Synthesize fused specializations only once

Cython/Compiler/FusedNode.pyx

@@ -748,7 +748,7 @@ class FusedCFuncDefNode(StatListNode):
             code.mark_pos(stat.pos)
             if isinstance(stat, ExprNodes.ExprNode):
                 stat.generate_evaluation_code(code)
-            elif not isinstance(stat, FuncDefNode) or stat.entry.used:
+            elif not isinstance(stat, FuncDefNode): # or stat.entry.used:
                 stat.generate_execution_code(code)
 
         if self.__signatures__:

Cython/Compiler/Importer.py

@@ -8,6 +8,7 @@ by Cython.
 import os
 import sys
 import imp
+import shutil
 
 import pyximport
 
@@ -33,3 +34,5 @@ def importer(modulename, version=None):
         exec open(filename).read() in mod.__dict__, mod.__dict__
         sys.modules[modulename] = mod
         return mod
+        #shutil.copy(filename, os.path.splitext(filename)[0] + '.py')
+        #return __import__(modulename, None, None, [''])

Cython/Compiler/Nodes.py

@@ -2630,7 +2630,7 @@ class DefNode(FuncDefNode):
                 decorator.decorator.analyse_expressions(env)
 
     def needs_assignment_synthesis(self, env, code=None):
-        if self.is_wrapper or self.specialized_cpdefs:
+        if self.is_wrapper or self.specialized_cpdefs or self.entry.is_fused_specialized:
             return False
         if self.is_staticmethod:
             return True

Cython/Compiler/PyrexTypes.py

@@ -2608,6 +2608,7 @@ def specialize_entry(entry, cname):
     """
     Specialize an entry of a copied fused function or method
     """
+    entry.is_fused_specialized = True
     entry.name = get_fused_cname(cname, entry.name)
 
     if entry.is_cmethod:

Cython/Compiler/Symtab.py

@@ -121,6 +121,8 @@ class Entry(object):
     # error_on_uninitialized      Have Control Flow issue an error when this entry is
     #                             used uninitialized
     # cf_used          boolean    Entry is used
+    # is_fused_specialized boolean Whether this entry of a cdef or def function
+    #                              is a specialization
 
     # TODO: utility_code and utility_code_definition serves the same purpose...
 
@@ -180,6 +182,7 @@ class Entry(object):
     prev_entry = None
     might_overflow = 0
     fused_cfunction = None
+    is_fused_specialized = False
     utility_code_definition = None
     in_with_gil_block = 0
     from_cython_utility_code = None