Configure rust-analyzer with project-specific config files

lib/index.js

@@ -1,5 +1,6 @@
 const cp = require("child_process")
 const os = require("os")
+const fs = require("fs")
 const path = require("path")
 const { CompositeDisposable, Disposable } = require("atom")
 const { AutoLanguageClient } = require("atom-languageclient")
@@ -450,6 +451,18 @@ class RustLanguageClient extends AutoLanguageClient {
     params.initializationOptions = params.initializationOptions || {}
     // Don't build straight after initialize, wait for first `workspace/didChangeConfiguration`
     params.initializationOptions.omitInitBuild = true
+
+    let rlsConfigPath = path.join(projectPath, "rust-analyzer.json")
+
+    if (fs.existsSync(rlsConfigPath)) {
+        try {
+            let options = fs.readFileSync(rlsConfigPath)
+            Object.assign(params.initializationOptions, JSON.parse(options))
+        } catch(e) {
+            atom.notifications.addError("Error reading rust-analyzer config file\n", e)
+        }
+    }
+
     return params
   }