report unused variables also across closures

Cython/Compiler/FlowControl.py

@@ -616,8 +616,7 @@ def check_definitions(flow, compiler_directives):
     # Unused entries
     for entry in flow.entries:
         if (not entry.cf_references
-                and not entry.is_pyclass_attr
-                and not entry.in_closure):
+                and not entry.is_pyclass_attr):
             if entry.name != '_':
                 # '_' is often used for unused variables, e.g. in loops
                 if entry.is_arg:

tests/errors/w_unused.pyx

@@ -38,6 +38,16 @@ def unused_and_unassigned():
 def unused_generic(*args, **kwargs):
     pass
 
+def unused_in_closure(a,b,c):
+    x = 1
+    def inner():
+        nonlocal c
+        c = 1
+        y = 2
+        return a+b
+    return inner()
+
+
 _ERRORS = """
 6:6: Unused entry 'a'
 9:9: Unused entry 'b'
@@ -49,4 +59,8 @@ _ERRORS = """
 36:13: Unused entry 'i'
 38:20: Unused argument 'args'
 38:28: Unused argument 'kwargs'
+41:26: Unused argument 'c'
+41:26: Unused entry 'c'
+42:6: Unused entry 'x'
+46:10: Unused entry 'y'
 """