Skip base type checks that can cause circularities

src/compiler/checker.ts

@@ -20082,6 +20082,14 @@ namespace ts {
             }
             (type as TypeReference).objectFlags |= ObjectFlags.IdenticalBaseTypeCalculated;
             const target = (type as TypeReference).target as InterfaceType;
+            if (getObjectFlags(target) & ObjectFlags.Class) {
+                const baseTypeNode = getBaseTypeNodeOfClass(target);
+                // A base type expression may circularly reference the class itself (e.g. as an argument to function call), so we only
+                // check for base types specified as simple qualified names.
+                if (baseTypeNode && baseTypeNode.expression.kind !== SyntaxKind.Identifier && baseTypeNode.expression.kind !== SyntaxKind.PropertyAccessExpression) {
+                    return undefined;
+                }
+            }
             const bases = getBaseTypes(target);
             if (bases.length !== 1) {
                 return undefined;

tests/baselines/reference/recursiveClassBaseType.js

@@ -0,0 +1,92 @@
+//// [recursiveClassBaseType.ts]
+// Repro from #44281
+
+declare const p: <T>(fn: () => T) => T;
+
+declare const Base: <T>(val: T) => { new(): T };
+
+class C extends Base({ x: p<C[]>(() => []) }) { }
+
+// Repro from #44359
+
+abstract class Base1 {
+    abstract root(): Derived1;
+}
+
+class Derived1 extends class extends Base1 {
+    root() {
+        return undefined as any;
+    }
+}
+{ }
+
+
+//// [recursiveClassBaseType.js]
+"use strict";
+// Repro from #44281
+var __extends = (this && this.__extends) || (function () {
+    var extendStatics = function (d, b) {
+        extendStatics = Object.setPrototypeOf ||
+            ({ __proto__: [] } instanceof Array && function (d, b) { d.__proto__ = b; }) ||
+            function (d, b) { for (var p in b) if (Object.prototype.hasOwnProperty.call(b, p)) d[p] = b[p]; };
+        return extendStatics(d, b);
+    };
+    return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
+        extendStatics(d, b);
+        function __() { this.constructor = d; }
+        d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
+    };
+})();
+var C = /** @class */ (function (_super) {
+    __extends(C, _super);
+    function C() {
+        return _super !== null && _super.apply(this, arguments) || this;
+    }
+    return C;
+}(Base({ x: p(function () { return []; }) })));
+// Repro from #44359
+var Base1 = /** @class */ (function () {
+    function Base1() {
+    }
+    return Base1;
+}());
+var Derived1 = /** @class */ (function (_super) {
+    __extends(Derived1, _super);
+    function Derived1() {
+        return _super !== null && _super.apply(this, arguments) || this;
+    }
+    return Derived1;
+}(/** @class */ (function (_super) {
+    __extends(class_1, _super);
+    function class_1() {
+        return _super !== null && _super.apply(this, arguments) || this;
+    }
+    class_1.prototype.root = function () {
+        return undefined;
+    };
+    return class_1;
+}(Base1))));
+
+
+//// [recursiveClassBaseType.d.ts]
+declare const p: <T>(fn: () => T) => T;
+declare const Base: <T>(val: T) => {
+    new (): T;
+};
+declare const C_base: new () => {
+    x: C[];
+};
+declare class C extends C_base {
+}
+declare abstract class Base1 {
+    abstract root(): Derived1;
+}
+declare const Derived1_base: {
+    new (): {
+        root(): any;
+    };
+};
+declare class Derived1 extends Derived1_base {
+}

