diff --git a/sphinx/domains/c.py b/sphinx/domains/c.py
index e3570b593..5896f4a80 100644
--- a/sphinx/domains/c.py
+++ b/sphinx/domains/c.py
@@ -1533,6 +1533,7 @@ class Symbol:
         self.declaration = declaration
         self.declaration.symbol = self
         self.docname = docname
+        self.line = line
         self._assert_invariants()
         # and symbol addition should be done as well
         self._add_function_params()