bjoernager/rust
bjoernager/rust
1
Fork 0
Code Activity

Accept arbitrary expressions in key-value attributes at parse time

Browse source
This commit is contained in:
Vadim Petrochenkov 2020-11-07 16:09:40 +03:00
parent fa55f668e5
commit 31d72c2658
24 changed files with 145 additions and 210 deletions
Download patch file Download diff file Expand all files Collapse all files

27
compiler/rustc_parse/src/parser/mod.rs
View file

@ -23,6 +23,7 @@ use rustc_ast::{self as ast, AnonConst, AttrStyle, AttrVec, Const, CrateSugar, E
use rustc_ast::{Async, Expr, ExprKind, MacArgs, MacDelimiter, Mutability, StrLit};
use rustc_ast::{Visibility, VisibilityKind};
use rustc_ast_pretty::pprust;
use rustc_data_structures::sync::Lrc;
use rustc_errors::PResult;
use rustc_errors::{struct_span_err, Applicability, DiagnosticBuilder, FatalError};
use rustc_session::parse::ParseSess;
@ -935,16 +936,24 @@ impl<'a> Parser<'a> {
is_interpolated_expr = true;
}
}
let token_tree = if is_interpolated_expr {
// We need to accept arbitrary interpolated expressions to continue
// supporting things like `doc = $expr` that work on stable.
// Non-literal interpolated expressions are rejected after expansion.
self.parse_token_tree()
} else {
self.parse_unsuffixed_lit()?.token_tree()
};
MacArgs::Eq(eq_span, token_tree.into())
// The value here is never passed to macros as tokens by itself (not as a part
// of the whole attribute), so we don't collect tokens here. If this changes,
// then token will need to be collected. One catch here is that we are using
// a nonterminal for keeping the expression, but this nonterminal should not
// be wrapped into a group when converting to token stream.
let expr = self.parse_expr()?;
let span = expr.span;
match &expr.kind {
// Not gated to supporte things like `doc = $expr` that work on stable.
_ if is_interpolated_expr => {}
ExprKind::Lit(lit) if lit.kind.is_unsuffixed() => {}
_ => self.sess.gated_spans.gate(sym::extended_key_value_attributes, span),
}
let token = token::Interpolated(Lrc::new(token::NtExpr(expr)));
MacArgs::Eq(eq_span, TokenTree::token(token, span).into())
} else {
MacArgs::Empty
}