diff --git a/patacrep/songs/chordpro/ast.py b/patacrep/songs/chordpro/ast.py
index f18bd395..ff0bc4cb 100644
--- a/patacrep/songs/chordpro/ast.py
+++ b/patacrep/songs/chordpro/ast.py
@@ -3,8 +3,11 @@
 # pylint: disable=too-few-public-methods
 
 from collections import OrderedDict
+import functools
 import logging
 
+from patacrep.songs import errors
+
 LOGGER = logging.getLogger()
 
 def _indent(string):
@@ -223,7 +226,7 @@ class Song(AST):
         "tag": "add_cumulative",
         }
 
-    def __init__(self, filename, directives, *, errors=None):
+    def __init__(self, filename, directives, *, error_builders=None):
         super().__init__()
         self.content = []
         self.meta = OrderedDict()
@@ -231,10 +234,10 @@ class Song(AST):
         self._titles = []
         self._subtitles = []
         self.filename = filename
-        if errors is None:
+        if error_builders is None:
             self.error_builders = []
         else:
-            self.error_builders = errors
+            self.error_builders = error_builders
         for directive in directives:
             self.add(directive)
 
@@ -265,7 +268,13 @@ class Song(AST):
             # Add a metadata directive. Some of them are added using special
             # methods listed in ``METADATA_ADD``.
             if data.keyword not in AVAILABLE_DIRECTIVES:
-                LOGGER.warning("Ignoring unknown directive '{}'.".format(data.keyword))
+                message = "Ignoring unknown directive '{}'.".format(data.keyword)
+                LOGGER.warning("File {}, line {}: {}".format(self.filename, data.lineno, message))
+                self.error_builders.append(functools.partial(
+                    errors.SongSyntaxError,
+                    line=data.lineno,
+                    message=message,
+                    ))
             if data.keyword in self.METADATA_ADD:
                 getattr(self, self.METADATA_ADD[data.keyword])(data)
             else:
diff --git a/patacrep/songs/chordpro/syntax.py b/patacrep/songs/chordpro/syntax.py
index 0315ad1f..04104ac6 100644
--- a/patacrep/songs/chordpro/syntax.py
+++ b/patacrep/songs/chordpro/syntax.py
@@ -49,7 +49,7 @@ class ChordproParser(Parser):
             symbols[0] = ast.Song(
                 self.filename,
                 directives=self._directives,
-                errors=self._errors,
+                error_builders=self._errors,
                 )
         else:
             symbols[0] = symbols[2].add(symbols[1])