Don't highlight prefix redirections as error

Fixes zsh-users/zsh-syntax-highlighting#146

highlighters/main/main-highlighter.zsh

@@ -66,6 +66,7 @@ _zsh_highlight_main_highlighter()
   emulate -L zsh
   setopt localoptions extendedglob bareglobqual
   local start_pos=0 end_pos highlight_glob=true new_expression=true arg style sudo=false sudo_arg=false
+  local redirection=false # true when we've seen a redirection operator before seeing the command word
   typeset -a ZSH_HIGHLIGHT_TOKENS_COMMANDSEPARATOR
   typeset -a ZSH_HIGHLIGHT_TOKENS_PRECOMMANDS
   typeset -a ZSH_HIGHLIGHT_TOKENS_FOLLOWED_BY_COMMANDS
@@ -104,7 +105,7 @@ _zsh_highlight_main_highlighter()
                      ;;
       esac
     fi
-    if $new_expression; then
+    if $new_expression && ! $redirection; then # $arg is the command word
       new_expression=false
      if [[ -n ${(M)ZSH_HIGHLIGHT_TOKENS_PRECOMMANDS:#"$arg"} ]]; then
       style=$ZSH_HIGHLIGHT_STYLES[precommand]
@@ -130,13 +131,20 @@ _zsh_highlight_main_highlighter()
                           style=$ZSH_HIGHLIGHT_STYLES[path]
                         elif [[ $arg[0,1] == $histchars[0,1] || $arg[0,1] == $histchars[2,2] ]]; then
                           style=$ZSH_HIGHLIGHT_STYLES[history-expansion]
+                        elif [[ $arg[1] == '<' || $arg[1] == '>' ]]; then
+                          style=$ZSH_HIGHLIGHT_STYLE[redirection]
+                          redirection=true
                         else
                           style=$ZSH_HIGHLIGHT_STYLES[unknown-token]
                         fi
                         ;;
       esac
      fi
-    else
+    else # $arg is the file target of a prefix redirection, or a non-command word
+      if $redirection; then
+        redirection=false
+        new_expression=true
+      fi
       case $arg in
         '--'*)   style=$ZSH_HIGHLIGHT_STYLES[double-hyphen-option];;
         '-'*)    style=$ZSH_HIGHLIGHT_STYLES[single-hyphen-option];;

highlighters/main/test-data/prefix-redirection.zsh

@@ -0,0 +1,39 @@
+#!/usr/bin/env zsh
+# -------------------------------------------------------------------------------------------------
+# Copyright (c) 2010-2011 zsh-syntax-highlighting contributors
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without modification, are permitted
+# provided that the following conditions are met:
+#
+#  * Redistributions of source code must retain the above copyright notice, this list of conditions
+#    and the following disclaimer.
+#  * Redistributions in binary form must reproduce the above copyright notice, this list of
+#    conditions and the following disclaimer in the documentation and/or other materials provided
+#    with the distribution.
+#  * Neither the name of the zsh-syntax-highlighting contributors nor the names of its contributors
+#    may be used to endorse or promote products derived from this software without specific prior
+#    written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR
+# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+# FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
+# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
+# IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+# OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+# -------------------------------------------------------------------------------------------------
+# -*- mode: zsh; sh-indentation: 2; indent-tabs-mode: nil; sh-basic-offset: 2; -*-
+# vim: ft=zsh sw=2 ts=2 et
+# -------------------------------------------------------------------------------------------------
+
+BUFFER='>/tmp >/tmp sudo echo foo'
+
+expected_region_highlight=(
+  "2  5  $ZSH_HIGHLIGHT_STYLES[path]"       # /tmp
+  "7  11 $ZSH_HIGHLIGHT_STYLES[path]"       # /tmp
+  "13 16 $ZSH_HIGHLIGHT_STYLES[precommand]" # sudo
+  "18 21 $ZSH_HIGHLIGHT_STYLES[builtin]"    # echo
+  "23 25 $ZSH_HIGHLIGHT_STYLES[default]"    # foo
+)