diff --git a/src/compiler/parser.ts b/src/compiler/parser.ts
index e146e809122..f28f82ed401 100644
--- a/src/compiler/parser.ts
+++ b/src/compiler/parser.ts
@@ -2538,13 +2538,11 @@ namespace ts {
         }
 
         function parseTypeOrTypePredicate(): TypeNode {
-            const typePredicateVariable = tryParse(() => {
-                const id = parseIdentifier();
-                if (token === SyntaxKind.IsKeyword && !scanner.hasPrecedingLineBreak()) {
-                    nextToken();
-                    return id;
-                }
-            });
+            let typePredicateVariable: Identifier;
+            if (isIdentifier()) {
+                typePredicateVariable = tryParse(parseTypePredicatePrefix);
+            }
+
             const type = parseType();
             if (typePredicateVariable) {
                 const node = <TypePredicateNode>createNode(SyntaxKind.TypePredicate, typePredicateVariable.pos);
@@ -2557,6 +2555,14 @@ namespace ts {
             }
         }
 
+        function parseTypePredicatePrefix() {
+            const id = parseIdentifier();
+            if (token === SyntaxKind.IsKeyword && !scanner.hasPrecedingLineBreak()) {
+                nextToken();
+                return id;
+            }
+        }
+
         function parseType(): TypeNode {
             // The rules about 'yield' only apply to actual code/expression contexts.  They don't
             // apply to 'type' contexts.  So we disable these parameters here before moving on.