fix: select correct override function

src/compiler.ts

@@ -6618,6 +6618,7 @@ export class Compiler extends DiagnosticEmitter {
     );
     let overrideInstances = this.resolver.resolveOverrides(instance);
     if (overrideInstances) {
+      let mostRecentInheritanceMapping = new Map<Class, Class>();
       for (let i = 0, k = overrideInstances.length; i < k; ++i) {
         let overrideInstance = overrideInstances[i];
         if (!overrideInstance.is(CommonFlags.Compiled)) continue; // errored
@@ -6680,7 +6681,18 @@ export class Compiler extends DiagnosticEmitter {
             if (instanceMembers && instanceMembers.has(instance.declaration.name.text)) {
               continue; // skip those not inheriting
             }
-            builder.addCase(extender.id, stmts);
+            if (mostRecentInheritanceMapping.has(extender)) {
+              let currentRecentParent = assert(mostRecentInheritanceMapping.get(extender));
+              if (currentRecentParent.extends(classInstance)) {
+                // already find recent parent, keep old stmt
+              } else {
+                mostRecentInheritanceMapping.set(extender, classInstance);
+                builder.replaceCase(extender.id, stmts);
+              }
+            } else {
+              mostRecentInheritanceMapping.set(extender, classInstance);
+              builder.addCase(extender.id, stmts);
+            }
           }
         }
       }

src/module.ts

@@ -3418,16 +3418,27 @@ export class SwitchBuilder {
     this.condition = condition;
   }
 
+  /** Replace case to the specified branch. */
+  replaceCase(value: i32, code: ExpressionRef[]): void {
+    let valueIndex = this.values.indexOf(value);
+    assert(valueIndex >= 0);
+    this.indexes[valueIndex] = this.addCode(code);
+  }
+
   /** Links a case to the specified branch. */
   addCase(value: i32, code: ExpressionRef[]): void {
+    this.values.push(value);
+    this.indexes.push(this.addCode(code));
+  }
+
+  private addCode(code: ExpressionRef[]): i32 {
     let cases = this.cases;
     let index = cases.indexOf(code);
     if (index < 0) {
       index = cases.length;
       cases.push(code);
     }
-    this.values.push(value);
-    this.indexes.push(index);
+    return index;
   }
 
   /** Links the default branch. */