produce an error if private field helpers are not up to date

src/compiler/checker.ts

@@ -26791,12 +26791,18 @@ namespace ts {
             const parentSymbol = getNodeLinks(left).resolvedSymbol;
             const assignmentKind = getAssignmentTargetKind(node);
             const apparentType = getApparentType(assignmentKind !== AssignmentKind.None || isMethodAccessForCall(node) ? getWidenedType(leftType) : leftType);
-            if (isPrivateIdentifier(right)) {
-                checkExternalEmitHelpers(node, ExternalEmitHelpers.ClassPrivateFieldGet);
-            }
             const isAnyLike = isTypeAny(apparentType) || apparentType === silentNeverType;
             let prop: Symbol | undefined;
             if (isPrivateIdentifier(right)) {
+                if (languageVersion < ScriptTarget.ESNext) {
+                    if (assignmentKind !== AssignmentKind.None) {
+                        checkExternalEmitHelpers(node, ExternalEmitHelpers.ClassPrivateFieldSet);
+                    }
+                    if (assignmentKind !== AssignmentKind.Definite) {
+                        checkExternalEmitHelpers(node, ExternalEmitHelpers.ClassPrivateFieldGet);
+                    }
+                }
+
                 const lexicallyScopedSymbol = lookupSymbolForPrivateIdentifierDeclaration(right.escapedText, right);
                 if (assignmentKind && lexicallyScopedSymbol && lexicallyScopedSymbol.valueDeclaration && isMethodDeclaration(lexicallyScopedSymbol.valueDeclaration)) {
                     grammarErrorOnNode(right, Diagnostics.Cannot_assign_to_private_method_0_Private_methods_are_not_writable, idText(right));
@@ -26817,7 +26823,7 @@ namespace ts {
                 }
                 else {
                     const isSetonlyAccessor = prop && prop.flags & SymbolFlags.SetAccessor && !(prop.flags & SymbolFlags.GetAccessor);
-                    if (isSetonlyAccessor && !isAssignmentTarget(node)) {
+                    if (isSetonlyAccessor && assignmentKind !== AssignmentKind.Definite) {
                         error(node, Diagnostics.Private_accessor_was_defined_without_a_getter);
                     }
                 }
@@ -39906,6 +39912,16 @@ namespace ts {
                                 if (!symbol) {
                                     error(location, Diagnostics.This_syntax_requires_an_imported_helper_named_1_which_does_not_exist_in_0_Consider_upgrading_your_version_of_0, externalHelpersModuleNameText, name);
                                 }
+                                else if (helper & ExternalEmitHelpers.ClassPrivateFieldGet) {
+                                    if (!some(getSignaturesOfSymbol(symbol), signature => getParameterCount(signature) > 3)) {
+                                        error(location, Diagnostics.This_syntax_requires_an_imported_helper_named_1_with_2_parameters_which_is_not_compatible_with_the_one_in_0_Consider_upgrading_your_version_of_0, externalHelpersModuleNameText, name, 4);
+                                    }
+                                }
+                                else if (helper & ExternalEmitHelpers.ClassPrivateFieldSet) {
+                                    if (!some(getSignaturesOfSymbol(symbol), signature => getParameterCount(signature) > 4)) {
+                                        error(location, Diagnostics.This_syntax_requires_an_imported_helper_named_1_with_2_parameters_which_is_not_compatible_with_the_one_in_0_Consider_upgrading_your_version_of_0, externalHelpersModuleNameText, name, 5);
+                                    }
+                                }
                             }
                         }
                     }

src/compiler/diagnosticMessages.json

@@ -3300,6 +3300,10 @@
         "category": "Error",
         "code": 2806
     },
+    "This syntax requires an imported helper named '{1}' with {2} parameters, which is not compatible with the one in '{0}'. Consider upgrading your version of '{0}'.": {
+        "category": "Error",
+        "code": 2807
+    },
 
     "Import declaration '{0}' is using private name '{1}'.": {
         "category": "Error",

tests/baselines/reference/privateNameEmitHelpers.errors.txt

@@ -0,0 +1,20 @@
+tests/cases/conformance/classes/members/privateNames/main.ts(3,12): error TS2807: This syntax requires an imported helper named '__classPrivateFieldSet' with 5 parameters, which is not compatible with the one in 'tslib'. Consider upgrading your version of 'tslib'.
+tests/cases/conformance/classes/members/privateNames/main.ts(4,25): error TS2807: This syntax requires an imported helper named '__classPrivateFieldGet' with 4 parameters, which is not compatible with the one in 'tslib'. Consider upgrading your version of 'tslib'.
+
+
+==== tests/cases/conformance/classes/members/privateNames/main.ts (2 errors) ====
+    export class C {
+        #a = 1;
+        #b() { this.#c = 42; }
+               ~~~~~~~
+!!! error TS2807: This syntax requires an imported helper named '__classPrivateFieldSet' with 5 parameters, which is not compatible with the one in 'tslib'. Consider upgrading your version of 'tslib'.
+        set #c(v: number) { this.#a += v; }
+                            ~~~~~~~
+!!! error TS2807: This syntax requires an imported helper named '__classPrivateFieldGet' with 4 parameters, which is not compatible with the one in 'tslib'. Consider upgrading your version of 'tslib'.
+    }
+
+==== tests/cases/conformance/classes/members/privateNames/tslib.d.ts (0 errors) ====
+    // these are pre-TS4.3 versions of emit helpers, which only supported private instance fields
+    export declare function __classPrivateFieldGet<T extends object, V>(receiver: T, state: any): V;
+    export declare function __classPrivateFieldSet<T extends object, V>(receiver: T, state: any, value: V): V;
+

tests/baselines/reference/privateNameEmitHelpers.js

@@ -0,0 +1,25 @@
+//// [tests/cases/conformance/classes/members/privateNames/privateNameEmitHelpers.ts] ////
+
+//// [main.ts]
+export class C {
+    #a = 1;
+    #b() { this.#c = 42; }
+    set #c(v: number) { this.#a += v; }
+}
+
+//// [tslib.d.ts]
+// these are pre-TS4.3 versions of emit helpers, which only supported private instance fields
+export declare function __classPrivateFieldGet<T extends object, V>(receiver: T, state: any): V;
+export declare function __classPrivateFieldSet<T extends object, V>(receiver: T, state: any, value: V): V;
+
+
+//// [main.js]
+var _C_instances, _C_a, _C_b, _C_c_set;
+import { __classPrivateFieldGet, __classPrivateFieldSet } from "tslib";
+export class C {
+    constructor() {
+        _C_instances.add(this);
+        _C_a.set(this, 1);
+    }
+}
+_C_a = new WeakMap(), _C_instances = new WeakSet(), _C_b = function _C_b() { __classPrivateFieldSet(this, _C_instances, 42, "a", _C_c_set); }, _C_c_set = function _C_c_set(v) { __classPrivateFieldSet(this, _C_a, __classPrivateFieldGet(this, _C_a, "f") + v, "f"); };

tests/baselines/reference/privateNameEmitHelpers.symbols

@@ -0,0 +1,42 @@
+=== tests/cases/conformance/classes/members/privateNames/main.ts ===
+export class C {
+>C : Symbol(C, Decl(main.ts, 0, 0))
+
+    #a = 1;
+>#a : Symbol(C.#a, Decl(main.ts, 0, 16))
+
+    #b() { this.#c = 42; }
+>#b : Symbol(C.#b, Decl(main.ts, 1, 11))
+>this.#c : Symbol(C.#c, Decl(main.ts, 2, 26))
+>this : Symbol(C, Decl(main.ts, 0, 0))
+
+    set #c(v: number) { this.#a += v; }
+>#c : Symbol(C.#c, Decl(main.ts, 2, 26))
+>v : Symbol(v, Decl(main.ts, 3, 11))
+>this.#a : Symbol(C.#a, Decl(main.ts, 0, 16))
+>this : Symbol(C, Decl(main.ts, 0, 0))
+>v : Symbol(v, Decl(main.ts, 3, 11))
+}
+
+=== tests/cases/conformance/classes/members/privateNames/tslib.d.ts ===
+// these are pre-TS4.3 versions of emit helpers, which only supported private instance fields
+export declare function __classPrivateFieldGet<T extends object, V>(receiver: T, state: any): V;
+>__classPrivateFieldGet : Symbol(__classPrivateFieldGet, Decl(tslib.d.ts, --, --))
+>T : Symbol(T, Decl(tslib.d.ts, --, --))
+>V : Symbol(V, Decl(tslib.d.ts, --, --))
+>receiver : Symbol(receiver, Decl(tslib.d.ts, --, --))
+>T : Symbol(T, Decl(tslib.d.ts, --, --))
+>state : Symbol(state, Decl(tslib.d.ts, --, --))
+>V : Symbol(V, Decl(tslib.d.ts, --, --))
+
+export declare function __classPrivateFieldSet<T extends object, V>(receiver: T, state: any, value: V): V;
+>__classPrivateFieldSet : Symbol(__classPrivateFieldSet, Decl(tslib.d.ts, --, --))
+>T : Symbol(T, Decl(tslib.d.ts, --, --))
+>V : Symbol(V, Decl(tslib.d.ts, --, --))
+>receiver : Symbol(receiver, Decl(tslib.d.ts, --, --))
+>T : Symbol(T, Decl(tslib.d.ts, --, --))
+>state : Symbol(state, Decl(tslib.d.ts, --, --))
+>value : Symbol(value, Decl(tslib.d.ts, --, --))
+>V : Symbol(V, Decl(tslib.d.ts, --, --))
+>V : Symbol(V, Decl(tslib.d.ts, --, --))
+

tests/baselines/reference/privateNameEmitHelpers.types

@@ -0,0 +1,37 @@
+=== tests/cases/conformance/classes/members/privateNames/main.ts ===
+export class C {
+>C : C
+
+    #a = 1;
+>#a : number
+>1 : 1
+
+    #b() { this.#c = 42; }
+>#b : () => void
+>this.#c = 42 : 42
+>this.#c : number
+>this : this
+>42 : 42
+
+    set #c(v: number) { this.#a += v; }
+>#c : number
+>v : number
+>this.#a += v : number
+>this.#a : number
+>this : this
+>v : number
+}
+
+=== tests/cases/conformance/classes/members/privateNames/tslib.d.ts ===
+// these are pre-TS4.3 versions of emit helpers, which only supported private instance fields
+export declare function __classPrivateFieldGet<T extends object, V>(receiver: T, state: any): V;
+>__classPrivateFieldGet : <T extends object, V>(receiver: T, state: any) => V
+>receiver : T
+>state : any
+
+export declare function __classPrivateFieldSet<T extends object, V>(receiver: T, state: any, value: V): V;
+>__classPrivateFieldSet : <T extends object, V>(receiver: T, state: any, value: V) => V
+>receiver : T
+>state : any
+>value : V
+

