clarify a few things

Author: Orion Gonzalez

compiler/rustc_driver_impl/src/lib.rs

@@ -359,11 +359,7 @@ fn run_compiler(
         // printing some information without compiling, or exiting immediately
         // after parsing, etc.
         let early_exit = || {
-            if let Some(guar) = sess.dcx().has_errors() {
-                Err(guar)
-            } else {
-                Ok(())
-            }
+            if let Some(guar) = sess.dcx().has_errors() { Err(guar) } else { Ok(()) }
         };
 
         // This implements `-Whelp`. It should be handled very early, like
@@ -395,13 +391,16 @@ fn run_compiler(
 
         let linker = compiler.enter(|queries| {
             let early_exit = || early_exit().map(|_| None);
+
+            // Parse the crate root source code (doesn't parse submodules yet)
             queries.parse()?;
 
-            if let Some(ppm) = &sess.opts.pretty {
-                if ppm.needs_ast_map() {
+            // If pretty printing is requested: Figure out the representation, print it and exit
+            if let Some(pp_mode) = sess.opts.pretty {
+                if pp_mode.needs_ast_map() {
                     queries.global_ctxt()?.enter(|tcx| {
                         tcx.ensure().early_lint_checks(());
-                        pretty::print(sess, *ppm, pretty::PrintExtra::NeedsAstMap { tcx });
+                        pretty::print(sess, pp_mode, pretty::PrintExtra::NeedsAstMap { tcx });
                         Ok(())
                     })?;
 
@@ -412,7 +411,7 @@ fn run_compiler(
                     let krate = queries.parse()?;
                     pretty::print(
                         sess,
-                        *ppm,
+                        pp_mode,
                         pretty::PrintExtra::AfterParsing { krate: &*krate.borrow() },
                     );
                 }
@@ -572,11 +571,7 @@ fn handle_explain(early_dcx: &EarlyDiagCtxt, registry: Registry, code: &str, col
 fn show_md_content_with_pager(content: &str, color: ColorConfig) {
     let mut fallback_to_println = false;
     let pager_name = env::var_os("PAGER").unwrap_or_else(|| {
-        if cfg!(windows) {
-            OsString::from("more.com")
-        } else {
-            OsString::from("less")
-        }
+        if cfg!(windows) { OsString::from("more.com") } else { OsString::from("less") }
     });
 
     let mut cmd = Command::new(&pager_name);

compiler/rustc_session/src/config.rs

@@ -2893,6 +2893,7 @@ pub enum PpHirMode {
 }
 
 #[derive(Copy, Clone, PartialEq, Debug)]
+/// Pretty print mode
 pub enum PpMode {
     /// Options that print the source code, i.e.
     /// `-Zunpretty=normal` and `-Zunpretty=expanded`