Improve error context for DI

src/di/factory/AbstractFactory.ts

@@ -41,4 +41,16 @@ export abstract class AbstractFactory<T> {
      * @return Collection<PropertyDependency>
      */
     abstract getInjectedProperties(): Collection<PropertyDependency>
+
+    /**
+     * Get a human-readable name of the token this factory produces.
+     * This is meant for debugging output only.
+     */
+    public getTokenName(): string {
+        if ( typeof this.token === 'string' ) {
+            return this.token
+        }
+
+        return this.token.name ?? '(unknown token)'
+    }
 }