diff options
Diffstat (limited to 'src/libsyntax/parse/parser/expr.rs')
| -rw-r--r-- | src/libsyntax/parse/parser/expr.rs | 199 |
1 files changed, 184 insertions, 15 deletions
diff --git a/src/libsyntax/parse/parser/expr.rs b/src/libsyntax/parse/parser/expr.rs index 23674ad589d..67a530ec683 100644 --- a/src/libsyntax/parse/parser/expr.rs +++ b/src/libsyntax/parse/parser/expr.rs @@ -1,18 +1,18 @@ -use super::{ - Parser, PResult, Restrictions, PrevTokenKind, TokenType, PathStyle, BlockMode, SemiColonMode, - SeqSep, TokenExpectType, -}; +use super::{Parser, PResult, Restrictions, PrevTokenKind, TokenType, PathStyle, BlockMode}; +use super::{SemiColonMode, SeqSep, TokenExpectType}; use super::pat::{GateOr, PARAM_EXPECTED}; +use super::diagnostics::Error; + +use crate::parse::literal::LitError; use crate::ast::{ self, DUMMY_NODE_ID, Attribute, AttrStyle, Ident, CaptureBy, BlockCheckMode, Expr, ExprKind, RangeLimits, Label, Movability, IsAsync, Arm, Ty, TyKind, - FunctionRetTy, Param, FnDecl, BinOpKind, BinOp, UnOp, Mac, AnonConst, Field, + FunctionRetTy, Param, FnDecl, BinOpKind, BinOp, UnOp, Mac, AnonConst, Field, Lit, }; use crate::maybe_recover_from_interpolated_ty_qpath; use crate::parse::classify; -use crate::parse::token::{self, Token}; -use crate::parse::diagnostics::Error; +use crate::parse::token::{self, Token, TokenKind}; use crate::print::pprust; use crate::ptr::P; use crate::source_map::{self, Span}; @@ -20,6 +20,7 @@ use crate::symbol::{kw, sym}; use crate::util::parser::{AssocOp, Fixity, prec_let_scrutinee_needs_par}; use errors::Applicability; +use syntax_pos::Symbol; use std::mem; use rustc_data_structures::thin_vec::ThinVec; @@ -238,7 +239,9 @@ impl<'a> Parser<'a> { self.bump(); if op.is_comparison() { - self.check_no_chained_comparison(&lhs, &op)?; + if let Some(expr) = self.check_no_chained_comparison(&lhs, &op)? { + return Ok(expr); + } } // Special cases: if op == AssocOp::As { @@ -420,7 +423,7 @@ impl<'a> Parser<'a> { self.struct_span_err(span_of_tilde, "`~` cannot be used as a unary operator") .span_suggestion_short( span_of_tilde, - "use `!` to perform bitwise negation", + "use `!` to perform bitwise not", "!".to_owned(), Applicability::MachineApplicable ) @@ -550,8 +553,11 @@ impl<'a> Parser<'a> { // Report non-fatal diagnostics, keep `x as usize` as an expression // in AST and continue parsing. - let msg = format!("`<` is interpreted as a start of generic \ - arguments for `{}`, not a {}", path, op_noun); + let msg = format!( + "`<` is interpreted as a start of generic arguments for `{}`, not a {}", + pprust::path_to_string(&path), + op_noun, + ); let span_after_type = parser_snapshot_after_type.token.span; let expr = mk_expr(self, P(Ty { span: path.span, @@ -1067,8 +1073,167 @@ impl<'a> Parser<'a> { self.maybe_recover_from_bad_qpath(expr, true) } + /// Matches `lit = true | false | token_lit`. + pub(super) fn parse_lit(&mut self) -> PResult<'a, Lit> { + let mut recovered = None; + if self.token == token::Dot { + // Attempt to recover `.4` as `0.4`. + recovered = self.look_ahead(1, |next_token| { + if let token::Literal(token::Lit { kind: token::Integer, symbol, suffix }) + = next_token.kind { + if self.token.span.hi() == next_token.span.lo() { + let s = String::from("0.") + &symbol.as_str(); + let kind = TokenKind::lit(token::Float, Symbol::intern(&s), suffix); + return Some(Token::new(kind, self.token.span.to(next_token.span))); + } + } + None + }); + if let Some(token) = &recovered { + self.bump(); + self.struct_span_err(token.span, "float literals must have an integer part") + .span_suggestion( + token.span, + "must have an integer part", + pprust::token_to_string(token), + Applicability::MachineApplicable, + ) + .emit(); + } + } + + let token = recovered.as_ref().unwrap_or(&self.token); + match Lit::from_token(token) { + Ok(lit) => { + self.bump(); + Ok(lit) + } + Err(LitError::NotLiteral) => { + let msg = format!("unexpected token: {}", self.this_token_descr()); + Err(self.span_fatal(token.span, &msg)) + } + Err(err) => { + let (lit, span) = (token.expect_lit(), token.span); + self.bump(); + self.error_literal_from_token(err, lit, span); + // Pack possible quotes and prefixes from the original literal into + // the error literal's symbol so they can be pretty-printed faithfully. + let suffixless_lit = token::Lit::new(lit.kind, lit.symbol, None); + let symbol = Symbol::intern(&suffixless_lit.to_string()); + let lit = token::Lit::new(token::Err, symbol, lit.suffix); + Lit::from_lit_token(lit, span).map_err(|_| unreachable!