Fix overflow

helix-term/src/ui/editor.rs

@@ -129,7 +129,7 @@ impl EditorView {
             })],
         };
         let mut spans = Vec::new();
-        let mut visual_x = 0;
+        let mut visual_x = 0u16;
         let mut line = 0u16;
         let tab_width = doc.tab_width();
 
@@ -185,7 +185,7 @@ impl EditorView {
                                 break 'outer;
                             }
                         } else if grapheme == "\t" {
-                            visual_x += (tab_width as u16);
+                            visual_x = visual_x.saturating_add(tab_width as u16);
                         } else {
                             let out_of_bounds = visual_x < view.first_col as u16
                                 || visual_x >= viewport.width + view.first_col as u16;
@@ -197,7 +197,7 @@ impl EditorView {
 
                             if out_of_bounds {
                                 // if we're offscreen just keep going until we hit a new line
-                                visual_x += width;
+                                visual_x = visual_x.saturating_add(width);
                                 continue;
                             }