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Rollup merge of #100250 - cjgillot:recover-token-stream, r=Aaron1011

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Manually cleanup token stream when macro expansion aborts.

In case of syntax error in macro expansion, the expansion code can decide to stop processing anything. In that case, the token stream is malformed. This makes downstream users, like derive macros, ICE.

In this case, this PR manually cleans up the token stream by closing all currently open delimiters.

Fixes https://github.com/rust-lang/rust/issues/96818.
Fixes https://github.com/rust-lang/rust/issues/80447.
Fixes https://github.com/rust-lang/rust/issues/81920.
Fixes https://github.com/rust-lang/rust/issues/91023.
This commit is contained in:
Michael Howell 2022-09-20 10:12:56 -07:00 • committed by GitHub
commit 14b27cfd11
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4 changed files with 84 additions and 29 deletions
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64
compiler/rustc_builtin_macros/src/cfg_eval.rs
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@ -7,6 +7,7 @@ use rustc_ast::visit::Visitor;
use rustc_ast::NodeId;
use rustc_ast::{mut_visit, visit};
use rustc_ast::{Attribute, HasAttrs, HasTokens};
use rustc_errors::PResult;
use rustc_expand::base::{Annotatable, ExtCtxt};
use rustc_expand::config::StripUnconfigured;
use rustc_expand::configure;
@ -144,33 +145,34 @@ impl CfgEval<'_, '_> {
// the location of `#[cfg]` and `#[cfg_attr]` in the token stream. The tokenization
// process is lossless, so this process is invisible to proc-macros.
let parse_annotatable_with: fn(&mut Parser<'_>) -> _ = match annotatable {
Annotatable::Item(_) => {
|parser| Annotatable::Item(parser.parse_item(ForceCollect::Yes).unwrap().unwrap())
}
Annotatable::TraitItem(_) => |parser| {
Annotatable::TraitItem(
parser.parse_trait_item(ForceCollect::Yes).unwrap().unwrap().unwrap(),
)
},
Annotatable::ImplItem(_) => |parser| {
Annotatable::ImplItem(
parser.parse_impl_item(ForceCollect::Yes).unwrap().unwrap().unwrap(),
)
},
Annotatable::ForeignItem(_) => |parser| {
Annotatable::ForeignItem(
parser.parse_foreign_item(ForceCollect::Yes).unwrap().unwrap().unwrap(),
)
},
Annotatable::Stmt(_) => |parser| {
Annotatable::Stmt(P(parser.parse_stmt(ForceCollect::Yes).unwrap().unwrap()))
},
Annotatable::Expr(_) => {
|parser| Annotatable::Expr(parser.parse_expr_force_collect().unwrap())
}
_ => unreachable!(),
};
let parse_annotatable_with: for<'a> fn(&mut Parser<'a>) -> PResult<'a, _> =
match annotatable {
Annotatable::Item(_) => {
|parser| Ok(Annotatable::Item(parser.parse_item(ForceCollect::Yes)?.unwrap()))
}
Annotatable::TraitItem(_) => |parser| {
Ok(Annotatable::TraitItem(
parser.parse_trait_item(ForceCollect::Yes)?.unwrap().unwrap(),
))
},
Annotatable::ImplItem(_) => |parser| {
Ok(Annotatable::ImplItem(
parser.parse_impl_item(ForceCollect::Yes)?.unwrap().unwrap(),
))
},
Annotatable::ForeignItem(_) => |parser| {
Ok(Annotatable::ForeignItem(
parser.parse_foreign_item(ForceCollect::Yes)?.unwrap().unwrap(),
))
},
Annotatable::Stmt(_) => |parser| {
Ok(Annotatable::Stmt(P(parser.parse_stmt(ForceCollect::Yes)?.unwrap())))
},
Annotatable::Expr(_) => {
|parser| Ok(Annotatable::Expr(parser.parse_expr_force_collect()?))
}
_ => unreachable!(),
};
// 'Flatten' all nonterminals (i.e. `TokenKind::Interpolated`)
// to `None`-delimited groups containing the corresponding tokens. This
@ -193,7 +195,13 @@ impl CfgEval<'_, '_> {
let mut parser =
rustc_parse::stream_to_parser(&self.cfg.sess.parse_sess, orig_tokens, None);
parser.capture_cfg = true;
annotatable = parse_annotatable_with(&mut parser);
match parse_annotatable_with(&mut parser) {
Ok(a) => annotatable = a,
Err(mut err) => {
err.emit();
return Some(annotatable);
}
}
// Now that we have our re-parsed `AttrTokenStream`, recursively configuring
// our attribute target will correctly the tokens as well.