diff --git a/packages/analysis/src/static/Parser.ts b/packages/analysis/src/static/Parser.ts
index 95f995b1..12f4bee3 100644
--- a/packages/analysis/src/static/Parser.ts
+++ b/packages/analysis/src/static/Parser.ts
@@ -98,7 +98,7 @@ export default class Parser
             throw new UnexpectedParseResult('a declaration definition');
         }
 
-        return model as ESDeclaration;
+        return model;
     }
 
     parseFunction(code: string): ESFunction
@@ -111,7 +111,7 @@ export default class Parser
             throw new UnexpectedParseResult('a function definition');
         }
 
-        return model as ESFunction;
+        return model;
     }
 
     parseClass(code: string): ESClass
@@ -124,7 +124,7 @@ export default class Parser
             throw new UnexpectedParseResult('a class definition');
         }
 
-        return model as ESClass;
+        return model;
     }
 
     #parseScope(tokenList: TokenList): ESScope
diff --git a/packages/build/src/source/segment/Reader.ts b/packages/build/src/source/segment/Reader.ts
index 6a4b2b50..38eb4d57 100644
--- a/packages/build/src/source/segment/Reader.ts
+++ b/packages/build/src/source/segment/Reader.ts
@@ -43,10 +43,10 @@ const DEFAULT_VERSION_NUMBER = '0.0.0';
 
 export default class SegmentReader
 {
-    #fileManager: FileManager;
-    #repository: ModuleRepository;
+    readonly #fileManager: FileManager;
+    readonly #repository: ModuleRepository;
 
-    #fileHelper = new FileHelper();
+    readonly #fileHelper = new FileHelper();
 
     constructor(fileManager: FileManager, repository: ModuleRepository)
     {
diff --git a/packages/execution/src/errors/ImplementationNotFound.ts b/packages/execution/src/errors/ImplementationNotFound.ts
index 0dd3e78d..01f961b6 100644
--- a/packages/execution/src/errors/ImplementationNotFound.ts
+++ b/packages/execution/src/errors/ImplementationNotFound.ts
@@ -3,8 +3,8 @@ import { NotFound } from '@jitar/errors';
 
 export default class ImplementationNotFound extends NotFound
 {
-    #fqn: string;
-    #version: string;
+    readonly #fqn: string;
+    readonly #version: string;
 
     constructor(fqn: string, version: string)
     {
diff --git a/packages/execution/src/errors/InvalidParameterValue.ts b/packages/execution/src/errors/InvalidParameterValue.ts
index 76f0cc1a..9294eb4f 100644
--- a/packages/execution/src/errors/InvalidParameterValue.ts
+++ b/packages/execution/src/errors/InvalidParameterValue.ts
@@ -3,7 +3,7 @@ import { BadRequest } from '@jitar/errors';
 
 export default class InvalidParameterValue extends BadRequest
 {
-    #parameterName: string;
+    readonly #parameterName: string;
 
     constructor(parameterName: string)
     {
diff --git a/packages/execution/src/errors/InvalidVersionNumber.ts b/packages/execution/src/errors/InvalidVersionNumber.ts
index 81761e5b..adb8cdfa 100644
--- a/packages/execution/src/errors/InvalidVersionNumber.ts
+++ b/packages/execution/src/errors/InvalidVersionNumber.ts
@@ -3,7 +3,7 @@ import { BadRequest } from '@jitar/errors';
 
 export default class InvalidVersionNumber extends BadRequest
 {
-    #number: string;
+    readonly #number: string;
 
     constructor(number: string)
     {
diff --git a/packages/execution/src/errors/MissingParameterValue.ts b/packages/execution/src/errors/MissingParameterValue.ts
index 9339f1f4..8ffdf12c 100644
--- a/packages/execution/src/errors/MissingParameterValue.ts
+++ b/packages/execution/src/errors/MissingParameterValue.ts
@@ -3,7 +3,7 @@ import { BadRequest } from '@jitar/errors';
 
 export default class MissingParameterValue extends BadRequest
 {
-    #parameterName: string;
+    readonly #parameterName: string;
 
     constructor(parameterName: string)
     {
diff --git a/packages/execution/src/errors/ProcedureNotFound.ts b/packages/execution/src/errors/ProcedureNotFound.ts
index 54091614..08827bd6 100644
--- a/packages/execution/src/errors/ProcedureNotFound.ts
+++ b/packages/execution/src/errors/ProcedureNotFound.ts
@@ -3,7 +3,7 @@ import { NotFound } from '@jitar/errors';
 
 export default class ProcedureNotFound extends NotFound
 {
-    #fqn: string;
+    readonly #fqn: string;
 
     constructor(fqn: string)
     {
diff --git a/packages/execution/src/errors/UnknownParameter.ts b/packages/execution/src/errors/UnknownParameter.ts
index 268d028f..ac3dddf7 100644
--- a/packages/execution/src/errors/UnknownParameter.ts
+++ b/packages/execution/src/errors/UnknownParameter.ts
@@ -3,7 +3,7 @@ import { BadRequest } from '@jitar/errors';
 
 export default class UnknownParameter extends BadRequest
 {
-    #parameterName: string;
+    readonly #parameterName: string;
 
     constructor(parameterName: string)
     {
diff --git a/packages/http/src/HttpServer.ts b/packages/http/src/HttpServer.ts
index b0337568..c329ec58 100644
--- a/packages/http/src/HttpServer.ts
+++ b/packages/http/src/HttpServer.ts
@@ -18,7 +18,7 @@ export default class HttpServer
     readonly #app: Express;
     #http?: Http;
 
-    #validator = new Validator();
+    readonly #validator = new Validator();
 
     constructor(server: Server, port: string = Defaults.PORT_NUMBER, bodyLimit: number = Defaults.BODY_LIMIT)
     {
diff --git a/packages/sourcing/src/errors/FileNotFound.ts b/packages/sourcing/src/errors/FileNotFound.ts
index bb886463..6246c422 100644
--- a/packages/sourcing/src/errors/FileNotFound.ts
+++ b/packages/sourcing/src/errors/FileNotFound.ts
@@ -1,7 +1,7 @@
 
 export default class FileNotFound extends Error
 {
-    #filename: string;
+    readonly #filename: string;
 
     constructor(filename: string)
     {