fix: class field is not accessible via super (microsoft#54056)

Co-authored-by: Nathan Shively-Sanders <[email protected]>

src/compiler/checker.ts

@@ -477,6 +477,7 @@ import {
     isClassDeclaration,
     isClassElement,
     isClassExpression,
+    isClassFieldAndNotAutoAccessor,
     isClassLike,
     isClassStaticBlockDeclaration,
     isCommaSequence,
@@ -31820,6 +31821,14 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
                 }
                 return false;
             }
+            // A class field cannot be accessed via super.* from a derived class.
+            // This is true for both [[Set]] (old) and [[Define]] (ES spec) semantics.
+            if (!(flags & ModifierFlags.Static) && prop.declarations?.some(isClassFieldAndNotAutoAccessor)) {
+                if (errorNode) {
+                    error(errorNode, Diagnostics.Class_field_0_defined_by_the_parent_class_is_not_accessible_in_the_child_class_via_super, symbolToString(prop));
+                }
+                return false;
+            }
         }
 
         // Referencing abstract properties within their own constructors is not allowed

src/compiler/diagnosticMessages.json

@@ -3663,6 +3663,10 @@
         "category": "Error",
         "code": 2854
     },
+    "Class field '{0}' defined by the parent class is not accessible in the child class via super.": {
+        "category": "Error",
+        "code": 2855
+    },
 
     "Import declaration '{0}' is using private name '{1}'.": {
         "category": "Error",

src/compiler/utilitiesPublic.ts

@@ -1704,6 +1704,11 @@ export function isAutoAccessorPropertyDeclaration(node: Node): node is AutoAcces
     return isPropertyDeclaration(node) && hasAccessorModifier(node);
 }
 
+/** @internal */
+export function isClassFieldAndNotAutoAccessor(node: Node): boolean {
+    return node.parent && isClassLike(node.parent) && isPropertyDeclaration(node) && !hasAccessorModifier(node);
+}
+
 /** @internal */
 export function isMethodOrAccessor(node: Node): node is MethodDeclaration | AccessorDeclaration {
     switch (node.kind) {

tests/baselines/reference/checkSuperCallBeforeThisAccess.errors.txt

@@ -1,19 +1,24 @@
 checkSuperCallBeforeThisAccess.ts(7,18): error TS17009: 'super' must be called before accessing 'this' in the constructor of a derived class.
 checkSuperCallBeforeThisAccess.ts(8,18): error TS17009: 'super' must be called before accessing 'this' in the constructor of a derived class.
 checkSuperCallBeforeThisAccess.ts(9,18): error TS17011: 'super' must be called before accessing a property of 'super' in the constructor of a derived class.
+checkSuperCallBeforeThisAccess.ts(9,24): error TS2855: Class field 'x' defined by the parent class is not accessible in the child class via super.
+checkSuperCallBeforeThisAccess.ts(12,30): error TS2855: Class field 'x' defined by the parent class is not accessible in the child class via super.
+checkSuperCallBeforeThisAccess.ts(17,28): error TS2855: Class field 'x' defined by the parent class is not accessible in the child class via super.
 checkSuperCallBeforeThisAccess.ts(20,22): error TS17009: 'super' must be called before accessing 'this' in the constructor of a derived class.
 checkSuperCallBeforeThisAccess.ts(21,22): error TS17009: 'super' must be called before accessing 'this' in the constructor of a derived class.
 checkSuperCallBeforeThisAccess.ts(22,22): error TS17011: 'super' must be called before accessing a property of 'super' in the constructor of a derived class.
+checkSuperCallBeforeThisAccess.ts(22,28): error TS2855: Class field 'x' defined by the parent class is not accessible in the child class via super.
 checkSuperCallBeforeThisAccess.ts(30,30): error TS17009: 'super' must be called before accessing 'this' in the constructor of a derived class.
 checkSuperCallBeforeThisAccess.ts(39,22): error TS17009: 'super' must be called before accessing 'this' in the constructor of a derived class.
 checkSuperCallBeforeThisAccess.ts(43,18): error TS17009: 'super' must be called before accessing 'this' in the constructor of a derived class.
 checkSuperCallBeforeThisAccess.ts(44,18): error TS17009: 'super' must be called before accessing 'this' in the constructor of a derived class.
 checkSuperCallBeforeThisAccess.ts(45,18): error TS17011: 'super' must be called before accessing a property of 'super' in the constructor of a derived class.
+checkSuperCallBeforeThisAccess.ts(45,24): error TS2855: Class field 'x' defined by the parent class is not accessible in the child class via super.
 checkSuperCallBeforeThisAccess.ts(59,27): error TS17009: 'super' must be called before accessing 'this' in the constructor of a derived class.
 checkSuperCallBeforeThisAccess.ts(75,27): error TS17009: 'super' must be called before accessing 'this' in the constructor of a derived class.
 
