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Simplify conversions between tokens and semantic literals

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This commit is contained in:
Vadim Petrochenkov 2019-05-10 03:00:51 +03:00
parent a5b3f33cb9
commit 8739668438
10 changed files with 260 additions and 325 deletions
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159
src/libsyntax/parse/parser.rs
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@ -15,7 +15,7 @@ use crate::ast::{ForeignItem, ForeignItemKind, FunctionRetTy};
use crate::ast::{GenericParam, GenericParamKind};
use crate::ast::GenericArg;
use crate::ast::{Ident, ImplItem, IsAsync, IsAuto, Item, ItemKind};
use crate::ast::{Label, Lifetime, Lit, LitKind};
use crate::ast::{Label, Lifetime, Lit};
use crate::ast::{Local, LocalSource};
use crate::ast::MacStmtStyle;
use crate::ast::{Mac, Mac_, MacDelimiter};
@ -46,7 +46,7 @@ use crate::ptr::P;
use crate::parse::PResult;
use crate::ThinVec;
use crate::tokenstream::{self, DelimSpan, TokenTree, TokenStream, TreeAndJoint};
use crate::symbol::{Symbol, keywords};
use crate::symbol::{keywords, Symbol};
use errors::{Applicability, DiagnosticBuilder, DiagnosticId, FatalError};
use rustc_target::spec::abi::{self, Abi};
@ -1109,43 +1109,7 @@ impl<'a> Parser<'a> {
}
fn expect_no_suffix(&self, sp: Span, kind: &str, suffix: Option<ast::Name>) {
match suffix {
None => {/* everything ok */}
Some(suf) => {
let text = suf.as_str();
if text.is_empty() {
self.span_bug(sp, "found empty literal suffix in Some")
}
let mut err = if kind == "a tuple index" &&
["i32", "u32", "isize", "usize"].contains(&text.to_string().as_str())
{
// #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.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",
text,
));
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 `{}`", text));
err.emit();
}
}
parse::expect_no_suffix(sp, &self.sess.span_diagnostic, kind, suffix)
}
/// Attempts to consume a `<`. If `<<` is seen, replaces it with a single
@ -1452,9 +1416,6 @@ impl<'a> Parser<'a> {
crate fn struct_span_err<S: Into<MultiSpan>>(&self, sp: S, m: &str) -> DiagnosticBuilder<'a> {
self.sess.span_diagnostic.struct_span_err(sp, m)
}
fn struct_span_warn<S: Into<MultiSpan>>(&self, sp: S, m: &str) -> DiagnosticBuilder<'a> {
self.sess.span_diagnostic.struct_span_warn(sp, m)
}
crate fn span_bug<S: Into<MultiSpan>>(&self, sp: S, m: &str) -> ! {
self.sess.span_diagnostic.span_bug(sp, m)
}
@ -2069,85 +2030,45 @@ impl<'a> Parser<'a> {
}
}
/// Matches `token_lit = LIT_INTEGER | ...`.
fn parse_lit_token(&mut self) -> PResult<'a, (LitKind, token::Lit, Option<Symbol>)> {
let out = match self.token {
token::Interpolated(ref nt) => match **nt {
token::NtExpr(ref v) | token::NtLiteral(ref v) => match v.node {
ExprKind::Lit(ref lit) => { (lit.node.clone(), lit.token, lit.suffix) }
_ => { return self.unexpected_last(&self.token); }
},
_ => { return self.unexpected_last(&self.token); }
},
token::Literal(lit, suf) => {
let diag = Some((self.span, &self.sess.span_diagnostic));
let (suffix_illegal, result) = parse::lit_token(lit, suf, diag);
if suffix_illegal {
let sp = self.span;
self.expect_no_suffix(sp, &format!("a {}", lit.literal_name()), suf)
}
(result.unwrap(), lit, suf)
}
token::Dot if self.look_ahead(1, |t| match t {
token::Literal(token::Lit::Integer(_) , _) => true,
_ => false,
}) => { // recover from `let x = .4;`
let lo = self.span;
self.bump();
if let token::Literal(
token::Lit::Integer(val),
suffix,
) = self.token {
let float_suffix = suffix.and_then(|s| {
let s = s.as_str();
if s == "f32" {
Some("f32")
} else if s == "f64" {
Some("f64")
} else {
None
}
}).unwrap_or("");
self.bump();
let sp = lo.to(self.prev_span);
let mut err = self.diagnostic()
.struct_span_err(sp, "float literals must have an integer part");
err.span_suggestion(
sp,
"must have an integer part",
format!("0.{}{}", val, float_suffix),
Applicability::MachineApplicable,
);
err.emit();
return Ok((match float_suffix {
"f32" => ast::LitKind::Float(val, ast::FloatTy::F32),
"f64" => ast::LitKind::Float(val, ast::FloatTy::F64),
_ => ast::LitKind::FloatUnsuffixed(val),
}, token::Float(val), suffix));
} else {
unreachable!();
};
}
_ => { return self.unexpected_last(&self.token); }
};
self.bump();
Ok(out)
}
/// Matches `lit = true | false | token_lit`.
crate fn parse_lit(&mut self) -> PResult<'a, Lit> {
let lo = self.span;
let (node, token, suffix) = if self.eat_keyword(keywords::True) {
(LitKind::Bool(true), token::Bool(keywords::True.name()), None)
} else if self.eat_keyword(keywords::False) {
(LitKind::Bool(false), token::Bool(keywords::False.name()), None)
} else {
self.parse_lit_token()?
};
Ok(Lit { node, token, suffix, span: lo.to(self.prev_span) })
let diag = Some((self.span, &self.sess.span_diagnostic));
if let Some(lit) = Lit::from_token(&self.token, self.span, diag) {
self.bump();
return Ok(lit);
} else if self.token == token::Dot {
// Recover `.4` as `0.4`.
let recovered = self.look_ahead(1, |t| {
if let token::Literal(token::Integer(val), suf) = *t {
let next_span = self.look_ahead_span(1);
if self.span.hi() == next_span.lo() {
let sym = String::from("0.") + &val.as_str();
let token = token::Literal(token::Float(Symbol::intern(&sym)), suf);
return Some((token, self.span.to(next_span)));
}
}
None
});
if let Some((token, span)) = recovered {
self.diagnostic()
.struct_span_err(span, "float literals must have an integer part")
.span_suggestion(
span,
"must have an integer part",
pprust::token_to_string(&token),
Applicability::MachineApplicable,
)
.emit();
let diag = Some((span, &self.sess.span_diagnostic));
if let Some(lit) = Lit::from_token(&token, span, diag) {
self.bump();
self.bump();
return Ok(lit);
}
}
}
self.unexpected_last(&self.token)
}
/// Matches `'-' lit | lit` (cf. `ast_validation::AstValidator::check_expr_within_pat`).