Fix TS2540 not reported for readonly properties accessed through imports

internal/checker/checker.go

@@ -26592,21 +26592,6 @@ func (c *Checker) isAssignmentToReadonlyEntity(expr *ast.Node, symbol *ast.Symbo
 		// no assignment means it doesn't matter whether the entity is readonly
 		return false
 	}
-	if ast.IsAccessExpression(expr) {
-		node := ast.SkipParentheses(expr.Expression())
-		if ast.IsIdentifier(node) {
-			expressionSymbol := c.getResolvedSymbol(node)
-			// CommonJS module.exports is never readonly
-			if expressionSymbol.Flags&ast.SymbolFlagsModuleExports != 0 {
-				return false
-			}
-			// references through namespace import should be readonly
-			if expressionSymbol.Flags&ast.SymbolFlagsAlias != 0 {
-				declaration := c.getDeclarationOfAliasSymbol(expressionSymbol)
-				return declaration != nil && ast.IsNamespaceImport(declaration)
-			}
-		}
-	}
 	if c.isReadonlySymbol(symbol) {
 		// Allow assignments to readonly properties within constructors of the same class declaration.
 		if symbol.Flags&ast.SymbolFlagsProperty != 0 && ast.IsAccessExpression(expr) && expr.Expression().Kind == ast.KindThisKeyword {
@@ -26627,6 +26612,21 @@ func (c *Checker) isAssignmentToReadonlyEntity(expr *ast.Node, symbol *ast.Symbo
 		}
 		return true
 	}
+	if ast.IsAccessExpression(expr) {
+		// references through namespace import should be readonly
+		node := ast.SkipParentheses(expr.Expression())
+		if ast.IsIdentifier(node) {
+			expressionSymbol := c.getResolvedSymbol(node)
+			// CommonJS module.exports is never readonly
+			if expressionSymbol.Flags&ast.SymbolFlagsModuleExports != 0 {
+				return false
+			}
+			if expressionSymbol.Flags&ast.SymbolFlagsAlias != 0 {
+				declaration := c.getDeclarationOfAliasSymbol(expressionSymbol)
+				return declaration != nil && ast.IsNamespaceImport(declaration)
+			}
+		}
+	}
 	return false
 }
 

testdata/baselines/reference/compiler/readonlyDefaultExport.errors.txt

@@ -0,0 +1,17 @@
+b.ts(3,5): error TS2540: Cannot assign to 'a' because it is a read-only property.
+
+
+==== a.ts (0 errors) ====
+    const foo = {
+      a: 1
+    }
+
+    export default foo as Readonly<typeof foo>
+
+==== b.ts (1 errors) ====
+    import foo from './a'
+
+    foo.a = 2
+        ~
+!!! error TS2540: Cannot assign to 'a' because it is a read-only property.
+

testdata/baselines/reference/compiler/readonlyDefaultExport.js

@@ -0,0 +1,30 @@
+//// [tests/cases/compiler/readonlyDefaultExport.ts] ////
+
+//// [a.ts]
+const foo = {
+  a: 1
+}
+
+export default foo as Readonly<typeof foo>
+
+//// [b.ts]
+import foo from './a'
+
+foo.a = 2
+
+
+//// [a.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+const foo = {
+    a: 1
+};
+exports.default = foo;
+//// [b.js]
+"use strict";
+var __importDefault = (this && this.__importDefault) || function (mod) {
+    return (mod && mod.__esModule) ? mod : { "default": mod };
+};
+Object.defineProperty(exports, "__esModule", { value: true });
+const a_1 = __importDefault(require("./a"));
+a_1.default.a = 2;

testdata/baselines/reference/compiler/readonlyDefaultExport.symbols

@@ -0,0 +1,24 @@
+//// [tests/cases/compiler/readonlyDefaultExport.ts] ////
+
+=== a.ts ===
+const foo = {
+>foo : Symbol(foo, Decl(a.ts, 0, 5))
+
+  a: 1
+>a : Symbol(a, Decl(a.ts, 0, 13))
+}
+
+export default foo as Readonly<typeof foo>
+>foo : Symbol(foo, Decl(a.ts, 0, 5))
+>Readonly : Symbol(Readonly, Decl(lib.es5.d.ts, --, --))
+>foo : Symbol(foo, Decl(a.ts, 0, 5))
+
+=== b.ts ===
+import foo from './a'
+>foo : Symbol(foo, Decl(b.ts, 0, 6))
+
+foo.a = 2
+>foo.a : Symbol(a, Decl(a.ts, 0, 13))
+>foo : Symbol(foo, Decl(b.ts, 0, 6))
+>a : Symbol(a, Decl(a.ts, 0, 13))
+