 
-==== checkSuperCallBeforeThisAccess.ts (13 errors) ====
+==== checkSuperCallBeforeThisAccess.ts (18 errors) ====
     class A {
         x = 1;
     }
@@ -29,14 +34,20 @@ checkSuperCallBeforeThisAccess.ts(75,27): error TS17009: 'super' must be called
             let a3 = super.x;  // Error
                      ~~~~~
 !!! error TS17011: 'super' must be called before accessing a property of 'super' in the constructor of a derived class.
+                           ~
+!!! error TS2855: Class field 'x' defined by the parent class is not accessible in the child class via super.
             let a4 = () => this;
             let a5 = () => this.x;
             let a6 = () => super.x;
+                                 ~
+!!! error TS2855: Class field 'x' defined by the parent class is not accessible in the child class via super.
             if (!!true) {
                 super();
                 let b1 = this;
                 let b2 = this.x;
                 let b3 = super.x;
+                               ~
+!!! error TS2855: Class field 'x' defined by the parent class is not accessible in the child class via super.
             }
             else {
                 let c1 = this;  // Error
@@ -48,6 +59,8 @@ checkSuperCallBeforeThisAccess.ts(75,27): error TS17009: 'super' must be called
                 let c3 = super.x;  // Error
                          ~~~~~
 !!! error TS17011: 'super' must be called before accessing a property of 'super' in the constructor of a derived class.
+                               ~
+!!! error TS2855: Class field 'x' defined by the parent class is not accessible in the child class via super.
             }
             if (!!true) {
                 switch (n) {
@@ -81,6 +94,8 @@ checkSuperCallBeforeThisAccess.ts(75,27): error TS17009: 'super' must be called
             let f3 = super.x;  // Error
                      ~~~~~
 !!! error TS17011: 'super' must be called before accessing a property of 'super' in the constructor of a derived class.
+                           ~
+!!! error TS2855: Class field 'x' defined by the parent class is not accessible in the child class via super.
         }
     }
 

tests/baselines/reference/classFieldSuperAccessible.js

@@ -0,0 +1,37 @@
+//// [tests/cases/compiler/classFieldSuperAccessible.ts] ////
+
+//// [classFieldSuperAccessible.ts]
+class A extends class Expr {} {
+    static {
+        console.log(super.name);
+    }
+}
+class B extends Number {
+    static {
+        console.log(super.EPSILON);
+    }
+}
+class C extends Array {
+    foo() {
+        console.log(super.length);
+    }
+}
+
+
+//// [classFieldSuperAccessible.js]
+class A extends class Expr {
+} {
+    static {
+        console.log(super.name);
+    }
+}
+class B extends Number {
+    static {
+        console.log(super.EPSILON);
+    }
+}
+class C extends Array {
+    foo() {
+        console.log(super.length);
+    }
+}

