Use experimental capability to enable color codes

crates/flycheck/src/lib.rs

@@ -47,6 +47,7 @@ pub enum FlycheckConfig {
         features: Vec<String>,
         extra_args: Vec<String>,
         extra_env: FxHashMap<String, String>,
+        ansi_color_output: bool,
     },
     CustomCommand {
         command: String,
@@ -293,16 +294,21 @@ fn check_command(&self) -> Command {
                 extra_args,
                 features,
                 extra_env,
+                ansi_color_output,
             } => {
                 let mut cmd = Command::new(toolchain::cargo());
                 cmd.arg(command);
                 cmd.current_dir(&self.root);
-                cmd.args([
-                    "--workspace",
-                    "--message-format=json-diagnostic-rendered-ansi",
-                    "--manifest-path",
-                ])
-                .arg(self.root.join("Cargo.toml").as_os_str());
+                cmd.arg("--workspace");
+
+                cmd.arg(if *ansi_color_output {
+                    "--message-format=json-diagnostic-rendered-ansi"
+                } else {
+                    "--message-format=json"
+                });
+
+                cmd.arg("--manifest-path");
+                cmd.arg(self.root.join("Cargo.toml").as_os_str());
 
                 for target in target_triples {
                     cmd.args(["--target", target.as_str()]);

crates/rust-analyzer/src/config.rs

@@ -161,8 +161,8 @@ struct ConfigData {
         /// Override the command rust-analyzer uses instead of `cargo check` for
         /// diagnostics on save. The command is required to output json and
         /// should therefore include `--message-format=json` or a similar option
-        /// (for colored diagnostics, use
-        /// `--message-format=json-diagnostic-rendered-ansi`).
+        /// (if your client supports the `colorDiagnosticOutput` experimental
+        /// capability, you can use `--message-format=json-diagnostic-rendered-ansi`).
         ///
         /// If you're changing this because you're using some tool wrapping
         /// Cargo, you might also want to change
@@ -1008,6 +1008,11 @@ pub fn server_status_notification(&self) -> bool {
         self.experimental("serverStatusNotification")
     }
 
+    /// Whether the client supports colored output for full diagnostics from `checkOnSave`.
+    pub fn color_diagnostic_output(&self) -> bool {
+        self.experimental("colorDiagnosticOutput")
+    }
+
     pub fn publish_diagnostics(&self) -> bool {
         self.data.diagnostics_enable
     }
@@ -1206,6 +1211,7 @@ pub fn flycheck(&self) -> FlycheckConfig {
                 },
                 extra_args: self.data.check_extraArgs.clone(),
                 extra_env: self.check_on_save_extra_env(),
+                ansi_color_output: self.color_diagnostic_output(),
             },
         }
     }

docs/user/generated_config.adoc

@@ -174,8 +174,8 @@ Whether to pass `--no-default-features` to Cargo. Defaults to
 Override the command rust-analyzer uses instead of `cargo check` for
 diagnostics on save. The command is required to output json and
 should therefore include `--message-format=json` or a similar option
-(for colored diagnostics, use
-`--message-format=json-diagnostic-rendered-ansi`).
+(if your client supports the `colorDiagnosticOutput` experimental
+capability, you can use `--message-format=json-diagnostic-rendered-ansi`).
 
 If you're changing this because you're using some tool wrapping
 Cargo, you might also want to change

editors/code/package.json

@@ -644,7 +644,7 @@
                     ]
                 },
                 "rust-analyzer.check.overrideCommand": {
-                    "markdownDescription": "Override the command rust-analyzer uses instead of `cargo check` for\ndiagnostics on save. The command is required to output json and\nshould therefore include `--message-format=json` or a similar option\n(for colored diagnostics, use\n`--message-format=json-diagnostic-rendered-ansi`).\n\nIf you're changing this because you're using some tool wrapping\nCargo, you might also want to change\n`#rust-analyzer.cargo.buildScripts.overrideCommand#`.\n\nIf there are multiple linked projects, this command is invoked for\neach of them, with the working directory being the project root\n(i.e., the folder containing the `Cargo.toml`).\n\nAn example command would be:\n\n```bash\ncargo check --workspace --message-format=json --all-targets\n```\n.",
+                    "markdownDescription": "Override the command rust-analyzer uses instead of `cargo check` for\ndiagnostics on save. The command is required to output json and\nshould therefore include `--message-format=json` or a similar option\n(if your client supports the `colorDiagnosticOutput` experimental\ncapability, you can use `--message-format=json-diagnostic-rendered-ansi`).\n\nIf you're changing this because you're using some tool wrapping\nCargo, you might also want to change\n`#rust-analyzer.cargo.buildScripts.overrideCommand#`.\n\nIf there are multiple linked projects, this command is invoked for\neach of them, with the working directory being the project root\n(i.e., the folder containing the `Cargo.toml`).\n\nAn example command would be:\n\n```bash\ncargo check --workspace --message-format=json --all-targets\n```\n.",
                     "default": null,
                     "type": [
                         "null",

editors/code/src/client.ts

@@ -333,6 +333,7 @@ class ExperimentalFeatures implements lc.StaticFeature {
         caps.codeActionGroup = true;
         caps.hoverActions = true;
         caps.serverStatusNotification = true;
+        caps.colorDiagnosticOutput = true;
         caps.commands = {
             commands: [
                 "rust-analyzer.runSingle",