Merge pull request #957 from rhendric/fix/anaphorization

fix bug in anaphorization logic

Author: gkz

lib/ast.js

@@ -1863,10 +1863,11 @@ class exports.Existence extends Node implements Negatable
     compile-node: (o) ->
         node = @it.unwrap! <<< {@front}
         code = [(node.compile o, LEVEL_OP + PREC\==)]
+        if @do-anaphorize
+            o.scope.declare \that Var \that
         if node instanceof Var and not o.scope.check code.join(""), true
             [op, eq] = if @negated then <[ || = ]> else <[ && ! ]>
             if @do-anaphorize
-                o.scope.declare 'that' Var \that
                 [anaph-pre, anaph-post] = if @negated
                     then [["(that = undefined) || "], []]
                     else [[], [" && (that = ", ...code, ", true)"]]

src/ast.ls

@@ -266,3 +266,6 @@ val = do ->
     while existent? and i--
         that
 eq val.join(' '), '5 4 3 2 1'
+
+# Ensure `var that` is declared even if the tested variable exists
+eq 'var a, that, b;\na = 0;\nif ((that = a) != null) {\n  b = that;\n}', LiveScript.compile 'a = 0; b = that if a?' {+bare,-header}