diff --git a/crates/ra_lsp_server/src/lib.rs b/crates/ra_lsp_server/src/lib.rs
index ca388e4722..2c5d7c72d9 100644
--- a/crates/ra_lsp_server/src/lib.rs
+++ b/crates/ra_lsp_server/src/lib.rs
@@ -11,5 +11,8 @@ mod world;
 
 pub type Result<T> = std::result::Result<T, Box<dyn std::error::Error + Send + Sync>>;
 pub use crate::{
-    caps::server_capabilities, config::ServerConfig, main_loop::main_loop, main_loop::LspError,
+    caps::server_capabilities,
+    config::ServerConfig,
+    main_loop::LspError,
+    main_loop::{main_loop, show_message},
 };
diff --git a/crates/ra_lsp_server/src/main.rs b/crates/ra_lsp_server/src/main.rs
index 36d4898bd9..ae1392cb5d 100644
--- a/crates/ra_lsp_server/src/main.rs
+++ b/crates/ra_lsp_server/src/main.rs
@@ -1,8 +1,7 @@
 use flexi_logger::{Duplicate, Logger};
 use gen_lsp_server::{run_server, stdio_transport};
-use serde::Deserialize;
 
-use ra_lsp_server::{Result, ServerConfig};
+use ra_lsp_server::{show_message, Result, ServerConfig};
 use ra_prof;
 
 fn main() -> Result<()> {
@@ -46,15 +45,23 @@ fn main_inner() -> Result<()> {
             .filter(|workspaces| !workspaces.is_empty())
             .unwrap_or_else(|| vec![root]);
 
-        let opts = params
+        let server_config: ServerConfig = params
             .initialization_options
             .and_then(|v| {
-                ServerConfig::deserialize(v)
-                    .map_err(|e| log::error!("failed to deserialize config: {}", e))
+                serde_json::from_value(v)
+                    .map_err(|e| {
+                        log::error!("failed to deserialize config: {}", e);
+                        show_message(
+                            lsp_types::MessageType::Error,
+                            format!("failed to deserialize config: {}", e),
+                            s,
+                        );
+                    })
                     .ok()
             })
             .unwrap_or_default();
-        ra_lsp_server::main_loop(workspace_roots, params.capabilities, opts, r, s)
+
+        ra_lsp_server::main_loop(workspace_roots, params.capabilities, server_config, r, s)
     })?;
     log::info!("shutting down IO...");
     threads.join()?;
diff --git a/crates/ra_lsp_server/src/main_loop.rs b/crates/ra_lsp_server/src/main_loop.rs
index fcb7823861..c0395c6d82 100644
--- a/crates/ra_lsp_server/src/main_loop.rs
+++ b/crates/ra_lsp_server/src/main_loop.rs
@@ -617,7 +617,11 @@ fn update_file_notifications_on_threadpool(
     });
 }
 
-fn show_message(typ: req::MessageType, message: impl Into<String>, sender: &Sender<RawMessage>) {
+pub fn show_message(
+    typ: req::MessageType,
+    message: impl Into<String>,
+    sender: &Sender<RawMessage>,
+) {
     let message = message.into();
     let params = req::ShowMessageParams { typ, message };
     let not = RawNotification::new::<req::ShowMessage>(&params);