bjoernager/rust
bjoernager/rust
1
Fork 0
Code Activity

Revert let_chains stabilization

Browse source 
This reverts commit 3266460749.

This is the revert against master, the beta revert was already done in #100538.
This commit is contained in:
Nilstrieb 2022-08-20 20:40:08 +02:00
parent 76eb4f3bfd
commit d1ef8180f9
59 changed files with 825 additions and 430 deletions
Download patch file Download diff file Expand all files Collapse all files

1
compiler/rustc_parse/src/lib.rs
View file

@ -3,6 +3,7 @@
#![feature(array_windows)]
#![feature(box_patterns)]
#![feature(if_let_guard)]
#![feature(let_chains)]
#![feature(let_else)]
#![feature(never_type)]
#![feature(rustc_attrs)]

28
compiler/rustc_parse/src/parser/expr.rs
View file

@ -2251,7 +2251,15 @@ impl<'a> Parser<'a> {
/// Parses the condition of a `if` or `while` expression.
fn parse_cond_expr(&mut self) -> PResult<'a, P<Expr>> {
self.parse_expr_res(Restrictions::NO_STRUCT_LITERAL | Restrictions::ALLOW_LET, None)
let cond =
self.parse_expr_res(Restrictions::NO_STRUCT_LITERAL | Restrictions::ALLOW_LET, None)?;
if let ExprKind::Let(..) = cond.kind {
// Remove the last feature gating of a `let` expression since it's stable.
self.sess.gated_spans.ungate_last(sym::let_chains, cond.span);
}
Ok(cond)
}
/// Parses a `let $pat = $expr` pseudo-expression.
@ -2280,6 +2288,7 @@ impl<'a> Parser<'a> {
this.parse_assoc_expr_with(1 + prec_let_scrutinee_needs_par(), None.into())
})?;
let span = lo.to(expr.span);
self.sess.gated_spans.gate(sym::let_chains, span);
Ok(self.mk_expr(span, ExprKind::Let(pat, expr, span)))
}
@ -2571,13 +2580,15 @@ impl<'a> Parser<'a> {
pub(super) fn parse_arm(&mut self) -> PResult<'a, Arm> {
// Used to check the `let_chains` and `if_let_guard` features mostly by scaning
// `&&` tokens.
fn check_let_expr(expr: &Expr) -> bool {
fn check_let_expr(expr: &Expr) -> (bool, bool) {
match expr.kind {
ExprKind::Binary(BinOp { node: BinOpKind::And, .. }, ref lhs, ref rhs) => {
check_let_expr(lhs) || check_let_expr(rhs)
let lhs_rslt = check_let_expr(lhs);
let rhs_rslt = check_let_expr(rhs);
(lhs_rslt.0 || rhs_rslt.0, false)
}
ExprKind::Let(..) => true,
_ => false,
ExprKind::Let(..) => (true, true),
_ => (false, true),
}
}
let attrs = self.parse_outer_attributes()?;
@ -2592,7 +2603,12 @@ impl<'a> Parser<'a> {
let guard = if this.eat_keyword(kw::If) {
let if_span = this.prev_token.span;
let cond = this.parse_expr_res(Restrictions::ALLOW_LET, None)?;
if check_let_expr(&cond) {
let (has_let_expr, does_not_have_bin_op) = check_let_expr(&cond);
if has_let_expr {
if does_not_have_bin_op {
// Remove the last feature gating of a `let` expression since it's stable.
this.sess.gated_spans.ungate_last(sym::let_chains, cond.span);
}
let span = if_span.to(cond.span);
this.sess.gated_spans.gate(sym::if_let_guard, span);
}