4 files changed, 37 insertions, 19 deletions

diff --git a/crates/ra_ide/src/feature_flags.rs b/crates/ra_ide/src/feature_flags.rs
index de4ae513d..85617640d 100644
--- a/crates/ra_ide/src/feature_flags.rs
+++ b/crates/ra_ide/src/feature_flags.rs
@@ -56,6 +56,7 @@ impl Default for FeatureFlags {
             ("completion.insertion.add-call-parenthesis", true),
             ("completion.enable-postfix", true),
             ("notifications.workspace-loaded", true),
+            ("notifications.cargo-toml-not-found", true),
         ])
     }
 }
diff --git a/crates/ra_lsp_server/src/main_loop.rs b/crates/ra_lsp_server/src/main_loop.rs
index 047c86a3b..7a49cad86 100644
--- a/crates/ra_lsp_server/src/main_loop.rs
+++ b/crates/ra_lsp_server/src/main_loop.rs
@@ -62,6 +62,22 @@ pub fn main_loop(
 
     let mut loop_state = LoopState::default();
     let mut world_state = {
+        let feature_flags = {
+            let mut ff = FeatureFlags::default();
+            for (flag, value) in config.feature_flags {
+                if ff.set(flag.as_str(), value).is_err() {
+                    log::error!("unknown feature flag: {:?}", flag);
+                    show_message(
+                        req::MessageType::Error,
+                        format!("unknown feature flag: {:?}", flag),
+                        &connection.sender,
+                    );
+                }
+            }
+            ff
+        };
+        log::info!("feature_flags: {:#?}", feature_flags);
+
         // FIXME: support dynamic workspace loading.
         let workspaces = {
             let mut loaded_workspaces = Vec::new();
@@ -75,7 +91,12 @@ pub fn main_loop(
                     Ok(workspace) => loaded_workspaces.push(workspace),
                     Err(e) => {
                         log::error!("loading workspace failed: {}", e);
-
+                        if let Some(ra_project_model::CargoTomlNotFoundError(_)) = e.downcast_ref()
+                        {
+                            if !feature_flags.get("notifications.cargo-toml-not-found") {
+                                continue;
+                            }
+                        }
                         show_message(
                             req::MessageType::Error,
                             format!("rust-analyzer failed to load workspace: {}", e),
@@ -136,22 +157,6 @@ pub fn main_loop(
             }
         };
 
-        let feature_flags = {
-            let mut ff = FeatureFlags::default();
-            for (flag, value) in config.feature_flags {
-                if ff.set(flag.as_str(), value).is_err() {
-                    log::error!("unknown feature flag: {:?}", flag);
-                    show_message(
-                        req::MessageType::Error,
-                        format!("unknown feature flag: {:?}", flag),
-                        &connection.sender,
-                    );
-                }
-            }
-            ff
-        };
-        log::info!("feature_flags: {:#?}", feature_flags);
-
         WorldState::new(
             ws_roots,
             workspaces,
diff --git a/crates/ra_project_model/src/lib.rs b/crates/ra_project_model/src/lib.rs
index d71b7031a..b7f6a9b57 100644
--- a/crates/ra_project_model/src/lib.rs
+++ b/crates/ra_project_model/src/lib.rs
@@ -23,9 +23,19 @@ pub use crate::{
     sysroot::Sysroot,
 };
 
-// FIXME use proper error enum
 pub type Result<T> = ::std::result::Result<T, Box<dyn Error + Send + Sync>>;
 
+#[derive(Clone, PartialEq, Eq, Hash, Debug)]
+pub struct CargoTomlNotFoundError(pub PathBuf);
+
+impl std::fmt::Display for CargoTomlNotFoundError {
+    fn fmt(&self, fmt: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(fmt, "can't find Cargo.toml at {}", self.0.display())
+    }
+}
+
+impl Error for CargoTomlNotFoundError {}
+
 #[derive(Debug, Clone)]
 pub enum ProjectWorkspace {
     /// Project workspace was discovered by running `cargo metadata` and `rustc --print sysroot`.
@@ -362,7 +372,7 @@ fn find_cargo_toml(path: &Path) -> Result<PathBuf> {
         }
         curr = path.parent();
     }
-    Err(format!("can't find Cargo.toml at {}", path.display()))?
+    Err(CargoTomlNotFoundError(path.to_path_buf()))?
 }
 
 pub fn get_rustc_cfg_options() -> CfgOptions {
diff --git a/docs/user/README.md b/docs/user/README.md
index 282445722..fa202f06c 100644
--- a/docs/user/README.md
+++ b/docs/user/README.md
@@ -122,6 +122,8 @@ host.
        "completion.enable-postfix": true,
        // Show notification when workspace is fully loaded
        "notifications.workspace-loaded": true,
+       // Show error when no Cargo.toml was found
+       "notifications.cargo-toml-not-found": true,
    }
    ```