'main': Let aliases be type-cached, and don't run type-checking twice (with slightly different settings) if path expansion returned the input unchanged.

In particular, note that applying all but the last hunk of this diff
would cause «time» in command position to be highlighted as «command»
rather than «reserved».  (This is covered by tests.)

Author: danielshahaf

highlighters/main/main-highlighter.zsh

@@ -152,16 +152,11 @@ _zsh_highlight_main_calculate_fallback() {
 _zsh_highlight_main__type() {
   integer -r aliases_allowed=${2-1}
   integer -r resword_allowed=${3-1}
-  # We won't cache replies of anything that exists as an alias at all, to
-  # ensure the cached value is correct regardless of $aliases_allowed.
-  #
-  # ### We probably _should_ cache them in a cache that's keyed on the value of
-  # ### $aliases_allowed, on the assumption that aliases are the common case.
-  integer may_cache=1
+  readonly cache_key="${1}:$(( aliases_allowed ? 1 : 0)):$((resword_allowed ? 1 : 0))"
 
   # Cache lookup
   if (( $+_zsh_highlight_main__command_type_cache )); then
-    REPLY=$_zsh_highlight_main__command_type_cache[(e)$1]
+    REPLY=$_zsh_highlight_main__command_type_cache[(e)$cache_key]
     if [[ -n "$REPLY" ]]; then
       return
     fi
@@ -173,9 +168,6 @@ _zsh_highlight_main__type() {
   fi
   unset REPLY
   if zmodload -e zsh/parameter; then
-    if (( $+aliases[(e)$1] )); then
-      may_cache=0
-    fi
     if (( aliases_allowed )) && (( $+aliases[(e)$1] )) &&; then
       REPLY=alias
     elif [[ $1 == *.* && -n ${1%.*} ]] && (( $+saliases[(e)${1##*.}] )); then
@@ -217,14 +209,11 @@ _zsh_highlight_main__type() {
     # «$(…)»], which is area that has had some parsing bugs before 5.6
     # (approximately).
     REPLY="${$(:; (( aliases_allowed )) || unalias -- "$1" 2>/dev/null; LC_ALL=C builtin type -w -- "$1" 2>/dev/null)##*: }"
-    if [[ $REPLY == 'alias' ]]; then
-      may_cache=0
-    fi
   fi
 
   # Cache population
-  if (( may_cache )) && (( $+_zsh_highlight_main__command_type_cache )); then
-    _zsh_highlight_main__command_type_cache[(e)$1]=$REPLY
+  if (( $+_zsh_highlight_main__command_type_cache )); then
+    _zsh_highlight_main__command_type_cache[(e)$cache_key]=$REPLY
   fi
   [[ -n $REPLY ]]
   return $?
@@ -627,8 +616,10 @@ _zsh_highlight_main_highlighter_highlight_list()
         continue
       else
         _zsh_highlight_main_highlighter_expand_path $arg
-        _zsh_highlight_main__type "$REPLY" 0 0
-        res="$REPLY"
+        if [[ $arg != $REPLY ]]; then
+          _zsh_highlight_main__type "$REPLY" 0 0
+          res="$REPLY"
+        fi
       fi
     fi