cleaned up and optimized fix for #1354 (d91ccd4003)

lib/nodes.js

@@ -1728,22 +1728,21 @@
     In.prototype.children = ['object', 'array'];
     In.prototype.invert = NEGATE;
     In.prototype.compileNode = function(o) {
-      var isArray, obj, splat, _i, _len, _ref2;
-      isArray = this.array instanceof Value && this.array.isArray();
-      if (isArray) {
+      var hasSplat, obj, _i, _len, _ref2;
+      if (this.array instanceof Value && this.array.isArray()) {
         _ref2 = this.array.base.objects;
         for (_i = 0, _len = _ref2.length; _i < _len; _i++) {
           obj = _ref2[_i];
           if (obj instanceof Splat) {
-            splat = obj;
+            hasSplat = true;
+            break;
           }
         }
+        if (!hasSplat) {
+          return this.compileOrTest(o);
+        }
       }
-      if (isArray && !splat) {
-        return this.compileOrTest(o);
-      } else {
-        return this.compileLoopTest(o);
-      }
+      return this.compileLoopTest(o);
     };
     In.prototype.compileOrTest = function(o) {
       var cmp, cnj, i, item, ref, sub, tests, _ref2, _ref3;

src/nodes.coffee

@@ -1349,12 +1349,13 @@ exports.In = class In extends Base
   invert: NEGATE
 
   compileNode: (o) ->
-    isArray = @array instanceof Value and @array.isArray()
-    splat   = obj for obj in @array.base.objects when obj instanceof Splat if isArray
-    if isArray and not splat
-      @compileOrTest o
-    else
-      @compileLoopTest o
+    if @array instanceof Value and @array.isArray()
+      for obj in @array.base.objects when obj instanceof Splat
+        hasSplat = yes
+        break
+      # `compileOrTest` only if we have an array literal with no splats
+      return @compileOrTest o unless hasSplat
+    @compileLoopTest o
 
   compileOrTest: (o) ->
     [sub, ref] = @object.cache o, LEVEL_OP