diff --git a/packages/localize/src/localize/src/localize.ts b/packages/localize/src/localize/src/localize.ts
index 660b4e2538..dbed0e879f 100644
--- a/packages/localize/src/localize/src/localize.ts
+++ b/packages/localize/src/localize/src/localize.ts
@@ -159,25 +159,12 @@ const BLOCK_MARKER = ':';
  * escaped with a backslash, `\:`. This function checks for this by looking at the `raw`
  * messagePart, which should still contain the backslash.
  *
- * ---
- *
- * If the template literal was synthesized and downleveled by TypeScript to ES5 then its
- * raw array will only contain empty strings. This is because the current TypeScript compiler uses
- * the original source code to find the raw text and in the case of synthesized AST nodes, there is
- * no source code to draw upon.
- *
- * The workaround in this function is to assume that the template literal did not contain an escaped
- * placeholder name, and fall back on checking the cooked array instead.
- * This is a limitation if compiling to ES5 in TypeScript but is not a problem if the TypeScript
- * output is ES2015 and the code is downleveled by a separate tool as happens in the Angular CLI.
- *
  * @param messagePart The cooked message part to process.
  * @param rawMessagePart The raw message part to check.
  * @returns the message part with the placeholder name stripped, if found.
  * @throws an error if the block is unterminated
  */
 function stripBlock(messagePart: string, rawMessagePart: string) {
-  rawMessagePart = rawMessagePart || messagePart;
   return rawMessagePart.charAt(0) === BLOCK_MARKER ?
       messagePart.substring(findEndOfBlock(messagePart, rawMessagePart) + 1) :
       messagePart;
diff --git a/packages/localize/src/utils/src/messages.ts b/packages/localize/src/utils/src/messages.ts
index 5188caa1d2..6664b4db67 100644
--- a/packages/localize/src/utils/src/messages.ts
+++ b/packages/localize/src/utils/src/messages.ts
@@ -182,18 +182,6 @@ export function parseMetadata(cooked: string, raw: string): MessageMetadata {
  * Since blocks are optional, it is possible that the content of a message block actually starts
  * with a block marker. In this case the marker must be escaped `\:`.
  *
- * ---
- *
- * If the template literal was synthesized and downleveled by TypeScript to ES5 then its
- * raw array will only contain empty strings. This is because the current TypeScript compiler uses
- * the original source code to find the raw text and in the case of synthesized AST nodes, there is
- * no source code to draw upon.
- *
- * The workaround in this function is to assume that the template literal did not contain an escaped
- * placeholder name, and fall back on checking the cooked array instead.
- * This is a limitation if compiling to ES5 in TypeScript but is not a problem if the TypeScript
- * output is ES2015 and the code is downlevelled by a separate tool as happens in the Angular CLI.
- *
  * @param cooked The cooked version of the message part to parse.
  * @param raw The raw version of the message part to parse.
  * @returns An object containing the `text` of the message part and the text of the `block`, if it
@@ -201,7 +189,6 @@ export function parseMetadata(cooked: string, raw: string): MessageMetadata {
  * @throws an error if the `block` is unterminated
  */
 export function splitBlock(cooked: string, raw: string): {text: string, block?: string} {
-  raw = raw || cooked;
   if (raw.charAt(0) !== BLOCK_MARKER) {
     return {text: cooked};
   } else {
diff --git a/packages/localize/src/utils/test/messages_spec.ts b/packages/localize/src/utils/test/messages_spec.ts
index 2167e8cfdd..5c7be42d9c 100644
--- a/packages/localize/src/utils/test/messages_spec.ts
+++ b/packages/localize/src/utils/test/messages_spec.ts
@@ -61,12 +61,6 @@ describe('messages utils', () => {
       expect(message.messageId).toEqual('2623373088949454037');
     });
 
-    it('should handle raw values that are empty (from synthesized AST)', () => {
-      const message =
-          parseMessage(makeTemplateObject(['a', ':one:b', ':two:c'], ['', '', '']), [1, 2]);
-      expect(message.messageId).toEqual('8865273085679272414');
-    });
-
     it('should extract the meaning, description and placeholder names', () => {
       const message1 = parseMessage(makeTemplateObject(['abc'], ['abc']), []);
       expect(message1.messageParts).toEqual(['abc']);
@@ -128,10 +122,6 @@ describe('messages utils', () => {
                  ':block with escaped : in it:abc def', ':block with escaped \\: in it:abc def'))
           .toEqual({text: 'abc def', block: 'block with escaped : in it'});
     });
-
-    it('should handle the empty raw part', () => {
-      expect(splitBlock(':block info:abc def', '')).toEqual({text: 'abc def', block: 'block info'});
-    });
   });
 
   describe('findEndOfBlock()', () => {
@@ -193,11 +183,5 @@ describe('messages utils', () => {
             id: undefined
           });
     });
-
-    it('should handle the empty raw part', () => {
-      expect(parseMetadata(':description:abc def', ''))
-          .toEqual(
-              {text: 'abc def', meaning: undefined, description: 'description', id: undefined});
-    });
   });
 });