.diff

diff --git a/core/src/main/java/org/jruby/ir/IRBuilder.java b/core/src/main/java/org/jruby/ir/IRBuilder.java
index b27f350233..49aebd9e90 100644
--- a/core/src/main/java/org/jruby/ir/IRBuilder.java
+++ b/core/src/main/java/org/jruby/ir/IRBuilder.java
@@ -630,6 +630,8 @@ public class IRBuilder {
         Variable ret = getValueInTemporaryVariable(values);
         if (valueNode instanceof ArrayNode) {
             buildMultipleAsgn19Assignment(multipleAsgnNode, null, ret);
+        } else if (valueNode instanceof SideEffectFree){
+            buildMultipleAsgn19Assignment(multipleAsgnNode, null, ret);
         } else {
             Variable tmp = createTemporaryVariable();
             addInstr(new ToAryInstr(tmp, ret));
@@ -3156,6 +3158,15 @@ public class IRBuilder {
             for (Node an: masgnPre.children()) {
                 if (values == null) {
                     buildArgsMasgn(an, argsArray, false, -1, -1, i, false);
+                } else if (values.canCopyPropagate()) {
+                    Variable rhsVal = createTemporaryVariable();
+                    // assign first argument to copy of value, rest get nil
+                    if (i == 0) {
+                        addInstr(new CopyInstr(rhsVal, values));
+                    } else {
+                        addInstr(new CopyInstr(rhsVal, new Nil()));
+                    }
+                    assigns.add(new Tuple<>(an, rhsVal));
                 } else {
                     Variable rhsVal = createTemporaryVariable();
                     addInstr(new ReqdArgMultipleAsgnInstr(rhsVal, values, i));