microsoft · RyanCavanaugh · Oct 19, 2016 · Oct 4, 2016
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
@@ -17114,7 +17114,9 @@ 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 && !isInAmbientContext(baseType.symbol.valueDeclaration)) {
+                    if (baseType.symbol.valueDeclaration &&
+                        !isInAmbientContext(baseType.symbol.valueDeclaration) &&
+                        baseType.symbol.valueDeclaration.kind === SyntaxKind.ClassDeclaration) {
                         if (!isBlockScopedNameDeclaredBeforeUse(baseType.symbol.valueDeclaration, node)) {
                             error(baseTypeNode, Diagnostics.A_class_must_be_declared_after_its_base_class);
                         }

diff --git a/tests/baselines/reference/classDeclaredBeforeClassFactory.js b/tests/baselines/reference/classDeclaredBeforeClassFactory.js
@@ -0,0 +1,30 @@
+//// [classDeclaredBeforeClassFactory.ts]
+// Should be OK due to hoisting
+class Derived extends makeBaseClass() {}
+
+function makeBaseClass() {
+    return class Base {};
+}
+
+
+//// [classDeclaredBeforeClassFactory.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 __());
+};
+// Should be OK due to hoisting
+var Derived = (function (_super) {
+    __extends(Derived, _super);
+    function Derived() {
+        return _super.apply(this, arguments) || this;
+    }
+    return Derived;
+}(makeBaseClass()));
+function makeBaseClass() {
+    return (function () {
+        function Base() {
+        }
+        return Base;
+    }());
+}
diff --git a/tests/baselines/reference/classDeclaredBeforeClassFactory.symbols b/tests/baselines/reference/classDeclaredBeforeClassFactory.symbols
@@ -0,0 +1,13 @@
+=== tests/cases/compiler/classDeclaredBeforeClassFactory.ts ===
+// Should be OK due to hoisting
+class Derived extends makeBaseClass() {}
+>Derived : Symbol(Derived, Decl(classDeclaredBeforeClassFactory.ts, 0, 0))
+>makeBaseClass : Symbol(makeBaseClass, Decl(classDeclaredBeforeClassFactory.ts, 1, 40))
+
+function makeBaseClass() {
+>makeBaseClass : Symbol(makeBaseClass, Decl(classDeclaredBeforeClassFactory.ts, 1, 40))
+
+    return class Base {};
+>Base : Symbol(Base, Decl(classDeclaredBeforeClassFactory.ts, 4, 10))
+}
+
diff --git a/tests/baselines/reference/classDeclaredBeforeClassFactory.types b/tests/baselines/reference/classDeclaredBeforeClassFactory.types
@@ -0,0 +1,15 @@
+=== tests/cases/compiler/classDeclaredBeforeClassFactory.ts ===
+// Should be OK due to hoisting
+class Derived extends makeBaseClass() {}
+>Derived : Derived
+>makeBaseClass() : Base
+>makeBaseClass : () => typeof Base
+
+function makeBaseClass() {
+>makeBaseClass : () => typeof Base
+
+    return class Base {};
+>class Base {} : typeof Base
+>Base : typeof Base
+}
+
diff --git a/tests/baselines/reference/classExpression3.errors.txt b/tests/baselines/reference/classExpression3.errors.txt
diff --git a/tests/baselines/reference/classExpression3.symbols b/tests/baselines/reference/classExpression3.symbols
@@ -0,0 +1,26 @@
+=== tests/cases/conformance/classes/classExpressions/classExpression3.ts ===
+let C = class extends class extends class { a = 1 } { b = 2 } { c = 3 };
+>C : Symbol(C, Decl(classExpression3.ts, 0, 3))
+>a : Symbol((Anonymous class).a, Decl(classExpression3.ts, 0, 43))
+>b : Symbol((Anonymous class).b, Decl(classExpression3.ts, 0, 53))
+>c : Symbol((Anonymous class).c, Decl(classExpression3.ts, 0, 63))
+
+let c = new C();
+>c : Symbol(c, Decl(classExpression3.ts, 1, 3))
+>C : Symbol(C, Decl(classExpression3.ts, 0, 3))
+
+c.a;
+>c.a : Symbol((Anonymous class).a, Decl(classExpression3.ts, 0, 43))
+>c : Symbol(c, Decl(classExpression3.ts, 1, 3))
+>a : Symbol((Anonymous class).a, Decl(classExpression3.ts, 0, 43))
+
+c.b;
+>c.b : Symbol((Anonymous class).b, Decl(classExpression3.ts, 0, 53))
+>c : Symbol(c, Decl(classExpression3.ts, 1, 3))
+>b : Symbol((Anonymous class).b, Decl(classExpression3.ts, 0, 53))
+
+c.c;
+>c.c : Symbol((Anonymous class).c, Decl(classExpression3.ts, 0, 63))
+>c : Symbol(c, Decl(classExpression3.ts, 1, 3))
+>c : Symbol((Anonymous class).c, Decl(classExpression3.ts, 0, 63))
+
diff --git a/tests/baselines/reference/classExpression3.types b/tests/baselines/reference/classExpression3.types
@@ -0,0 +1,33 @@
