fix #18862: E0601 false positive with lambda functions

3 files changed, 10 insertions, 1 deletions

diff --git a/ChangeLog b/ChangeLog
index d84bd2cfd..c5ce38e7a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -6,6 +6,7 @@ ChangeLog for PyLint
     * include James Lingar patches for function call arguments checker
     * improved flymake code and doc provided by Derek Harland
     * refactor & fix the imports checker
+    * fix #18862: E0601 false positive with lambda functions
     * fix #8764: More than one statement on a single line false positive with
       try/except/finally
     * Nathaniel's fix for w0108 false positive
diff --git a/checkers/variables.py b/checkers/variables.py
index 454fc9c63..f17c94033 100644
--- a/checkers/variables.py
+++ b/checkers/variables.py
@@ -380,7 +380,8 @@ builtins. Remember that you should avoid to define new builtins when possible.'
                         if defstmt is stmt and isinstance(node, (astng.DelName,
                                                                  astng.AssName)):
                             self.add_message('E0602', args=name, node=node)
-                        else:
+                        elif self._to_consume[-1][-1] != 'lambda':
+                            # E0601 may *not* occurs in lambda scope
                             self.add_message('E0601', args=name, node=node)
                 if not isinstance(node, astng.AssName): # Aug AssName
                     del to_consume[name]
diff --git a/test/input/func_noerror_lambda_use_before_assign.py b/test/input/func_noerror_lambda_use_before_assign.py
new file mode 100644
index 000000000..0ab8c2c33
--- /dev/null
+++ b/test/input/func_noerror_lambda_use_before_assign.py
@@ -0,0 +1,7 @@
+"""https://www.logilab.net/elo/ticket/18862"""
+__revision__ = 1
+def function():
+    """hop"""
+    ggg = lambda: xxx
+    xxx = 1
+    print ggg()