bjoernager/rust
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Formally implement let chains

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Caio 2022-01-18 19:38:17 -03:00
parent 9ad5d82f82
commit 5f74ef4fb1
31 changed files with 536 additions and 340 deletions
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18
compiler/rustc_ast_lowering/src/expr.rs
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@ -392,14 +392,20 @@ impl<'hir> LoweringContext<'_, 'hir> {
// If `cond` kind is `let`, returns `let`. Otherwise, wraps and returns `cond`
// in a temporary block.
fn manage_let_cond(&mut self, cond: &'hir hir::Expr<'hir>) -> &'hir hir::Expr<'hir> {
match cond.kind {
hir::ExprKind::Let(..) => cond,
_ => {
let span_block =
self.mark_span_with_reason(DesugaringKind::CondTemporary, cond.span, None);
self.expr_drop_temps(span_block, cond, AttrVec::new())
fn has_let_expr<'hir>(expr: &'hir hir::Expr<'hir>) -> bool {
match expr.kind {
hir::ExprKind::Binary(_, lhs, rhs) => has_let_expr(lhs) || has_let_expr(rhs),
hir::ExprKind::Let(..) => true,
_ => false,
}
}
if has_let_expr(cond) {
cond
} else {
let reason = DesugaringKind::CondTemporary;
let span_block = self.mark_span_with_reason(reason, cond.span, None);
self.expr_drop_temps(span_block, cond, AttrVec::new())
}
}
// We desugar: `'label: while $cond $body` into: