patch.diff

diff --git a/core/src/main/java/org/jruby/ast/SymbolNode.java b/core/src/main/java/org/jruby/ast/SymbolNode.java
index 747f28a..aa4d811 100644
--- a/core/src/main/java/org/jruby/ast/SymbolNode.java
+++ b/core/src/main/java/org/jruby/ast/SymbolNode.java
@@ -48,6 +48,7 @@ import org.jruby.runtime.Block;
 import org.jruby.runtime.ThreadContext;
 import org.jruby.runtime.builtin.IRubyObject;
 import org.jruby.util.ByteList;
+import org.jruby.util.StringSupport;

 /**
  * Represents a symbol (:symbol_name).
@@ -67,9 +68,10 @@ public class SymbolNode extends Node implements ILiteralNode, INameNode {
     public SymbolNode(ISourcePosition position, ByteList value) {
         super(position);
         this.name = value.toString().intern();
+
         // FIXME: A full scan to determine whether we should back off to US-ASCII.  Lexer should just do this properly.
-        if (value.lengthEnc() == value.length()) {
-            this.encoding = USASCIIEncoding.INSTANCE;
+        if (value.getEncoding().isAsciiCompatible() && StringSupport.codeRangeScan(value.getEncoding(), value) == StringSupport.CR_7BIT) {
+            encoding = USASCIIEncoding.INSTANCE;
         } else {
             this.encoding = value.getEncoding();
         }