Issue an error when a derived class precedes its base class

src/compiler/checker.ts

@@ -15603,6 +15603,12 @@ namespace ts {
                     checkTypeAssignableTo(staticType, getTypeWithoutSignatures(staticBaseType), node.name || node,
                         Diagnostics.Class_static_side_0_incorrectly_extends_base_class_static_side_1);
 
+                    if (baseType.symbol.valueDeclaration && !(baseType.symbol.valueDeclaration.flags & NodeFlags.Ambient)) {
+                        if (!isBlockScopedNameDeclaredBeforeUse(baseType.symbol.valueDeclaration, node)) {
+                            error(baseTypeNode, Diagnostics.A_class_must_be_declared_after_its_base_class);
+                        }
+                    }
+
                     if (!(staticBaseType.symbol && staticBaseType.symbol.flags & SymbolFlags.Class)) {
                         // When the static base type is a "class-like" constructor function (but not actually a class), we verify
                         // that all instantiated base constructor signatures return the same type. We can simply compare the type

src/compiler/diagnosticMessages.json

@@ -1943,6 +1943,10 @@
         "category": "Error",
         "code": 2689
     },
+    "A class must be declared after its base class.": {
+        "category": "Error",
+        "code": 2690
+    },
     "Import declaration '{0}' is using private name '{1}'.": {
         "category": "Error",
         "code": 4000

tests/baselines/reference/baseTypeWrappingInstantiationChain.js

@@ -1,63 +1,50 @@
 //// [baseTypeWrappingInstantiationChain.ts]
-class C<T1> extends CBase<T1> {
-    public works() {
-        new CBaseBase<Wrapper<T1>>(this);
-    }
-    public alsoWorks() {
-        new CBase<T1>(this); // Should not error, parameter is of type Parameter<Wrapper<T1>>
-    }
-
-    public method(t: Wrapper<T1>) { }
+class CBaseBase<T3> {
+    constructor(x: Parameter<T3>) { }
 }
 
 class CBase<T2> extends CBaseBase<Wrapper<T2>> {
 
 }
 
-class CBaseBase<T3> {
-    constructor(x: Parameter<T3>) { }
-}
-
 class Parameter<T4> {
     method(t: T4) { }
 }
 
 class Wrapper<T5> {
     property: T5;
-}
+}
+
+class C<T1> extends CBase<T1> {
+    public works() {
+        new CBaseBase<Wrapper<T1>>(this);
+    }
+    public alsoWorks() {
+        new CBase<T1>(this); // Should not error, parameter is of type Parameter<Wrapper<T1>>
+    }
+
+    public method(t: Wrapper<T1>) { }
+}
+
 
 //// [baseTypeWrappingInstantiationChain.js]
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
     d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
-var C = (function (_super) {
-    __extends(C, _super);
-    function C() {
-        _super.apply(this, arguments);
+var CBaseBase = (function () {
+    function CBaseBase(x) {
     }
-    C.prototype.works = function () {
-        new CBaseBase(this);
-    };
-    C.prototype.alsoWorks = function () {
-        new CBase(this); // Should not error, parameter is of type Parameter<Wrapper<T1>>
-    };
-    C.prototype.method = function (t) { };
-    return C;
-}(CBase));
+    return CBaseBase;
+}());
 var CBase = (function (_super) {
     __extends(CBase, _super);
     function CBase() {
         _super.apply(this, arguments);
     }
     return CBase;
 }(CBaseBase));
-var CBaseBase = (function () {
-    function CBaseBase(x) {
-    }
-    return CBaseBase;
-}());
 var Parameter = (function () {
     function Parameter() {
     }
@@ -69,3 +56,17 @@ var Wrapper = (function () {
     }
     return Wrapper;
 }());
+var C = (function (_super) {
+    __extends(C, _super);
+    function C() {
+        _super.apply(this, arguments);
+    }
+    C.prototype.works = function () {
+        new CBaseBase(this);
+    };
+    C.prototype.alsoWorks = function () {
+        new CBase(this); // Should not error, parameter is of type Parameter<Wrapper<T1>>
+    };
+    C.prototype.method = function (t) { };
+    return C;
+}(CBase));

tests/baselines/reference/baseTypeWrappingInstantiationChain.symbols

@@ -1,69 +1,70 @@
 === tests/cases/compiler/baseTypeWrappingInstantiationChain.ts ===
-class C<T1> extends CBase<T1> {
->C : Symbol(C, Decl(baseTypeWrappingInstantiationChain.ts, 0, 0))
->T1 : Symbol(T1, Decl(baseTypeWrappingInstantiationChain.ts, 0, 8))
->CBase : Symbol(CBase, Decl(baseTypeWrappingInstantiationChain.ts, 9, 1))
->T1 : Symbol(T1, Decl(baseTypeWrappingInstantiationChain.ts, 0, 8))
-
-    public works() {
->works : Symbol(C.works, Decl(baseTypeWrappingInstantiationChain.ts, 0, 31))
-
-        new CBaseBase<Wrapper<T1>>(this);
->CBaseBase : Symbol(CBaseBase, Decl(baseTypeWrappingInstantiationChain.ts, 13, 1))
->Wrapper : Symbol(Wrapper, Decl(baseTypeWrappingInstantiationChain.ts, 21, 1))
->T1 : Symbol(T1, Decl(baseTypeWrappingInstantiationChain.ts, 0, 8))
->this : Symbol(C, Decl(baseTypeWrappingInstantiationChain.ts, 0, 0))
-    }
-    public alsoWorks() {
->alsoWorks : Symbol(C.alsoWorks, Decl(baseTypeWrappingInstantiationChain.ts, 3, 5))
-
-        new CBase<T1>(this); // Should not error, parameter is of type Parameter<Wrapper<T1>>
->CBase : Symbol(CBase, Decl(baseTypeWrappingInstantiationChain.ts, 9, 1))
->T1 : Symbol(T1, Decl(baseTypeWrappingInstantiationChain.ts, 0, 8))
->this : Symbol(C, Decl(baseTypeWrappingInstantiationChain.ts, 0, 0))
-    }
+class CBaseBase<T3> {
+>CBaseBase : Symbol(CBaseBase, Decl(baseTypeWrappingInstantiationChain.ts, 0, 0))
+>T3 : Symbol(T3, Decl(baseTypeWrappingInstantiationChain.ts, 0, 16))
 
-    public method(t: Wrapper<T1>) { }
->method : Symbol(C.method, Decl(baseTypeWrappingInstantiationChain.ts, 6, 5))
->t : Symbol(t, Decl(baseTypeWrappingInstantiationChain.ts, 8, 18))
->Wrapper : Symbol(Wrapper, Decl(baseTypeWrappingInstantiationChain.ts, 21, 1))
->T1 : Symbol(T1, Decl(baseTypeWrappingInstantiationChain.ts, 0, 8))
+    constructor(x: Parameter<T3>) { }
+>x : Symbol(x, Decl(baseTypeWrappingInstantiationChain.ts, 1, 16))
+>Parameter : Symbol(Parameter, Decl(baseTypeWrappingInstantiationChain.ts, 6, 1))
+>T3 : Symbol(T3, Decl(baseTypeWrappingInstantiationChain.ts, 0, 16))
 }
 
 class CBase<T2> extends CBaseBase<Wrapper<T2>> {
->CBase : Symbol(CBase, Decl(baseTypeWrappingInstantiationChain.ts, 9, 1))
->T2 : Symbol(T2, Decl(baseTypeWrappingInstantiationChain.ts, 11, 12))
->CBaseBase : Symbol(CBaseBase, Decl(baseTypeWrappingInstantiationChain.ts, 13, 1))
->Wrapper : Symbol(Wrapper, Decl(baseTypeWrappingInstantiationChain.ts, 21, 1))
->T2 : Symbol(T2, Decl(baseTypeWrappingInstantiationChain.ts, 11, 12))
+>CBase : Symbol(CBase, Decl(baseTypeWrappingInstantiationChain.ts, 2, 1))
+>T2 : Symbol(T2, Decl(baseTypeWrappingInstantiationChain.ts, 4, 12))
+>CBaseBase : Symbol(CBaseBase, Decl(baseTypeWrappingInstantiationChain.ts, 0, 0))
+>Wrapper : Symbol(Wrapper, Decl(baseTypeWrappingInstantiationChain.ts, 10, 1))
+>T2 : Symbol(T2, Decl(baseTypeWrappingInstantiationChain.ts, 4, 12))
 
 }
 
-class CBaseBase<T3> {
->CBaseBase : Symbol(CBaseBase, Decl(baseTypeWrappingInstantiationChain.ts, 13, 1))
->T3 : Symbol(T3, Decl(baseTypeWrappingInstantiationChain.ts, 15, 16))
-
-    constructor(x: Parameter<T3>) { }
->x : Symbol(x, Decl(baseTypeWrappingInstantiationChain.ts, 16, 16))
->Parameter : Symbol(Parameter, Decl(baseTypeWrappingInstantiationChain.ts, 17, 1))
->T3 : Symbol(T3, Decl(baseTypeWrappingInstantiationChain.ts, 15, 16))
-}
-
 class Parameter<T4> {
->Parameter : Symbol(Parameter, Decl(baseTypeWrappingInstantiationChain.ts, 17, 1))
->T4 : Symbol(T4, Decl(baseTypeWrappingInstantiationChain.ts, 19, 16))
+>Parameter : Symbol(Parameter, Decl(baseTypeWrappingInstantiationChain.ts, 6, 1))
+>T4 : Symbol(T4, Decl(baseTypeWrappingInstantiationChain.ts, 8, 16))
 
     method(t: T4) { }
->method : Symbol(Parameter.method, Decl(baseTypeWrappingInstantiationChain.ts, 19, 21))
->t : Symbol(t, Decl(baseTypeWrappingInstantiationChain.ts, 20, 11))
->T4 : Symbol(T4, Decl(baseTypeWrappingInstantiationChain.ts, 19, 16))
+>method : Symbol(Parameter.method, Decl(baseTypeWrappingInstantiationChain.ts, 8, 21))
+>t : Symbol(t, Decl(baseTypeWrappingInstantiationChain.ts, 9, 11))
+>T4 : Symbol(T4, Decl(baseTypeWrappingInstantiationChain.ts, 8, 16))
 }
 
 class Wrapper<T5> {
->Wrapper : Symbol(Wrapper, Decl(baseTypeWrappingInstantiationChain.ts, 21, 1))
->T5 : Symbol(T5, Decl(baseTypeWrappingInstantiationChain.ts, 23, 14))
+>Wrapper : Symbol(Wrapper, Decl(baseTypeWrappingInstantiationChain.ts, 10, 1))
+>T5 : Symbol(T5, Decl(baseTypeWrappingInstantiationChain.ts, 12, 14))
 
     property: T5;
->property : Symbol(Wrapper.property, Decl(baseTypeWrappingInstantiationChain.ts, 23, 19))
->T5 : Symbol(T5, Decl(baseTypeWrappingInstantiationChain.ts, 23, 14))
+>property : Symbol(Wrapper.property, Decl(baseTypeWrappingInstantiationChain.ts, 12, 19))
+>T5 : Symbol(T5, Decl(baseTypeWrappingInstantiationChain.ts, 12, 14))
+}
+
+class C<T1> extends CBase<T1> {
+>C : Symbol(C, Decl(baseTypeWrappingInstantiationChain.ts, 14, 1))
+>T1 : Symbol(T1, Decl(baseTypeWrappingInstantiationChain.ts, 16, 8))
+>CBase : Symbol(CBase, Decl(baseTypeWrappingInstantiationChain.ts, 2, 1))
+>T1 : Symbol(T1, Decl(baseTypeWrappingInstantiationChain.ts, 16, 8))
+
+    public works() {
+>works : Symbol(C.works, Decl(baseTypeWrappingInstantiationChain.ts, 16, 31))
+
+        new CBaseBase<Wrapper<T1>>(this);
+>CBaseBase : Symbol(CBaseBase, Decl(baseTypeWrappingInstantiationChain.ts, 0, 0))
+>Wrapper : Symbol(Wrapper, Decl(baseTypeWrappingInstantiationChain.ts, 10, 1))
+>T1 : Symbol(T1, Decl(baseTypeWrappingInstantiationChain.ts, 16, 8))
+>this : Symbol(C, Decl(baseTypeWrappingInstantiationChain.ts, 14, 1))
+    }
+    public alsoWorks() {
+>alsoWorks : Symbol(C.alsoWorks, Decl(baseTypeWrappingInstantiationChain.ts, 19, 5))
+
+        new CBase<T1>(this); // Should not error, parameter is of type Parameter<Wrapper<T1>>
+>CBase : Symbol(CBase, Decl(baseTypeWrappingInstantiationChain.ts, 2, 1))
+>T1 : Symbol(T1, Decl(baseTypeWrappingInstantiationChain.ts, 16, 8))
+>this : Symbol(C, Decl(baseTypeWrappingInstantiationChain.ts, 14, 1))
+    }
+
+    public method(t: Wrapper<T1>) { }
+>method : Symbol(C.method, Decl(baseTypeWrappingInstantiationChain.ts, 22, 5))
+>t : Symbol(t, Decl(baseTypeWrappingInstantiationChain.ts, 24, 18))
+>Wrapper : Symbol(Wrapper, Decl(baseTypeWrappingInstantiationChain.ts, 10, 1))
+>T1 : Symbol(T1, Decl(baseTypeWrappingInstantiationChain.ts, 16, 8))
 }
+

