Initial commit: Go 1.23 release state

test/typeparam/issue50690a.go

@@ -0,0 +1,75 @@
+// run
+
+// Copyright 2022 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 main
+
+import (
+	"fmt"
+)
+
+// Numeric expresses a type constraint satisfied by any numeric type.
+type Numeric interface {
+	~uint | ~uint8 | ~uint16 | ~uint32 | ~uint64 |
+		~int | ~int8 | ~int16 | ~int32 | ~int64 |
+		~float32 | ~float64 |
+		~complex64 | ~complex128
+}
+
+// Sum returns the sum of the provided arguments.
+func Sum[T Numeric](args ...T) T {
+	var sum T
+	for i := 0; i < len(args); i++ {
+		sum += args[i]
+	}
+	return sum
+}
+
+// Ledger is an identifiable, financial record.
+type Ledger[T ~string, K Numeric] struct {
+	// ID identifies the ledger.
+	ID_ T
+
+	// Amounts is a list of monies associated with this ledger.
+	Amounts_ []K
+
+	// SumFn is a function that can be used to sum the amounts
+	// in this ledger.
+	SumFn_ func(...K) K
+}
+
+// Field accesses through type parameters are disabled
+// until we have a more thorough understanding of the
+// implications on the spec. See issue #51576.
+// Use accessor methods instead.
+
+func (l Ledger[T, _]) ID() T               { return l.ID_ }
+func (l Ledger[_, K]) Amounts() []K        { return l.Amounts_ }
+func (l Ledger[_, K]) SumFn() func(...K) K { return l.SumFn_ }
+
+func PrintLedger[
+	T ~string,
+	K Numeric,
+	L interface {
+		~struct {
+			ID_      T
+			Amounts_ []K
+			SumFn_   func(...K) K
+		}
+		ID() T
+		Amounts() []K
+		SumFn() func(...K) K
+	},
+](l L) {
+	fmt.Printf("%s has a sum of %v\n", l.ID(), l.SumFn()(l.Amounts()...))
+}
+
+func main() {
+	PrintLedger(Ledger[string, int]{
+		ID_:      "fake",
+		Amounts_: []int{1, 2, 3},
+		SumFn_:   Sum[int],
+	})
+}