Add comment and fix fmt issue

This commit is contained in:
Roxane 2021-08-27 09:00:50 -04:00
parent 8fcfd6e136
commit 110a9b3b1c

View File

@ -268,10 +268,21 @@ impl<'a, 'tcx> ExprUseVisitor<'a, 'tcx> {
if def.variants.len() > 1 {
needs_to_be_read = true;
} else if let Some(variant) = def.variants.iter().next() {
// We need to handle `const` in match arms slightly differently
// as they are not processed the same way as other match arms.
// Consider this const `const OP1: Opcode = Opcode(0x1)`, this
// will generate a pattern with kind Path while if use Opcode(0x1)
// this will generate pattern TupleStruct and Lit.
// When dealing with pat kind Path we need to make additional checks
// to ensure we have all the info needed to make a decision on whether
// to borrow discr.
//
// If the pat kind is a Path we want to check whether the
// variant contains at least one field. If that's the case,
// we want to borrow discr.
if matches!(pat.kind, PatKind::Path(..)) && variant.fields.len() > 0 {
if matches!(pat.kind, PatKind::Path(..))
&& variant.fields.len() > 0
{
needs_to_be_read = true;
}
}