tests/baselines/reference/baseTypeWrappingInstantiationChain.types

@@ -1,4 +1,42 @@
 === tests/cases/compiler/baseTypeWrappingInstantiationChain.ts ===
+class CBaseBase<T3> {
+>CBaseBase : CBaseBase<T3>
+>T3 : T3
+
+    constructor(x: Parameter<T3>) { }
+>x : Parameter<T3>
+>Parameter : Parameter<T4>
+>T3 : T3
+}
+
+class CBase<T2> extends CBaseBase<Wrapper<T2>> {
+>CBase : CBase<T2>
+>T2 : T2
+>CBaseBase : CBaseBase<Wrapper<T2>>
+>Wrapper : Wrapper<T5>
+>T2 : T2
+
+}
+
+class Parameter<T4> {
+>Parameter : Parameter<T4>
+>T4 : T4
+
+    method(t: T4) { }
+>method : (t: T4) => void
+>t : T4
+>T4 : T4
+}
+
+class Wrapper<T5> {
+>Wrapper : Wrapper<T5>
+>T5 : T5
+
+    property: T5;
+>property : T5
+>T5 : T5
+}
+
 class C<T1> extends CBase<T1> {
 >C : C<T1>
 >T1 : T1
@@ -32,40 +70,3 @@ class C<T1> extends CBase<T1> {
 >T1 : T1
 }
 
-class CBase<T2> extends CBaseBase<Wrapper<T2>> {
->CBase : CBase<T2>
->T2 : T2
->CBaseBase : CBaseBase<Wrapper<T2>>
->Wrapper : Wrapper<T5>
->T2 : T2
-
-}
-
-class CBaseBase<T3> {
->CBaseBase : CBaseBase<T3>
->T3 : T3
-
-    constructor(x: Parameter<T3>) { }
->x : Parameter<T3>
->Parameter : Parameter<T4>
->T3 : T3
-}
-
-class Parameter<T4> {
->Parameter : Parameter<T4>
->T4 : T4
-
-    method(t: T4) { }
->method : (t: T4) => void
->t : T4
->T4 : T4
-}
-
-class Wrapper<T5> {
->Wrapper : Wrapper<T5>
->T5 : T5
-
-    property: T5;
->property : T5
->T5 : T5
-}

tests/baselines/reference/circularImportAlias.errors.txt

@@ -0,0 +1,25 @@
+tests/cases/conformance/internalModules/importDeclarations/circularImportAlias.ts(5,28): error TS2690: A class must be declared after its base class.
+
+
+==== tests/cases/conformance/internalModules/importDeclarations/circularImportAlias.ts (1 errors) ====
+    // expected no error
+
+    module B {
+        export import a = A;
+        export class D extends a.C {
+                               ~~~
+!!! error TS2690: A class must be declared after its base class.
+            id: number;
+        }
+    }
+
+    module A {
+        export class C { name: string }
+        export import b = B;
+    }
+
+    var c: { name: string };
+    var c = new B.a.C();
+
+
+