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Rollup merge of #96421 - nnethercote:less-NoDelim, r=petrochenkov

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Less `NoDelim`

Currently there are several places where `NoDelim` (which really means "implicit delimiter" or "invisible delimiter") is used to mean "no delimiter". The name `NoDelim` is a bit misleading, and may be a cause.

This PR changes these places, e.g. by changing a `DelimToken` to `Option<DelimToken>` and then using `None` to mean "no delimiter". As a result, the *only* place where `NoDelim` values are now produced is within:
- `Delimiter::to_internal()`, when converting from `Delimiter::None`.
- `FlattenNonterminals::process_token()`, when converting `TokenKind::Interpolated`.

r? ````@petrochenkov````
This commit is contained in:
Dylan DPC 2022-04-28 02:40:34 +02:00 • committed by GitHub
commit 80045d65e1
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10 changed files with 86 additions and 84 deletions
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27
compiler/rustc_parse/src/parser/attr_wrapper.rs
View file

@ -5,7 +5,7 @@ use rustc_ast::tokenstream::{AttrAnnotatedTokenTree, DelimSpan, LazyTokenStream,
use rustc_ast::{self as ast};
use rustc_ast::{AstLike, AttrVec, Attribute};
use rustc_errors::PResult;
use rustc_span::{sym, Span, DUMMY_SP};
use rustc_span::{sym, Span};
use std::convert::TryInto;
use std::ops::Range;
@ -400,24 +400,26 @@ fn make_token_stream(
) -> AttrAnnotatedTokenStream {
#[derive(Debug)]
struct FrameData {
open: Span,
open_delim: DelimToken,
// This is `None` for the first frame, `Some` for all others.
open_delim_sp: Option<(DelimToken, Span)>,
inner: Vec<(AttrAnnotatedTokenTree, Spacing)>,
}
let mut stack =
vec![FrameData { open: DUMMY_SP, open_delim: DelimToken::NoDelim, inner: vec![] }];
let mut stack = vec![FrameData { open_delim_sp: None, inner: vec![] }];
let mut token_and_spacing = iter.next();
while let Some((token, spacing)) = token_and_spacing {
match token {
FlatToken::Token(Token { kind: TokenKind::OpenDelim(delim), span }) => {
stack.push(FrameData { open: span, open_delim: delim, inner: vec![] });
stack.push(FrameData { open_delim_sp: Some((delim, span)), inner: vec![] });
}
FlatToken::Token(Token { kind: TokenKind::CloseDelim(delim), span }) => {
// HACK: If we encounter a mismatched `None` delimiter at the top
// level, just ignore it.
if matches!(delim, DelimToken::NoDelim)
&& (stack.len() == 1
|| !matches!(stack.last_mut().unwrap().open_delim, DelimToken::NoDelim))
|| !matches!(
stack.last_mut().unwrap().open_delim_sp.unwrap().0,
DelimToken::NoDelim
))
{
token_and_spacing = iter.next();
continue;
@ -430,7 +432,7 @@ fn make_token_stream(
// merge our current frame with the one above it. That is, transform
// `[ { < first second } third ]` into `[ { first second } third ]`
if !matches!(delim, DelimToken::NoDelim)
&& matches!(frame_data.open_delim, DelimToken::NoDelim)
&& matches!(frame_data.open_delim_sp.unwrap().0, DelimToken::NoDelim)
{
stack.last_mut().unwrap().inner.extend(frame_data.inner);
// Process our closing delimiter again, this time at the previous
@ -439,12 +441,13 @@ fn make_token_stream(
continue;
}
let (open_delim, open_sp) = frame_data.open_delim_sp.unwrap();
assert_eq!(
frame_data.open_delim, delim,
open_delim, delim,
"Mismatched open/close delims: open={:?} close={:?}",
frame_data.open, span
open_delim, span
);
let dspan = DelimSpan::from_pair(frame_data.open, span);
let dspan = DelimSpan::from_pair(open_sp, span);
let stream = AttrAnnotatedTokenStream::new(frame_data.inner);
let delimited = AttrAnnotatedTokenTree::Delimited(dspan, delim, stream);
stack
@ -472,7 +475,7 @@ fn make_token_stream(
// HACK: If we don't have a closing `None` delimiter for our last
// frame, merge the frame with the top-level frame. That is,
// turn `< first second` into `first second`
if stack.len() == 2 && stack[1].open_delim == DelimToken::NoDelim {
if stack.len() == 2 && stack[1].open_delim_sp.unwrap().0 == DelimToken::NoDelim {
let temp_buf = stack.pop().unwrap();
stack.last_mut().unwrap().inner.extend(temp_buf.inner);
}

3
compiler/rustc_parse/src/parser/expr.rs
View file

@ -2043,7 +2043,8 @@ impl<'a> Parser<'a> {
self.sess.gated_spans.gate(sym::async_closure, span);
}
if self.token.kind == TokenKind::Semi && self.token_cursor.frame.delim == DelimToken::Paren
if self.token.kind == TokenKind::Semi
&& matches!(self.token_cursor.frame.delim_sp, Some((DelimToken::Paren, _)))
{
// It is likely that the closure body is a block but where the
// braces have been removed. We will recover and eat the next

34
compiler/rustc_parse/src/parser/mod.rs
View file

@ -244,14 +244,13 @@ struct TokenCursor {
#[derive(Clone)]
struct TokenCursorFrame {
delim: token::DelimToken,
span: DelimSpan,
delim_sp: Option<(DelimToken, DelimSpan)>,
tree_cursor: tokenstream::Cursor,
}
impl TokenCursorFrame {
fn new(span: DelimSpan, delim: DelimToken, tts: TokenStream) -> Self {
TokenCursorFrame { delim, span, tree_cursor: tts.into_trees() }
fn new(delim_sp: Option<(DelimToken, DelimSpan)>, tts: TokenStream) -> Self {
TokenCursorFrame { delim_sp, tree_cursor: tts.into_trees() }
}
}
@ -266,7 +265,7 @@ impl TokenCursor {
loop {
// FIXME: we currently don't return `NoDelim` open/close delims. To fix #67062 we will
// need to, whereupon the `delim != DelimToken::NoDelim` conditions below can be
// removed, as well as the loop.
// removed.
if let Some((tree, spacing)) = self.frame.tree_cursor.next_with_spacing_ref() {
match tree {
&TokenTree::Token(ref token) => match (desugar_doc_comments, token) {
@ -277,7 +276,7 @@ impl TokenCursor {
},
&TokenTree::Delimited(sp, delim, ref tts) => {
// Set `open_delim` to true here because we deal with it immediately.
let frame = TokenCursorFrame::new(sp, delim, tts.clone());
let frame = TokenCursorFrame::new(Some((delim, sp)), tts.clone());
self.stack.push(mem::replace(&mut self.frame, frame));
if delim != DelimToken::NoDelim {
return (Token::new(token::OpenDelim(delim), sp.open), Spacing::Alone);
@ -286,12 +285,11 @@ impl TokenCursor {
}
};
} else if let Some(frame) = self.stack.pop() {
let delim = self.frame.delim;
let span = self.frame.span;
self.frame = frame;
if delim != DelimToken::NoDelim {
if let Some((delim, span)) = self.frame.delim_sp && delim != DelimToken::NoDelim {
self.frame = frame;
return (Token::new(token::CloseDelim(delim), span.close), Spacing::Alone);
}
self.frame = frame;
// No close delimiter to return; continue on to the next iteration.
} else {
return (Token::new(token::Eof, DUMMY_SP), Spacing::Alone);
@ -330,8 +328,7 @@ impl TokenCursor {
self.stack.push(mem::replace(
&mut self.frame,
TokenCursorFrame::new(
delim_span,
token::NoDelim,
None,
if attr_style == AttrStyle::Inner {
[TokenTree::token(token::Pound, span), TokenTree::token(token::Not, span), body]
.iter()
@ -431,10 +428,6 @@ impl<'a> Parser<'a> {
desugar_doc_comments: bool,
subparser_name: Option<&'static str>,
) -> Self {
// Note: because of the way `TokenCursor::inlined_next` is structured, the `span` and
// `delim` arguments here are never used.
let start_frame = TokenCursorFrame::new(DelimSpan::dummy(), token::NoDelim, tokens);
let mut parser = Parser {
sess,
token: Token::dummy(),
@ -444,7 +437,7 @@ impl<'a> Parser<'a> {
restrictions: Restrictions::empty(),
expected_tokens: Vec::new(),
token_cursor: TokenCursor {
frame: start_frame,
frame: TokenCursorFrame::new(None, tokens),
stack: Vec::new(),
num_next_calls: 0,
desugar_doc_comments,
@ -1025,7 +1018,7 @@ impl<'a> Parser<'a> {
}
let frame = &self.token_cursor.frame;
if frame.delim != DelimToken::NoDelim {
if let Some((delim, span)) = frame.delim_sp && delim != DelimToken::NoDelim {
let all_normal = (0..dist).all(|i| {
let token = frame.tree_cursor.look_ahead(i);
!matches!(token, Some(TokenTree::Delimited(_, DelimToken::NoDelim, _)))
@ -1038,7 +1031,7 @@ impl<'a> Parser<'a> {
looker(&Token::new(token::OpenDelim(*delim), dspan.open))
}
},
None => looker(&Token::new(token::CloseDelim(frame.delim), frame.span.close)),
None => looker(&Token::new(token::CloseDelim(delim), span.close)),
};
}
}
@ -1198,8 +1191,7 @@ impl<'a> Parser<'a> {
// Grab the tokens from this frame.
let frame = &self.token_cursor.frame;
let stream = frame.tree_cursor.stream.clone();
let span = frame.span;
let delim = frame.delim;
let (delim, span) = frame.delim_sp.unwrap();
// Advance the token cursor through the entire delimited
// sequence. After getting the `OpenDelim` we are *within* the

