1 files changed, 43 insertions, 0 deletions
diff --git a/src/go/types/object_test.go b/src/go/types/object_test.go
new file mode 100644
index 0000000000..16d7d5c723
--- /dev/null
+++ b/src/go/types/object_test.go
@@ -0,0 +1,43 @@
+// Copyright 2016 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.
+
+package types
+
+import "testing"
+
+func TestIsAlias(t *testing.T) {
+	check := func(obj *TypeName, want bool) {
+		if got := obj.IsAlias(); got != want {
+			t.Errorf("%v: got IsAlias = %v; want %v", obj, got, want)
+		}
+	}
+
+	// predeclared types
+	for _, name := range Universe.Names() {
+		if obj, _ := Universe.Lookup(name).(*TypeName); obj != nil {
+			check(obj, name == "byte" || name == "rune")
+		}
+	}
+
+	// various other types
+	pkg := NewPackage("p", "p")
+	t1 := NewTypeName(0, pkg, "t1", nil)
+	n1 := NewNamed(t1, new(Struct), nil)
+	for _, test := range []struct {
+		name  *TypeName
+		alias bool
+	}{
+		{NewTypeName(0, nil, "t0", nil), false}, // no type yet
+		{NewTypeName(0, pkg, "t0", nil), false}, // no type yet
+		{t1, false},                             // type name refers to named type and vice versa
+		{NewTypeName(0, nil, "t2", new(Interface)), true}, // type name refers to unnamed type
+		{NewTypeName(0, pkg, "t3", n1), true},             // type name refers to named type with different type name
+		{NewTypeName(0, nil, "t4", Typ[Int32]), true},     // type name refers to basic type with different name
+		{NewTypeName(0, nil, "int32", Typ[Int32]), false}, // type name refers to basic type with same name
+		{NewTypeName(0, pkg, "int32", Typ[Int32]), true},  // type name is declared in user-defined package (outside Universe)
+		{NewTypeName(0, nil, "rune", Typ[Rune]), true},    // type name refers to basic type rune which is an alias already
+	} {
+		check(test.name, test.alias)
+	}
+}