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Parse inline const expressions

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This commit is contained in:
Santiago Pastorino 2020-09-21 17:55:58 -03:00
parent 3c4ad55082
commit c3e8d7965c
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GPG key ID: 8131A24E0C79EFAF
10 changed files with 60 additions and 3 deletions
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27
compiler/rustc_parse/src/parser/mod.rs
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@ -18,8 +18,9 @@ use rustc_ast::ptr::P;
use rustc_ast::token::{self, DelimToken, Token, TokenKind};
use rustc_ast::tokenstream::{self, DelimSpan, TokenStream, TokenTree, TreeAndSpacing};
use rustc_ast::DUMMY_NODE_ID;
use rustc_ast::{self as ast, AttrStyle, AttrVec, Const, CrateSugar, Extern, Unsafe};
use rustc_ast::{Async, MacArgs, MacDelimiter, Mutability, StrLit, Visibility, VisibilityKind};
use rustc_ast::{self as ast, AnonConst, AttrStyle, AttrVec, Const, CrateSugar, Extern, Unsafe};
use rustc_ast::{Async, Expr, ExprKind, MacArgs, MacDelimiter, Mutability, StrLit};
use rustc_ast::{Visibility, VisibilityKind};
use rustc_ast_pretty::pprust;
use rustc_errors::{struct_span_err, Applicability, DiagnosticBuilder, FatalError, PResult};
use rustc_session::parse::ParseSess;
@ -545,6 +546,11 @@ impl<'a> Parser<'a> {
self.check_or_expected(self.token.can_begin_const_arg(), TokenType::Const)
}
fn check_inline_const(&mut self) -> bool {
self.check_keyword(kw::Const)
&& self.look_ahead(1, |t| t == &token::OpenDelim(DelimToken::Brace))
}
/// Checks to see if the next token is either `+` or `+=`.
/// Otherwise returns `false`.
fn check_plus(&mut self) -> bool {
@ -864,13 +870,28 @@ impl<'a> Parser<'a> {
/// Parses constness: `const` or nothing.
fn parse_constness(&mut self) -> Const {
if self.eat_keyword(kw::Const) {
// Avoid const blocks to be parsed as const items
if self.look_ahead(1, |t| t != &token::OpenDelim(DelimToken::Brace))
&& self.eat_keyword(kw::Const)
{
Const::Yes(self.prev_token.uninterpolated_span())
} else {
Const::No
}
}
/// Parses inline const expressions.
fn parse_const_expr(&mut self, span: Span) -> PResult<'a, P<Expr>> {
self.sess.gated_spans.gate(sym::inline_const, span);
self.eat_keyword(kw::Const);
let blk = self.parse_block()?;
let anon_const = AnonConst {
id: DUMMY_NODE_ID,
value: self.mk_expr(blk.span, ExprKind::Block(blk, None), AttrVec::new()),
};
Ok(self.mk_expr(span, ExprKind::ConstBlock(anon_const), AttrVec::new()))
}
/// Parses mutability (`mut` or nothing).
fn parse_mutability(&mut self) -> Mutability {
if self.eat_keyword(kw::Mut) { Mutability::Mut } else { Mutability::Not }