diff --git a/tools/isledecomp/isledecomp/parser/error.py b/tools/isledecomp/isledecomp/parser/error.py
index 8bda90da..dce99448 100644
--- a/tools/isledecomp/isledecomp/parser/error.py
+++ b/tools/isledecomp/isledecomp/parser/error.py
@@ -18,9 +18,6 @@ class ParserError(Enum):
     # to handle it
     BOGUS_MARKER = 104
 
-    # WARN: Under a synthetic marker we expected a comment but found a code line instead
-    SYNTHETIC_NOT_COMMENT = 110
-
     # WARN: New function marker appeared while we were inside a function
     MISSED_END_OF_FUNCTION = 117
 
@@ -31,3 +28,6 @@ class ParserError(Enum):
     # with the preceding markers.
     # For example, a GLOBAL cannot follow FUNCTION/STUB
     INCOMPATIBLE_MARKER = 201
+
+    # ERROR: The line following a synthetic marker was not a comment
+    BAD_SYNTHETIC = 202
diff --git a/tools/isledecomp/isledecomp/parser/parser.py b/tools/isledecomp/isledecomp/parser/parser.py
index cea4523c..24dc0b23 100644
--- a/tools/isledecomp/isledecomp/parser/parser.py
+++ b/tools/isledecomp/isledecomp/parser/parser.py
@@ -7,7 +7,7 @@
     is_blank_or_comment,
     match_marker,
     is_marker_exact,
-    get_template_function_name,
+    get_synthetic_name,
     remove_trailing_comment,
 )
 from .node import (
@@ -307,9 +307,13 @@ def read_line(self, line: str):
         if self.state == ReaderState.IN_TEMPLATE:
             # TEMPLATE functions are a special case. The signature is
             # given on the next line (in a // comment)
-            self.function_sig = get_template_function_name(line)
-            self._function_starts_here()
-            self._function_done()
+            name = get_synthetic_name(line)
+            if name is None:
+                self._syntax_error(ParserError.BAD_SYNTHETIC)
+            else:
+                self.function_sig = name
+                self._function_starts_here()
+                self._function_done()
 
         elif self.state == ReaderState.WANT_SIG:
             # Skip blank lines or comments that come after the offset
diff --git a/tools/isledecomp/isledecomp/parser/util.py b/tools/isledecomp/isledecomp/parser/util.py
index 38515cfa..e0b25d85 100644
--- a/tools/isledecomp/isledecomp/parser/util.py
+++ b/tools/isledecomp/isledecomp/parser/util.py
@@ -23,15 +23,15 @@
 trailingCommentRegex = re.compile(r"(\s*(?://|/\*).*)$")
 
 
-def get_template_function_name(line: str) -> str:
-    """Parse function signature for special TEMPLATE functions"""
+def get_synthetic_name(line: str) -> str | None:
+    """Synthetic names appear on a single line comment on the line after the marker.
+    If that's not what we have, return None"""
     template_match = templateCommentRegex.match(line)
 
-    # If we don't match, you get whatever is on the line as the signature
     if template_match is not None:
         return template_match.group(1)
 
-    return line
+    return None
 
 
 def remove_trailing_comment(line: str) -> str:
diff --git a/tools/isledecomp/tests/test_parser.py b/tools/isledecomp/tests/test_parser.py
index ce8ad307..222a9ac1 100644
--- a/tools/isledecomp/tests/test_parser.py
+++ b/tools/isledecomp/tests/test_parser.py
@@ -228,7 +228,6 @@ def test_synthetic_same_module(parser):
     assert parser.functions[0].offset == 0x1234
 
 
-@pytest.mark.skip(reason="todo")
 def test_synthetic_no_comment(parser):
     """Synthetic marker followed by a code line (i.e. non-comment)"""
     parser.read_lines(
@@ -238,6 +237,9 @@ def test_synthetic_no_comment(parser):
         ]
     )
     assert len(parser.functions) == 0
+    assert len(parser.alerts) == 1
+    assert parser.alerts[0].code == ParserError.BAD_SYNTHETIC
+    assert parser.state == ReaderState.SEARCH
 
 
 def test_single_line_function(parser):