tests/baselines/reference/classFieldSuperAccessible.symbols

@@ -0,0 +1,48 @@
+//// [tests/cases/compiler/classFieldSuperAccessible.ts] ////
+
+=== classFieldSuperAccessible.ts ===
+class A extends class Expr {} {
+>A : Symbol(A, Decl(classFieldSuperAccessible.ts, 0, 0))
+>Expr : Symbol(Expr, Decl(classFieldSuperAccessible.ts, 0, 15))
+
+    static {
+        console.log(super.name);
+>console.log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
+>console : Symbol(console, Decl(lib.dom.d.ts, --, --))
+>log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
+>super.name : Symbol(Function.name, Decl(lib.es2015.core.d.ts, --, --))
+>super : Symbol(Expr, Decl(classFieldSuperAccessible.ts, 0, 15))
+>name : Symbol(Function.name, Decl(lib.es2015.core.d.ts, --, --))
+    }
+}
+class B extends Number {
+>B : Symbol(B, Decl(classFieldSuperAccessible.ts, 4, 1))
+>Number : Symbol(Number, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es2020.number.d.ts, --, --))
+
+    static {
+        console.log(super.EPSILON);
+>console.log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
+>console : Symbol(console, Decl(lib.dom.d.ts, --, --))
+>log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
+>super.EPSILON : Symbol(NumberConstructor.EPSILON, Decl(lib.es2015.core.d.ts, --, --))
+>super : Symbol(NumberConstructor, Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>EPSILON : Symbol(NumberConstructor.EPSILON, Decl(lib.es2015.core.d.ts, --, --))
+    }
+}
+class C extends Array {
+>C : Symbol(C, Decl(classFieldSuperAccessible.ts, 9, 1))
+>Array : Symbol(Array, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --) ... and 4 more)
+
+    foo() {
+>foo : Symbol(C.foo, Decl(classFieldSuperAccessible.ts, 10, 23))
+
+        console.log(super.length);
+>console.log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
+>console : Symbol(console, Decl(lib.dom.d.ts, --, --))
+>log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
+>super.length : Symbol(Array.length, Decl(lib.es5.d.ts, --, --))
+>super : Symbol(Array, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --) ... and 4 more)
+>length : Symbol(Array.length, Decl(lib.es5.d.ts, --, --))
+    }
+}
+

tests/baselines/reference/classFieldSuperAccessible.types

@@ -0,0 +1,52 @@
+//// [tests/cases/compiler/classFieldSuperAccessible.ts] ////
+
+=== classFieldSuperAccessible.ts ===
+class A extends class Expr {} {
+>A : A
+>class Expr {} : Expr
+>Expr : typeof Expr
+
+    static {
+        console.log(super.name);
+>console.log(super.name) : void
+>console.log : (...data: any[]) => void
+>console : Console
+>log : (...data: any[]) => void
+>super.name : string
+>super : typeof Expr
+>name : string
+    }
+}
+class B extends Number {
+>B : B
+>Number : Number
+
+    static {
+        console.log(super.EPSILON);
+>console.log(super.EPSILON) : void
+>console.log : (...data: any[]) => void
+>console : Console
+>log : (...data: any[]) => void
+>super.EPSILON : number
+>super : NumberConstructor
+>EPSILON : number
+    }
+}
+class C extends Array {
+>C : C
+>Array : any[]
+
+    foo() {
+>foo : () => void
+
+        console.log(super.length);
+>console.log(super.length) : void
+>console.log : (...data: any[]) => void
+>console : Console
+>log : (...data: any[]) => void
+>super.length : number
+>super : any[]
+>length : number
+    }
+}
+

