bjoernager/rust
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syntax: Make _ an identifier

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This commit is contained in:
Vadim Petrochenkov 2018-03-08 14:27:23 +03:00
parent 61b6bf54fd
commit 5d06c890fe
20 changed files with 109 additions and 119 deletions
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36
src/libsyntax/parse/parser.rs
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@ -549,7 +549,7 @@ impl<'a> Parser<'a> {
-> Self {
let mut parser = Parser {
sess,
token: token::Underscore,
token: token::Whitespace,
span: syntax_pos::DUMMY_SP,
prev_span: syntax_pos::DUMMY_SP,
meta_var_span: None,
@ -800,11 +800,7 @@ impl<'a> Parser<'a> {
Err(if self.prev_token_kind == PrevTokenKind::DocComment {
self.span_fatal_err(self.prev_span, Error::UselessDocComment)
} else {
let mut err = self.expected_ident_found();
if self.token == token::Underscore {
err.note("`_` is a wildcard pattern, not an identifier");
}
err
self.expected_ident_found()
})
}
}
@ -1602,7 +1598,7 @@ impl<'a> Parser<'a> {
let e = self.parse_expr()?;
self.expect(&token::CloseDelim(token::Paren))?;
TyKind::Typeof(e)
} else if self.eat(&token::Underscore) {
} else if self.eat_keyword(keywords::Underscore) {
// A type to be inferred `_`
TyKind::Infer
} else if self.token_is_bare_fn_keyword() {
@ -1796,7 +1792,7 @@ impl<'a> Parser<'a> {
_ => 0,
};
self.look_ahead(offset, |t| t.is_ident() || t == &token::Underscore) &&
self.look_ahead(offset, |t| t.is_ident()) &&
self.look_ahead(offset + 1, |t| t == &token::Colon)
}
@ -2782,7 +2778,7 @@ impl<'a> Parser<'a> {
},
token::CloseDelim(_) | token::Eof => unreachable!(),
_ => {
let (token, span) = (mem::replace(&mut self.token, token::Underscore), self.span);
let (token, span) = (mem::replace(&mut self.token, token::Whitespace), self.span);
self.bump();
TokenTree::Token(span, token)
}
@ -3815,11 +3811,6 @@ impl<'a> Parser<'a> {
let lo = self.span;
let pat;
match self.token {
token::Underscore => {
// Parse _
self.bump();
pat = PatKind::Wild;
}
token::BinOp(token::And) | token::AndAnd => {
// Parse &pat / &mut pat
self.expect_and()?;
@ -3849,8 +3840,11 @@ impl<'a> Parser<'a> {
self.expect(&token::CloseDelim(token::Bracket))?;
pat = PatKind::Slice(before, slice, after);
}
// At this point, token != _, &, &&, (, [
_ => if self.eat_keyword(keywords::Mut) {
// At this point, token != &, &&, (, [
_ => if self.eat_keyword(keywords::Underscore) {
// Parse _
pat = PatKind::Wild;
} else if self.eat_keyword(keywords::Mut) {
// Parse mut ident @ pat / mut ref ident @ pat
let mutref_span = self.prev_span.to(self.span);
let binding_mode = if self.eat_keyword(keywords::Ref) {
@ -7065,10 +7059,12 @@ impl<'a> Parser<'a> {
fn parse_rename(&mut self) -> PResult<'a, Option<Ident>> {
if self.eat_keyword(keywords::As) {
if self.eat(&token::Underscore) {
Ok(Some(Ident::with_empty_ctxt(Symbol::gensym("_"))))
} else {
self.parse_ident().map(Some)
match self.token {
token::Ident(ident) if ident.name == keywords::Underscore.name() => {
self.bump(); // `_`
Ok(Some(Ident { name: ident.name.gensymed(), ..ident }))
}
_ => self.parse_ident().map(Some),
}
} else {
Ok(None)