diff --git a/parso/python/normalizer.py b/parso/python/normalizer.py
index 7f10838..5b132af 100644
--- a/parso/python/normalizer.py
+++ b/parso/python/normalizer.py
@@ -231,6 +231,10 @@ class ErrorFinder(Normalizer):
                     self._add_syntax_error(message, lhs.parent)
             else:
                 self._add_syntax_error(message % type_, lhs.parent)
+        elif node.type == 'argument':
+            if node.children[1] == '=' and node.children[0].type != 'name':
+                message = "keyword can't be an expression"
+                self._add_syntax_error(message, node.children[0])
 
         yield
 
diff --git a/test/test_python_errors.py b/test/test_python_errors.py
index d1521b6..82f5aa5 100644
--- a/test/test_python_errors.py
+++ b/test/test_python_errors.py
@@ -90,6 +90,7 @@ def test_indentation_errors(code, positions):
         '(a, b): int',
         '*star,: int',
         'a, b: int = 3',
+        'foo(+a=3)',
 
         # IndentationError
         ' foo',