diff --git a/format/desktop_entry/error.ha b/format/desktop_entry/error.ha
index ff00992..f3921a4 100644
--- a/format/desktop_entry/error.ha
+++ b/format/desktop_entry/error.ha
@@ -7,9 +7,12 @@ export type error = !(syntaxerr | io::error | utf8::invalid);
 // All syntax errors defined in this module.
 export type syntaxerr = !(
 	invalid_group_header |
-	invalid_entry |
-	invalid_ascii |
-	invalid_escape);
+	invalid_entry        |
+	invalid_ascii        |
+	invalid_escape       |
+	invalid_boolean      |
+	invalid_numeric      |
+	expected_single);
 
 // Returned when a malformed group header is encountered while parsing.
 export type invalid_group_header = !void;
@@ -24,6 +27,18 @@ export type invalid_ascii = !void;
 // Returned when an invalid escape sequence was enctountered while parsing.
 export type invalid_escape = !void;
 
+// Returned when a boolean value was expected while parsing, but something else
+// was given.
+export type invalid_boolean = !void;
+
+// Returned when a numeric value was expected while parsing, but something else
+// was given.
+export type invalid_numeric = !void;
+
+// Returned when a singular value was expected while parsing, but multiple
+// values were given.
+export type expected_single = !void;
+
 // Returns a user-friendly representation of [[error]]. The result may be
 // statically allocated.
 export fn strerror(err: error) str = match (err) {
@@ -31,6 +46,9 @@ case invalid_group_header   => yield "invalid group header";
 case invalid_entry          => yield "invalid entry";
 case invalid_ascii          => yield "invalid ascii";
 case invalid_escape         => yield "invalid escape";
+case invalid_boolean        => yield "invalid boolean";
+case invalid_numeric        => yield "invalid numeric";
+case expected_single        => yield "expected single";
 case let err: io::error     => yield io::strerror(err);
 case let err: utf8::invalid => yield utf8::strerror(err);
 };