tests/baselines/reference/recursiveClassBaseType.symbols

@@ -0,0 +1,47 @@
+=== tests/cases/compiler/recursiveClassBaseType.ts ===
+// Repro from #44281
+
+declare const p: <T>(fn: () => T) => T;
+>p : Symbol(p, Decl(recursiveClassBaseType.ts, 2, 13))
+>T : Symbol(T, Decl(recursiveClassBaseType.ts, 2, 18))
+>fn : Symbol(fn, Decl(recursiveClassBaseType.ts, 2, 21))
+>T : Symbol(T, Decl(recursiveClassBaseType.ts, 2, 18))
+>T : Symbol(T, Decl(recursiveClassBaseType.ts, 2, 18))
+
+declare const Base: <T>(val: T) => { new(): T };
+>Base : Symbol(Base, Decl(recursiveClassBaseType.ts, 4, 13))
+>T : Symbol(T, Decl(recursiveClassBaseType.ts, 4, 21))
+>val : Symbol(val, Decl(recursiveClassBaseType.ts, 4, 24))
+>T : Symbol(T, Decl(recursiveClassBaseType.ts, 4, 21))
+>T : Symbol(T, Decl(recursiveClassBaseType.ts, 4, 21))
+
+class C extends Base({ x: p<C[]>(() => []) }) { }
+>C : Symbol(C, Decl(recursiveClassBaseType.ts, 4, 48))
+>Base : Symbol(Base, Decl(recursiveClassBaseType.ts, 4, 13))
+>x : Symbol(x, Decl(recursiveClassBaseType.ts, 6, 22))
+>p : Symbol(p, Decl(recursiveClassBaseType.ts, 2, 13))
+>C : Symbol(C, Decl(recursiveClassBaseType.ts, 4, 48))
+
+// Repro from #44359
+
+abstract class Base1 {
+>Base1 : Symbol(Base1, Decl(recursiveClassBaseType.ts, 6, 49))
+
+    abstract root(): Derived1;
+>root : Symbol(Base1.root, Decl(recursiveClassBaseType.ts, 10, 22))
+>Derived1 : Symbol(Derived1, Decl(recursiveClassBaseType.ts, 12, 1))
+}
+
+class Derived1 extends class extends Base1 {
+>Derived1 : Symbol(Derived1, Decl(recursiveClassBaseType.ts, 12, 1))
+>Base1 : Symbol(Base1, Decl(recursiveClassBaseType.ts, 6, 49))
+
+    root() {
+>root : Symbol((Anonymous class).root, Decl(recursiveClassBaseType.ts, 14, 44))
+
+        return undefined as any;
+>undefined : Symbol(undefined)
+    }
+}
+{ }
+

tests/baselines/reference/recursiveClassBaseType.types

@@ -0,0 +1,46 @@
+=== tests/cases/compiler/recursiveClassBaseType.ts ===
+// Repro from #44281
+
+declare const p: <T>(fn: () => T) => T;
+>p : <T>(fn: () => T) => T
+>fn : () => T
+
+declare const Base: <T>(val: T) => { new(): T };
+>Base : <T>(val: T) => new () => T
+>val : T
+
+class C extends Base({ x: p<C[]>(() => []) }) { }
+>C : C
+>Base({ x: p<C[]>(() => []) }) : { x: C[]; }
+>Base : <T>(val: T) => new () => T
+>{ x: p<C[]>(() => []) } : { x: C[]; }
+>x : C[]
+>p<C[]>(() => []) : C[]
+>p : <T>(fn: () => T) => T
+>() => [] : () => never[]
+>[] : never[]
+
+// Repro from #44359
+
+abstract class Base1 {
+>Base1 : Base1
+
+    abstract root(): Derived1;
+>root : () => Derived1
+}
+
+class Derived1 extends class extends Base1 {
+>Derived1 : Derived1
+>class extends Base1 {    root() {        return undefined as any;    }} : (Anonymous class)
+>Base1 : Base1
+
+    root() {
+>root : () => any
+
+        return undefined as any;
+>undefined as any : any
+>undefined : undefined
+    }
+}
+{ }
+

tests/cases/compiler/recursiveClassBaseType.ts

@@ -0,0 +1,23 @@
+// @strict: true
+// @declaration: true
+
+// Repro from #44281
+
+declare const p: <T>(fn: () => T) => T;
+
+declare const Base: <T>(val: T) => { new(): T };
+
+class C extends Base({ x: p<C[]>(() => []) }) { }
+
+// Repro from #44359
+
+abstract class Base1 {
+    abstract root(): Derived1;
+}
+
+class Derived1 extends class extends Base1 {
+    root() {
+        return undefined as any;
+    }
+}
+{ }