From 8e45d0fe495358bbb2415f1c0eec92d28b50c743 Mon Sep 17 00:00:00 2001
From: clubby789 <jamie@hill-daniel.co.uk>
Date: Wed, 6 Mar 2024 21:59:03 +0000
Subject: [PATCH] Cancel parsing ever made during recovery

---
 compiler/rustc_parse/src/parser/stmt.rs          | 16 ++++++++++------
 .../recover-colon-instead-of-eq-in-local.rs      |  7 +++++++
 .../recover-colon-instead-of-eq-in-local.stderr  | 12 ++++++++++--
 3 files changed, 27 insertions(+), 8 deletions(-)

diff --git a/compiler/rustc_parse/src/parser/stmt.rs b/compiler/rustc_parse/src/parser/stmt.rs
index 54854cd2da995..ea9c78ca34c08 100644
--- a/compiler/rustc_parse/src/parser/stmt.rs
+++ b/compiler/rustc_parse/src/parser/stmt.rs
@@ -787,13 +787,17 @@ impl<'a> Parser<'a> {
                             let suggest_eq = if self.token.kind == token::Dot
                                 && let _ = self.bump()
                                 && let mut snapshot = self.create_snapshot_for_diagnostic()
-                                && let Ok(_) = snapshot.parse_dot_suffix_expr(
-                                    colon_sp,
-                                    self.mk_expr_err(
+                                && let Ok(_) = snapshot
+                                    .parse_dot_suffix_expr(
                                         colon_sp,
-                                        self.dcx().delayed_bug("error during `:` -> `=` recovery"),
-                                    ),
-                                ) {
+                                        self.mk_expr_err(
+                                            colon_sp,
+                                            self.dcx()
+                                                .delayed_bug("error during `:` -> `=` recovery"),
+                                        ),
+                                    )
+                                    .map_err(Diag::cancel)
+                            {
                                 true
                             } else if let Some(op) = self.check_assoc_op()
                                 && op.node.can_continue_expr_unambiguously()
diff --git a/tests/ui/parser/recover/recover-colon-instead-of-eq-in-local.rs b/tests/ui/parser/recover/recover-colon-instead-of-eq-in-local.rs
index ed4de58cd23ce..521eb6a818b0c 100644
--- a/tests/ui/parser/recover/recover-colon-instead-of-eq-in-local.rs
+++ b/tests/ui/parser/recover/recover-colon-instead-of-eq-in-local.rs
@@ -1,3 +1,10 @@
+#![allow(unused)]
+
+fn test_122112() {
+    // Make sure we don't ICE if parsing in recovery fails
+    let _: std::env::temp_dir().join(&self, push: Box<usize>);  //~ ERROR expected one of
+}
+
 fn main() {
     let _: std::env::temp_dir().join("foo"); //~ ERROR expected one of
 }
diff --git a/tests/ui/parser/recover/recover-colon-instead-of-eq-in-local.stderr b/tests/ui/parser/recover/recover-colon-instead-of-eq-in-local.stderr
index d03f3ae02830b..15c27bb9451b6 100644
--- a/tests/ui/parser/recover/recover-colon-instead-of-eq-in-local.stderr
+++ b/tests/ui/parser/recover/recover-colon-instead-of-eq-in-local.stderr
@@ -1,5 +1,13 @@
 error: expected one of `!`, `+`, `->`, `::`, `;`, or `=`, found `.`
-  --> $DIR/recover-colon-instead-of-eq-in-local.rs:2:32
+  --> $DIR/recover-colon-instead-of-eq-in-local.rs:5:32
+   |
+LL |     let _: std::env::temp_dir().join(&self, push: Box<usize>);
+   |          -                     ^ expected one of `!`, `+`, `->`, `::`, `;`, or `=`
+   |          |
+   |          while parsing the type for `_`
+
+error: expected one of `!`, `+`, `->`, `::`, `;`, or `=`, found `.`
+  --> $DIR/recover-colon-instead-of-eq-in-local.rs:9:32
    |
 LL |     let _: std::env::temp_dir().join("foo");
    |          -                     ^ expected one of `!`, `+`, `->`, `::`, `;`, or `=`
@@ -7,5 +15,5 @@ LL |     let _: std::env::temp_dir().join("foo");
    |          while parsing the type for `_`
    |          help: use `=` if you meant to assign
 
-error: aborting due to 1 previous error
+error: aborting due to 2 previous errors