Index: method.h
===================================================================
--- method.h	(revision 26395)
+++ method.h	(working copy)
@@ -49,6 +49,11 @@
     int argc;
 } rb_method_cfunc_t;
 
+typedef struct rb_method_attr_struct {
+    ID id;
+    VALUE location;
+} rb_method_attr_t;
+
 typedef struct rb_iseq_struct rb_iseq_t;
 
 typedef struct rb_method_definition_struct {
@@ -57,7 +62,7 @@
     union {
 	rb_iseq_t *iseq;            /* should be mark */
 	rb_method_cfunc_t cfunc;
-	ID attr_id;
+	rb_method_attr_t attr;
 	VALUE proc;                 /* should be mark */
 	enum method_optimized_type {
 	    OPTIMIZED_METHOD_TYPE_SEND,
Index: vm_eval.c
===================================================================
--- vm_eval.c	(revision 26395)
+++ vm_eval.c	(working copy)
@@ -89,14 +89,14 @@
 	if (argc != 1) {
 	    rb_raise(rb_eArgError, "wrong number of arguments (%d for 1)", argc);
 	}
-	val = rb_ivar_set(recv, def->body.attr_id, argv[0]);
+	val = rb_ivar_set(recv, def->body.attr.id, argv[0]);
 	break;
       }
       case VM_METHOD_TYPE_IVAR: {
 	if (argc != 0) {
 	    rb_raise(rb_eArgError, "wrong number of arguments (%d for 0)", argc);
 	}
-	val = rb_attr_get(recv, def->body.attr_id);
+	val = rb_attr_get(recv, def->body.attr.id);
 	break;
       }
       case VM_METHOD_TYPE_BMETHOD: {
Index: proc.c
===================================================================
--- proc.c	(revision 26395)
+++ proc.c	(working copy)
@@ -1634,15 +1634,18 @@
     return rb_mod_method_arity(CLASS_OF(obj), id);
 }
 
-rb_iseq_t *
-rb_method_get_iseq(VALUE method)
+static inline rb_method_definition_t *
+method_get_def(VALUE method)
 {
     struct METHOD *data;
-    rb_method_definition_t *def;
 
     TypedData_Get_Struct(method, struct METHOD, &method_data_type, data);
-    def = data->me.def;
+    return data->me.def;
+}
 
+static rb_iseq_t *
+method_get_iseq(rb_method_definition_t *def)
+{
     switch (def->type) {
       case VM_METHOD_TYPE_BMETHOD:
 	return get_proc_iseq(def->body.proc, 0);
@@ -1653,6 +1656,12 @@
     }
 }
 
+rb_iseq_t *
+rb_method_get_iseq(VALUE method)
+{
+    return method_get_iseq(method_get_def(method));
+}
+
 /*
  * call-seq:
  *    meth.source_location  => [String, Fixnum]
@@ -1664,7 +1673,13 @@
 VALUE
 rb_method_location(VALUE method)
 {
-    return iseq_location(rb_method_get_iseq(method));
+    rb_method_definition_t *def = method_get_def(method);
+    if (def->type == VM_METHOD_TYPE_ATTRSET || def->type == VM_METHOD_TYPE_IVAR) {
+	if (!def->body.attr.location)
+	    return Qnil;
+	return rb_ary_dup(def->body.attr.location);
+    }
+    return iseq_location(method_get_iseq(def));
 }
 
 /*
Index: vm_method.c
===================================================================
--- vm_method.c	(revision 26395)
+++ vm_method.c	(working copy)
@@ -260,6 +260,9 @@
 rb_method_entry_t *
 rb_add_method(VALUE klass, ID mid, rb_method_type_t type, void *opts, rb_method_flag_t noex)
 {
+    rb_thread_t *th;
+    rb_control_frame_t *cfp;
+    int line;
     rb_method_entry_t *me = rb_add_method_def(klass, mid, type, 0, noex);
     rb_method_definition_t *def = ALLOC(rb_method_definition_t);
     me->def = def;
@@ -275,7 +278,15 @@
 	break;
       case VM_METHOD_TYPE_ATTRSET:
       case VM_METHOD_TYPE_IVAR:
-	def->body.attr_id = (ID)opts;
+	def->body.attr.id = (ID)opts;
+	th = GET_THREAD();
+	cfp = rb_vm_get_ruby_level_next_cfp(th, th->cfp);
+	if (cfp && (line = rb_vm_get_sourceline(cfp))) {
+	    VALUE location = rb_ary_new3(2, cfp->iseq->filename, INT2FIX(line));
+	    def->body.attr.location = rb_ary_freeze(location);
+	} else {
+	    def->body.attr.location = Qfalse;
+	}
 	break;
       case VM_METHOD_TYPE_BMETHOD:
 	def->body.proc = (VALUE)opts;
@@ -838,7 +849,7 @@
 	  d1->body.cfunc.argc == d2->body.cfunc.argc;
       case VM_METHOD_TYPE_ATTRSET:
       case VM_METHOD_TYPE_IVAR:
-	return d1->body.attr_id == d2->body.attr_id;
+	return d1->body.attr.id == d2->body.attr.id;
       case VM_METHOD_TYPE_BMETHOD:
 	return RTEST(rb_equal(d1->body.proc, d2->body.proc));
       case VM_METHOD_TYPE_MISSING:
Index: gc.c
===================================================================
--- gc.c	(revision 26395)
+++ gc.c	(working copy)
@@ -1423,6 +1423,10 @@
       case VM_METHOD_TYPE_BMETHOD:
 	gc_mark(objspace, def->body.proc, lev);
 	break;
+      case VM_METHOD_TYPE_ATTRSET:
+      case VM_METHOD_TYPE_IVAR:
+	gc_mark(objspace, def->body.attr.location, lev);
+	break;
       default:
 	break; /* ignore */
     }
Index: vm_insnhelper.c
===================================================================
--- vm_insnhelper.c	(revision 26395)
+++ vm_insnhelper.c	(working copy)
@@ -505,7 +505,7 @@
 		if (num != 1) {
 		    rb_raise(rb_eArgError, "wrong number of arguments (%d for 1)", num);
 		}
-		val = rb_ivar_set(recv, me->def->body.attr_id, *(cfp->sp - 1));
+		val = rb_ivar_set(recv, me->def->body.attr.id, *(cfp->sp - 1));
 		cfp->sp -= 2;
 		break;
 	      }
@@ -513,7 +513,7 @@
 		if (num != 0) {
 		    rb_raise(rb_eArgError, "wrong number of arguments (%d for 0)", num);
 		}
-		val = rb_attr_get(recv, me->def->body.attr_id);
+		val = rb_attr_get(recv, me->def->body.attr.id);
 		cfp->sp -= 1;
 		break;
 	      }