Merge pull request microsoft#3473 from randombk/bug-genericConstraintCrash

Fix crash with unmet generic constraints

Author: DanielRosenwasser

src/compiler/checker.ts

@@ -7275,8 +7275,8 @@ namespace ts {
                 checkApplicableSignature(node, args, candidateForArgumentError, assignableRelation, /*excludeArgument*/ undefined, /*reportErrors*/ true);
             }
             else if (candidateForTypeArgumentError) {
-                if (!isTaggedTemplate && (<CallExpression>node).typeArguments) {
-                    checkTypeArguments(candidateForTypeArgumentError, (<CallExpression>node).typeArguments, [], /*reportErrors*/ true)
+                if (!isTaggedTemplate && typeArguments) {
+                    checkTypeArguments(candidateForTypeArgumentError, typeArguments, [], /*reportErrors*/ true)
                 }
                 else {
                     Debug.assert(resultOfFailedInference.failedTypeParameterIndex >= 0);

tests/baselines/reference/genericTypeConstraints.errors.txt

@@ -0,0 +1,24 @@
+tests/cases/compiler/genericTypeConstraints.ts(9,27): error TS2344: Type 'FooExtended' does not satisfy the constraint 'Foo'.
+  Property 'fooMethod' is missing in type 'FooExtended'.
+tests/cases/compiler/genericTypeConstraints.ts(9,31): error TS2344: Type 'FooExtended' does not satisfy the constraint 'Foo'.
+
+
+==== tests/cases/compiler/genericTypeConstraints.ts (2 errors) ====
+    class Foo {
+        fooMethod() {}
+    }
+    
+    class FooExtended { }
+    
+    class Bar<T extends Foo> { }
+    
+    class BarExtended extends Bar<FooExtended> {
+                              ~~~~~~~~~~~~~~~~
+!!! error TS2344: Type 'FooExtended' does not satisfy the constraint 'Foo'.
+!!! error TS2344:   Property 'fooMethod' is missing in type 'FooExtended'.
+                                  ~~~~~~~~~~~
+!!! error TS2344: Type 'FooExtended' does not satisfy the constraint 'Foo'.
+        constructor() {
+            super();
+        }
+    }

tests/baselines/reference/genericTypeConstraints.js

@@ -0,0 +1,45 @@
+//// [genericTypeConstraints.ts]
+class Foo {
+    fooMethod() {}
+}
+
+class FooExtended { }
+
+class Bar<T extends Foo> { }
+
+class BarExtended extends Bar<FooExtended> {
+    constructor() {
+        super();
+    }
+}
+
+//// [genericTypeConstraints.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; }
+    __.prototype = b.prototype;
+    d.prototype = new __();
+};
+var Foo = (function () {
+    function Foo() {
+    }
+    Foo.prototype.fooMethod = function () { };
+    return Foo;
+})();
+var FooExtended = (function () {
+    function FooExtended() {
+    }
+    return FooExtended;
+})();
+var Bar = (function () {
+    function Bar() {
+    }
+    return Bar;
+})();
+var BarExtended = (function (_super) {
+    __extends(BarExtended, _super);
+    function BarExtended() {
+        _super.call(this);
+    }
+    return BarExtended;
+})(Bar);

tests/cases/compiler/genericTypeConstraints.ts

@@ -0,0 +1,13 @@
+class Foo {
+    fooMethod() {}
+}
+
+class FooExtended { }
+
+class Bar<T extends Foo> { }
+
+class BarExtended extends Bar<FooExtended> {
+    constructor() {
+        super();
+    }
+}