diff --git a/src/compiler/comments.ts b/src/compiler/comments.ts
index 7ad380f06af..79bb795efe5 100644
--- a/src/compiler/comments.ts
+++ b/src/compiler/comments.ts
@@ -82,12 +82,9 @@ namespace ts {
             function getLeadingComments(range: TextRange): CommentRange[];
             function getLeadingComments(range: TextRange, contextNode: Node, ignoreNodeCallback: (contextNode: Node) => boolean, getTextRangeCallback: (contextNode: Node) => TextRange): CommentRange[];
             function getLeadingComments(range: TextRange, contextNode?: Node, ignoreNodeCallback?: (contextNode: Node) => boolean, getTextRangeCallback?: (contextNode: Node) => TextRange) {
-                let comments: CommentRange[] = [];
-                let ignored = false;
                 if (contextNode) {
                     range = getTextRangeCallback(contextNode) || range;
                     if (ignoreNodeCallback(contextNode)) {
-                        ignored = true;
                         // If the node will not be emitted in JS, remove all the comments (normal,
                         // pinned and `///`) associated with the node, unless it is a triple slash
                         // comment at the top of the file.
@@ -101,16 +98,14 @@ namespace ts {
                         // The first `///` will NOT be removed while the second one will be removed
                         // even though both nodes will not be emitted.
                         if (range.pos === 0) {
-                            comments = filter(getLeadingCommentsOfPosition(0), isTripleSlashComment);
+                            return filter(getLeadingCommentsOfPosition(0), isTripleSlashComment);
                         }
+
+                        return;
                     }
                 }
 
-                if (!ignored) {
-                    comments = getLeadingCommentsOfPosition(range.pos);
-                }
-
-                return comments;
+                return getLeadingCommentsOfPosition(range.pos);
             }
 
             /**
diff --git a/src/compiler/factory.ts b/src/compiler/factory.ts
index 2fc5a437565..d04d7f0fd0d 100644
--- a/src/compiler/factory.ts
+++ b/src/compiler/factory.ts
@@ -91,16 +91,6 @@ namespace ts {
         return clone;
     }
 
-    /**
-     * Gets a clone of a node with a unique node ID.
-     */
-    export function getUniqueClone<T extends Node>(node: T): T {
-        const clone = getMutableClone(node);
-        clone.id = 0;
-        getNodeId(clone);
-        return clone;
-    }
-
     // Literals
 
     export function createLiteral(textSource: StringLiteral | Identifier, location?: TextRange): StringLiteral;
@@ -821,8 +811,9 @@ namespace ts {
     }
 
     function createReactNamespace(reactNamespace: string, parent: JsxOpeningLikeElement) {
-        // Create an identifier and give it a parent. This allows us to resolve the react
-        // namespace during emit.
+        // To ensure the emit resolver can properly resolve the namespace, we need to
+        // treat this identifier as if it were a source tree node by clearing the `Synthesized`
+        // flag and setting a parent node.
         const react = createIdentifier(reactNamespace || "React");
         react.flags &= ~NodeFlags.Synthesized;
         react.parent = parent;
diff --git a/src/compiler/transformers/es6.ts b/src/compiler/transformers/es6.ts
index e2d41783982..1c412f98af7 100644
--- a/src/compiler/transformers/es6.ts
+++ b/src/compiler/transformers/es6.ts
@@ -1003,7 +1003,7 @@ namespace ts {
             }
 
             // `declarationName` is the name of the local declaration for the parameter.
-            const declarationName = getUniqueClone(<Identifier>parameter.name);
+            const declarationName = getMutableClone(<Identifier>parameter.name);
             setNodeEmitFlags(declarationName, NodeEmitFlags.NoSourceMap);
 
             // `expressionName` is the name of the parameter used in expressions.
@@ -2916,7 +2916,7 @@ namespace ts {
          */
         function getDeclarationName(node: DeclarationStatement | ClassExpression, allowComments?: boolean, allowSourceMaps?: boolean, emitFlags?: NodeEmitFlags) {
             if (node.name && !isGeneratedIdentifier(node.name)) {
-                const name = getUniqueClone(node.name);
+                const name = getMutableClone(node.name);
                 emitFlags |= getNodeEmitFlags(node.name);
                 if (!allowSourceMaps) {
                     emitFlags |= NodeEmitFlags.NoSourceMap;
diff --git a/src/compiler/transformers/ts.ts b/src/compiler/transformers/ts.ts
index 488b76cc469..d4f7ea020cb 100644
--- a/src/compiler/transformers/ts.ts
+++ b/src/compiler/transformers/ts.ts
@@ -928,10 +928,10 @@ namespace ts {
         function transformParameterWithPropertyAssignment(node: ParameterDeclaration) {
             Debug.assert(isIdentifier(node.name));
             const name = node.name as Identifier;
-            const propertyName = getUniqueClone(name);
+            const propertyName = getMutableClone(name);
             setNodeEmitFlags(propertyName, NodeEmitFlags.NoComments | NodeEmitFlags.NoSourceMap);
 
-            const localName = getUniqueClone(name);
+            const localName = getMutableClone(name);
             setNodeEmitFlags(localName, NodeEmitFlags.NoComments);
 
             return startOnNewLine(
@@ -2922,7 +2922,7 @@ namespace ts {
          */
         function getDeclarationName(node: DeclarationStatement | ClassExpression, allowComments?: boolean, allowSourceMaps?: boolean, emitFlags?: NodeEmitFlags) {
             if (node.name) {
-                const name = getUniqueClone(node.name);
+                const name = getMutableClone(node.name);
                 emitFlags |= getNodeEmitFlags(node.name);
                 if (!allowSourceMaps) {
                     emitFlags |= NodeEmitFlags.NoSourceMap;