diff --git a/src/cmd/gc/typecheck.c b/src/cmd/gc/typecheck.c
index 0cf11684da..66fc77a973 100644
--- a/src/cmd/gc/typecheck.c
+++ b/src/cmd/gc/typecheck.c
@@ -794,7 +794,7 @@ reswitch:
 		defaultlit(&n->left, T);
 		l = n->left;
 		if(l->op == OTYPE) {
-			if(n->isddd)
+			if(n->isddd || l->type->bound == -100)
 				yyerror("invalid use of ... in type conversion", l);
 			// pick off before type-checking arguments
 			ok |= Erv;
diff --git a/test/ddd1.go b/test/ddd1.go
index a0bc73814f..96a358e1c0 100644
--- a/test/ddd1.go
+++ b/test/ddd1.go
@@ -43,4 +43,5 @@ func bad(args ...int) {
 	var x int
 	_ = unsafe.Pointer(&x...)	// ERROR "[.][.][.]"
 	_ = unsafe.Sizeof(x...)	// ERROR "[.][.][.]"
+	_ = [...]byte("foo") // ERROR "[.][.][.]"
 }