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Rollup merge of rust-lang#96421 - nnethercote:less-NoDelim, r=petroch…
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…enkov

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``
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@Dylan-DPC
Dylan-DPC committed Apr 27, 2022
2 parents 3eeda5c + 86f0117 commit f485572
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Showing 10 changed files with 86 additions and 84 deletions.
6 changes: 3 additions & 3 deletions compiler/rustc_ast/src/ast.rs
View file
Expand Up @@ -1542,10 +1542,10 @@ pub enum MacArgs {
}

impl MacArgs {
pub fn delim(&self) -> DelimToken {
pub fn delim(&self) -> Option<DelimToken> {
match self {
MacArgs::Delimited(_, delim, _) => delim.to_token(),
MacArgs::Empty | MacArgs::Eq(..) => token::NoDelim,
MacArgs::Delimited(_, delim, _) => Some(delim.to_token()),
MacArgs::Empty | MacArgs::Eq(..) => None,
}
}

Expand Down
38 changes: 20 additions & 18 deletions compiler/rustc_ast_pretty/src/pprust/state.rs
View file
Expand Up @@ -464,7 +464,7 @@ pub trait PrintState<'a>: std::ops::Deref<Target = pp::Printer> + std::ops::Dere
Some(MacHeader::Path(&item.path)),
false,
None,
delim.to_token(),
Some(delim.to_token()),
tokens,
true,
span,
Expand Down Expand Up @@ -530,7 +530,7 @@ pub trait PrintState<'a>: std::ops::Deref<Target = pp::Printer> + std::ops::Dere
None,
false,
None,
*delim,
Some(*delim),
tts,
convert_dollar_crate,
dspan.entire(),
Expand All @@ -556,12 +556,12 @@ pub trait PrintState<'a>: std::ops::Deref<Target = pp::Printer> + std::ops::Dere
header: Option<MacHeader<'_>>,
has_bang: bool,
ident: Option<Ident>,
delim: DelimToken,
delim: Option<DelimToken>,
tts: &TokenStream,
convert_dollar_crate: bool,
span: Span,
) {
if delim == DelimToken::Brace {
if delim == Some(DelimToken::Brace) {
self.cbox(INDENT_UNIT);
}
match header {
Expand All @@ -577,31 +577,33 @@ pub trait PrintState<'a>: std::ops::Deref<Target = pp::Printer> + std::ops::Dere
self.print_ident(ident);
}
match delim {
DelimToken::Brace => {
Some(DelimToken::Brace) => {
if header.is_some() || has_bang || ident.is_some() {
self.nbsp();
}
self.word("{");
if !tts.is_empty() {
self.space();
}
}
_ => {
let token_str = self.token_kind_to_string(&token::OpenDelim(delim));
self.word(token_str)
}
}
self.ibox(0);
self.print_tts(tts, convert_dollar_crate);
self.end();
match delim {
DelimToken::Brace => {
self.ibox(0);
self.print_tts(tts, convert_dollar_crate);
self.end();
let empty = tts.is_empty();
self.bclose(span, empty);
}
_ => {
Some(delim) => {
let token_str = self.token_kind_to_string(&token::OpenDelim(delim));
self.word(token_str);
self.ibox(0);
self.print_tts(tts, convert_dollar_crate);
self.end();
let token_str = self.token_kind_to_string(&token::CloseDelim(delim));
self.word(token_str)
self.word(token_str);
}
None => {
self.ibox(0);
self.print_tts(tts, convert_dollar_crate);
self.end();
}
}
}
Expand Down
9 changes: 4 additions & 5 deletions compiler/rustc_expand/src/mbe/macro_rules.rs
View file
Expand Up @@ -260,16 +260,15 @@ fn generic_extension<'cx, 'tt>(
// Merge the gated spans from parsing the matcher with the pre-existing ones.
sess.gated_spans.merge(gated_spans_snapshot);

// Ignore the delimiters on the RHS.
let rhs = match &rhses[i] {
mbe::TokenTree::Delimited(_, delimited) => &delimited.tts,
let (rhs, rhs_span): (&mbe::Delimited, DelimSpan) = match &rhses[i] {
mbe::TokenTree::Delimited(span, delimited) => (&delimited, *span),
_ => cx.span_bug(sp, "malformed macro rhs"),
};
let arm_span = rhses[i].span();

let rhs_spans = rhs.iter().map(|t| t.span()).collect::<Vec<_>>();
let rhs_spans = rhs.tts.iter().map(|t| t.span()).collect::<Vec<_>>();
// rhs has holes ( `$id` and `$(...)` that need filled)
let mut tts = match transcribe(cx, &named_matches, &rhs, transparency) {
let mut tts = match transcribe(cx, &named_matches, &rhs, rhs_span, transparency) {
Ok(tts) => tts,
Err(mut err) => {
err.emit();
Expand Down
13 changes: 7 additions & 6 deletions compiler/rustc_expand/src/mbe/transcribe.rs
View file
Expand Up @@ -29,8 +29,8 @@ impl MutVisitor for Marker {
enum Frame<'a> {
Delimited {
tts: &'a [mbe::TokenTree],
delim_token: token::DelimToken,
idx: usize,
delim_token: token::DelimToken,
span: DelimSpan,
},
Sequence {
Expand All @@ -42,8 +42,8 @@ enum Frame<'a> {

impl<'a> Frame<'a> {
/// Construct a new frame around the delimited set of tokens.
fn new(tts: &'a [mbe::TokenTree]) -> Frame<'a> {
Frame::Delimited { tts, delim_token: token::NoDelim, idx: 0, span: DelimSpan::dummy() }
fn new(src: &'a mbe::Delimited, span: DelimSpan) -> Frame<'a> {
Frame::Delimited { tts: &src.tts, idx: 0, delim_token: src.delim, span }
}
}

Expand Down Expand Up @@ -85,17 +85,18 @@ impl<'a> Iterator for Frame<'a> {
pub(super) fn transcribe<'a>(
cx: &ExtCtxt<'a>,
interp: &FxHashMap<MacroRulesNormalizedIdent, NamedMatch>,
src: &[mbe::TokenTree],
src: &mbe::Delimited,
src_span: DelimSpan,
transparency: Transparency,
) -> PResult<'a, TokenStream> {
// Nothing for us to transcribe...
if src.is_empty() {
if src.tts.is_empty() {
return Ok(TokenStream::default());
}

// We descend into the RHS (`src`), expanding things as we go. This stack contains the things
// we have yet to expand/are still expanding. We start the stack off with the whole RHS.
let mut stack: SmallVec<[Frame<'_>; 1]> = smallvec![Frame::new(&src)];
let mut stack: SmallVec<[Frame<'_>; 1]> = smallvec![Frame::new(&src, src_span)];

// As we descend in the RHS, we will need to be able to match nested sequences of matchers.
// `repeats` keeps track of where we are in matching at each level, with the last element being
Expand Down
27 changes: 15 additions & 12 deletions compiler/rustc_parse/src/parser/attr_wrapper.rs
View file
Expand Up @@ -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;
Expand Down Expand Up @@ -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;
Expand All @@ -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
Expand All @@ -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
Expand Down Expand Up @@ -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);
}
Expand Down
3 changes: 2 additions & 1 deletion compiler/rustc_parse/src/parser/expr.rs
View file
Expand Up @@ -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
Expand Down
34 changes: 13 additions & 21 deletions compiler/rustc_parse/src/parser/mod.rs
View file
Expand Up @@ -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() }
}
}

Expand All @@ -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) {
Expand All @@ -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);
Expand All @@ -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);
Expand Down Expand Up @@ -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()
Expand Down Expand Up @@ -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(),
Expand All @@ -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,
Expand Down Expand Up @@ -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, _)))
Expand All @@ -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)),
};
}
}
Expand Down Expand Up @@ -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
Expand Down

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