Fix panic on anonymous class declaration with decorator targeting ES2022 (#3926)

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: jakebailey <5341706+jakebailey@users.noreply.github.com>

Author: Copilot

internal/transformers/tstransforms/runtimesyntax.go

@@ -676,7 +676,7 @@ func (tx *RuntimeSyntaxTransformer) visitClassDeclaration(node *ast.ClassDeclara
 	}
 
 	name := tx.Visitor().VisitNode(node.Name())
-	if exported && name == nil {
+	if name == nil && (exported || ast.ChildIsDecorated(tx.compilerOptions.ExperimentalDecorators.IsTrue(), node.AsNode(), nil)) {
 		name = tx.Factory().NewGeneratedNameForNode(node.AsNode())
 	}
 	heritageClauses := tx.Visitor().VisitNodes(node.HeritageClauses)

testdata/baselines/reference/compiler/anonymousClassDecoratorEs2022.errors.txt

@@ -0,0 +1,16 @@
+anonymousClassDecoratorEs2022.ts(1,1): error TS1211: A class declaration without the 'default' modifier must have a name.
+anonymousClassDecoratorEs2022.ts(2,4): error TS2304: Cannot find name 'x'.
+
+
+==== anonymousClassDecoratorEs2022.ts (2 errors) ====
+    class {
+    ~~~~~
+!!! error TS1211: A class declaration without the 'default' modifier must have a name.
+      @x
+       ~
+!!! error TS2304: Cannot find name 'x'.
+      m() {
+        // ...
+      }
+    };
+    

testdata/baselines/reference/compiler/anonymousClassDecoratorEs2022.js

@@ -0,0 +1,66 @@
+//// [tests/cases/compiler/anonymousClassDecoratorEs2022.ts] ////
+
+//// [anonymousClassDecoratorEs2022.ts]
+class {
+  @x
+  m() {
+    // ...
+  }
+};
+
+
+//// [anonymousClassDecoratorEs2022.js]
+"use strict";
+var __runInitializers = (this && this.__runInitializers) || function (thisArg, initializers, value) {
+    var useValue = arguments.length > 2;
+    for (var i = 0; i < initializers.length; i++) {
+        value = useValue ? initializers[i].call(thisArg, value) : initializers[i].call(thisArg);
+    }
+    return useValue ? value : void 0;
+};
+var __esDecorate = (this && this.__esDecorate) || function (ctor, descriptorIn, decorators, contextIn, initializers, extraInitializers) {
+    function accept(f) { if (f !== void 0 && typeof f !== "function") throw new TypeError("Function expected"); return f; }
+    var kind = contextIn.kind, key = kind === "getter" ? "get" : kind === "setter" ? "set" : "value";
+    var target = !descriptorIn && ctor ? contextIn["static"] ? ctor : ctor.prototype : null;
+    var descriptor = descriptorIn || (target ? Object.getOwnPropertyDescriptor(target, contextIn.name) : {});
+    var _, done = false;
+    for (var i = decorators.length - 1; i >= 0; i--) {
+        var context = {};
+        for (var p in contextIn) context[p] = p === "access" ? {} : contextIn[p];
+        for (var p in contextIn.access) context.access[p] = contextIn.access[p];
+        context.addInitializer = function (f) { if (done) throw new TypeError("Cannot add initializers after decoration has completed"); extraInitializers.push(accept(f || null)); };
+        var result = (0, decorators[i])(kind === "accessor" ? { get: descriptor.get, set: descriptor.set } : descriptor[key], context);
+        if (kind === "accessor") {
+            if (result === void 0) continue;
+            if (result === null || typeof result !== "object") throw new TypeError("Object expected");
+            if (_ = accept(result.get)) descriptor.get = _;
+            if (_ = accept(result.set)) descriptor.set = _;
+            if (_ = accept(result.init)) initializers.unshift(_);
+        }
+        else if (_ = accept(result)) {
+            if (kind === "field") initializers.unshift(_);
+            else descriptor[key] = _;
+        }
+    }
+    if (target) Object.defineProperty(target, contextIn.name, descriptor);
+    done = true;
+};
+let default_1 = (() => {
+    let _instanceExtraInitializers = [];
+    let _m_decorators;
+    return class default_1 {
+        static {
+            const _metadata = typeof Symbol === "function" && Symbol.metadata ? Object.create(null) : void 0;
+            _m_decorators = [x];
+            __esDecorate(this, null, _m_decorators, { kind: "method", name: "m", static: false, private: false, access: { has: obj => "m" in obj, get: obj => obj.m }, metadata: _metadata }, null, _instanceExtraInitializers);
+            if (_metadata) Object.defineProperty(this, Symbol.metadata, { enumerable: true, configurable: true, writable: true, value: _metadata });
+        }
+        m() {
+            // ...
+        }
+        constructor() {
+            __runInitializers(this, _instanceExtraInitializers);
+        }
+    };
+})();
+;

testdata/baselines/reference/compiler/anonymousClassDecoratorEs2022.symbols

@@ -0,0 +1,12 @@
+//// [tests/cases/compiler/anonymousClassDecoratorEs2022.ts] ////
+
+=== anonymousClassDecoratorEs2022.ts ===
+class {
+  @x
+  m() {
+>m : Symbol(__missing.m, Decl(anonymousClassDecoratorEs2022.ts, 0, 7))
+
+    // ...
+  }
+};
+

testdata/baselines/reference/compiler/anonymousClassDecoratorEs2022.types

@@ -0,0 +1,14 @@
+//// [tests/cases/compiler/anonymousClassDecoratorEs2022.ts] ////
+
+=== anonymousClassDecoratorEs2022.ts ===
+class {
+  @x
+>x : any
+
+  m() {
+>m : () => void
+
+    // ...
+  }
+};
+

testdata/tests/cases/compiler/anonymousClassDecoratorEs2022.ts

@@ -0,0 +1,8 @@
+// @target: es2022
+
+class {
+  @x
+  m() {
+    // ...
+  }
+};