A few more code cleanups

Author: LeSeulArtichaut

compiler/rustc_driver/src/pretty.rs

@@ -391,16 +391,13 @@ pub fn print_after_parsing(
 ) {
     let (src, src_name) = get_source(input, sess);
 
-    let mut out = String::new();
-
-    if let Source(s) = ppm {
+    let out = if let Source(s) = ppm {
         // Silently ignores an identified node.
-        let out = &mut out;
         call_with_pp_support(&s, sess, None, move |annotation| {
             debug!("pretty printing source code {:?}", s);
             let sess = annotation.sess();
             let parse = &sess.parse_sess;
-            *out = pprust::print_crate(
+            pprust::print_crate(
                 sess.source_map(),
                 krate,
                 src_name,
@@ -411,7 +408,7 @@ pub fn print_after_parsing(
             )
         })
     } else {
-        unreachable!();
+        unreachable!()
     };
 
     write_or_print(&out, ofile);
@@ -431,17 +428,14 @@ pub fn print_after_hir_lowering<'tcx>(
 
     let (src, src_name) = get_source(input, tcx.sess);
 
-    let mut out = String::new();
-
-    match ppm {
+    let out = match ppm {
         Source(s) => {
             // Silently ignores an identified node.
-            let out = &mut out;
             call_with_pp_support(&s, tcx.sess, Some(tcx), move |annotation| {
                 debug!("pretty printing source code {:?}", s);
                 let sess = annotation.sess();
                 let parse = &sess.parse_sess;
-                *out = pprust::print_crate(
+                pprust::print_crate(
                     sess.source_map(),
                     krate,
                     src_name,
@@ -453,26 +447,20 @@ pub fn print_after_hir_lowering<'tcx>(
             })
         }
 
-        Hir(s) => {
-            let out = &mut out;
-            call_with_pp_support_hir(&s, tcx, move |annotation, krate| {
-                debug!("pretty printing HIR {:?}", s);
-                let sess = annotation.sess();
-                let sm = sess.source_map();
-                *out = pprust_hir::print_crate(sm, krate, src_name, src, annotation.pp_ann())
-            })
-        }
+        Hir(s) => call_with_pp_support_hir(&s, tcx, move |annotation, krate| {
+            debug!("pretty printing HIR {:?}", s);
+            let sess = annotation.sess();
+            let sm = sess.source_map();
+            pprust_hir::print_crate(sm, krate, src_name, src, annotation.pp_ann())
+        }),
 
-        HirTree => {
-            let out = &mut out;
-            call_with_pp_support_hir(&PpHirMode::Normal, tcx, move |_annotation, krate| {
-                debug!("pretty printing HIR tree");
-                *out = format!("{:#?}", krate);
-            });
-        }
+        HirTree => call_with_pp_support_hir(&PpHirMode::Normal, tcx, move |_annotation, krate| {
+            debug!("pretty printing HIR tree");
+            format!("{:#?}", krate)
+        }),
 
         _ => unreachable!(),
-    }
+    };
 
     write_or_print(&out, ofile);
 }
@@ -491,14 +479,10 @@ fn print_with_analysis(
     tcx.analysis(LOCAL_CRATE)?;
 
     match ppm {
-        Mir | MirCFG => match ppm {
-            Mir => write_mir_pretty(tcx, None, &mut out),
-            MirCFG => write_mir_graphviz(tcx, None, &mut out),
-            _ => unreachable!(),
-        },
+        Mir => write_mir_pretty(tcx, None, &mut out).unwrap(),
+        MirCFG => write_mir_graphviz(tcx, None, &mut out).unwrap(),
         _ => unreachable!(),
     }
-    .unwrap();
 
     let out = std::str::from_utf8(&out).unwrap();
     write_or_print(out, ofile);