Rollup merge of #62249 - czipperz:use-mem-take-instead-of-replace-default, r=dtolnay,Centril

Use mem::take instead of mem::replace with default

3 files changed, 5 insertions, 7 deletions

diff --git a/src/librustc_codegen_ssa/back/command.rs b/src/librustc_codegen_ssa/back/command.rs
index 78570cce57d..d610805b5bb 100644
--- a/src/librustc_codegen_ssa/back/command.rs
+++ b/src/librustc_codegen_ssa/back/command.rs
@@ -110,7 +110,7 @@ impl Command {
     }
 
     pub fn take_args(&mut self) -> Vec<OsString> {
-        mem::replace(&mut self.args, Vec::new())
+        mem::take(&mut self.args)
     }
 
     /// Returns a `true` if we're pretty sure that this'll blow OS spawn limits,
diff --git a/src/librustc_codegen_ssa/back/write.rs b/src/librustc_codegen_ssa/back/write.rs
index 6364843d772..fbf57701c5a 100644
--- a/src/librustc_codegen_ssa/back/write.rs
+++ b/src/librustc_codegen_ssa/back/write.rs
@@ -1345,12 +1345,9 @@ fn start_executing_work<B: ExtraBackendMethods>(
                     assert!(!started_lto);
                     started_lto = true;
 
-                    let needs_fat_lto =
-                        mem::replace(&mut needs_fat_lto, Vec::new());
-                    let needs_thin_lto =
-                        mem::replace(&mut needs_thin_lto, Vec::new());
-                    let import_only_modules =
-                        mem::replace(&mut lto_import_only_modules, Vec::new());
+                    let needs_fat_lto = mem::take(&mut needs_fat_lto);
+                    let needs_thin_lto = mem::take(&mut needs_thin_lto);
+                    let import_only_modules = mem::take(&mut lto_import_only_modules);
 
                     for (work, cost) in generate_lto_work(&cgcx, needs_fat_lto,
                                                           needs_thin_lto, import_only_modules) {
diff --git a/src/librustc_codegen_ssa/lib.rs b/src/librustc_codegen_ssa/lib.rs
index b76f098773f..3c1ab600040 100644
--- a/src/librustc_codegen_ssa/lib.rs
+++ b/src/librustc_codegen_ssa/lib.rs
@@ -10,6 +10,7 @@
 #![feature(in_band_lifetimes)]
 #![feature(nll)]
 #![feature(trusted_len)]
+#![feature(mem_take)]
 #![allow(unused_attributes)]
 #![allow(dead_code)]
 #![deny(rust_2018_idioms)]