blob: fd48405f37e618707b87e29d168c3bc0d62d4aa3 [file] [log] [blame]
// Copyright 2021 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.
// go:build ignore
package testdata
// TestNodeTypeUniqueness checks if semantically equivalent types
// are being represented using the same pointer value in vta nodes.
// If not, some edges become missing in the string representation
// of the graph.
type I interface {
type A struct{}
func (a A) Foo() {}
func Baz(a *A) (I, I, interface{}, interface{}) {
var i I
i = a
var ii I
aa := &A{}
ii = aa
m := make(map[int]int)
var iii interface{}
iii = m
var iiii interface{}
iiii = m
return i, ii, iii, iiii
// Relevant SSA:
// func Baz(a *A) (I, I, interface{}, interface{}):
// t0 = make I <- *A (a)
// t1 = new A (complit)
// t2 = make I <- *A (t1)
// t3 = make map[int]int
// t4 = make interface{} <- map[int]int (t3)
// t5 = make interface{} <- map[int]int (t3)
// return t0, t2, t4, t5
// Without canon approach, one of Pointer(*A) -> Local(t0) and Pointer(*A) -> Local(t2) edges is
// missing in the graph string representation. The original graph has both of the edges but the
// source node Pointer(*A) is not the same; two occurrences of Pointer(*A) are considered separate
// nodes. Since they have the same string representation, one edge gets overridden by the other
// during the graph stringification, instead of being joined together as in below.
// WANT:
// Pointer(*testdata.A) -> Local(t0), Local(t2)
// Local(t3) -> Local(t4), Local(t5)