Add circularity tests

Author: ahejlsberg

tests/baselines/reference/circularIndexedAccessErrors.errors.txt

@@ -0,0 +1,57 @@
+tests/cases/conformance/types/keyof/circularIndexedAccessErrors.ts(3,5): error TS2502: 'x' is referenced directly or indirectly in its own type annotation.
+tests/cases/conformance/types/keyof/circularIndexedAccessErrors.ts(7,5): error TS2502: 'x' is referenced directly or indirectly in its own type annotation.
+tests/cases/conformance/types/keyof/circularIndexedAccessErrors.ts(15,5): error TS2502: 'x' is referenced directly or indirectly in its own type annotation.
+tests/cases/conformance/types/keyof/circularIndexedAccessErrors.ts(19,5): error TS2502: 'x' is referenced directly or indirectly in its own type annotation.
+tests/cases/conformance/types/keyof/circularIndexedAccessErrors.ts(23,5): error TS2502: 'x' is referenced directly or indirectly in its own type annotation.
+tests/cases/conformance/types/keyof/circularIndexedAccessErrors.ts(27,5): error TS2502: 'x' is referenced directly or indirectly in its own type annotation.
+tests/cases/conformance/types/keyof/circularIndexedAccessErrors.ts(28,5): error TS2502: 'y' is referenced directly or indirectly in its own type annotation.
+tests/cases/conformance/types/keyof/circularIndexedAccessErrors.ts(29,5): error TS2502: 'z' is referenced directly or indirectly in its own type annotation.
+
+
+==== tests/cases/conformance/types/keyof/circularIndexedAccessErrors.ts (8 errors) ====
+    
+    type T1 = {
+        x: T1["x"];  // Error
+        ~~~~~~~~~~~
+!!! error TS2502: 'x' is referenced directly or indirectly in its own type annotation.
+    };
+    
+    type T2<K extends "x" | "y"> = {
+        x: T2<K>[K];  // Error
+        ~~~~~~~~~~~~
+!!! error TS2502: 'x' is referenced directly or indirectly in its own type annotation.
+        y: number;
+    }
+    
+    declare let x2: T2<"x">;
+    let x2x = x2.x;
+    
+    interface T3<T extends T3<T>> {
+        x: T["x"];  // Error
+        ~~~~~~~~~~
+!!! error TS2502: 'x' is referenced directly or indirectly in its own type annotation.
+    }
+    
+    interface T4<T extends T4<T>> {
+        x: T4<T>["x"];  // Error
+        ~~~~~~~~~~~~~~
+!!! error TS2502: 'x' is referenced directly or indirectly in its own type annotation.
+    }
+    
+    class C1 {
+        x: C1["x"];  // Error
+        ~~~~~~~~~~~
+!!! error TS2502: 'x' is referenced directly or indirectly in its own type annotation.
+    }
+    
+    class C2 {
+        x: this["y"];  // Error
+        ~~~~~~~~~~~~~
+!!! error TS2502: 'x' is referenced directly or indirectly in its own type annotation.
+        y: this["z"];  // Error
+        ~~~~~~~~~~~~~
+!!! error TS2502: 'y' is referenced directly or indirectly in its own type annotation.
+        z: this["x"];  // Error
+        ~~~~~~~~~~~~~
+!!! error TS2502: 'z' is referenced directly or indirectly in its own type annotation.
+    }

tests/baselines/reference/circularIndexedAccessErrors.js

@@ -0,0 +1,70 @@
+//// [circularIndexedAccessErrors.ts]
+
+type T1 = {
+    x: T1["x"];  // Error
+};
+
+type T2<K extends "x" | "y"> = {
+    x: T2<K>[K];  // Error
+    y: number;
+}
+
+declare let x2: T2<"x">;
+let x2x = x2.x;
+
+interface T3<T extends T3<T>> {
+    x: T["x"];  // Error
+}
+
+interface T4<T extends T4<T>> {
+    x: T4<T>["x"];  // Error
+}
+
+class C1 {
+    x: C1["x"];  // Error
+}
+
+class C2 {
+    x: this["y"];  // Error
+    y: this["z"];  // Error
+    z: this["x"];  // Error
+}
+
+//// [circularIndexedAccessErrors.js]
+var x2x = x2.x;
+var C1 = (function () {
+    function C1() {
+    }
+    return C1;
+}());
+var C2 = (function () {
+    function C2() {
+    }
+    return C2;
+}());
+
+
+//// [circularIndexedAccessErrors.d.ts]
+declare type T1 = {
+    x: T1["x"];
+};
+declare type T2<K extends "x" | "y"> = {
+    x: T2<K>[K];
+    y: number;
+};
+declare let x2: T2<"x">;
+declare let x2x: any;
+interface T3<T extends T3<T>> {
+    x: T["x"];
+}
+interface T4<T extends T4<T>> {
+    x: T4<T>["x"];
+}
+declare class C1 {
+    x: C1["x"];
+}
+declare class C2 {
+    x: this["y"];
+    y: this["z"];
+    z: this["x"];
+}

tests/cases/conformance/types/keyof/circularIndexedAccessErrors.ts

@@ -0,0 +1,31 @@
+// @declaration: true
+
+type T1 = {
+    x: T1["x"];  // Error
+};
+
+type T2<K extends "x" | "y"> = {
+    x: T2<K>[K];  // Error
+    y: number;
+}
+
+declare let x2: T2<"x">;
+let x2x = x2.x;
+
+interface T3<T extends T3<T>> {
+    x: T["x"];  // Error
+}
+
+interface T4<T extends T4<T>> {
+    x: T4<T>["x"];  // Error
+}
+
+class C1 {
+    x: C1["x"];  // Error
+}
+
+class C2 {
+    x: this["y"];  // Error
+    y: this["z"];  // Error
+    z: this["x"];  // Error
+}