diff --git a/src/cmd/gc/typecheck.c b/src/cmd/gc/typecheck.c
index 8a3b486bd6..1abdb83c58 100644
--- a/src/cmd/gc/typecheck.c
+++ b/src/cmd/gc/typecheck.c
@@ -1346,7 +1346,7 @@ reswitch:
 			goto error;
 
 		// Unpack multiple-return result before type-checking.
-		if(istype(t, TSTRUCT)) {
+		if(istype(t, TSTRUCT) && t->funarg) {
 			t = t->type;
 			if(istype(t, TFIELD))
 				t = t->type;
diff --git a/test/fixedbugs/issue9634.go b/test/fixedbugs/issue9634.go
new file mode 100644
index 0000000000..2d5aae4a30
--- /dev/null
+++ b/test/fixedbugs/issue9634.go
@@ -0,0 +1,18 @@
+// errorcheck
+
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Issue 9634: Structs are incorrectly unpacked when passed as an argument
+// to append.
+
+package main
+
+func main() {
+	s := struct{
+		t []int
+		u int
+	}{}
+	_ = append(s, 0) // ERROR "must be a slice|must be slice"
+}