type predicate support

src/services/codefixes/fixAddMissingMember.ts

@@ -65,10 +65,10 @@ namespace ts.codefix {
             stringTypeNode,
             /*initializer*/ undefined);
         const indexSignature = createIndexSignatureDeclaration(
-            [indexingParameter],
-            typeNode,
             /*decorators*/undefined,
-            /*modifiers*/ undefined);
+            /*modifiers*/ undefined,
+            [indexingParameter],
+            typeNode);
 
         const indexSignatureChangeTracker = textChanges.ChangeTracker.fromCodeFixContext(context);
         indexSignatureChangeTracker.insertNodeAfter(sourceFile, openBrace, indexSignature, { suffix: context.newLineCharacter });

src/services/codefixes/helpers.ts

@@ -230,12 +230,4 @@ namespace ts.codefix {
         }
         return undefined;
     }
-
-    function stripComments(node: Node): Node {
-        if (node === undefined) {
-            return node;
-        }
-        const strippedChildren = visitEachChild(node, stripComments, nullTransformationContext);
-        return strippedChildren === node ? getSynthesizedClone(strippedChildren) : strippedChildren;
-    }
 }

src/services/textChanges.ts

@@ -528,6 +528,26 @@ namespace ts.textChanges {
         return skipTrivia(s, 0) === s.length;
     }
 
+    const nullTransformationContext: TransformationContext = {
+        enableEmitNotification: noop,
+        enableSubstitution: noop,
+        endLexicalEnvironment: () => undefined,
+        getCompilerOptions: notImplemented,
+        getEmitHost: notImplemented,
+        getEmitResolver: notImplemented,
+        hoistFunctionDeclaration: noop,
+        hoistVariableDeclaration: noop,
+        isEmitNotificationEnabled: notImplemented,
+        isSubstitutionEnabled: notImplemented,
+        onEmitNode: noop,
+        onSubstituteNode: notImplemented,
+        readEmitHelpers: notImplemented,
+        requestEmitHelper: noop,
+        resumeLexicalEnvironment: noop,
+        startLexicalEnvironment: noop,
+        suspendLexicalEnvironment: noop
+    };
+
     function assignPositionsToNode(node: Node): Node {
         const visited = visitEachChild(node, assignPositionsToNode, nullTransformationContext, assignPositionsToNodeArray, assignPositionsToNode);
         // create proxy node for non synthesized nodes