splice literals should evaluate to their right hand side, like any other type of assignment.

lib/nodes.js

@@ -1208,7 +1208,7 @@
       return new Op(this.context.slice(0, -1), left, new Assign(rite, this.value, '=')).compile(o);
     };
     Assign.prototype.compileSplice = function(o) {
-      var exclusive, from, fromDecl, fromRef, name, to, val, _ref, _ref2;
+      var code, exclusive, from, fromDecl, fromRef, name, to, valDef, valRef, _ref, _ref2, _ref3;
       _ref = this.variable.properties.pop().range, from = _ref.from, to = _ref.to, exclusive = _ref.exclusive;
       name = this.variable.compile(o);
       _ref2 = (from != null ? from.cache(o, LEVEL_OP) : void 0) || ['0', '0'], fromDecl = _ref2[0], fromRef = _ref2[1];
@@ -1227,8 +1227,13 @@
       } else {
         to = "9e9";
       }
-      val = this.value.compile(o);
-      return "[].splice.apply(" + name + ", [" + fromDecl + ", " + to + "].concat(" + val + "))";
+      _ref3 = this.value.cache(o, LEVEL_LIST), valDef = _ref3[0], valRef = _ref3[1];
+      code = "[].splice.apply(" + name + ", [" + fromDecl + ", " + to + "].concat(" + valDef + ")), " + valRef;
+      if (o.level > LEVEL_TOP) {
+        return "(" + code + ")";
+      } else {
+        return code;
+      }
     };
     return Assign;
   })();

src/nodes.coffee

@@ -983,8 +983,9 @@ exports.Assign = class Assign extends Base
         to += ' + 1' unless exclusive
     else
       to = "9e9"
-    val = @value.compile(o)
-    "[].splice.apply(#{name}, [#{fromDecl}, #{to}].concat(#{val}))"
+    [valDef, valRef] = @value.cache o, LEVEL_LIST
+    code = "[].splice.apply(#{name}, [#{fromDecl}, #{to}].concat(#{valDef})), #{valRef}"
+    if o.level > LEVEL_TOP then "(#{code})" else code
 
 #### Code
 

test/ranges_slices_and_splices.coffee

@@ -175,3 +175,12 @@ test "splicing to the end, against a one-time function", ->
   fn()[0..] = 1
 
   arrayEq ary, [1]
+
+test "the return value of a splice literal should be the RHS", ->
+  ary = [0, 0, 0]
+  eq (ary[0..1] = 2), 2
+
+  ary = [0, 0, 0]
+  eq (ary[0..] = 3), 3
+
+  arrayEq [ary[0..0] = 0], [0]