main: Only expand aliases in command position

highlighters/main/main-highlighter.zsh

@@ -498,6 +498,7 @@ _zsh_highlight_main_highlighter_highlight_list()
       continue
     fi
 
+    if [[ $this_word == *:start:* ]] && ! (( in_redirection )); then
       # Expand aliases.
       # TODO: this should be done iteratively, e.g., 'alias x=y y=z z=w\n x'
       #       And then the entire 'alias' branch of the 'case' statement should
@@ -518,6 +519,7 @@ _zsh_highlight_main_highlighter_highlight_list()
           arg=$reply[1]
         }
       fi
+    fi
 
     # Analyse the current word.
     if _zsh_highlight_main__is_redirection $arg ; then