Update to go v1.23.2

test/fixedbugs/issue69507.go

@@ -0,0 +1,133 @@
+// run
+
+// Copyright 2024 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
+
+func main() {
+	err := run()
+	if err != nil {
+		panic(err)
+	}
+}
+
+func run() error {
+	methods := "AB"
+
+	type node struct {
+		tag     string
+		choices []string
+	}
+	all := []node{
+		{"000", permutations(methods)},
+	}
+
+	next := 1
+	for len(all) > 0 {
+		cur := all[0]
+		k := copy(all, all[1:])
+		all = all[:k]
+
+		if len(cur.choices) == 1 {
+			continue
+		}
+
+		var bestM map[byte][]string
+		bMax := len(cur.choices) + 1
+		bMin := -1
+		for sel := range selections(methods) {
+			m := make(map[byte][]string)
+			for _, order := range cur.choices {
+				x := findFirstMatch(order, sel)
+				m[x] = append(m[x], order)
+			}
+
+			min := len(cur.choices) + 1
+			max := -1
+			for _, v := range m {
+				if len(v) < min {
+					min = len(v)
+				}
+				if len(v) > max {
+					max = len(v)
+				}
+			}
+			if max < bMax || (max == bMax && min > bMin) {
+				bestM = m
+				bMin = min
+				bMax = max
+			}
+		}
+
+		if bMax == len(cur.choices) {
+			continue
+		}
+
+		cc := Keys(bestM)
+		for c := range cc {
+			choices := bestM[c]
+			next++
+
+			switch c {
+			case 'A':
+			case 'B':
+			default:
+				panic("unexpected selector type " + string(c))
+			}
+			all = append(all, node{"", choices})
+		}
+	}
+	return nil
+}
+
+func permutations(s string) []string {
+	if len(s) <= 1 {
+		return []string{s}
+	}
+
+	var result []string
+	for i, char := range s {
+		rest := s[:i] + s[i+1:]
+		for _, perm := range permutations(rest) {
+			result = append(result, string(char)+perm)
+		}
+	}
+	return result
+}
+
+type Seq[V any] func(yield func(V) bool)
+
+func selections(s string) Seq[string] {
+	return func(yield func(string) bool) {
+		for bits := 1; bits < 1<<len(s); bits++ {
+			var choice string
+			for j, char := range s {
+				if bits&(1<<j) != 0 {
+					choice += string(char)
+				}
+			}
+			if !yield(choice) {
+				break
+			}
+		}
+	}
+}
+
+func findFirstMatch(order, sel string) byte {
+	for _, c := range order {
+		return byte(c)
+	}
+	return 0
+}
+
+func Keys[Map ~map[K]V, K comparable, V any](m Map) Seq[K] {
+	return func(yield func(K) bool) {
+		for k := range m {
+			if !yield(k) {
+				return
+			}
+		}
+	}
+}