tests/baselines/reference/privateNameStaticEmitHelpers.errors.txt

@@ -0,0 +1,20 @@
+tests/cases/conformance/classes/members/privateNames/main.ts(3,19): error TS2807: This syntax requires an imported helper named '__classPrivateFieldSet' with 5 parameters, which is not compatible with the one in 'tslib'. Consider upgrading your version of 'tslib'.
+tests/cases/conformance/classes/members/privateNames/main.ts(4,30): error TS2807: This syntax requires an imported helper named '__classPrivateFieldGet' with 4 parameters, which is not compatible with the one in 'tslib'. Consider upgrading your version of 'tslib'.
+
+
+==== tests/cases/conformance/classes/members/privateNames/main.ts (2 errors) ====
+    export class S {
+        static #a = 1;
+        static #b() { this.#a = 42; }
+                      ~~~~~~~
+!!! error TS2807: This syntax requires an imported helper named '__classPrivateFieldSet' with 5 parameters, which is not compatible with the one in 'tslib'. Consider upgrading your version of 'tslib'.
+        static get #c() { return S.#b(); }
+                                 ~~~~
+!!! error TS2807: This syntax requires an imported helper named '__classPrivateFieldGet' with 4 parameters, which is not compatible with the one in 'tslib'. Consider upgrading your version of 'tslib'.
+    }
+
+==== tests/cases/conformance/classes/members/privateNames/tslib.d.ts (0 errors) ====
+    // these are pre-TS4.3 versions of emit helpers, which only supported private instance fields
+    export declare function __classPrivateFieldGet<T extends object, V>(receiver: T, state: any): V;
+    export declare function __classPrivateFieldSet<T extends object, V>(receiver: T, state: any, value: V): V;
+

tests/baselines/reference/privateNameStaticEmitHelpers.js

@@ -0,0 +1,22 @@
+//// [tests/cases/conformance/classes/members/privateNames/privateNameStaticEmitHelpers.ts] ////
+
+//// [main.ts]
+export class S {
+    static #a = 1;
+    static #b() { this.#a = 42; }
+    static get #c() { return S.#b(); }
+}
+
+//// [tslib.d.ts]
+// these are pre-TS4.3 versions of emit helpers, which only supported private instance fields
+export declare function __classPrivateFieldGet<T extends object, V>(receiver: T, state: any): V;
+export declare function __classPrivateFieldSet<T extends object, V>(receiver: T, state: any, value: V): V;
+
+
+//// [main.js]
+var _a, _S_a, _S_b, _S_c_get;
+import { __classPrivateFieldGet, __classPrivateFieldSet } from "tslib";
+export class S {
+}
+_a = S, _S_b = function _S_b() { __classPrivateFieldSet(this, _a, 42, "f", _S_a); }, _S_c_get = function _S_c_get() { return __classPrivateFieldGet(S, _a, "m", _S_b).call(S); };
+_S_a = { value: 1 };

tests/baselines/reference/privateNameStaticEmitHelpers.symbols

@@ -0,0 +1,40 @@
+=== tests/cases/conformance/classes/members/privateNames/main.ts ===
+export class S {
+>S : Symbol(S, Decl(main.ts, 0, 0))
+
+    static #a = 1;
+>#a : Symbol(S.#a, Decl(main.ts, 0, 16))
+
+    static #b() { this.#a = 42; }
+>#b : Symbol(S.#b, Decl(main.ts, 1, 18))
+>this.#a : Symbol(S.#a, Decl(main.ts, 0, 16))
+>this : Symbol(S, Decl(main.ts, 0, 0))
+
+    static get #c() { return S.#b(); }
+>#c : Symbol(S.#c, Decl(main.ts, 2, 33))
+>S.#b : Symbol(S.#b, Decl(main.ts, 1, 18))
+>S : Symbol(S, Decl(main.ts, 0, 0))
+}
+
+=== tests/cases/conformance/classes/members/privateNames/tslib.d.ts ===
+// these are pre-TS4.3 versions of emit helpers, which only supported private instance fields
+export declare function __classPrivateFieldGet<T extends object, V>(receiver: T, state: any): V;
+>__classPrivateFieldGet : Symbol(__classPrivateFieldGet, Decl(tslib.d.ts, --, --))
+>T : Symbol(T, Decl(tslib.d.ts, --, --))
+>V : Symbol(V, Decl(tslib.d.ts, --, --))
+>receiver : Symbol(receiver, Decl(tslib.d.ts, --, --))
+>T : Symbol(T, Decl(tslib.d.ts, --, --))
+>state : Symbol(state, Decl(tslib.d.ts, --, --))
+>V : Symbol(V, Decl(tslib.d.ts, --, --))
+
+export declare function __classPrivateFieldSet<T extends object, V>(receiver: T, state: any, value: V): V;
+>__classPrivateFieldSet : Symbol(__classPrivateFieldSet, Decl(tslib.d.ts, --, --))
+>T : Symbol(T, Decl(tslib.d.ts, --, --))
+>V : Symbol(V, Decl(tslib.d.ts, --, --))
+>receiver : Symbol(receiver, Decl(tslib.d.ts, --, --))
+>T : Symbol(T, Decl(tslib.d.ts, --, --))
+>state : Symbol(state, Decl(tslib.d.ts, --, --))
+>value : Symbol(value, Decl(tslib.d.ts, --, --))
+>V : Symbol(V, Decl(tslib.d.ts, --, --))
+>V : Symbol(V, Decl(tslib.d.ts, --, --))
+