+=== tests/cases/conformance/classes/classExpressions/classExpression3.ts ===
+let C = class extends class extends class { a = 1 } { b = 2 } { c = 3 };
+>C : typeof (Anonymous class)
+>class extends class extends class { a = 1 } { b = 2 } { c = 3 } : typeof (Anonymous class)
+>class extends class { a = 1 } { b = 2 } : (Anonymous class)
+>class { a = 1 } : (Anonymous class)
+>a : number
+>1 : 1
+>b : number
+>2 : 2
+>c : number
+>3 : 3
+
+let c = new C();
+>c : (Anonymous class)
+>new C() : (Anonymous class)
+>C : typeof (Anonymous class)
+
+c.a;
+>c.a : number
+>c : (Anonymous class)
+>a : number
+
+c.b;
+>c.b : number
+>c : (Anonymous class)
+>b : number
+
+c.c;
+>c.c : number
+>c : (Anonymous class)
+>c : number
+
diff --git a/tests/baselines/reference/classExpressionES63.errors.txt b/tests/baselines/reference/classExpressionES63.errors.txt
diff --git a/tests/baselines/reference/classExpressionES63.symbols b/tests/baselines/reference/classExpressionES63.symbols
@@ -0,0 +1,26 @@
+=== tests/cases/conformance/es6/classExpressions/classExpressionES63.ts ===
+let C = class extends class extends class { a = 1 } { b = 2 } { c = 3 };
+>C : Symbol(C, Decl(classExpressionES63.ts, 0, 3))
+>a : Symbol((Anonymous class).a, Decl(classExpressionES63.ts, 0, 43))
+>b : Symbol((Anonymous class).b, Decl(classExpressionES63.ts, 0, 53))
+>c : Symbol((Anonymous class).c, Decl(classExpressionES63.ts, 0, 63))
+
+let c = new C();
+>c : Symbol(c, Decl(classExpressionES63.ts, 1, 3))
+>C : Symbol(C, Decl(classExpressionES63.ts, 0, 3))
+
+c.a;
+>c.a : Symbol((Anonymous class).a, Decl(classExpressionES63.ts, 0, 43))
+>c : Symbol(c, Decl(classExpressionES63.ts, 1, 3))
+>a : Symbol((Anonymous class).a, Decl(classExpressionES63.ts, 0, 43))
+
+c.b;
+>c.b : Symbol((Anonymous class).b, Decl(classExpressionES63.ts, 0, 53))
+>c : Symbol(c, Decl(classExpressionES63.ts, 1, 3))
+>b : Symbol((Anonymous class).b, Decl(classExpressionES63.ts, 0, 53))
+
+c.c;
+>c.c : Symbol((Anonymous class).c, Decl(classExpressionES63.ts, 0, 63))
+>c : Symbol(c, Decl(classExpressionES63.ts, 1, 3))
+>c : Symbol((Anonymous class).c, Decl(classExpressionES63.ts, 0, 63))
+
diff --git a/tests/baselines/reference/classExpressionES63.types b/tests/baselines/reference/classExpressionES63.types
@@ -0,0 +1,33 @@
+=== tests/cases/conformance/es6/classExpressions/classExpressionES63.ts ===
+let C = class extends class extends class { a = 1 } { b = 2 } { c = 3 };
+>C : typeof (Anonymous class)
+>class extends class extends class { a = 1 } { b = 2 } { c = 3 } : typeof (Anonymous class)
+>class extends class { a = 1 } { b = 2 } : (Anonymous class)
+>class { a = 1 } : (Anonymous class)
+>a : number
+>1 : 1
+>b : number
+>2 : 2
+>c : number
+>3 : 3
+
+let c = new C();
+>c : (Anonymous class)
+>new C() : (Anonymous class)
+>C : typeof (Anonymous class)
+
+c.a;
+>c.a : number
+>c : (Anonymous class)
+>a : number
+
+c.b;
+>c.b : number
+>c : (Anonymous class)
+>b : number
+
+c.c;
+>c.c : number
+>c : (Anonymous class)
+>c : number
+
diff --git a/tests/baselines/reference/missingPropertiesOfClassExpression.errors.txt b/tests/baselines/reference/missingPropertiesOfClassExpression.errors.txt
@@ -1,11 +1,8 @@
-tests/cases/compiler/missingPropertiesOfClassExpression.ts(1,22): error TS2690: A class must be declared after its base class.
 tests/cases/compiler/missingPropertiesOfClassExpression.ts(1,52): error TS2339: Property 'y' does not exist on type '(Anonymous class)'.
 
 
-==== tests/cases/compiler/missingPropertiesOfClassExpression.ts (2 errors) ====
+==== tests/cases/compiler/missingPropertiesOfClassExpression.ts (1 errors) ====
     class George extends class { reset() { return this.y; } } {
-                         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2690: A class must be declared after its base class.
                                                        ~
 !!! error TS2339: Property 'y' does not exist on type '(Anonymous class)'.
         constructor() {

diff --git a/tests/cases/compiler/classDeclaredBeforeClassFactory.ts b/tests/cases/compiler/classDeclaredBeforeClassFactory.ts
@@ -0,0 +1,6 @@
+// Should be OK due to hoisting
+class Derived extends makeBaseClass() {}
+
+function makeBaseClass() {
+    return class Base {};
+}