diff --git a/src/compiler/binder.ts b/src/compiler/binder.ts
index 65cd8e7ae8f..5e89cd89b98 100644
--- a/src/compiler/binder.ts
+++ b/src/compiler/binder.ts
@@ -439,7 +439,8 @@ namespace ts {
                 //       during global merging in the checker. Why? The only case when ambient module is permitted inside another module is module augmentation
                 //       and this case is specially handled. Module augmentations should only be merged with original module definition
                 //       and should never be merged directly with other augmentation, and the latter case would be possible if automatic merge is allowed.
-                const isJSDocTypedefInJSDocNamespace = isInJavaScriptFile(node) && node.kind === SyntaxKind.JSDocTypedefTag &&
+                if (node.kind === SyntaxKind.JSDocTypedefTag) Debug.assert(isInJavaScriptFile(node)); // We shouldn't add symbols for JSDoc nodes if not in a JS file.
+                const isJSDocTypedefInJSDocNamespace = node.kind === SyntaxKind.JSDocTypedefTag &&
                     (node as JSDocTypedefTag).name &&
                     (node as JSDocTypedefTag).name.kind === SyntaxKind.Identifier &&
                     ((node as JSDocTypedefTag).name as Identifier).isInJSDocNamespace;
@@ -603,9 +604,7 @@ namespace ts {
             // Binding of JsDocComment should be done before the current block scope container changes.
             // because the scope of JsDocComment should not be affected by whether the current node is a
             // container or not.
-            if (node.jsDoc) {
-                forEach(node.jsDoc, bind);
-            }
+            forEach(node.jsDoc, bind);
             if (checkUnreachable(node)) {
                 bindEachChild(node);
                 return;
@@ -2071,10 +2070,7 @@ namespace ts {
                     return bindVariableDeclarationOrBindingElement(<VariableDeclaration | BindingElement>node);
                 case SyntaxKind.PropertyDeclaration:
                 case SyntaxKind.PropertySignature:
-                case SyntaxKind.JSDocRecordMember:
-                    return bindPropertyOrMethodOrAccessor(<Declaration>node, SymbolFlags.Property | ((<PropertyDeclaration>node).questionToken ? SymbolFlags.Optional : SymbolFlags.None), SymbolFlags.PropertyExcludes);
-                case SyntaxKind.JSDocPropertyTag:
-                    return bindJSDocProperty(<JSDocPropertyTag>node);
+                    return bindPropertyWorker(node as PropertyDeclaration | PropertySignature);
                 case SyntaxKind.PropertyAssignment:
                 case SyntaxKind.ShorthandPropertyAssignment:
                     return bindPropertyOrMethodOrAccessor(<Declaration>node, SymbolFlags.Property, SymbolFlags.PropertyExcludes);
@@ -2119,13 +2115,10 @@ namespace ts {
                     return bindPropertyOrMethodOrAccessor(<Declaration>node, SymbolFlags.SetAccessor, SymbolFlags.SetAccessorExcludes);
                 case SyntaxKind.FunctionType:
                 case SyntaxKind.ConstructorType:
-                case SyntaxKind.JSDocFunctionType:
                     return bindFunctionOrConstructorType(<SignatureDeclaration>node);
                 case SyntaxKind.TypeLiteral:
                 case SyntaxKind.MappedType:
-                case SyntaxKind.JSDocTypeLiteral:
-                case SyntaxKind.JSDocRecordType:
-                    return bindAnonymousDeclaration(<Declaration>node, SymbolFlags.TypeLiteral, "__type");
+                    return bindAnonymousTypeWorker(node as TypeLiteralNode | MappedTypeNode);
                 case SyntaxKind.ObjectLiteralExpression:
                     return bindObjectLiteralExpression(<ObjectLiteralExpression>node);
                 case SyntaxKind.FunctionExpression:
@@ -2146,11 +2139,6 @@ namespace ts {
                     return bindClassLikeDeclaration(<ClassLikeDeclaration>node);
                 case SyntaxKind.InterfaceDeclaration:
                     return bindBlockScopedDeclaration(<Declaration>node, SymbolFlags.Interface, SymbolFlags.InterfaceExcludes);
-                case SyntaxKind.JSDocTypedefTag:
-                    if (isInJavaScriptFile(node) && (!(<JSDocTypedefTag>node).fullName || (<JSDocTypedefTag>node).fullName.kind === SyntaxKind.Identifier)) {
-                        return bindBlockScopedDeclaration(<Declaration>node, SymbolFlags.TypeAlias, SymbolFlags.TypeAliasExcludes);
-                    }
-                    break;
                 case SyntaxKind.TypeAliasDeclaration:
                     return bindBlockScopedDeclaration(<Declaration>node, SymbolFlags.TypeAlias, SymbolFlags.TypeAliasExcludes);
                 case SyntaxKind.EnumDeclaration:
@@ -2188,9 +2176,41 @@ namespace ts {
                 // falls through
                 case SyntaxKind.ModuleBlock:
                     return updateStrictModeStatementList((<Block | ModuleBlock>node).statements);
+
+                default:
+                    if (isInJavaScriptFile(node)) return bindJSDocWorker(node);
             }
         }
 
