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move parse_lit to expr.rs

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This commit is contained in:
Mazdak Farrokhzad 2019-10-11 18:40:56 +02:00
parent 52d0e86b9a
commit 79d02867b8
3 changed files with 170 additions and 177 deletions
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167
src/libsyntax/parse/literal.rs
View file

@ -1,14 +1,10 @@
//! Code related to parsing literals.
use crate::ast::{self, Lit, LitKind};
use crate::parse::parser::Parser;
use crate::parse::PResult;
use crate::parse::token::{self, Token, TokenKind};
use crate::print::pprust;
use crate::parse::token::{self, Token};
use crate::symbol::{kw, sym, Symbol};
use crate::tokenstream::{TokenStream, TokenTree};
use errors::{Applicability, Handler};
use log::debug;
use rustc_data_structures::sync::Lrc;
use syntax_pos::Span;
@ -28,72 +24,6 @@ crate enum LitError {
IntTooLarge,
}
impl LitError {
fn report(&self, diag: &Handler, lit: token::Lit, span: Span) {
let token::Lit { kind, suffix, .. } = lit;
match *self {
// `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 => {
expect_no_suffix(
diag, 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..]);
diag.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);
diag.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..]);
diag.struct_span_err(span, &msg)
.help("valid widths are 32 and 64")
.emit();
} else {
let msg = format!("invalid suffix `{}` for float literal", suf);
diag.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!(),
};
diag.struct_span_err(span, &format!("{} float literal is not supported", descr))
.span_label(span, "not supported")
.emit();
}
LitError::IntTooLarge => {
diag.struct_span_err(span, "integer literal is too large")
.emit();
}
}
}
}
impl LitKind {
/// Converts literal token into a semantic literal.
fn from_lit_token(lit: token::Lit) -> Result<LitKind, LitError> {
@ -254,7 +184,7 @@ impl LitKind {
impl Lit {
/// Converts literal token into an AST literal.
fn from_lit_token(token: token::Lit, span: Span) -> Result<Lit, LitError> {
crate fn from_lit_token(token: token::Lit, span: Span) -> Result<Lit, LitError> {
Ok(Lit { token, kind: LitKind::from_lit_token(token)?, span })
}
@ -296,99 +226,6 @@ impl Lit {
}
}
impl<'a> Parser<'a> {
/// Matches `lit = true | false | token_lit`.
crate 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.diagnostic()
.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();
err.report(&self.sess.span_diagnostic, 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!())
}
}
}
}
crate fn expect_no_suffix(diag: &Handler, 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 = diag.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 {
diag.struct_span_err(sp, &format!("suffixes on {} are invalid", kind))
};
err.span_label(sp, format!("invalid suffix `{}`", suf));
err.emit();
}
}
// 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())
}
fn strip_underscores(symbol: Symbol) -> Symbol {
// Do not allocate a new string unless necessary.
let s = symbol.as_str();

8
src/libsyntax/parse/parser.rs
View file

@ -15,10 +15,10 @@ use crate::ast::{
self, DUMMY_NODE_ID, AttrStyle, Attribute, CrateSugar, Ident,
IsAsync, MacDelimiter, Mutability, StrStyle, Visibility, VisibilityKind, Unsafety,
};
use crate::parse::{ParseSess, PResult, Directory, DirectoryOwnership, SeqSep, literal, token};
use crate::parse::{ParseSess, PResult, Directory, DirectoryOwnership, SeqSep};
use crate::parse::lexer::UnmatchedBrace;
use crate::parse::lexer::comments::{doc_comment_style, strip_doc_comment_decoration};
use crate::parse::token::{Token, TokenKind, DelimToken};
use crate::parse::token::{self, Token, TokenKind, DelimToken};
use crate::print::pprust;
use crate::ptr::P;
use crate::source_map::respan;
@ -637,10 +637,6 @@ impl<'a> Parser<'a> {
}
}
fn expect_no_suffix(&self, sp: Span, kind: &str, suffix: Option<ast::Name>) {
literal::expect_no_suffix(&self.sess.span_diagnostic, sp, kind, suffix)
}
/// Attempts to consume a `<`. If `<<` is seen, replaces it with a single
/// `<` and continue. If `<-` is seen, replaces it with a single `<`
/// and continue. If a `<` is not seen, returns false.

172
src/libsyntax/parse/parser/expr.rs
View file

@ -1,17 +1,17 @@
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 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::token::{self, Token, TokenKind};
use crate::parse::diagnostics::Error;
use crate::print::pprust;
use crate::ptr::P;
@ -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;
@ -1072,6 +1073,165 @@ impl<'a> Parser<'a> {
self.maybe_recover_from_bad_qpath(expr, true)
}
/// Matches `lit = true | false | token_lit`.
crate 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>> {
maybe_whole_expr!(self);