Index: org/apache/el/parser/AstValue.java
===================================================================
--- org/apache/el/parser/AstValue.java	(revision 656429)
+++ org/apache/el/parser/AstValue.java	(working copy)
@@ -129,10 +129,15 @@
         Target t = getTarget(ctx);
         ctx.setPropertyResolved(false);
         ELResolver resolver = ctx.getELResolver();
-        resolver.setValue(ctx, t.base, t.property, 
-        		// coerce to the expected type
-        		ELSupport.coerceToType(value, 
-        				resolver.getType(ctx, t.base, t.property)));
+        
+        Class<?> targetClass = resolver.getType(ctx, t.base, t.property);
+        
+        // value is not assignable so coerce to the expected type
+        if ((value == null && targetClass.isPrimitive()) || (value != null && !targetClass.isInstance(value))) {
+            value = ELSupport.coerceToType(value, resolver.getType(ctx, t.base, t.property));
+        }
+
+        resolver.setValue(ctx, t.base, t.property, value);
     }
 
     public MethodInfo getMethodInfo(EvaluationContext ctx, Class[] paramTypes)