From 2ed5f418a1715677e567940462312d0406239f63 Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Thu, 20 Nov 2014 13:45:55 -0800
Subject: [PATCH] Destructuring of tuple type cannot specify extra variables

---
 src/compiler/checker.ts                       | 24 +++++++++++++++----
 .../diagnosticInformationMap.generated.ts     |  3 ++-
 src/compiler/diagnosticMessages.json          |  6 ++++-
 3 files changed, 26 insertions(+), 7 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index b1a0b4ebd1a..a188e720005 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -1644,10 +1644,18 @@ module ts {
                 }
             }
             else {
-                var index = indexOf(pattern.elements, declaration);
-                var type = getTypeOfPropertyOfType(parentType, "" + index) || getIndexTypeOfType(parentType, IndexKind.Number);
-                if (!type) {
-                    error(declaration, Diagnostics.Type_0_has_no_property_1_and_no_numeric_index_signature, typeToString(parentType), "" + index);
+                if (getPropertyOfType(parentType, "0")) {
+                    var propName = "" + indexOf(pattern.elements, declaration);
+                    var type = getTypeOfPropertyOfType(parentType, propName);
+                    if (!type) {
+                        error(declaration, Diagnostics.Type_0_has_no_property_1, typeToString(parentType), propName);
+                    }
+                }
+                else {
+                    var type = getIndexTypeOfType(parentType, IndexKind.Number);
+                    if (!type) {
+                        error(declaration, Diagnostics.Type_0_has_no_numeric_index_signature, typeToString(parentType));
+                    }
                 }
             }
             return type || unknownType;
@@ -4775,7 +4783,13 @@ module ts {
                     return getTypeFromTypeNode(declaration.type);
                 }
                 if (declaration.kind === SyntaxKind.Parameter) {
-                    return getContextuallyTypedParameterType(declaration);
+                    var type = getContextuallyTypedParameterType(declaration);
+                    if (type) {
+                        return type;
+                    }
+                }
+                if (isBindingPattern(declaration.name)) {
+                    return getTypeFromBindingPattern(<BindingPattern>declaration.name);
                 }
             }
             return undefined;
diff --git a/src/compiler/diagnosticInformationMap.generated.ts b/src/compiler/diagnosticInformationMap.generated.ts
index 72a58797791..ffb09786c7e 100644
--- a/src/compiler/diagnosticInformationMap.generated.ts
+++ b/src/compiler/diagnosticInformationMap.generated.ts
@@ -275,7 +275,8 @@ module ts {
         Type_alias_0_circularly_references_itself: { code: 2456, category: DiagnosticCategory.Error, key: "Type alias '{0}' circularly references itself." },
         Type_alias_name_cannot_be_0: { code: 2457, category: DiagnosticCategory.Error, key: "Type alias name cannot be '{0}'" },
         Type_0_has_no_property_1_and_no_string_index_signature: { code: 2458, category: DiagnosticCategory.Error, key: "Type '{0}' has no property '{1}' and no string index signature." },
-        Type_0_has_no_property_1_and_no_numeric_index_signature: { code: 2459, category: DiagnosticCategory.Error, key: "Type '{0}' has no property '{1}' and no numeric index signature." },
+        Type_0_has_no_property_1: { code: 2459, category: DiagnosticCategory.Error, key: "Type '{0}' has no property '{1}'." },
+        Type_0_has_no_numeric_index_signature: { code: 2460, category: DiagnosticCategory.Error, key: "Type '{0}' has no numeric index signature." },
         Import_declaration_0_is_using_private_name_1: { code: 4000, category: DiagnosticCategory.Error, key: "Import declaration '{0}' is using private name '{1}'." },
         Type_parameter_0_of_exported_class_has_or_is_using_name_1_from_private_module_2: { code: 4001, category: DiagnosticCategory.Error, key: "Type parameter '{0}' of exported class has or is using name '{1}' from private module '{2}'." },
         Type_parameter_0_of_exported_class_has_or_is_using_private_name_1: { code: 4002, category: DiagnosticCategory.Error, key: "Type parameter '{0}' of exported class has or is using private name '{1}'." },
diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index 7a9deff62eb..132117414f7 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -1096,10 +1096,14 @@
         "category": "Error",
         "code": 2458
     },
-    "Type '{0}' has no property '{1}' and no numeric index signature.": {
+    "Type '{0}' has no property '{1}'.": {
         "category": "Error",
         "code": 2459
     },
+    "Type '{0}' has no numeric index signature.": {
+        "category": "Error",
+        "code": 2460
+    },
 
     "Import declaration '{0}' is using private name '{1}'.": {
         "category": "Error",