From 6eb1bd4c3e3ad9a28d0a3b0f1579a4769d9a88d2 Mon Sep 17 00:00:00 2001 From: Ömer Sinan Ağacan Date: Mon, 8 Feb 2021 10:43:54 +0300 Subject: parser: Fix panic in 'const impl' recovery The panic happens when in recovery parsing a full `impl` (`parse_item_impl`) fails and we drop the `DiagnosticBuilder` for the recovery suggestion and return the `parse_item_impl` error. We now raise the original error "expected identifier found `impl`" when parsing the `impl` fails. Note that the regression test is slightly simplified version of the original repro in #81806, to make the error output smaller and more resilient to unrelated changes in parser error messages. Fixes #81806 --- compiler/rustc_parse/src/parser/item.rs | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) (limited to 'compiler/rustc_parse/src/parser') diff --git a/compiler/rustc_parse/src/parser/item.rs b/compiler/rustc_parse/src/parser/item.rs index c44ccfadda5..ee242862414 100644 --- a/compiler/rustc_parse/src/parser/item.rs +++ b/compiler/rustc_parse/src/parser/item.rs @@ -1010,9 +1010,18 @@ impl<'a> Parser<'a> { ) -> PResult<'a, ItemInfo> { let impl_span = self.token.span; let mut err = self.expected_ident_found(); - let mut impl_info = self.parse_item_impl(attrs, defaultness)?; + + // Only try to recover if this is implementing a trait for a type + let mut impl_info = match self.parse_item_impl(attrs, defaultness) { + Ok(impl_info) => impl_info, + Err(mut recovery_error) => { + // Recovery failed, raise the "expected identifier" error + recovery_error.cancel(); + return Err(err); + } + }; + match impl_info.1 { - // only try to recover if this is implementing a trait for a type ItemKind::Impl(box ImplKind { of_trait: Some(ref trai), ref mut constness, .. }) => { @@ -1030,6 +1039,7 @@ impl<'a> Parser<'a> { ItemKind::Impl { .. } => return Err(err), _ => unreachable!(), } + Ok(impl_info) } -- cgit 1.4.1-3-g733a5