tests/baselines/reference/classFieldSuperNotAccessible.errors.txt

@@ -0,0 +1,17 @@
+classFieldSuperNotAccessible.ts(6,15): error TS2855: Class field 'field' defined by the parent class is not accessible in the child class via super.
+
+
+==== classFieldSuperNotAccessible.ts (1 errors) ====
+    class T {
+        field = () => {}
+    }
+    class T2 extends T {
+        f() {
+            super.field() // error
+                  ~~~~~
+!!! error TS2855: Class field 'field' defined by the parent class is not accessible in the child class via super.
+        }
+    }
+
+    new T2().f()
+

tests/baselines/reference/classFieldSuperNotAccessible.js

@@ -0,0 +1,25 @@
+//// [tests/cases/compiler/classFieldSuperNotAccessible.ts] ////
+
+//// [classFieldSuperNotAccessible.ts]
+class T {
+    field = () => {}
+}
+class T2 extends T {
+    f() {
+        super.field() // error
+    }
+}
+
+new T2().f()
+
+
+//// [classFieldSuperNotAccessible.js]
+class T {
+    field = () => { };
+}
+class T2 extends T {
+    f() {
+        super.field(); // error
+    }
+}
+new T2().f();

tests/baselines/reference/classFieldSuperNotAccessible.symbols

@@ -0,0 +1,28 @@
+//// [tests/cases/compiler/classFieldSuperNotAccessible.ts] ////
+
+=== classFieldSuperNotAccessible.ts ===
+class T {
+>T : Symbol(T, Decl(classFieldSuperNotAccessible.ts, 0, 0))
+
+    field = () => {}
+>field : Symbol(T.field, Decl(classFieldSuperNotAccessible.ts, 0, 9))
+}
+class T2 extends T {
+>T2 : Symbol(T2, Decl(classFieldSuperNotAccessible.ts, 2, 1))
+>T : Symbol(T, Decl(classFieldSuperNotAccessible.ts, 0, 0))
+
+    f() {
+>f : Symbol(T2.f, Decl(classFieldSuperNotAccessible.ts, 3, 20))
+
+        super.field() // error
+>super.field : Symbol(T.field, Decl(classFieldSuperNotAccessible.ts, 0, 9))
+>super : Symbol(T, Decl(classFieldSuperNotAccessible.ts, 0, 0))
+>field : Symbol(T.field, Decl(classFieldSuperNotAccessible.ts, 0, 9))
+    }
+}
+
+new T2().f()
+>new T2().f : Symbol(T2.f, Decl(classFieldSuperNotAccessible.ts, 3, 20))
+>T2 : Symbol(T2, Decl(classFieldSuperNotAccessible.ts, 2, 1))
+>f : Symbol(T2.f, Decl(classFieldSuperNotAccessible.ts, 3, 20))
+

tests/baselines/reference/classFieldSuperNotAccessible.types

@@ -0,0 +1,32 @@
+//// [tests/cases/compiler/classFieldSuperNotAccessible.ts] ////
+
+=== classFieldSuperNotAccessible.ts ===
+class T {
+>T : T
+
+    field = () => {}
+>field : () => void
+>() => {} : () => void
+}
+class T2 extends T {
+>T2 : T2
+>T : T
+
+    f() {
+>f : () => void
+
+        super.field() // error
+>super.field() : void
+>super.field : () => void
+>super : T
+>field : () => void
+    }
+}
+
+new T2().f()
+>new T2().f() : void
+>new T2().f : () => void
+>new T2() : T2
+>T2 : typeof T2
+>f : () => void
+

tests/cases/compiler/classFieldSuperAccessible.ts

@@ -0,0 +1,16 @@
+// @target: esnext
+class A extends class Expr {} {
+    static {
+        console.log(super.name);
+    }
+}
+class B extends Number {
+    static {
+        console.log(super.EPSILON);
+    }
+}
+class C extends Array {
+    foo() {
+        console.log(super.length);
+    }
+}

tests/cases/compiler/classFieldSuperNotAccessible.ts

@@ -0,0 +1,11 @@
+// @target: esnext
+class T {
+    field = () => {}
+}
+class T2 extends T {
+    f() {
+        super.field() // error
+    }
+}
+
+new T2().f()