Cancel parsing ever made during recovery

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()

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
 }

tests/ui/parser/recover/recover-colon-instead-of-eq-in-local.stderr

@@ -1,11 +1,19 @@
 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 `=`
    |          |
    |          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