tests/baselines/reference/privateNameStaticEmitHelpers.types

@@ -0,0 +1,35 @@
+=== tests/cases/conformance/classes/members/privateNames/main.ts ===
+export class S {
+>S : S
+
+    static #a = 1;
+>#a : number
+>1 : 1
+
+    static #b() { this.#a = 42; }
+>#b : () => void
+>this.#a = 42 : 42
+>this.#a : number
+>this : typeof S
+>42 : 42
+
+    static get #c() { return S.#b(); }
+>#c : void
+>S.#b() : void
+>S.#b : () => void
+>S : typeof S
+}
+
+=== tests/cases/conformance/classes/members/privateNames/tslib.d.ts ===
+// these are pre-TS4.3 versions of emit helpers, which only supported private instance fields
+export declare function __classPrivateFieldGet<T extends object, V>(receiver: T, state: any): V;
+>__classPrivateFieldGet : <T extends object, V>(receiver: T, state: any) => V
+>receiver : T
+>state : any
+
+export declare function __classPrivateFieldSet<T extends object, V>(receiver: T, state: any, value: V): V;
+>__classPrivateFieldSet : <T extends object, V>(receiver: T, state: any, value: V) => V
+>receiver : T
+>state : any
+>value : V
+

tests/baselines/reference/privateWriteOnlyAccessorRead.errors.txt

@@ -1,17 +1,19 @@
-tests/cases/conformance/classes/members/privateNames/privateWriteOnlyAccessorRead.ts(8,17): error TS2806: Private accessor was defined without a getter.
-tests/cases/conformance/classes/members/privateNames/privateWriteOnlyAccessorRead.ts(11,5): error TS2806: Private accessor was defined without a getter.
-tests/cases/conformance/classes/members/privateNames/privateWriteOnlyAccessorRead.ts(16,13): error TS2806: Private accessor was defined without a getter.
-tests/cases/conformance/classes/members/privateNames/privateWriteOnlyAccessorRead.ts(18,17): error TS2806: Private accessor was defined without a getter.
-tests/cases/conformance/classes/members/privateNames/privateWriteOnlyAccessorRead.ts(21,18): error TS2806: Private accessor was defined without a getter.
-tests/cases/conformance/classes/members/privateNames/privateWriteOnlyAccessorRead.ts(25,9): error TS2806: Private accessor was defined without a getter.
-tests/cases/conformance/classes/members/privateNames/privateWriteOnlyAccessorRead.ts(26,12): error TS2806: Private accessor was defined without a getter.
+tests/cases/conformance/classes/members/privateNames/privateWriteOnlyAccessorRead.ts(9,17): error TS2806: Private accessor was defined without a getter.
+tests/cases/conformance/classes/members/privateNames/privateWriteOnlyAccessorRead.ts(12,5): error TS2806: Private accessor was defined without a getter.
+tests/cases/conformance/classes/members/privateNames/privateWriteOnlyAccessorRead.ts(17,13): error TS2806: Private accessor was defined without a getter.
+tests/cases/conformance/classes/members/privateNames/privateWriteOnlyAccessorRead.ts(19,17): error TS2806: Private accessor was defined without a getter.
+tests/cases/conformance/classes/members/privateNames/privateWriteOnlyAccessorRead.ts(22,18): error TS2806: Private accessor was defined without a getter.
+tests/cases/conformance/classes/members/privateNames/privateWriteOnlyAccessorRead.ts(26,9): error TS2806: Private accessor was defined without a getter.
+tests/cases/conformance/classes/members/privateNames/privateWriteOnlyAccessorRead.ts(27,12): error TS2806: Private accessor was defined without a getter.
+tests/cases/conformance/classes/members/privateNames/privateWriteOnlyAccessorRead.ts(30,5): error TS2806: Private accessor was defined without a getter.
 
