,21 @@ impl<'a> Parser<'a> { } } - // Eat tokens until we can be relatively sure we reached the end of the - // statement. This is something of a best-effort heuristic. - // - // We terminate when we find an unmatched `}` (without consuming it). + /// Eats tokens until we can be relatively sure we reached the end of the + /// statement. This is something of a best-effort heuristic. + /// + /// We terminate when we find an unmatched `}` (without consuming it). crate fn recover_stmt(&mut self) { self.recover_stmt_(SemiColonMode::Ignore, BlockMode::Ignore) } - // If `break_on_semi` is `Break`, then we will stop consuming tokens after - // finding (and consuming) a `;` outside of `{}` or `[]` (note that this is - // approximate - it can mean we break too early due to macros, but that - // should only lead to sub-optimal recovery, not inaccurate parsing). - // - // If `break_on_block` is `Break`, then we will stop consuming tokens - // after finding (and consuming) a brace-delimited block. + /// If `break_on_semi` is `Break`, then we will stop consuming tokens after + /// finding (and consuming) a `;` outside of `{}` or `[]` (note that this is + /// approximate -- it can mean we break too early due to macros, but that + /// should only lead to sub-optimal recovery, not inaccurate parsing). + /// + /// If `break_on_block` is `Break`, then we will stop consuming tokens + /// after finding (and consuming) a brace-delimited block. crate fn recover_stmt_(&mut self, break_on_semi: SemiColonMode, break_on_block: BlockMode) { let mut brace_depth = 0; let mut bracket_depth = 0; |