Restore aliases via 'builtin' consistently

Aliases were unaliased defensively with 'builtin unalias' before this
script runs, but restored afterwards via a plain 'eval "$aliases"',
which calls 'alias' rather than 'builtin alias'. If the user had
aliased or otherwise overridden 'alias' itself, the script would wipe
out their aliases and then silently fail to restore them.

Fixes #972.

changelog.md

@@ -4,6 +4,11 @@
 - Highlight `&>` `>&|` `>&!` `&>|` and `&>!` as redirection.
   [#942]
 
+- Fixed: aliases were restored via a plain (non-`builtin`) call to `alias`,
+  so if the user had overridden/aliased `alias` itself, restoration could
+  fail silently.
+  [#972]
+
 
 # Changes in 0.8.0
 

zsh-syntax-highlighting.zsh

@@ -579,9 +579,16 @@ if (( $+X_ZSH_HIGHLIGHT_DIRS_BLACKLIST )); then
   unset X_ZSH_HIGHLIGHT_DIRS_BLACKLIST
 fi
 
-# Restore the aliases we unned
-eval "$zsh_highlight__aliases"
-builtin unset zsh_highlight__aliases
+# Restore the aliases we unned.
+#
+# We use 'builtin' here (and not just when capturing them above) in case the
+# 'alias' command has itself been aliased or overridden by the user; see
+# issue #972.
+typeset zsh_highlight__alias
+for zsh_highlight__alias in ${(f)zsh_highlight__aliases}; do
+  eval "builtin $zsh_highlight__alias"
+done
+builtin unset zsh_highlight__aliases zsh_highlight__alias
 
 # Set $?.
 true