src/go/types/testdata/check/typeinference.go2

// 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.

package typeInference

// basic inference
type Tb[P ~*Q, Q any] int
func _() {
	var x Tb[*int]
	var y Tb[*int, int]
	x = y
	_ = x
}

// recursive inference
type Tr[A any, B ~*C, C ~*D, D ~*A] int
func _() {
	var x Tr[string]
	var y Tr[string, ***string, **string, *string]
	var z Tr[int, ***int, **int, *int]
	x = y
	x = z // ERROR cannot use z .* as Tr
	_ = x
}

// other patterns of inference
type To0[A any, B ~[]A] int
type To1[A any, B ~struct{a A}] int
type To2[A any, B ~[][]A] int
type To3[A any, B ~[3]*A] int
type To4[A any, B any, C ~struct{a A; b B}] int
func _() {
	var _ To0[int]
	var _ To1[int]
	var _ To2[int]
	var _ To3[int]
	var _ To4[int, string]
}

// failed inference
type Tf0[A, B any] int
type Tf1[A any, B ~struct{a A; c C}, C any] int
func _() {
	var _ Tf0 /* ERROR cannot infer B */ /* ERROR got 1 arguments but 2 type parameters */ [int]
	var _ Tf1 /* ERROR cannot infer B */ /* ERROR got 1 arguments but 3 type parameters */ [int]
}