Fix CVarDefNode's in_pxd flag

Cython/Compiler/Nodes.py

@@ -1074,7 +1074,8 @@ class CVarDefNode(StatNode):
         self.dest_scope = dest_scope
         base_type = self.base_type.analyse(env)
 
-        if base_type.is_fused and (env.is_c_class_scope or env.is_module_scope):
+        if base_type.is_fused and not self.in_pxd and (env.is_c_class_scope or
+                                                       env.is_module_scope):
             error(self.pos, "Fused types not allowed here")
             return error_type
 

Cython/Compiler/Parsing.py

@@ -2734,7 +2734,7 @@ def p_c_func_or_var_declaration(s, pos, ctx):
             visibility = ctx.visibility,
             base_type = base_type,
             declarators = declarators,
-            in_pxd = ctx.level == 'module_pxd',
+            in_pxd = ctx.level in ('module_pxd', 'c_class_pxd'),
             api = ctx.api,
             overridable = ctx.overridable)
     return result