diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 228ee1d7468..b0a42c20a6d 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -3799,7 +3799,7 @@ namespace ts {
             if (node.initializer) {
                 const signatureDeclaration = <SignatureDeclaration>node.parent;
                 const signature = getSignatureFromDeclaration(signatureDeclaration);
-                const parameterIndex = signatureDeclaration.parameters.indexOf(node);
+                const parameterIndex = ts.indexOf(signatureDeclaration.parameters, node);
                 Debug.assert(parameterIndex >= 0);
                 return parameterIndex >= signature.minArgumentCount;
             }
diff --git a/src/services/formatting/tokenRange.ts b/src/services/formatting/tokenRange.ts
index 19185cdf78d..1afde613618 100644
--- a/src/services/formatting/tokenRange.ts
+++ b/src/services/formatting/tokenRange.ts
@@ -14,7 +14,7 @@ namespace ts.formatting {
             constructor(from: SyntaxKind, to: SyntaxKind, except: SyntaxKind[]) {
                 this.tokens = [];
                 for (let token = from; token <= to; token++) {
-                    if (except.indexOf(token) < 0) {
+                    if (ts.indexOf(except, token) < 0) {
                         this.tokens.push(token);
                     }
                 }
@@ -123,4 +123,4 @@ namespace ts.formatting {
             static TypeNames = TokenRange.FromTokens([SyntaxKind.Identifier, SyntaxKind.NumberKeyword, SyntaxKind.StringKeyword, SyntaxKind.BooleanKeyword, SyntaxKind.SymbolKeyword, SyntaxKind.VoidKeyword, SyntaxKind.AnyKeyword]);
         }
     }
-}
\ No newline at end of file
+}