diff options
| -rw-r--r-- | map.go | 18 | ||||
| -rw-r--r-- | map_go118.go | 9 | ||||
| -rw-r--r-- | map_go120.go | 9 |
3 files changed, 35 insertions, 1 deletions
@@ -8,7 +8,23 @@ import ( "sync" ) -type Map[K comparable, V any] struct { +// Map is a type-safe equivalent of the standard library's sync.Map. +// +// With versions of Go prior to Go 1.20, Map is specified too loosely, +// as +// +// Map[K any, V any] +// +// while with Go 1.20 and later, Map is specified as +// +// Map[K comparable, V any] +// +// This is because with Go versions prior to 1.20, 'comparable' was +// overly strict, disallowing many types that are valid map-keys (see +// https://github.com/golang/go/issues/56548). The type used as K in +// a Map older versions of Go must be a valid map-key type, even +// though the type specification of Map does not enforce that. +type Map[K mapkey, V any] struct { inner sync.Map } diff --git a/map_go118.go b/map_go118.go new file mode 100644 index 0000000..5446c88 --- /dev/null +++ b/map_go118.go @@ -0,0 +1,9 @@ +// Copyright (C) 2023 Luke Shumaker <lukeshu@lukeshu.com> +// +// SPDX-License-Identifier: GPL-2.0-or-later + +//go:build !go1.20 + +package typedsync + +type mapkey = any diff --git a/map_go120.go b/map_go120.go new file mode 100644 index 0000000..0d4ff5b --- /dev/null +++ b/map_go120.go @@ -0,0 +1,9 @@ +// Copyright (C) 2023 Luke Shumaker <lukeshu@lukeshu.com> +// +// SPDX-License-Identifier: GPL-2.0-or-later + +//go:build go1.20 + +package typedsync + +type mapkey = comparable |