From 38fd5a9acfd4893e572f20591ffea4f3cfd2fc2e Mon Sep 17 00:00:00 2001
From: Esteban Küber <esteban@kuber.com.ar>
Date: Wed, 28 Dec 2022 18:26:59 -0800
Subject: Account for ADT bodies and struct expressions

---
 compiler/rustc_parse/src/parser/expr.rs |  1 +
 compiler/rustc_parse/src/parser/item.rs | 31 +++++++++++++++++++++++++++++--
 2 files changed, 30 insertions(+), 2 deletions(-)

(limited to 'compiler/rustc_parse/src/parser')

diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs
index 6a115088eca..1fc1ffd6cb6 100644
--- a/compiler/rustc_parse/src/parser/expr.rs
+++ b/compiler/rustc_parse/src/parser/expr.rs
@@ -3039,6 +3039,7 @@ impl<'a> Parser<'a> {
     /// Parses `ident (COLON expr)?`.
     fn parse_expr_field(&mut self) -> PResult<'a, ExprField> {
         let attrs = self.parse_outer_attributes()?;
+        self.recover_diff_marker();
         self.collect_tokens_trailing_token(attrs, ForceCollect::No, |this, attrs| {
             let lo = this.token.span;
 
diff --git a/compiler/rustc_parse/src/parser/item.rs b/compiler/rustc_parse/src/parser/item.rs
index 51de3d40d91..b996ce0a155 100644
--- a/compiler/rustc_parse/src/parser/item.rs
+++ b/compiler/rustc_parse/src/parser/item.rs
@@ -1385,7 +1385,9 @@ impl<'a> Parser<'a> {
     }
 
     fn parse_enum_variant(&mut self) -> PResult<'a, Option<Variant>> {
+        self.recover_diff_marker();
         let variant_attrs = self.parse_outer_attributes()?;
+        self.recover_diff_marker();
         self.collect_tokens_trailing_token(
             variant_attrs,
             ForceCollect::No,
@@ -1579,9 +1581,32 @@ impl<'a> Parser<'a> {
         self.parse_paren_comma_seq(|p| {
             let attrs = p.parse_outer_attributes()?;
             p.collect_tokens_trailing_token(attrs, ForceCollect::No, |p, attrs| {
+                let mut snapshot = None;
+                if p.is_diff_marker(&TokenKind::BinOp(token::Shl), &TokenKind::Lt) {
+                    // Account for `<<<<<<<` diff markers. We can't proactivelly error here because
+                    // that can be a valid type start, so we snapshot and reparse only we've
+                    // encountered another parse error.
+                    snapshot = Some(p.create_snapshot_for_diagnostic());
+                }
                 let lo = p.token.span;
-                let vis = p.parse_visibility(FollowedByType::Yes)?;
-                let ty = p.parse_ty()?;
+                let vis = match p.parse_visibility(FollowedByType::Yes) {
+                    Ok(vis) => vis,
+                    Err(err) => {
+                        if let Some(ref mut snapshot) = snapshot {
+                            snapshot.recover_diff_marker();
+                        }
+                        return Err(err);
+                    }
+                };
+                let ty = match p.parse_ty() {
+                    Ok(ty) => ty,
+                    Err(err) => {
+                        if let Some(ref mut snapshot) = snapshot {
+                            snapshot.recover_diff_marker();
+                        }
+                        return Err(err);
+                    }
+                };
 
                 Ok((
                     FieldDef {
@@ -1602,7 +1627,9 @@ impl<'a> Parser<'a> {
 
     /// Parses an element of a struct declaration.
     fn parse_field_def(&mut self, adt_ty: &str) -> PResult<'a, FieldDef> {
+        self.recover_diff_marker();
         let attrs = self.parse_outer_attributes()?;
+        self.recover_diff_marker();
         self.collect_tokens_trailing_token(attrs, ForceCollect::No, |this, attrs| {
             let lo = this.token.span;
             let vis = this.parse_visibility(FollowedByType::No)?;
-- 
cgit 1.4.1-3-g733a5