From 31331ff6d1399acf51ec68edef0d6052a468b255 Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Thu, 5 Nov 2015 16:31:30 -0800
Subject: [PATCH] Addressing CR feedback

---
 src/compiler/checker.ts | 30 ++++++++++++++++--------------
 1 file changed, 16 insertions(+), 14 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 1fde2711e12..836c16b51d8 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -5603,28 +5603,30 @@ namespace ts {
             return compareTypes(getTypeOfSymbol(sourceProp), getTypeOfSymbol(targetProp));
         }
 
-        // A source signature matches a target signature if the two signatures have the same number of required,
-        // optional, and rest parameters.
-        function isMatchingSignature(source: Signature, target: Signature) {
-            return source.parameters.length === target.parameters.length &&
+        function isMatchingSignature(source: Signature, target: Signature, partialMatch: boolean) {
+            // A source signature matches a target signature if the two signatures have the same number of required,
+            // optional, and rest parameters.
+            if (source.parameters.length === target.parameters.length &&
                 source.minArgumentCount === target.minArgumentCount &&
-                source.hasRestParameter === target.hasRestParameter;
-        }
-
-        // A source signature partially matches a target signature if the target signature has no fewer required
-        // parameters and no more overall parameters than the source signature (where a signature with a rest
-        // parameter is always considered to have more overall parameters than one without).
-        function isPartiallyMatchingSignature(source: Signature, target: Signature) {
-            return source.minArgumentCount <= target.minArgumentCount && (
+                source.hasRestParameter === target.hasRestParameter) {
+                return true;
+            }
+            // A source signature partially matches a target signature if the target signature has no fewer required
+            // parameters and no more overall parameters than the source signature (where a signature with a rest
+            // parameter is always considered to have more overall parameters than one without).
+            if (partialMatch && source.minArgumentCount <= target.minArgumentCount && (
                 source.hasRestParameter && !target.hasRestParameter ||
-                source.hasRestParameter === target.hasRestParameter && source.parameters.length >= target.parameters.length);
+                source.hasRestParameter === target.hasRestParameter && source.parameters.length >= target.parameters.length)) {
+                return true;
+            }
+            return false;
         }
 
         function compareSignatures(source: Signature, target: Signature, partialMatch: boolean, ignoreReturnTypes: boolean, compareTypes: (s: Type, t: Type) => Ternary): Ternary {
             if (source === target) {
                 return Ternary.True;
             }
-            if (!(isMatchingSignature(source, target) || partialMatch && isPartiallyMatchingSignature(source, target))) {
+            if (!(isMatchingSignature(source, target, partialMatch))) {
                 return Ternary.False;
             }
             let result = Ternary.True;