From 0f26eade6047b6407fc866bc53c655fbec00a127 Mon Sep 17 00:00:00 2001
From: Lindsay Roberts <lsr0@users.noreply.github.com>
Date: Tue, 22 Nov 2022 15:25:10 +0200
Subject: [PATCH] Add const to generated enum values() (#2011)

* Add const to generated enum values()

Enum values() functions return static arrays of static strings and could
be of compile time use. Make callable in const contexts.

* Add reference to PR in changelog next for const enum values()

* Correct changelog next target to all for const enum values()

Co-authored-by: Luca Palmieri <20745048+LukeMathWalker@users.noreply.github.com>
---
 CHANGELOG.next.toml                                         | 6 ++++++
 .../rust/codegen/core/smithy/generators/EnumGenerator.kt    | 4 ++--
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.next.toml b/CHANGELOG.next.toml
index fea153453a..f0a3bf3c70 100644
--- a/CHANGELOG.next.toml
+++ b/CHANGELOG.next.toml
@@ -478,3 +478,9 @@ x-amzn-errortype: com.example.service#InvalidRequestException
 references = ["smithy-rs#1982"]
 meta = { "breaking" = true, "tada" = false, "bug" = false, "target" = "server" }
 author = "david-perez"
+
+[[smithy-rs]]
+message = "Make generated enum `values()` functions callable in const contexts."
+references = ["smithy-rs#2011"]
+meta = { "breaking" = false, "tada" = false, "bug" = false, "target" = "all" }
+author = "lsr0"
diff --git a/codegen-core/src/main/kotlin/software/amazon/smithy/rust/codegen/core/smithy/generators/EnumGenerator.kt b/codegen-core/src/main/kotlin/software/amazon/smithy/rust/codegen/core/smithy/generators/EnumGenerator.kt
index 0acfe2641d..95a46649ea 100644
--- a/codegen-core/src/main/kotlin/software/amazon/smithy/rust/codegen/core/smithy/generators/EnumGenerator.kt
+++ b/codegen-core/src/main/kotlin/software/amazon/smithy/rust/codegen/core/smithy/generators/EnumGenerator.kt
@@ -141,7 +141,7 @@ open class EnumGenerator(
             }
 
             docs("Returns all the `&str` representations of the enum members.")
-            rustBlock("pub fn $Values() -> &'static [&'static str]") {
+            rustBlock("pub const fn $Values() -> &'static [&'static str]") {
                 withBlock("&[", "]") {
                     val memberList = sortedMembers.joinToString(", ") { it.value.dq() }
                     rust(memberList)
@@ -198,7 +198,7 @@ open class EnumGenerator(
             }
 
             rust("/// Returns all the `&str` values of the enum members.")
-            rustBlock("pub fn $Values() -> &'static [&'static str]") {
+            rustBlock("pub const fn $Values() -> &'static [&'static str]") {
                 withBlock("&[", "]") {
                     val memberList = sortedMembers.joinToString(", ") { it.value.doubleQuote() }
                     write(memberList)