fix(es/minifier): Fix cycle detection

.changeset/breezy-experts-complain.md

@@ -0,0 +1,9 @@
+---
+swc_ecma_utils: patch
+swc_core: patch
+swc_ecma_lexer: patch
+swc_ecma_parser: patch
+swc_ecma_usage_analyzer: patch
+---
+
+fix(es/minifier): Fix cycle detection

crates/swc/tests/tsc-references/privateNamesConstructorChain-1.2.minified.js

@@ -1,5 +1,32 @@
 //// [privateNamesConstructorChain-1.ts]
-import "@swc/helpers/_/_class_private_field_get";
-import "@swc/helpers/_/_class_private_field_init";
-import "@swc/helpers/_/_class_private_field_set";
-import "@swc/helpers/_/_class_static_private_field_spec_get";
+import { _ as _class_private_field_get } from "@swc/helpers/_/_class_private_field_get";
+import { _ as _class_private_field_init } from "@swc/helpers/_/_class_private_field_init";
+import { _ as _class_private_field_set } from "@swc/helpers/_/_class_private_field_set";
+import { _ as _class_static_private_field_spec_get } from "@swc/helpers/_/_class_static_private_field_spec_get";
+var _foo = /*#__PURE__*/ new WeakMap();
+class Parent {
+    accessChildProps() {
+        _class_private_field_get(new Child(), _foo), _class_static_private_field_spec_get(Child, Parent, _bar);
+    }
+    constructor(){
+        _class_private_field_init(this, _foo, {
+            writable: !0,
+            value: void 0
+        }), _class_private_field_set(this, _foo, 3);
+    }
+}
+var _bar = {
+    writable: !0,
+    value: 5
+}, _foo1 = /*#__PURE__*/ new WeakMap(), _bar1 = /*#__PURE__*/ new WeakMap();
+class Child extends Parent {
+    constructor(...args){
+        super(...args), _class_private_field_init(this, _foo1, {
+            writable: !0,
+            value: void 0
+        }), _class_private_field_init(this, _bar1, {
+            writable: !0,
+            value: void 0
+        }), _class_private_field_set(this, _foo1, "foo"), _class_private_field_set(this, _bar1, "bar");
+    }
+}

crates/swc_ecma_minifier/tests/fixture/issues/cycle-1/input.js

@@ -0,0 +1,26 @@
+(() => {
+    class A {
+      cycle() {
+        return B;
+      }
+    }
+    class B {
+      cycle() {
+        return A
+      }
+    }
+
+    class ExtendsA1 extends sideEffectWith(A) {}
+    class Unused1 {
+      constructor() {
+        ExtendsA1
+      }
+    }
+    class ExtendsA2 extends sideEffectWith(A) {}
+    class Unused2 {
+      async put() {
+        ExtendsA2
+      }
+    }
+  })();
+

crates/swc_ecma_minifier/tests/fixture/issues/cycle-1/output.js

@@ -0,0 +1,11 @@
+class A {
+    cycle() {
+        return B;
+    }
+}
+class B {
+    cycle() {
+        return A;
+    }
+}
+sideEffectWith(A), sideEffectWith(A);

crates/swc_ecma_minifier/tests/fixture/issues/cycle-2/input.js

@@ -0,0 +1,20 @@
+
+(() => {
+    class C {
+      cycle() {
+        return D;
+      }
+    }
+    class D {
+      cycle() {
+        return C
+      }
+    }
+
+    class ExtendsC extends sideEffectWith(C) {}
+    class Unused {
+      constructor() {
+        ExtendsC
+      }
+    }
+  })();

crates/swc_ecma_minifier/tests/fixture/issues/cycle-2/output.js

@@ -0,0 +1,11 @@
+class C {
+    cycle() {
+        return D;
+    }
+}
+class D {
+    cycle() {
+        return C;
+    }
+}
+sideEffectWith(C);

crates/swc_ecma_transforms_optimization/src/simplify/dce/mod.rs

@@ -471,10 +471,16 @@ impl Visit for Analyzer<'_> {
     }
 
     fn visit_class_decl(&mut self, n: &ClassDecl) {
+        if let Some(super_class) = &n.class.super_class {
+            super_class.visit_with(self);
+        }
+
         self.with_ast_path(vec![n.ident.to_id()], |v| {
             let old = v.cur_class_id.take();
             v.cur_class_id = Some(n.ident.to_id());
-            n.visit_children_with(v);
+            n.ident.visit_with(v);
+            n.class.decorators.visit_with(v);
+            n.class.body.visit_with(v);
             v.cur_class_id = old;
 
             if !n.class.decorators.is_empty() {