Evaluate subscript index first to prevent nested cypclass lock acquisition

Cython/Compiler/ExprNodes.py

@@ -3597,7 +3597,7 @@ class IndexNode(_IndexingBaseNode):
     #  is_fused_index boolean   Whether the index is used to specialize a
     #                           c(p)def function
 
-    subexprs = ['base', 'index']
+    subexprs = ['index', 'base'] # evaluate the index first
     type_indices = None
 
     is_subscript = True