Inline and remove HumanEmitter::stderr.

Because `HumanEmitter::new` is enough, in conjunction with the (renamed)
`stderr_destination` function.

Author: nnethercote

src/parse/session.rs

@@ -3,7 +3,7 @@ use std::path::Path;
 use std::sync::atomic::{AtomicBool, Ordering};
 
 use rustc_data_structures::sync::{IntoDynSyncSend, Lrc};
-use rustc_errors::emitter::{DynEmitter, Emitter, HumanEmitter};
+use rustc_errors::emitter::{stderr_destination, DynEmitter, Emitter, HumanEmitter};
 use rustc_errors::translation::Translate;
 use rustc_errors::{
     ColorConfig, Diag, DiagCtxt, DiagInner, ErrorGuaranteed, Level as DiagnosticLevel,
@@ -152,7 +152,10 @@ fn default_dcx(
             rustc_driver::DEFAULT_LOCALE_RESOURCES.to_vec(),
             false,
         );
-        Box::new(HumanEmitter::stderr(emit_color, fallback_bundle).sm(Some(source_map.clone())))
+        Box::new(
+            HumanEmitter::new(stderr_destination(emit_color), fallback_bundle)
+                .sm(Some(source_map.clone())),
+        )
     };
     DiagCtxt::new(Box::new(SilentOnIgnoredFilesEmitter {
         has_non_ignorable_parser_errors: false,