1 files changed, 108 insertions, 0 deletions
diff --git a/test/typeparam/mapsimp.dir/a.go b/test/typeparam/mapsimp.dir/a.go
new file mode 100644
index 0000000000..696e2a5680
--- /dev/null
+++ b/test/typeparam/mapsimp.dir/a.go
@@ -0,0 +1,108 @@
+// 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 a
+
+// SliceEqual reports whether two slices are equal: the same length and all
+// elements equal. All floating point NaNs are considered equal.
+func SliceEqual[Elem comparable](s1, s2 []Elem) bool {
+	if len(s1) != len(s2) {
+		return false
+	}
+	for i, v1 := range s1 {
+		v2 := s2[i]
+		if v1 != v2 {
+			isNaN := func(f Elem) bool { return f != f }
+			if !isNaN(v1) || !isNaN(v2) {
+				return false
+			}
+		}
+	}
+	return true
+}
+
+// Keys returns the keys of the map m.
+// The keys will be an indeterminate order.
+func Keys[K comparable, V any](m map[K]V) []K {
+	r := make([]K, 0, len(m))
+	for k := range m {
+		r = append(r, k)
+	}
+	return r
+}
+
+// Values returns the values of the map m.
+// The values will be in an indeterminate order.
+func Values[K comparable, V any](m map[K]V) []V {
+	r := make([]V, 0, len(m))
+	for _, v := range m {
+		r = append(r, v)
+	}
+	return r
+}
+
+// Equal reports whether two maps contain the same key/value pairs.
+// Values are compared using ==.
+func Equal[K, V comparable](m1, m2 map[K]V) bool {
+	if len(m1) != len(m2) {
+		return false
+	}
+	for k, v1 := range m1 {
+		if v2, ok := m2[k]; !ok || v1 != v2 {
+			return false
+		}
+	}
+	return true
+}
+
+// Copy returns a copy of m.
+func Copy[K comparable, V any](m map[K]V) map[K]V {
+	r := make(map[K]V, len(m))
+	for k, v := range m {
+		r[k] = v
+	}
+	return r
+}
+
+// Add adds all key/value pairs in m2 to m1. Keys in m2 that are already
+// present in m1 will be overwritten with the value in m2.
+func Add[K comparable, V any](m1, m2 map[K]V) {
+	for k, v := range m2 {
+		m1[k] = v
+	}
+}
+
+// Sub removes all keys in m2 from m1. Keys in m2 that are not present
+// in m1 are ignored. The values in m2 are ignored.
+func Sub[K comparable, V any](m1, m2 map[K]V) {
+	for k := range m2 {
+		delete(m1, k)
+	}
+}
+
+// Intersect removes all keys from m1 that are not present in m2.
+// Keys in m2 that are not in m1 are ignored. The values in m2 are ignored.
+func Intersect[K comparable, V any](m1, m2 map[K]V) {
+	for k := range m1 {
+		if _, ok := m2[k]; !ok {
+			delete(m1, k)
+		}
+	}
+}
+
+// Filter deletes any key/value pairs from m for which f returns false.
+func Filter[K comparable, V any](m map[K]V, f func(K, V) bool) {
+	for k, v := range m {
+		if !f(k, v) {
+			delete(m, k)
+		}
+	}
+}
+
+// TransformValues applies f to each value in m. The keys remain unchanged.
+func TransformValues[K comparable, V any](m map[K]V, f func(V) V) {
+	for k, v := range m {
+		m[k] = f(v)
+	}
+}