Add 'indexOfNode' and use it in cases which may handle long lists.

src/compiler/checker.ts

@@ -13319,7 +13319,7 @@ namespace ts {
                 case SyntaxKind.ArrayLiteralExpression: {
                     const arrayLiteral = <ArrayLiteralExpression>parent;
                     const type = getApparentTypeOfContextualType(arrayLiteral);
-                    return getContextualTypeForElementExpression(type, indexOf(arrayLiteral.elements, node));
+                    return getContextualTypeForElementExpression(type, indexOfNode(arrayLiteral.elements, node));
                 }
                 case SyntaxKind.ConditionalExpression:
                     return getContextualTypeForConditionalOperand(node);

src/compiler/utilities.ts

@@ -321,6 +321,18 @@ namespace ts {
         return getSourceTextOfNodeFromSourceFile(getSourceFileOfNode(node), node, includeTrivia);
     }
 
+    /**
+     * Note: it is expected that the `nodeArray` and the `node` are within the same file.
+     * For example, searching for a `SourceFile` in a `SourceFile[]` wouldn't work.
+     */
+    export function indexOfNode(nodeArray: ReadonlyArray<Node>, node: Node) {
+        return binarySearch(nodeArray, node, compareNodePos);
+    }
+
+    function compareNodePos({ pos: aPos }: Node, { pos: bPos}: Node) {
+        return aPos < bPos ? Comparison.LessThan : bPos < aPos ? Comparison.GreaterThan : Comparison.EqualTo;
+    }
+
     /**
      * Gets flags that control emit behavior of a node.
      */

src/services/textChanges.ts

@@ -224,7 +224,7 @@ namespace ts.textChanges {
                 Debug.fail("node is not a list element");
                 return this;
             }
-            const index = containingList.indexOf(node);
+            const index = indexOfNode(containingList, node);
             if (index < 0) {
                 return this;
             }
@@ -356,7 +356,7 @@ namespace ts.textChanges {
                 Debug.fail("node is not a list element");
                 return this;
             }
-            const index = containingList.indexOf(after);
+            const index = indexOfNode(containingList, after);
             if (index < 0) {
                 return this;
             }

src/services/utilities.ts

@@ -597,7 +597,7 @@ namespace ts {
         }
 
         const children = list.getChildren();
-        const listItemIndex = indexOf(children, node);
+        const listItemIndex = indexOfNode(children, node);
 
         return {
             listItemIndex,