Add test based on jashkenas#1349

Author: Zdenko Vujasinovic

lib/coffee-script/nodes.js

@@ -1827,7 +1827,15 @@ exports.Splat = class Splat extends Base
     if not (@name instanceof Value) or
         (not (@name.base instanceof Parens) and @propHasSoak())
       @name = new Value new Parens @name
-    @name.compileToFragments o
+      # We need to replace `void 0` with `[]` in compiled fragments.
+      # Example: [a?.b...]
+      # slice.call((typeof a !== "undefined" && a !== null ? a.b : []));
+      fragments = @name.compileToFragments o
+      for fragment, ix in fragments
+        fragments[ix].code = "[]" if fragment.code == "void 0" and fragment.type == "If"
+      fragments
+    else
+      @name.compileToFragments o
 
   unwrap: -> @name
 

src/nodes.coffee

@@ -72,6 +72,13 @@ test "#4260: splat after existential operator soak", ->
   arrayEq [a?.b...], [3]
   arrayEq [c?.b...], []
 
+test "#1349: trailing if after splat", ->
+  a = [3]
+  b = yes
+  c = null
+  arrayEq [a if b...], [3]
+  arrayEq [a if c...], []
+
 test "#1274: `[] = a()` compiles to `false` instead of `a()`", ->
   a = false
   fn = -> a = true