36
compiler/rustc_parse/src/parser/stmt.rs
View file

@ -164,25 +164,29 @@ impl<'a> Parser<'a> {
let delim = args.delim();
let hi = self.prev_token.span;
let style =
if delim == token::Brace { MacStmtStyle::Braces } else { MacStmtStyle::NoBraces };
let style = match delim {
Some(token::Brace) => MacStmtStyle::Braces,
Some(_) => MacStmtStyle::NoBraces,
None => unreachable!(),
};
let mac = MacCall { path, args, prior_type_ascription: self.last_type_ascription };
let kind =
if (delim == token::Brace && self.token != token::Dot && self.token != token::Question)
|| self.token == token::Semi
|| self.token == token::Eof
{
StmtKind::MacCall(P(MacCallStmt { mac, style, attrs, tokens: None }))
} else {
// Since none of the above applied, this is an expression statement macro.
let e = self.mk_expr(lo.to(hi), ExprKind::MacCall(mac), AttrVec::new());
let e = self.maybe_recover_from_bad_qpath(e, true)?;
let e = self.parse_dot_or_call_expr_with(e, lo, attrs.into())?;
let e = self.parse_assoc_expr_with(0, LhsExpr::AlreadyParsed(e))?;
StmtKind::Expr(e)
};
let kind = if (style == MacStmtStyle::Braces
&& self.token != token::Dot
&& self.token != token::Question)
|| self.token == token::Semi
|| self.token == token::Eof
{
StmtKind::MacCall(P(MacCallStmt { mac, style, attrs, tokens: None }))
} else {
// Since none of the above applied, this is an expression statement macro.
let e = self.mk_expr(lo.to(hi), ExprKind::MacCall(mac), AttrVec::new());
let e = self.maybe_recover_from_bad_qpath(e, true)?;
let e = self.parse_dot_or_call_expr_with(e, lo, attrs.into())?;
let e = self.parse_assoc_expr_with(0, LhsExpr::AlreadyParsed(e))?;
StmtKind::Expr(e)
};
Ok(self.mk_stmt(lo.to(hi), kind))
}