Fix decoding Array of LSPAnyCodable

Sources/LanguageServerProtocol/SupportTypes/LSPAny.swift

@@ -152,12 +152,50 @@ extension Array: LSPAnyCodable where Element: LSPAnyCodable {
     guard case .array(let array) = array else {
       return nil
     }
+
     var result = [Element]()
-    for case .dictionary(let editDict) in array {
-      guard let element = Element.init(fromLSPDictionary: editDict) else {
+    for element in array {
+      switch element {
+      case .dictionary(let dict):
+        if let value = Element(fromLSPDictionary: dict) {
+          result.append(value)
+        } else {
+          return nil
+        }
+      case .array(let value):
+        if let value = value as? [Element] {
+          result.append(contentsOf: value)
+        } else {
+          return nil
+        }
+      case .string(let value):
+        if let value = value as? Element {
+          result.append(value)
+        } else {
+          return nil
+        }
+      case .int(let value):
+        if let value = value as? Element {
+          result.append(value)
+        } else {
+          return nil
+        }
+      case .double(let value):
+        if let value = value as? Element {
+          result.append(value)
+        } else {
+          return nil
+        }
+      case .bool(let value):
+        if let value = value as? Element {
+          result.append(value)
+        } else {
+          return nil
+        }
+      case .null:
+        // null is not expected for non-optional Element
         return nil
       }
-      result.append(element)
     }
     self = result
   }

Tests/SourceKitLSPTests/SemanticTokensTests.swift

@@ -71,11 +71,22 @@ final class SemanticTokensTests: XCTestCase {
 
     let registerCapabilityExpectation = expectation(description: "\(#function) - register semantic tokens capability")
     testClient.handleNextRequest { (req: RegisterCapabilityRequest) -> VoidResponse in
-      XCTAssert(
-        req.registrations.contains { reg in
-          reg.method == SemanticTokensRegistrationOptions.method
-        }
+      let capabilityRegistration = req.registrations.first { reg in
+        reg.method == SemanticTokensRegistrationOptions.method
+      }
+
+      guard case .dictionary(let registerOptionsDict) = capabilityRegistration?.registerOptions,
+        let registerOptions = SemanticTokensRegistrationOptions(fromLSPDictionary: registerOptionsDict)
+      else {
+        XCTFail("Expected semantic tokens registration options dictionary")
+        return VoidResponse()
+      }
+
+      XCTAssertFalse(
+        registerOptions.semanticTokenOptions.legend.tokenTypes.isEmpty,
+        "Expected semantic tokens legend"
       )
+
       registerCapabilityExpectation.fulfill()
       return VoidResponse()
     }