Fix unused results from mem::replace

4 files changed, 8 insertions, 9 deletions

diff --git a/src/librustc_parse/parser/expr.rs b/src/librustc_parse/parser/expr.rs
index 4e3c5fa63de..a04a1b220fe 100644
--- a/src/librustc_parse/parser/expr.rs
+++ b/src/librustc_parse/parser/expr.rs
@@ -547,8 +547,7 @@ impl<'a> Parser<'a> {
                 // Rewind to before attempting to parse the type with generics, to recover
                 // from situations like `x as usize < y` in which we first tried to parse
                 // `usize < y` as a type with generic arguments.
-                let parser_snapshot_after_type = self.clone();
-                mem::replace(self, parser_snapshot_before_type);
+                let parser_snapshot_after_type = mem::replace(self, parser_snapshot_before_type);
 
                 match self.parse_path(PathStyle::Expr) {
                     Ok(path) => {
@@ -560,7 +559,7 @@ impl<'a> Parser<'a> {
                                 // example because `parse_ty_no_plus` returns `Err` on keywords,
                                 // but `parse_path` returns `Ok` on them due to error recovery.
                                 // Return original error and parser state.
-                                mem::replace(self, parser_snapshot_after_type);
+                                *self = parser_snapshot_after_type;
                                 return Err(type_err);
                             }
                         };
@@ -601,7 +600,7 @@ impl<'a> Parser<'a> {
                     Err(mut path_err) => {
                         // Couldn't parse as a path, return original error and parser state.
                         path_err.cancel();
-                        mem::replace(self, parser_snapshot_after_type);
+                        *self = parser_snapshot_after_type;
                         return Err(type_err);
                     }
                 }
diff --git a/src/librustc_parse/parser/generics.rs b/src/librustc_parse/parser/generics.rs
index 3442c5081c1..85e0414369a 100644
--- a/src/librustc_parse/parser/generics.rs
+++ b/src/librustc_parse/parser/generics.rs
@@ -105,7 +105,7 @@ impl<'a> Parser<'a> {
                     }
                     Err(mut err) => {
                         err.cancel();
-                        std::mem::replace(self, snapshot);
+                        *self = snapshot;
                         break;
                     }
                 }
diff --git a/src/librustc_parse/parser/item.rs b/src/librustc_parse/parser/item.rs
index 798eb85f36f..0496b0f3348 100644
--- a/src/librustc_parse/parser/item.rs
+++ b/src/librustc_parse/parser/item.rs
@@ -1650,7 +1650,7 @@ impl<'a> Parser<'a> {
                 // Recover from attempting to parse the argument as a type without pattern.
                 Err(mut err) => {
                     err.cancel();
-                    mem::replace(self, parser_snapshot_before_ty);
+                    *self = parser_snapshot_before_ty;
                     self.recover_arg_parse()?
                 }
             }
diff --git a/src/librustc_parse/parser/stmt.rs b/src/librustc_parse/parser/stmt.rs
index b3764d2d47b..e5d0ab247aa 100644
--- a/src/librustc_parse/parser/stmt.rs
+++ b/src/librustc_parse/parser/stmt.rs
@@ -163,8 +163,8 @@ impl<'a> Parser<'a> {
                 Ok(ty) => (None, Some(ty)),
                 Err(mut err) => {
                     // Rewind to before attempting to parse the type and continue parsing.
-                    let parser_snapshot_after_type = self.clone();
-                    mem::replace(self, parser_snapshot_before_type);
+                    let parser_snapshot_after_type =
+                        mem::replace(self, parser_snapshot_before_type);
                     if let Ok(snip) = self.span_to_snippet(pat.span) {
                         err.span_label(pat.span, format!("while parsing the type for `{}`", snip));
                     }
@@ -201,7 +201,7 @@ impl<'a> Parser<'a> {
                 // Couldn't parse the type nor the initializer, only raise the type error and
                 // return to the parser state before parsing the type as the initializer.
                 // let x: <parse_error>;
-                mem::replace(self, snapshot);
+                *self = snapshot;
                 return Err(ty_err);
             }
             (Err(err), None) => {