testdata/baselines/reference/compiler/readonlyDefaultExport.types

@@ -0,0 +1,28 @@
+//// [tests/cases/compiler/readonlyDefaultExport.ts] ////
+
+=== a.ts ===
+const foo = {
+>foo : { a: number; }
+>{  a: 1} : { a: number; }
+
+  a: 1
+>a : number
+>1 : 1
+}
+
+export default foo as Readonly<typeof foo>
+>foo as Readonly<typeof foo> : Readonly<{ a: number; }>
+>foo : { a: number; }
+>foo : { a: number; }
+
+=== b.ts ===
+import foo from './a'
+>foo : Readonly<{ a: number; }>
+
+foo.a = 2
+>foo.a = 2 : 2
+>foo.a : any
+>foo : Readonly<{ a: number; }>
+>a : any
+>2 : 2
+

testdata/baselines/reference/conformance/typedefModuleExportsIndirect1.errors.txt

@@ -0,0 +1,14 @@
+typedefModuleExportsIndirect1.js(3,8): error TS2540: Cannot assign to 'exports' because it is a read-only property.
+
+
+==== typedefModuleExportsIndirect1.js (1 errors) ====
+    /** @typedef {{ a: 1, m: 1 }} C */
+    const dummy = 0;
+    module.exports = dummy;
+           ~~~~~~~
+!!! error TS2540: Cannot assign to 'exports' because it is a read-only property.
+==== use.js (0 errors) ====
+    /** @typedef {import('./typedefModuleExportsIndirect1').C} C */
+    /** @type {C} */
+    var c
+

testdata/baselines/reference/conformance/typedefModuleExportsIndirect1.js

@@ -33,32 +33,3 @@ type C = import('./typedefModuleExportsIndirect1').C;
 /** @typedef {import('./typedefModuleExportsIndirect1').C} C */
 /** @type {C} */
 declare var c: C;
-
-
-//// [DtsFileErrors]
-
-
-dist/typedefModuleExportsIndirect1.d.ts(5,1): error TS2309: An export assignment cannot be used in a module with other exported elements.
-dist/typedefModuleExportsIndirect1.d.ts(5,10): error TS2304: Cannot find name 'dummy'.
-dist/use.d.ts(1,52): error TS2694: Namespace 'unknown' has no exported member 'C'.
-
-
-==== dist/typedefModuleExportsIndirect1.d.ts (2 errors) ====
-    export type C = {
-        a: 1;
-        m: 1;
-    };
-    export = dummy;
-    ~~~~~~~~~~~~~~~
-!!! error TS2309: An export assignment cannot be used in a module with other exported elements.
-             ~~~~~
-!!! error TS2304: Cannot find name 'dummy'.
-
-==== dist/use.d.ts (1 errors) ====
-    type C = import('./typedefModuleExportsIndirect1').C;
-                                                       ~
-!!! error TS2694: Namespace 'unknown' has no exported member 'C'.
-    /** @typedef {import('./typedefModuleExportsIndirect1').C} C */
-    /** @type {C} */
-    declare var c: C;
-

testdata/baselines/reference/conformance/typedefModuleExportsIndirect1.types

@@ -8,9 +8,9 @@ const dummy = 0;
 
 module.exports = dummy;
 >module.exports = dummy : 0
->module.exports : 0
+>module.exports : any
 >module : { readonly dummy: 0; }
->exports : 0
+>exports : any
 >dummy : 0
 
 === use.js ===

testdata/baselines/reference/conformance/typedefModuleExportsIndirect2.errors.txt

@@ -0,0 +1,14 @@
+typedefModuleExportsIndirect2.js(3,8): error TS2540: Cannot assign to 'exports' because it is a read-only property.
+
+
+==== typedefModuleExportsIndirect2.js (1 errors) ====
+    /** @typedef {{ a: 1, m: 1 }} C */
+    const f = function() {};
+    module.exports = f;
+           ~~~~~~~
+!!! error TS2540: Cannot assign to 'exports' because it is a read-only property.
+==== use.js (0 errors) ====
+    /** @typedef {import('./typedefModuleExportsIndirect2').C} C */
+    /** @type {C} */
+    var c
+

