Merge pull request #19046 from Microsoft/fix15395

Fix emit for classes with both fields and 'extends null'

src/compiler/transformers/ts.ts

@@ -26,7 +26,7 @@ namespace ts {
         IsExportOfNamespace = 1 << 3,
         IsNamedExternalExport = 1 << 4,
         IsDefaultExternalExport = 1 << 5,
-        HasExtendsClause = 1 << 6,
+        IsDerivedClass = 1 << 6,
         UseImmediatelyInvokedFunctionExpression = 1 << 7,
 
         HasAnyDecorators = HasConstructorDecorators | HasMemberDecorators,
@@ -553,7 +553,8 @@ namespace ts {
         function getClassFacts(node: ClassDeclaration, staticProperties: ReadonlyArray<PropertyDeclaration>) {
             let facts = ClassFacts.None;
             if (some(staticProperties)) facts |= ClassFacts.HasStaticInitializedProperties;
-            if (getClassExtendsHeritageClauseElement(node)) facts |= ClassFacts.HasExtendsClause;
+            const extendsClauseElement = getClassExtendsHeritageClauseElement(node);
+            if (extendsClauseElement && skipOuterExpressions(extendsClauseElement.expression).kind !== SyntaxKind.NullKeyword) facts |= ClassFacts.IsDerivedClass;
             if (shouldEmitDecorateCallForClass(node)) facts |= ClassFacts.HasConstructorDecorators;
             if (childIsDecorated(node)) facts |= ClassFacts.HasMemberDecorators;
             if (isExportOfNamespace(node)) facts |= ClassFacts.IsExportOfNamespace;
@@ -699,7 +700,7 @@ namespace ts {
                 name,
                 /*typeParameters*/ undefined,
                 visitNodes(node.heritageClauses, visitor, isHeritageClause),
-                transformClassMembers(node, (facts & ClassFacts.HasExtendsClause) !== 0)
+                transformClassMembers(node, (facts & ClassFacts.IsDerivedClass) !== 0)
             );
 
             // To better align with the old emitter, we should not emit a trailing source map
@@ -814,7 +815,7 @@ namespace ts {
             //      ${members}
             //  }
             const heritageClauses = visitNodes(node.heritageClauses, visitor, isHeritageClause);
-            const members = transformClassMembers(node, (facts & ClassFacts.HasExtendsClause) !== 0);
+            const members = transformClassMembers(node, (facts & ClassFacts.IsDerivedClass) !== 0);
             const classExpression = createClassExpression(/*modifiers*/ undefined, name, /*typeParameters*/ undefined, heritageClauses, members);
             setOriginalNode(classExpression, node);
             setTextRange(classExpression, location);
@@ -887,11 +888,11 @@ namespace ts {
          * Transforms the members of a class.
          *
          * @param node The current class.
-         * @param hasExtendsClause A value indicating whether the class has an extends clause.
+         * @param isDerivedClass A value indicating whether the class has an extends clause that does not extend 'null'.
          */
-        function transformClassMembers(node: ClassDeclaration | ClassExpression, hasExtendsClause: boolean) {
+        function transformClassMembers(node: ClassDeclaration | ClassExpression, isDerivedClass: boolean) {
             const members: ClassElement[] = [];
-            const constructor = transformConstructor(node, hasExtendsClause);
+            const constructor = transformConstructor(node, isDerivedClass);
             if (constructor) {
                 members.push(constructor);
             }
@@ -904,9 +905,9 @@ namespace ts {
          * Transforms (or creates) a constructor for a class.
          *
          * @param node The current class.
-         * @param hasExtendsClause A value indicating whether the class has an extends clause.
+         * @param isDerivedClass A value indicating whether the class has an extends clause that does not extend 'null'.
          */
-        function transformConstructor(node: ClassDeclaration | ClassExpression, hasExtendsClause: boolean) {
+        function transformConstructor(node: ClassDeclaration | ClassExpression, isDerivedClass: boolean) {
             // Check if we have property assignment inside class declaration.
             // If there is a property assignment, we need to emit constructor whether users define it or not
             // If there is no property assignment, we can omit constructor if users do not define it
@@ -921,7 +922,7 @@ namespace ts {
             }
 
             const parameters = transformConstructorParameters(constructor);
-            const body = transformConstructorBody(node, constructor, hasExtendsClause);
+            const body = transformConstructorBody(node, constructor, isDerivedClass);
 
