use for (idx, item) in iter.enumerate() instead of manually counting loop iterations by variables

Author: matthiaskrgr

src/librustc/ty/layout.rs

@@ -1382,10 +1382,8 @@ impl<'tcx> LayoutCx<'tcx, TyCtxt<'tcx>> {
 
         // Write down the order of our locals that will be promoted to the prefix.
         {
-            let mut idx = 0u32;
-            for local in ineligible_locals.iter() {
-                assignments[local] = Ineligible(Some(idx));
-                idx += 1;
+            for (idx, local) in ineligible_locals.iter().enumerate() {
+                assignments[local] = Ineligible(Some(idx as u32));
             }
         }
         debug!("generator saved local assignments: {:?}", assignments);

src/librustc_errors/emitter.rs

@@ -1574,9 +1574,9 @@ impl EmitterWriter {
 
             let line_start = sm.lookup_char_pos(parts[0].span.lo()).line;
             draw_col_separator_no_space(&mut buffer, 1, max_line_num_len + 1);
-            let mut line_pos = 0;
             let mut lines = complete.lines();
-            for line in lines.by_ref().take(MAX_SUGGESTION_HIGHLIGHT_LINES) {
+            for (line_pos, line) in lines.by_ref().take(MAX_SUGGESTION_HIGHLIGHT_LINES).enumerate()
+            {
                 // Print the span column to avoid confusion
                 buffer.puts(
                     row_num,
@@ -1587,7 +1587,6 @@ impl EmitterWriter {
                 // print the suggestion
                 draw_col_separator(&mut buffer, row_num, max_line_num_len + 1);
                 buffer.append(row_num, line, Style::NoStyle);
-                line_pos += 1;
                 row_num += 1;
             }