Make args lock depend on their const-ness

Cython/Compiler/Nodes.py

@@ -2599,7 +2599,8 @@ class CFuncDefNode(FuncDefNode):
             entry.is_variable = 1
             # Even if it is checklock it should be OK to mess with self without locking
             self_locking_state = self.local_scope.declare_tracked(entry)
-            self_locking_state.is_wlocked = True
+            self_locking_state.is_rlocked = self.is_const_method
+            self_locking_state.is_wlocked = not self.is_const_method
 
     def declare_cpdef_wrapper(self, env):
         if self.overridable:

Cython/Compiler/Symtab.py

@@ -1825,7 +1825,8 @@ class LocalScope(Scope):
         entry.is_arg = 1
         if type.is_cyp_class and type.lock_mode == "autolock":
             arg_lock_state = self.declare_tracked(entry)
-            arg_lock_state.is_wlocked = True
+            arg_lock_state.is_rlocked = type.is_const
+            arg_lock_state.is_wlocked = not type.is_const
         #entry.borrowed = 1 # Not using borrowed arg refs for now
         self.arg_entries.append(entry)
         return entry