 
-==== tests/cases/conformance/classes/members/privateNames/privateWriteOnlyAccessorRead.ts (7 errors) ====
+==== tests/cases/conformance/classes/members/privateNames/privateWriteOnlyAccessorRead.ts (8 errors) ====
     class Test {
       set #value(v: { foo: { bar: number } }) {}
       set #valueRest(v: number[]) {}
       set #valueOne(v: number) {}
+      set #valueCompound(v: number) {}
 
       m() {
         const foo = { bar: 1 };
@@ -49,6 +51,10 @@ tests/cases/conformance/classes/members/privateNames/privateWriteOnlyAccessorRea
                ~~~~~~~~~~~~~~~
 !!! error TS2806: Private accessor was defined without a getter.
         ];
+
+        this.#valueCompound += 3;
+        ~~~~~~~~~~~~~~~~~~~
+!!! error TS2806: Private accessor was defined without a getter.
       }
     }
     new Test().m();

tests/baselines/reference/privateWriteOnlyAccessorRead.js

@@ -3,6 +3,7 @@ class Test {
   set #value(v: { foo: { bar: number } }) {}
   set #valueRest(v: number[]) {}
   set #valueOne(v: number) {}
+  set #valueCompound(v: number) {}
 
   m() {
     const foo = { bar: 1 };
@@ -26,6 +27,8 @@ class Test {
         this.#valueOne,
         ...this.#valueRest
     ];
+
+    this.#valueCompound += 3;
   }
 }
 new Test().m();
@@ -54,7 +57,7 @@ var __rest = (this && this.__rest) || function (s, e) {
         }
     return t;
 };
-var _Test_instances, _Test_value_set, _Test_valueRest_set, _Test_valueOne_set;
+var _Test_instances, _Test_value_set, _Test_valueRest_set, _Test_valueOne_set, _Test_valueCompound_set;
 class Test {
     constructor() {
         _Test_instances.add(this);
@@ -81,7 +84,8 @@ class Test {
             __classPrivateFieldGet(this, _Test_instances, "a"),
             ...__classPrivateFieldGet(this, _Test_instances, "a")
         ];
+        __classPrivateFieldSet(this, _Test_instances, __classPrivateFieldGet(this, _Test_instances, "a") + 3, "a", _Test_valueCompound_set);
     }
 }
-_Test_instances = new WeakSet(), _Test_value_set = function _Test_value_set(v) { }, _Test_valueRest_set = function _Test_valueRest_set(v) { }, _Test_valueOne_set = function _Test_valueOne_set(v) { };
+_Test_instances = new WeakSet(), _Test_value_set = function _Test_value_set(v) { }, _Test_valueRest_set = function _Test_valueRest_set(v) { }, _Test_valueOne_set = function _Test_valueOne_set(v) { }, _Test_valueCompound_set = function _Test_valueCompound_set(v) { };
 new Test().m();