From 56f82563aedd1713903172fc217d362a6c198f17 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <293473+sandersn@users.noreply.github.com>
Date: Thu, 16 Aug 2018 08:38:41 -0700
Subject: [PATCH] Check SymbolFlags instead

---
 src/compiler/checker.ts | 11 +----------
 1 file changed, 1 insertion(+), 10 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 829d11bd09..2bb112d6c4 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -17739,12 +17739,6 @@ namespace ts {
             }
         }
 
-        // If a symbol is a synthesized symbol with no value declaration, we assume it is a property. Example of this are the synthesized
-        // '.prototype' property as well as synthesized tuple index properties.
-        function getDeclarationKindFromSymbol(s: Symbol) {
-            return s.valueDeclaration ? s.valueDeclaration.kind : SyntaxKind.PropertyDeclaration;
-        }
-
         function getDeclarationNodeFlagsFromSymbol(s: Symbol): NodeFlags {
             return s.valueDeclaration ? getCombinedNodeFlags(s.valueDeclaration) : 0;
         }
@@ -17881,10 +17875,7 @@ namespace ts {
         }
 
         function symbolHasNonMethodDeclaration(symbol: Symbol) {
-            return forEachProperty(symbol, prop => {
-                const propKind = getDeclarationKindFromSymbol(prop);
-                return propKind !== SyntaxKind.MethodDeclaration && propKind !== SyntaxKind.MethodSignature;
-            });
+            return !!forEachProperty(symbol, prop => !(prop.flags & SymbolFlags.Method));
         }
 
         function checkNonNullExpression(