             //  constructor(${parameters}) {
             //      ${body}
@@ -947,7 +948,6 @@ namespace ts {
          * parameter property assignments or instance property initializers.
          *
          * @param constructor The constructor declaration.
-         * @param hasExtendsClause A value indicating whether the class has an extends clause.
          */
         function transformConstructorParameters(constructor: ConstructorDeclaration) {
             // The ES2015 spec specifies in 14.5.14. Runtime Semantics: ClassDefinitionEvaluation:
@@ -975,9 +975,9 @@ namespace ts {
          *
          * @param node The current class.
          * @param constructor The current class constructor.
-         * @param hasExtendsClause A value indicating whether the class has an extends clause.
+         * @param isDerivedClass A value indicating whether the class has an extends clause that does not extend 'null'.
          */
-        function transformConstructorBody(node: ClassExpression | ClassDeclaration, constructor: ConstructorDeclaration, hasExtendsClause: boolean) {
+        function transformConstructorBody(node: ClassExpression | ClassDeclaration, constructor: ConstructorDeclaration, isDerivedClass: boolean) {
             let statements: Statement[] = [];
             let indexOfFirstStatement = 0;
 
@@ -1001,7 +1001,7 @@ namespace ts {
                 const propertyAssignments = getParametersWithPropertyAssignments(constructor);
                 addRange(statements, map(propertyAssignments, transformParameterWithPropertyAssignment));
             }
-            else if (hasExtendsClause) {
+            else if (isDerivedClass) {
                 // Add a synthetic `super` call:
                 //
                 //  super(...arguments);

tests/baselines/reference/classExtendingNull.js

@@ -1,7 +1,8 @@
 //// [classExtendingNull.ts]
 class C1 extends null { }
 class C2 extends (null) { }
-
+class C3 extends null { x = 1; }
+class C4 extends (null) { x = 1; }
 
 //// [classExtendingNull.js]
 var __extends = (this && this.__extends) || (function () {
@@ -26,3 +27,17 @@ var C2 = /** @class */ (function (_super) {
     }
     return C2;
 }((null)));
+var C3 = /** @class */ (function (_super) {
+    __extends(C3, _super);
+    function C3() {
+        this.x = 1;
+    }
+    return C3;
+}(null));
+var C4 = /** @class */ (function (_super) {
+    __extends(C4, _super);
+    function C4() {
+        this.x = 1;
+    }
+    return C4;
+}((null)));

tests/baselines/reference/classExtendingNull.symbols

@@ -5,3 +5,11 @@ class C1 extends null { }
 class C2 extends (null) { }
 >C2 : Symbol(C2, Decl(classExtendingNull.ts, 0, 25))
 
+class C3 extends null { x = 1; }
+>C3 : Symbol(C3, Decl(classExtendingNull.ts, 1, 27))
+>x : Symbol(C3.x, Decl(classExtendingNull.ts, 2, 23))
+
+class C4 extends (null) { x = 1; }
+>C4 : Symbol(C4, Decl(classExtendingNull.ts, 2, 32))
+>x : Symbol(C4.x, Decl(classExtendingNull.ts, 3, 25))
+

tests/baselines/reference/classExtendingNull.types

@@ -8,3 +8,16 @@ class C2 extends (null) { }
 >(null) : null
 >null : null
 
+class C3 extends null { x = 1; }
+>C3 : C3
+>null : null
+>x : number
+>1 : 1
+
+class C4 extends (null) { x = 1; }
+>C4 : C4
+>(null) : null
+>null : null
+>x : number
+>1 : 1
+

tests/cases/conformance/classes/classDeclarations/classExtendingNull.ts

@@ -1,2 +1,4 @@
 class C1 extends null { }
 class C2 extends (null) { }
+class C3 extends null { x = 1; }
+class C4 extends (null) { x = 1; }