diff --git a/go/types/builtins.go b/go/types/builtins.go
index a13db14d..75d74c01 100644
--- a/go/types/builtins.go
+++ b/go/types/builtins.go
@@ -88,13 +88,9 @@ func (check *checker) builtin(x *operand, call *ast.CallExpr, id builtinId) (_ b
 			}
 			if isString(x.typ) {
 				if check.Types != nil {
-					// TODO(gri, adonovan) change this to:
-					//
-					//	sig := makeSig(S, S, NewSlice(Typ[Byte]))
-					//	sig.isVariadic = true
-					//
-					// once ssa has been adjusted
-					check.recordBuiltinType(call.Fun, makeSig(S, S, x.typ))
+					sig := makeSig(S, S, NewSlice(Typ[Byte]))
+					sig.isVariadic = true
+					check.recordBuiltinType(call.Fun, sig)
 				}
 				x.mode = value
 				x.typ = S
@@ -420,7 +416,6 @@ func (check *checker) builtin(x *operand, call *ast.CallExpr, id builtinId) (_ b
 
 		x.mode = novalue
 		if check.Types != nil {
-			// TODO(gri) we need a global empty interface somewhere
 			check.recordBuiltinType(call.Fun, makeSig(nil, new(Interface)))
 		}
 
@@ -449,7 +444,7 @@ func (check *checker) builtin(x *operand, call *ast.CallExpr, id builtinId) (_ b
 	case _Recover:
 		// recover() interface{}
 		x.mode = value
-		x.typ = new(Interface) // TODO(gri) we need a global empty interface somewhere
+		x.typ = new(Interface)
 		if check.Types != nil {
 			check.recordBuiltinType(call.Fun, makeSig(x.typ))
 		}
diff --git a/go/types/builtins_test.go b/go/types/builtins_test.go
index 346c25ae..af1ad9e6 100644
--- a/go/types/builtins_test.go
+++ b/go/types/builtins_test.go
@@ -20,8 +20,11 @@ var builtinCalls = []struct {
 	{_Append, `var s []int; _ = append(s, 0)`, `func([]int, ...int) []int`},
 	{_Append, `var s []int; _ = (append)(s, 0)`, `func([]int, ...int) []int`},
 	{_Append, `var s []byte; _ = ((append))(s, 0)`, `func([]byte, ...byte) []byte`},
-	{_Append, `var s []byte; _ = append(s, "foo"...)`, `func([]byte, string) []byte`},
-	{_Append, `type T []byte; var s T; _ = append(s, "foo"...)`, `func(p.T, string) p.T`},
+	// Note that ...uint8 (instead of ..byte) appears below because that is the type
+	// that corresponds to Typ[byte] (an alias) - in the other cases, the type name
+	// is chosen by the source. Either way, byte and uint8 denote identical types.
+	{_Append, `var s []byte; _ = append(s, "foo"...)`, `func([]byte, ...uint8) []byte`},
+	{_Append, `type T []byte; var s T; _ = append(s, "foo"...)`, `func(p.T, ...uint8) p.T`},
 
 	{_Cap, `var s [10]int; _ = cap(s)`, `invalid type`},  // constant
 	{_Cap, `var s [10]int; _ = cap(&s)`, `invalid type`}, // constant