Rollup merge of #101165 - ldm0:drain_to_iter, r=cjgillot

Use more `into_iter` rather than `drain(..)`

Clearer semantic.

compiler/rustc_errors/src/diagnostic.rs

@@ -974,12 +974,12 @@ impl Diagnostic {
     fn sub_with_highlights<M: Into<SubdiagnosticMessage>>(
         &mut self,
         level: Level,
-        mut message: Vec<(M, Style)>,
+        message: Vec<(M, Style)>,
         span: MultiSpan,
         render_span: Option<MultiSpan>,
     ) {
         let message = message
-            .drain(..)
+            .into_iter()
             .map(|m| (self.subdiagnostic_message_to_diagnostic_message(m.0), m.1))
             .collect();
         let sub = SubDiagnostic { level, message, span, render_span };

compiler/rustc_errors/src/translation.rs

@@ -21,7 +21,7 @@ pub trait Translate {
     /// Typically performed once for each diagnostic at the start of `emit_diagnostic` and then
     /// passed around as a reference thereafter.
     fn to_fluent_args<'arg>(&self, args: &[DiagnosticArg<'arg>]) -> FluentArgs<'arg> {
-        FromIterator::from_iter(args.to_vec().drain(..))
+        FromIterator::from_iter(args.iter().cloned())
     }
 
     /// Convert `DiagnosticMessage`s to a string, performing translation if necessary.