From d7a4ac25f495d5ba78ff27b90fd4f23caf09abac Mon Sep 17 00:00:00 2001
From: Daniel Rosenwasser <drosen@microsoft.com>
Date: Thu, 25 Jun 2015 15:52:10 -0400
Subject: [PATCH] Allow semantic operations to be performed on property names.

Provide the property symbol of the type being destructured when referring to the property name.
---
 src/compiler/checker.ts | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index efee668a24b..763e4173287 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -12352,10 +12352,21 @@ namespace ts {
                 return getSymbolOfNode(node.parent);
             }
 
-            if (node.kind === SyntaxKind.Identifier && isInRightSideOfImportOrExportAssignment(<Identifier>node)) {
-                return node.parent.kind === SyntaxKind.ExportAssignment
-                    ? getSymbolOfEntityNameOrPropertyAccessExpression(<Identifier>node)
-                    : getSymbolOfPartOfRightHandSideOfImportEquals(<Identifier>node);
+            if (node.kind === SyntaxKind.Identifier) {
+                if (isInRightSideOfImportOrExportAssignment(<Identifier>node)) {
+                    return node.parent.kind === SyntaxKind.ExportAssignment
+                        ? getSymbolOfEntityNameOrPropertyAccessExpression(<Identifier>node)
+                        : getSymbolOfPartOfRightHandSideOfImportEquals(<Identifier>node);
+                }
+                else if (node.parent.kind === SyntaxKind.BindingElement &&
+                        node.parent.parent.kind === SyntaxKind.ObjectBindingPattern &&
+                        node === (<BindingElement>node.parent).propertyName) {
+                    let typeOfPattern = getTypeAtLocation(node.parent.parent);
+                    let propertyDeclaration = getPropertyOfType(typeOfPattern, (<Identifier>node).text);
+                    if (propertyDeclaration) {
+                        return propertyDeclaration;
+                    }
+                }
             }
 
             switch (node.kind) {