diff --git a/src/cmd/gc/go.h b/src/cmd/gc/go.h
index dc6de63c6c..775a4cca12 100644
--- a/src/cmd/gc/go.h
+++ b/src/cmd/gc/go.h
@@ -156,6 +156,7 @@ struct	Type
 	uchar	embedded;	// TFIELD embedded type
 	uchar	siggen;
 	uchar	funarg;
+	uchar	copyany;
 
 	// TFUNCT
 	uchar	thistuple;
diff --git a/src/cmd/gc/subr.c b/src/cmd/gc/subr.c
index cd2fc4d2d5..5638df4b7d 100644
--- a/src/cmd/gc/subr.c
+++ b/src/cmd/gc/subr.c
@@ -1779,6 +1779,8 @@ loop:
 		goto loop;
 
 	case TANY:
+		if(!st->copyany)
+			return 0;
 		*stp = t;
 		break;
 
@@ -1841,6 +1843,11 @@ deep(Type *t)
 		nt = t;	// share from here down
 		break;
 
+	case TANY:
+		nt = shallow(t);
+		nt->copyany = 1;
+		break;
+
 	case TPTR32:
 	case TPTR64:
 	case TCHAN: