diff --git a/lib/filecheck/src/checker.rs b/lib/filecheck/src/checker.rs
index d48c0ba3e4..bad8e4774e 100644
--- a/lib/filecheck/src/checker.rs
+++ b/lib/filecheck/src/checker.rs
@@ -132,8 +132,7 @@ impl CheckerBuilder {
     pub fn finish(&mut self) -> Checker {
         // Move directives into the new checker, leaving `self.directives` empty and ready for
         // building a new checker.
-        let mut new_directives = Vec::new();
-        mem::swap(&mut new_directives, &mut self.directives);
+        let new_directives = mem::replace(&mut self.directives, Vec::new());
         Checker::new(new_directives)
     }
 }
diff --git a/lib/frontend/src/ssa.rs b/lib/frontend/src/ssa.rs
index 13c3dbbfc3..60c5663866 100644
--- a/lib/frontend/src/ssa.rs
+++ b/lib/frontend/src/ssa.rs
@@ -370,8 +370,7 @@ where
                 debug_assert!(!data.sealed);
                 // Extract the undef_variables data from the block so that we
                 // can iterate over it without borrowing the whole builder.
-                let mut undef_variables = Vec::new();
-                mem::swap(&mut data.undef_variables, &mut undef_variables);
+                let undef_variables = mem::replace(&mut data.undef_variables, Vec::new());
                 (undef_variables, data.ebb)
             }
         };
@@ -415,8 +414,7 @@ where
         // Iterate over the predecessors. To avoid borrowing `self` for the whole loop,
         // temporarily detach the predecessors list and replace it with an empty list.
         // `use_var`'s traversal won't revisit these predecesors.
-        let mut preds = Vec::new();
-        mem::swap(&mut preds, &mut self.predecessors_mut(dest_ebb));
+        let mut preds = mem::replace(self.predecessors_mut(dest_ebb), Vec::new());
         for &(pred, _) in &preds {
             // For each predecessor, we query what is the local SSA value corresponding
             // to var and we put it as an argument of the branch instruction.