Properly restore snapshot when failing to recover parsing ternary

Author: clubby789

compiler/rustc_parse/src/parser/diagnostics.rs

@@ -1454,13 +1454,11 @@ impl<'a> Parser<'a> {
                     }
                     Err(err) => {
                         err.cancel();
-                        self.restore_snapshot(snapshot);
                     }
                 };
             }
-        } else {
-            self.restore_snapshot(snapshot);
-        };
+        }
+        self.restore_snapshot(snapshot);
 
         false
     }

tests/ui/parser/ternary_operator.rs

@@ -49,6 +49,13 @@ fn c() { //~ NOTE this function should return `Result` or `Option` to accept `?`
     //~| NOTE in this expansion of desugaring of operator `?`
 }
 
+fn bad() {
+    // regression test for #117208
+    v ? return;
+    //~^ ERROR expected one of
+    //~| NOTE expected one of
+}
+
 fn main() { //~ NOTE this function should return `Result` or `Option` to accept `?`
     let x = 5 > 2 ? { let x = vec![]: Vec<u16>; x } : { false };
     //~^ ERROR Rust has no ternary operator

tests/ui/parser/ternary_operator.stderr

@@ -22,16 +22,22 @@ LL |     let x = 5 > 2 ? f32::MAX : f32::MIN;
    |
    = help: use an `if-else` expression instead
 
+error: expected one of `.`, `;`, `?`, `}`, or an operator, found keyword `return`
+  --> $DIR/ternary_operator.rs:54:9
+   |
+LL |     v ? return;
+   |         ^^^^^^ expected one of `.`, `;`, `?`, `}`, or an operator
+
 error: expected one of `.`, `;`, `?`, `else`, or an operator, found `:`
-  --> $DIR/ternary_operator.rs:53:37
+  --> $DIR/ternary_operator.rs:60:37
    |
 LL |     let x = 5 > 2 ? { let x = vec![]: Vec<u16>; x } : { false };
    |                                     ^ expected one of `.`, `;`, `?`, `else`, or an operator
    |
    = note: type ascription syntax has been removed, see issue #101728 <https://github.com/rust-lang/rust/issues/101728>
 
 error: Rust has no ternary operator
-  --> $DIR/ternary_operator.rs:53:19
+  --> $DIR/ternary_operator.rs:60:19
    |
 LL |     let x = 5 > 2 ? { let x = vec![]: Vec<u16>; x } : { false };
    |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -93,15 +99,15 @@ LL |     let x = 5 > 2 ? f32::MAX : f32::MIN;
    = help: the trait `FromResidual<_>` is not implemented for `()`
 
 error[E0277]: the `?` operator can only be applied to values that implement `Try`
-  --> $DIR/ternary_operator.rs:53:17
+  --> $DIR/ternary_operator.rs:60:17
    |
 LL |     let x = 5 > 2 ? { let x = vec![]: Vec<u16>; x } : { false };
    |                 ^^^ the `?` operator cannot be applied to type `{integer}`
    |
    = help: the trait `Try` is not implemented for `{integer}`
 
 error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
-  --> $DIR/ternary_operator.rs:53:19
+  --> $DIR/ternary_operator.rs:60:19
    |
 LL | fn main() {
    | --------- this function should return `Result` or `Option` to accept `?`
@@ -110,6 +116,6 @@ LL |     let x = 5 > 2 ? { let x = vec![]: Vec<u16>; x } : { false };
    |
    = help: the trait `FromResidual<_>` is not implemented for `()`
 
-error: aborting due to 13 previous errors
+error: aborting due to 14 previous errors
 
 For more information about this error, try `rustc --explain E0277`.