Fix class alias reference in static initializer for legacy class decorators (#54046)

src/compiler/transformers/legacyDecorators.ts

@@ -37,6 +37,7 @@ import {
     isBlock,
     isCallToHelper,
     isClassElement,
+    isClassStaticBlockDeclaration,
     isComputedPropertyName,
     isDecorator,
     isExportOrDefaultModifier,
@@ -339,6 +340,27 @@ export function transformLegacyDecorators(context: TransformationContext): (x: S
         let decorationStatements: Statement[] | undefined = [];
         ({ members, decorationStatements } = transformDecoratorsOfClassElements(node, members));
 
+        // If we're emitting to ES2022 or later then we need to reassign the class alias before
+        // static initializers are evaluated.
+        const assignClassAliasInStaticBlock =
+            languageVersion >= ScriptTarget.ES2022 &&
+            !!classAlias &&
+            some(members, member =>
+                isPropertyDeclaration(member) && hasSyntacticModifier(member, ModifierFlags.Static) ||
+                isClassStaticBlockDeclaration(member));
+        if (assignClassAliasInStaticBlock) {
+            members = setTextRange(factory.createNodeArray([
+                factory.createClassStaticBlockDeclaration(
+                    factory.createBlock([
+                        factory.createExpressionStatement(
+                            factory.createAssignment(classAlias, factory.createThis())
+                        )
+                    ])
+                ),
+                ...members
+            ]), members);
+        }
+
         const classExpression = factory.createClassExpression(
             modifiers,
             name && isGeneratedIdentifier(name) ? undefined : name,
@@ -355,7 +377,7 @@ export function transformLegacyDecorators(context: TransformationContext): (x: S
             declName,
             /*exclamationToken*/ undefined,
             /*type*/ undefined,
-            classAlias ? factory.createAssignment(classAlias, classExpression) : classExpression
+            classAlias && !assignClassAliasInStaticBlock ? factory.createAssignment(classAlias, classExpression) : classExpression
         );
         setOriginalNode(varDecl, node);
 

tests/baselines/reference/staticInitializersAndLegacyClassDecorators.js

@@ -0,0 +1,43 @@
+//// [staticInitializersAndLegacyClassDecorators.ts]
+// https://github.com/microsoft/TypeScript/issues/52004
+declare var dec: any;
+
+@dec
+class C1
+{
+    static instance = new C1();
+}
+
+@dec
+class C2
+{
+    static {
+        new C2();
+    }
+}
+
+
+//// [staticInitializersAndLegacyClassDecorators.js]
+var __decorate = (this && this.__decorate) || function (decorators, target, key, desc) {
+    var c = arguments.length, r = c < 3 ? target : desc === null ? desc = Object.getOwnPropertyDescriptor(target, key) : desc, d;
+    if (typeof Reflect === "object" && typeof Reflect.decorate === "function") r = Reflect.decorate(decorators, target, key, desc);
+    else for (var i = decorators.length - 1; i >= 0; i--) if (d = decorators[i]) r = (c < 3 ? d(r) : c > 3 ? d(target, key, r) : d(target, key)) || r;
+    return c > 3 && r && Object.defineProperty(target, key, r), r;
+};
+var C1_1, C2_1;
+let C1 = class C1 {
+    static { C1_1 = this; }
+    static instance = new C1_1();
+};
+C1 = C1_1 = __decorate([
+    dec
+], C1);
+let C2 = class C2 {
+    static { C2_1 = this; }
+    static {
+        new C2_1();
+    }
+};
+C2 = C2_1 = __decorate([
+    dec
+], C2);

tests/cases/compiler/staticInitializersAndLegacyClassDecorators.ts

@@ -0,0 +1,20 @@
+// @target: es2022
+// @experimentalDecorators: true
+// @noTypesAndSymbols: true
+
+// https://github.com/microsoft/TypeScript/issues/52004
+declare var dec: any;
+
+@dec
+class C1
+{
+    static instance = new C1();
+}
+
+@dec
+class C2
+{
+    static {
+        new C2();
+    }
+}