cargo: update MSRV to 1.64

We need 1.64 to bump `clap` to `4.1`. We don't really need to upgrade
to that, but being on an older version causes minor confusions like
#1393. Rust 1.64 is very close to 6 months old at this point.

.github/workflows/build.yml

@@ -20,7 +20,7 @@ jobs:
           rust_version: stable
         - build: linux-msrv
           os: ubuntu-latest
-          rust_version: "1.61"
+          rust_version: "1.64"
         - build: macos
           os: macos-latest
           rust_version: stable

CHANGELOG.md

@@ -21,6 +21,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   current commit has no content and no description, such as right after
   a `jj squash`.
 
+* The minimum supported Rust version (MSRV) is now 1.64.0.
+
 ### New features
 
 * `jj git push --deleted` will remove all locally deleted branches from the remote.

Cargo.toml

@@ -3,7 +3,7 @@ name = "jujutsu"
 version = "0.7.0"
 authors = ["Martin von Zweigbergk <martinvonz@google.com>"]
 edition = "2021"
-rust-version = "1.61"  # Remember to update CI, contributing.md, and flake.nix
+rust-version = "1.64"  # Remember to update CI, contributing.md, and flake.nix
 license = "Apache-2.0"
 description = "Jujutsu (an experimental VCS)"
 homepage = "https://github.com/martinvonz/jj"

docs/contributing.md

@@ -117,7 +117,7 @@ These are listed roughly in order of decreasing importance.
 
 3. Your code will be rejected if it cannot be compiled with the minimal
    supported version of Rust. This version is listed as
-   `rust-version` in [`Cargo.toml`](../Cargo.toml); it is 1.61 as of this
+   `rust-version` in [`Cargo.toml`](../Cargo.toml); it is 1.64 as of this
    writing.
 
 4. Your code needs to pass `cargo clippy`. You can also

flake.nix

@@ -92,7 +92,7 @@
         buildInputs = with pkgs; [
           # Using the minimal profile with explicit "clippy" extension to avoid
           # two versions of rustfmt
-          (rust-bin.stable."1.61.0".minimal.override {
+          (rust-bin.stable."1.64.0".minimal.override {
             extensions = [
               "rust-src" # for rust-analyzer
               "clippy"

lib/Cargo.toml

@@ -3,7 +3,7 @@ name = "jujutsu-lib"
 version = "0.7.0"
 authors = ["Martin von Zweigbergk <martinvonz@google.com>"]
 edition = "2021"
-rust-version = "1.61"
+rust-version = "1.64"
 license = "Apache-2.0"
 description = "Library for Jujutsu (an experimental VCS)"
 homepage = "https://github.com/martinvonz/jj"

lib/src/revset.rs

@@ -1205,7 +1205,7 @@ fn internalize_filter(expression: &Rc<RevsetExpression>) -> Option<Rc<RevsetExpr
         expression: &RevsetExpression,
     ) -> Option<(&Rc<RevsetExpression>, &Rc<RevsetExpression>)> {
         if let RevsetExpression::Intersection(expression1, expression2) = expression {
-            is_filter(expression2).then(|| (expression1, expression2))
+            is_filter(expression2).then_some((expression1, expression2))
         } else {
             None
         }

src/cli_util.rs

@@ -795,7 +795,7 @@ impl WorkspaceCommandHelper {
                         .iter()
                         .map(|c| self.format_commit_summary(c))
                         .join("\n"),
-                    ellipsis = elided.then(|| "\n...").unwrap_or_default()
+                    ellipsis = elided.then_some("\n...").unwrap_or_default()
                 );
                 Err(user_error_with_hint(
                     format!(r#"Revset "{revision_str}" resolved to more than one revision"#),

src/commands/git.rs

@@ -302,7 +302,7 @@ fn cmd_git_fetch(
                 tx.mut_repo(),
                 &git_repo,
                 &remote,
-                (!branches.is_empty()).then(|| &*branches),
+                (!branches.is_empty()).then_some(&*branches),
                 cb,
                 &command.settings().git_settings(),
             )

src/diff_util.rs

@@ -98,7 +98,7 @@ fn diff_formats_from_args(args: &DiffFormatArgs) -> Vec<DiffFormat> {
         (args.color_words, DiffFormat::ColorWords),
     ]
     .into_iter()
-    .filter_map(|(arg, format)| arg.then(|| format))
+    .filter_map(|(arg, format)| arg.then_some(format))
     .collect()
 }
 

src/ui.rs

@@ -36,19 +36,14 @@ fn progress_indicator_setting(config: &config::Config) -> bool {
     config.get_bool("ui.progress-indicator").unwrap_or(true)
 }
 
-#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+#[derive(Clone, Copy, Debug, Default, Eq, PartialEq)]
 pub enum ColorChoice {
     Always,
     Never,
+    #[default]
     Auto,
 }
 
-impl Default for ColorChoice {
-    fn default() -> Self {
-        ColorChoice::Auto
-    }
-}
-
 impl FromStr for ColorChoice {
     type Err = &'static str;
 
@@ -89,18 +84,13 @@ fn use_color(choice: ColorChoice) -> bool {
     }
 }
 
-#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+#[derive(Clone, Copy, Debug, Default, Eq, PartialEq)]
 pub enum PaginationChoice {
     No,
+    #[default]
     Auto,
 }
 
-impl Default for PaginationChoice {
-    fn default() -> Self {
-        PaginationChoice::Auto
-    }
-}
-
 fn pager_setting(config: &config::Config) -> CommandNameAndArgs {
     config
         .get("ui.pager")