()) + } + } + } + + fn error_literal_from_token(&self, err: LitError, lit: token::Lit, span: Span) { + // Checks if `s` looks like i32 or u1234 etc. + fn looks_like_width_suffix(first_chars: &[char], s: &str) -> bool { + s.len() > 1 + && s.starts_with(first_chars) + && s[1..].chars().all(|c| c.is_ascii_digit()) + } + + let token::Lit { kind, suffix, .. } = lit; + match err { + // `NotLiteral` is not an error by itself, so we don't report + // it and give the parser opportunity to try something else. + LitError::NotLiteral => {} + // `LexerError` *is* an error, but it was already reported + // by lexer, so here we don't report it the second time. + LitError::LexerError => {} + LitError::InvalidSuffix => { + self.expect_no_suffix( + span, + &format!("{} {} literal", kind.article(), kind.descr()), + suffix, + ); + } + LitError::InvalidIntSuffix => { + let suf = suffix.expect("suffix error with no suffix").as_str(); + if looks_like_width_suffix(&['i', 'u'], &suf) { + // If it looks like a width, try to be helpful. + let msg = format!("invalid width `{}` for integer literal", &suf[1..]); + self.struct_span_err(span, &msg) + .help("valid widths are 8, 16, 32, 64 and 128") + .emit(); + } else { + let msg = format!("invalid suffix `{}` for integer literal", suf); + self.struct_span_err(span, &msg) + .span_label(span, format!("invalid suffix `{}`", suf)) + .help("the suffix must be one of the integral types (`u32`, `isize`, etc)") + .emit(); + } + } + LitError::InvalidFloatSuffix => { + let suf = suffix.expect("suffix error with no suffix").as_str(); + if looks_like_width_suffix(&['f'], &suf) { + // If it looks like a width, try to be helpful. + let msg = format!("invalid width `{}` for float literal", &suf[1..]); + self.struct_span_err(span, &msg) + .help("valid widths are 32 and 64") + .emit(); + } else { + let msg = format!("invalid suffix `{}` for float literal", suf); + self.struct_span_err(span, &msg) + .span_label(span, format!("invalid suffix `{}`", suf)) + .help("valid suffixes are `f32` and `f64`") + .emit(); + } + } + LitError::NonDecimalFloat(base) => { + let descr = match base { + 16 => "hexadecimal", + 8 => "octal", + 2 => "binary", + _ => unreachable!(), + }; + self.struct_span_err(span, &format!("{} float literal is not supported", descr)) + .span_label(span, "not supported") + .emit(); + } + LitError::IntTooLarge => { + self.struct_span_err(span, "integer literal is too large") + .emit(); + } + } + } + + pub(super) fn expect_no_suffix(&self, sp: Span, kind: &str, suffix: Option<Symbol>) { + if let Some(suf) = suffix { + let mut err = if kind == "a tuple index" + && [sym::i32, sym::u32, sym::isize, sym::usize].contains(&suf) + { + // #59553: warn instead of reject out of hand to allow the fix to percolate + // through the ecosystem when people fix their macros + let mut err = self.sess.span_diagnostic.struct_span_warn( + sp, + &format!("suffixes on {} are invalid", kind), + ); + err.note(&format!( + "`{}` is *temporarily* accepted on tuple index fields as it was \ + incorrectly accepted on stable for a few releases", + suf, + )); + err.help( + "on proc macros, you'll want to use `syn::Index::from` or \ + `proc_macro::Literal::*_unsuffixed` for code that will desugar \ + to tuple field access", + ); + err.note( + "for more context, see https://github.com/rust-lang/rust/issues/60210", + ); + err + } else { + self.struct_span_err(sp, &format!("suffixes on {} are invalid", kind)) + }; + err.span_label(sp, format!("invalid suffix `{}`", suf)); + err.emit(); + } + } + /// Matches `'-' lit | lit` (cf. `ast_validation::AstValidator::check_expr_within_pat`). - crate fn parse_literal_maybe_minus(&mut self) -> PResult<'a, P<Expr>> { + pub fn parse_literal_maybe_minus(&mut self) -> PResult<'a, P<Expr>> { maybe_whole_expr!(self); let minus_lo = self.token.span; @@ -1088,7 +1253,7 @@ impl<'a> Parser<'a> { } /// Parses a block or unsafe block. - crate fn parse_block_expr( + pub(super) fn parse_block_expr( &mut self, opt_label: Option<Label>, lo: Span, @@ -1393,7 +1558,7 @@ impl<'a> Parser<'a> { return Ok(self.mk_expr(lo.to(hi), ExprKind::Match(discriminant, arms), attrs)); } - crate fn parse_arm(&mut self) -> PResult<'a, Arm> { + pub(super) fn parse_arm(&mut self) -> PResult<'a, Arm> { let attrs = self.parse_outer_attributes()?; let lo = self.token.span; let pat = self.parse_top_pat(GateOr::No)?; @@ -1501,7 +1666,7 @@ impl<'a> Parser<'a> { } /// Parses an `async move? {...}` expression. - pub fn parse_async_block(&mut self, mut attrs: ThinVec<Attribute>) -> PResult<'a, P<Expr>> { + fn parse_async_block(&mut self, mut attrs: ThinVec<Attribute>) -> PResult<'a, P<Expr>> { let span_lo = self.token.span; self.expect_keyword(kw::Async)?; let capture_clause = self.parse_capture_clause(); @@ -1781,4 +1946,8 @@ impl<'a> Parser<'a> { crate fn mk_expr(&self, span: Span, kind: ExprKind, attrs: ThinVec<Attribute>) -> P<Expr> { P(Expr { kind, span, attrs, id: DUMMY_NODE_ID }) } + + pub(super) fn mk_expr_err(&self, span: Span) -> P<Expr> { + self.mk_expr(span, ExprKind::Err, ThinVec::new()) + } } |