fix: Inconsistencies in ESM-style imports of accessibility-modified proper...

src/compiler/checker.ts

@@ -4069,14 +4069,19 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
 
                 let symbolFromVariable: Symbol | undefined;
                 // First check if module was specified with "export=". If so, get the member from the resolved type
-                if (moduleSymbol && moduleSymbol.exports && moduleSymbol.exports.get(InternalSymbolName.ExportEquals)) {
+                const isExportEquals = !!(moduleSymbol && moduleSymbol.exports && moduleSymbol.exports.get(InternalSymbolName.ExportEquals));
+                if (isExportEquals) {
                     symbolFromVariable = getPropertyOfType(getTypeOfSymbol(targetSymbol), nameText, /*skipObjectFunctionPropertyAugment*/ true);
                 }
                 else {
                     symbolFromVariable = getPropertyOfVariable(targetSymbol, nameText);
                 }
                 // if symbolFromVariable is export - get its final target
                 symbolFromVariable = resolveSymbol(symbolFromVariable, dontResolveAlias);
+                // Check accessibility for named imports from CJS export= modules whose exports are class members
+                if (!dontResolveAlias && isExportEquals && symbolFromVariable && isImportSpecifier(specifier)) {
+                    checkPropertyAccessibilityAtLocation(specifier, /*isSuper*/ false, /*writing*/ false, getTypeOfSymbol(targetSymbol), symbolFromVariable, name);
+                }
 
                 let symbolFromModule = getExportOfModule(targetSymbol, nameText, specifier, dontResolveAlias);
                 if (symbolFromModule === undefined && nameText === InternalSymbolName.Default) {

tests/baselines/reference/namedImportFromCjsClassExportAccessibility.errors.txt

@@ -0,0 +1,22 @@
+main.ts(1,13): error TS2445: Property 'b' is protected and only accessible within class 'X' and its subclasses.
+main.ts(1,16): error TS2341: Property 'c' is private and only accessible within class 'X'.
+main.ts(1,25): error TS2497: This module can only be referenced with ECMAScript imports/exports by turning on the 'esModuleInterop' flag and referencing its default export.
+
+
+==== module.ts (0 errors) ====
+    class X {
+        public static a = 1;
+        protected static b = 2;
+        private static c = 3;
+    }
+    export = X;
+
+==== main.ts (3 errors) ====
+    import { a, b, c } from "./module";
+                ~
+!!! error TS2445: Property 'b' is protected and only accessible within class 'X' and its subclasses.
+                   ~
+!!! error TS2341: Property 'c' is private and only accessible within class 'X'.
+                            ~~~~~~~~~~
+!!! error TS2497: This module can only be referenced with ECMAScript imports/exports by turning on the 'esModuleInterop' flag and referencing its default export.
+

tests/baselines/reference/namedImportFromCjsClassExportAccessibility.js

@@ -0,0 +1,25 @@
+//// [tests/cases/compiler/namedImportFromCjsClassExportAccessibility.ts] ////
+
+//// [module.ts]
+class X {
+    public static a = 1;
+    protected static b = 2;
+    private static c = 3;
+}
+export = X;
+
+//// [main.ts]
+import { a, b, c } from "./module";
+
+
+//// [module.js]
+"use strict";
+class X {
+}
+X.a = 1;
+X.b = 2;
+X.c = 3;
+module.exports = X;
+//// [main.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });

tests/baselines/reference/namedImportFromCjsClassExportAccessibility.symbols

@@ -0,0 +1,24 @@
+//// [tests/cases/compiler/namedImportFromCjsClassExportAccessibility.ts] ////
+
+=== module.ts ===
+class X {
+>X : Symbol(X, Decl(module.ts, 0, 0))
+
+    public static a = 1;
+>a : Symbol(X.a, Decl(module.ts, 0, 9))
+
+    protected static b = 2;
+>b : Symbol(X.b, Decl(module.ts, 1, 24))
+
+    private static c = 3;
+>c : Symbol(X.c, Decl(module.ts, 2, 27))
+}
+export = X;
+>X : Symbol(X, Decl(module.ts, 0, 0))
+
+=== main.ts ===
+import { a, b, c } from "./module";
+>a : Symbol(a, Decl(main.ts, 0, 8))
+>b : Symbol(b, Decl(main.ts, 0, 11))
+>c : Symbol(c, Decl(main.ts, 0, 14))
+

tests/baselines/reference/namedImportFromCjsClassExportAccessibility.types

@@ -0,0 +1,38 @@
+//// [tests/cases/compiler/namedImportFromCjsClassExportAccessibility.ts] ////
+
+=== module.ts ===
+class X {
+>X : X
+>  : ^
+
+    public static a = 1;
+>a : number
+>  : ^^^^^^
+>1 : 1
+>  : ^
+
+    protected static b = 2;
+>b : number
+>  : ^^^^^^
+>2 : 2
+>  : ^
+
+    private static c = 3;
+>c : number
+>  : ^^^^^^
+>3 : 3
+>  : ^
+}
+export = X;
+>X : X
+>  : ^
+
+=== main.ts ===
+import { a, b, c } from "./module";
+>a : number
+>  : ^^^^^^
+>b : number
+>  : ^^^^^^
+>c : number
+>  : ^^^^^^
+

tests/cases/compiler/namedImportFromCjsClassExportAccessibility.ts

@@ -0,0 +1,15 @@
+// @target: es2020
+// @module: commonjs
+// @strict: true
+// @esModuleInterop: true
+
+// @Filename: module.ts
+class X {
+    public static a = 1;
+    protected static b = 2;
+    private static c = 3;
+}
+export = X;
+
+// @Filename: main.ts
+import { a, b, c } from "./module";