+        function bindJSDocWorker(node: Node) {
+            switch (node.kind) {
+                case SyntaxKind.JSDocRecordMember:
+                    return bindPropertyWorker(node as JSDocRecordMember);
+                case SyntaxKind.JSDocPropertyTag:
+                    return declareSymbolAndAddToSymbolTable(node as JSDocPropertyTag, SymbolFlags.Property, SymbolFlags.PropertyExcludes);
+                case SyntaxKind.JSDocFunctionType:
+                    return bindFunctionOrConstructorType(<SignatureDeclaration>node);
+                case SyntaxKind.JSDocTypeLiteral:
+                case SyntaxKind.JSDocRecordType:
+                    return bindAnonymousTypeWorker(node as JSDocTypeLiteral | JSDocRecordType);
+                case SyntaxKind.JSDocTypedefTag: {
+                    const { fullName } = node as JSDocTypedefTag;
+                    if (!fullName || fullName.kind === SyntaxKind.Identifier) {
+                        return bindBlockScopedDeclaration(<Declaration>node, SymbolFlags.TypeAlias, SymbolFlags.TypeAliasExcludes);
+                    }
+                    break;
+                }
+            }
+        }
+
+        function bindPropertyWorker(node: PropertyDeclaration | PropertySignature) {
+            return bindPropertyOrMethodOrAccessor(node, SymbolFlags.Property | (node.questionToken ? SymbolFlags.Optional : SymbolFlags.None), SymbolFlags.PropertyExcludes);
+        }
+
+        function bindAnonymousTypeWorker(node: TypeLiteralNode | MappedTypeNode | JSDocTypeLiteral | JSDocRecordType) {
+            return bindAnonymousDeclaration(<Declaration>node, SymbolFlags.TypeLiteral, "__type");
+        }
+
         function checkTypePredicate(node: TypePredicateNode) {
             const { parameterName, type } = node;
             if (parameterName && parameterName.kind === SyntaxKind.Identifier) {
@@ -2556,10 +2576,8 @@ namespace ts {
         }
 
         function bindPropertyOrMethodOrAccessor(node: Declaration, symbolFlags: SymbolFlags, symbolExcludes: SymbolFlags) {
-            if (!isDeclarationFile(file) && !isInAmbientContext(node)) {
-                if (isAsyncFunction(node)) {
-                    emitFlags |= NodeFlags.HasAsyncFunctions;
-                }
+            if (!isDeclarationFile(file) && !isInAmbientContext(node) && isAsyncFunction(node)) {
+                emitFlags |= NodeFlags.HasAsyncFunctions;
             }
 
             if (currentFlow && isObjectLiteralOrClassExpressionMethod(node)) {
@@ -2571,10 +2589,6 @@ namespace ts {
                 : declareSymbolAndAddToSymbolTable(node, symbolFlags, symbolExcludes);
         }
 
-        function bindJSDocProperty(node: JSDocPropertyTag) {
-            return declareSymbolAndAddToSymbolTable(node, SymbolFlags.Property, SymbolFlags.PropertyExcludes);
-        }
-
         // reachability checks
 
         function shouldReportErrorOnModuleDeclaration(node: ModuleDeclaration): boolean {