testdata/baselines/reference/conformance/typedefModuleExportsIndirect2.js

@@ -33,32 +33,3 @@ type C = import('./typedefModuleExportsIndirect2').C;
 /** @typedef {import('./typedefModuleExportsIndirect2').C} C */
 /** @type {C} */
 declare var c: C;
-
-
-//// [DtsFileErrors]
-
-
-dist/typedefModuleExportsIndirect2.d.ts(5,1): error TS2309: An export assignment cannot be used in a module with other exported elements.
-dist/typedefModuleExportsIndirect2.d.ts(5,10): error TS2304: Cannot find name 'f'.
-dist/use.d.ts(1,52): error TS2694: Namespace 'unknown' has no exported member 'C'.
-
-
-==== dist/typedefModuleExportsIndirect2.d.ts (2 errors) ====
-    export type C = {
-        a: 1;
-        m: 1;
-    };
-    export = f;
-    ~~~~~~~~~~~
-!!! error TS2309: An export assignment cannot be used in a module with other exported elements.
-             ~
-!!! error TS2304: Cannot find name 'f'.
-
-==== dist/use.d.ts (1 errors) ====
-    type C = import('./typedefModuleExportsIndirect2').C;
-                                                       ~
-!!! error TS2694: Namespace 'unknown' has no exported member 'C'.
-    /** @typedef {import('./typedefModuleExportsIndirect2').C} C */
-    /** @type {C} */
-    declare var c: C;
-

testdata/baselines/reference/conformance/typedefModuleExportsIndirect2.types

@@ -8,9 +8,9 @@ const f = function() {};
 
 module.exports = f;
 >module.exports = f : () => void
->module.exports : () => void
+>module.exports : any
 >module : { readonly f: () => void; }
->exports : () => void
+>exports : any
 >f : () => void
 
 === use.js ===

testdata/baselines/reference/conformance/typedefModuleExportsIndirect3.errors.txt

@@ -0,0 +1,14 @@
+typedefModuleExportsIndirect3.js(3,8): error TS2540: Cannot assign to 'exports' because it is a read-only property.
+
+
+==== typedefModuleExportsIndirect3.js (1 errors) ====
+    /** @typedef {{ a: 1, m: 1 }} C */
+    const o = {};
+    module.exports = o;
+           ~~~~~~~
+!!! error TS2540: Cannot assign to 'exports' because it is a read-only property.
+==== use.js (0 errors) ====
+    /** @typedef {import('./typedefModuleExportsIndirect3').C} C */
+    /** @type {C} */
+    var c
+

testdata/baselines/reference/conformance/typedefModuleExportsIndirect3.js

@@ -33,32 +33,3 @@ type C = import('./typedefModuleExportsIndirect3').C;
 /** @typedef {import('./typedefModuleExportsIndirect3').C} C */
 /** @type {C} */
 declare var c: C;
-
-
-//// [DtsFileErrors]
-
-
-dist/typedefModuleExportsIndirect3.d.ts(5,1): error TS2309: An export assignment cannot be used in a module with other exported elements.
-dist/typedefModuleExportsIndirect3.d.ts(5,10): error TS2304: Cannot find name 'o'.
-dist/use.d.ts(1,52): error TS2694: Namespace 'unknown' has no exported member 'C'.
-
-
-==== dist/typedefModuleExportsIndirect3.d.ts (2 errors) ====
-    export type C = {
-        a: 1;
-        m: 1;
-    };
-    export = o;
-    ~~~~~~~~~~~
-!!! error TS2309: An export assignment cannot be used in a module with other exported elements.
-             ~
-!!! error TS2304: Cannot find name 'o'.
-
-==== dist/use.d.ts (1 errors) ====
-    type C = import('./typedefModuleExportsIndirect3').C;
-                                                       ~
-!!! error TS2694: Namespace 'unknown' has no exported member 'C'.
-    /** @typedef {import('./typedefModuleExportsIndirect3').C} C */
-    /** @type {C} */
-    declare var c: C;
-

testdata/baselines/reference/conformance/typedefModuleExportsIndirect3.types

@@ -8,9 +8,9 @@ const o = {};
 
 module.exports = o;
 >module.exports = o : {}
->module.exports : {}
+>module.exports : any
 >module : { readonly o: {}; }
->exports : {}
+>exports : any
 >o : {}
 
 === use.js ===