Add regression test

Author: ahejlsberg

tests/baselines/reference/noCrashOnMixin2.errors.txt

@@ -0,0 +1,41 @@
+noCrashOnMixin2.ts(11,33): error TS2370: A rest parameter must be of an array type.
+noCrashOnMixin2.ts(11,40): error TS1047: A rest parameter cannot be optional.
+noCrashOnMixin2.ts(14,12): error TS2545: A mixin class must have a constructor with a single rest parameter of type 'any[]'.
+noCrashOnMixin2.ts(23,9): error TS2674: Constructor of class 'Abstract' is protected and only accessible within the class declaration.
+
+
+==== noCrashOnMixin2.ts (4 errors) ====
+    // https://github.com/microsoft/TypeScript/issues/62921
+    
+    class Abstract {
+        protected constructor() {
+        }
+    }
+    
+    class Concrete extends Abstract {
+    }
+    
+    type Constructor<T = {}> = new (...args?: any[]) => T;
+                                    ~~~~~~~~~~~~~~~
+!!! error TS2370: A rest parameter must be of an array type.
+                                           ~
+!!! error TS1047: A rest parameter cannot be optional.
+    
+    function Mixin<TBase extends Constructor>(Base: TBase) {
+        return class extends Base {
+               ~~~~~
+!!! error TS2545: A mixin class must have a constructor with a single rest parameter of type 'any[]'.
+        };
+    }
+    
+    class Empty {
+    }
+    
+    class CrashTrigger extends Mixin(Empty) {
+        public trigger() {
+            new Concrete();
+            ~~~~~~~~~~~~~~
+!!! error TS2674: Constructor of class 'Abstract' is protected and only accessible within the class declaration.
+        }
+    }
+    

tests/baselines/reference/noCrashOnMixin2.symbols

@@ -0,0 +1,53 @@
+//// [tests/cases/compiler/noCrashOnMixin2.ts] ////
+
+=== noCrashOnMixin2.ts ===
+// https://github.com/microsoft/TypeScript/issues/62921
+
+class Abstract {
+>Abstract : Symbol(Abstract, Decl(noCrashOnMixin2.ts, 0, 0))
+
+    protected constructor() {
+    }
+}
+
+class Concrete extends Abstract {
+>Concrete : Symbol(Concrete, Decl(noCrashOnMixin2.ts, 5, 1))
+>Abstract : Symbol(Abstract, Decl(noCrashOnMixin2.ts, 0, 0))
+}
+
+type Constructor<T = {}> = new (...args?: any[]) => T;
+>Constructor : Symbol(Constructor, Decl(noCrashOnMixin2.ts, 8, 1))
+>T : Symbol(T, Decl(noCrashOnMixin2.ts, 10, 17))
+>args : Symbol(args, Decl(noCrashOnMixin2.ts, 10, 32))
+>T : Symbol(T, Decl(noCrashOnMixin2.ts, 10, 17))
+
+function Mixin<TBase extends Constructor>(Base: TBase) {
+>Mixin : Symbol(Mixin, Decl(noCrashOnMixin2.ts, 10, 54))
+>TBase : Symbol(TBase, Decl(noCrashOnMixin2.ts, 12, 15))
+>Constructor : Symbol(Constructor, Decl(noCrashOnMixin2.ts, 8, 1))
+>Base : Symbol(Base, Decl(noCrashOnMixin2.ts, 12, 42))
+>TBase : Symbol(TBase, Decl(noCrashOnMixin2.ts, 12, 15))
+
+    return class extends Base {
+>Base : Symbol(Base, Decl(noCrashOnMixin2.ts, 12, 42))
+
+    };
+}
+
+class Empty {
+>Empty : Symbol(Empty, Decl(noCrashOnMixin2.ts, 15, 1))
+}
+
+class CrashTrigger extends Mixin(Empty) {
+>CrashTrigger : Symbol(CrashTrigger, Decl(noCrashOnMixin2.ts, 18, 1))
+>Mixin : Symbol(Mixin, Decl(noCrashOnMixin2.ts, 10, 54))
+>Empty : Symbol(Empty, Decl(noCrashOnMixin2.ts, 15, 1))
+
+    public trigger() {
+>trigger : Symbol(CrashTrigger.trigger, Decl(noCrashOnMixin2.ts, 20, 41))
+
+        new Concrete();
+>Concrete : Symbol(Concrete, Decl(noCrashOnMixin2.ts, 5, 1))
+    }
+}
+

tests/baselines/reference/noCrashOnMixin2.types

@@ -0,0 +1,68 @@
+//// [tests/cases/compiler/noCrashOnMixin2.ts] ////
+
+=== noCrashOnMixin2.ts ===
+// https://github.com/microsoft/TypeScript/issues/62921
+
+class Abstract {
+>Abstract : Abstract
+>         : ^^^^^^^^
+
+    protected constructor() {
+    }
+}
+
+class Concrete extends Abstract {
+>Concrete : Concrete
+>         : ^^^^^^^^
+>Abstract : Abstract
+>         : ^^^^^^^^
+}
+
+type Constructor<T = {}> = new (...args?: any[]) => T;
+>Constructor : Constructor<T>
+>            : ^^^^^^^^^^^^^^
+>args : any[] | undefined
+>     : ^^^^^^^^^^^^^^^^^
+
+function Mixin<TBase extends Constructor>(Base: TBase) {
+>Mixin : <TBase extends Constructor>(Base: TBase) => { new (...args?: any[]): (Anonymous class); prototype: Mixin<any>.(Anonymous class); } & TBase
+>      : ^     ^^^^^^^^^           ^^    ^^     ^^^^^^^^^^^^^^^    ^^^     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+>Base : TBase
+>     : ^^^^^
+
+    return class extends Base {
+>class extends Base {    } : { new (...args?: any[]): (Anonymous class); prototype: Mixin<any>.(Anonymous class); } & TBase
+>                          : ^^^^^^^^^^    ^^^     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+>Base : {}
+>     : ^^
+
+    };
+}
+
+class Empty {
+>Empty : Empty
+>      : ^^^^^
+}
+
+class CrashTrigger extends Mixin(Empty) {
+>CrashTrigger : CrashTrigger
+>             : ^^^^^^^^^^^^
+>Mixin(Empty) : Mixin<typeof Empty>.(Anonymous class)
+>             : ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+>Mixin : <TBase extends Constructor>(Base: TBase) => { new (...args?: any[]): (Anonymous class); prototype: Mixin<any>.(Anonymous class); } & TBase
+>      : ^     ^^^^^^^^^           ^^    ^^     ^^^^^^^^^^^^^^^    ^^^     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+>Empty : typeof Empty
+>      : ^^^^^^^^^^^^
+
+    public trigger() {
+>trigger : () => void
+>        : ^^^^^^^^^^
+
+        new Concrete();
+>new Concrete() : any
+>               : ^^^
+>Concrete : typeof Concrete
+>         : ^^^^^^^^^^^^^^^
+    }
+}
+

tests/cases/compiler/noCrashOnMixin2.ts

@@ -0,0 +1,28 @@
+// @strict: true
+// @noEmit: true
+
+// https://github.com/microsoft/TypeScript/issues/62921
+
+class Abstract {
+    protected constructor() {
+    }
+}
+
+class Concrete extends Abstract {
+}
+
+type Constructor<T = {}> = new (...args?: any[]) => T;
+
+function Mixin<TBase extends Constructor>(Base: TBase) {
+    return class extends Base {
+    };
+}
+
+class Empty {
+}
+
+class CrashTrigger extends Mixin(Empty) {
+    public trigger() {
+        new Concrete();
+    }
+}