diff --git a/src/cmd/gc/subr.c b/src/cmd/gc/subr.c
index 4f646fbc1e..9dfb445c63 100644
--- a/src/cmd/gc/subr.c
+++ b/src/cmd/gc/subr.c
@@ -333,7 +333,7 @@ algtype(Type *t)
 		a = ASTRING;	// string
 	else if(isnilinter(t))
 		a = ANILINTER;	// nil interface
-	else if(t->etype == TINTER)
+	else if(t->etype == TINTER || t->etype == TFORWINTER)
 		a = AINTER;	// interface
 	else
 		a = ANOEQ;	// just bytes, but no hash/eq