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rustc: Correctly pretty-print macro delimiters

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This commit updates the `Mac_` AST structure to keep track of the delimiters
that it originally had for its invocation. This allows us to faithfully
pretty-print macro invocations not using parentheses (e.g. `vec![...]`). This in
turn helps procedural macros due to #43081.

Closes #50840
This commit is contained in:
Alex Crichton 2018-05-22 08:01:21 -07:00
parent ff8fa5cc69
commit a137d00ce5
9 changed files with 156 additions and 82 deletions
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66
src/libsyntax/parse/parser.rs
View file

@ -26,7 +26,7 @@ use ast::{Ident, ImplItem, IsAuto, Item, ItemKind};
use ast::{Label, Lifetime, LifetimeDef, Lit, LitKind, UintTy};
use ast::Local;
use ast::MacStmtStyle;
use ast::{Mac, Mac_};
use ast::{Mac, Mac_, MacDelimiter};
use ast::{MutTy, Mutability};
use ast::{Pat, PatKind, PathSegment};
use ast::{PolyTraitRef, QSelf};
@ -1611,8 +1611,9 @@ impl<'a> Parser<'a> {
let path = self.parse_path(PathStyle::Type)?;
if self.eat(&token::Not) {
// Macro invocation in type position
let (_, tts) = self.expect_delimited_token_tree()?;
TyKind::Mac(respan(lo.to(self.prev_span), Mac_ { path: path, tts: tts }))
let (delim, tts) = self.expect_delimited_token_tree()?;
let node = Mac_ { path, tts, delim };
TyKind::Mac(respan(lo.to(self.prev_span), node))
} else {
// Just a type path or bound list (trait object type) starting with a trait.
// `Type`
@ -2181,19 +2182,27 @@ impl<'a> Parser<'a> {
})
}
fn expect_delimited_token_tree(&mut self) -> PResult<'a, (token::DelimToken, ThinTokenStream)> {
match self.token {
token::OpenDelim(delim) => match self.parse_token_tree() {
TokenTree::Delimited(_, delimited) => Ok((delim, delimited.stream().into())),
_ => unreachable!(),
},
fn expect_delimited_token_tree(&mut self) -> PResult<'a, (MacDelimiter, ThinTokenStream)> {
let delim = match self.token {
token::OpenDelim(delim) => delim,
_ => {
let msg = "expected open delimiter";
let mut err = self.fatal(msg);
err.span_label(self.span, msg);
Err(err)
return Err(err)
}
}
};
let delimited = match self.parse_token_tree() {
TokenTree::Delimited(_, delimited) => delimited,
_ => unreachable!(),
};
let delim = match delim {
token::Paren => MacDelimiter::Parenthesis,
token::Bracket => MacDelimiter::Bracket,
token::Brace => MacDelimiter::Brace,
token::NoDelim => self.bug("unexpected no delimiter"),
};
Ok((delim, delimited.stream().into()))
}
/// At the bottom (top?) of the precedence hierarchy,
@ -2406,9 +2415,10 @@ impl<'a> Parser<'a> {
// `!`, as an operator, is prefix, so we know this isn't that
if self.eat(&token::Not) {
// MACRO INVOCATION expression
let (_, tts) = self.expect_delimited_token_tree()?;
let (delim, tts) = self.expect_delimited_token_tree()?;
let hi = self.prev_span;
return Ok(self.mk_mac_expr(lo.to(hi), Mac_ { path: pth, tts: tts }, attrs));
let node = Mac_ { path: pth, tts, delim };
return Ok(self.mk_mac_expr(lo.to(hi), node, attrs))
}
if self.check(&token::OpenDelim(token::Brace)) {
// This is a struct literal, unless we're prohibited
@ -3881,8 +3891,8 @@ impl<'a> Parser<'a> {
token::Not if qself.is_none() => {
// Parse macro invocation
self.bump();
let (_, tts) = self.expect_delimited_token_tree()?;
let mac = respan(lo.to(self.prev_span), Mac_ { path: path, tts: tts });
let (delim, tts) = self.expect_delimited_token_tree()?;
let mac = respan(lo.to(self.prev_span), Mac_ { path, tts, delim });
pat = PatKind::Mac(mac);
}
token::DotDotDot | token::DotDotEq | token::DotDot => {
@ -4275,7 +4285,7 @@ impl<'a> Parser<'a> {
let ident = self.parse_ident()?;
let (delim, tokens) = self.expect_delimited_token_tree()?;
if delim != token::Brace {
if delim != MacDelimiter::Brace {
if !self.eat(&token::Semi) {
let msg = "macros that expand to items must either \
be surrounded with braces or followed by a semicolon";
@ -4360,8 +4370,8 @@ impl<'a> Parser<'a> {
// check that we're pointing at delimiters (need to check
// again after the `if`, because of `parse_ident`
// consuming more tokens).
let delim = match self.token {
token::OpenDelim(delim) => delim,
match self.token {
token::OpenDelim(_) => {}
_ => {
// we only expect an ident if we didn't parse one
// above.
@ -4377,20 +4387,20 @@ impl<'a> Parser<'a> {
err.span_label(self.span, format!("expected {}`(` or `{{`", ident_str));
return Err(err)
},
};
}
let (_, tts) = self.expect_delimited_token_tree()?;
let (delim, tts) = self.expect_delimited_token_tree()?;
let hi = self.prev_span;
let style = if delim == token::Brace {
let style = if delim == MacDelimiter::Brace {
MacStmtStyle::Braces
} else {
MacStmtStyle::NoBraces
};
if id.name == keywords::Invalid.name() {
let mac = respan(lo.to(hi), Mac_ { path: pth, tts: tts });
let node = if delim == token::Brace ||
let mac = respan(lo.to(hi), Mac_ { path: pth, tts, delim });
let node = if delim == MacDelimiter::Brace ||
self.token == token::Semi || self.token == token::Eof {
StmtKind::Mac(P((mac, style, attrs.into())))
}
@ -4438,7 +4448,7 @@ impl<'a> Parser<'a> {
node: StmtKind::Item({
self.mk_item(
span, id /*id is good here*/,
ItemKind::Mac(respan(span, Mac_ { path: pth, tts: tts })),
ItemKind::Mac(respan(span, Mac_ { path: pth, tts, delim })),
respan(lo, VisibilityKind::Inherited),
attrs)
}),
@ -6871,7 +6881,7 @@ impl<'a> Parser<'a> {
};
// eat a matched-delimiter token tree:
let (delim, tts) = self.expect_delimited_token_tree()?;
if delim != token::Brace {
if delim != MacDelimiter::Brace {
if !self.eat(&token::Semi) {
self.span_err(self.prev_span,
"macros that expand to items must either \
@ -6881,7 +6891,7 @@ impl<'a> Parser<'a> {
}
let hi = self.prev_span;
let mac = respan(mac_lo.to(hi), Mac_ { path: pth, tts: tts });
let mac = respan(mac_lo.to(hi), Mac_ { path: pth, tts, delim });
let item = self.mk_item(lo.to(hi), id, ItemKind::Mac(mac), visibility, attrs);
return Ok(Some(item));
}
@ -6925,11 +6935,11 @@ impl<'a> Parser<'a> {
// eat a matched-delimiter token tree:
let (delim, tts) = self.expect_delimited_token_tree()?;
if delim != token::Brace {
if delim != MacDelimiter::Brace {
self.expect(&token::Semi)?
}
Ok(Some(respan(lo.to(self.prev_span), Mac_ { path: pth, tts: tts })))
Ok(Some(respan(lo.to(self.prev_span), Mac_ { path: pth, tts, delim })))
} else {
Ok(None)
}