work around bug in fused types code that prevents typing the signature of the...

work around bug in fused types code that prevents typing the signature of the runtime dispatch function

Cython/Compiler/FusedNode.py

@@ -519,15 +519,15 @@ class FusedCFuncDefNode(StatListNode):
         pyx_code.put_chunk(
             u"""
                 # PROCESSING ARGUMENT {{arg_tuple_idx}}
-                if {{arg_tuple_idx}} < len(args):
-                    arg = args[{{arg_tuple_idx}}]
-                elif '{{arg.name}}' in kwargs:
-                    arg = kwargs['{{arg.name}}']
+                if {{arg_tuple_idx}} < len(<tuple>args):
+                    arg = (<tuple>args)[{{arg_tuple_idx}}]
+                elif '{{arg.name}}' in <dict>kwargs:
+                    arg = (<dict>kwargs)['{{arg.name}}']
                 else:
                 {{if arg.default}}
-                    arg = defaults[{{default_idx}}]
+                    arg = (<tuple>defaults)[{{default_idx}}]
                 {{else}}
-                    raise TypeError("Expected at least %d arguments" % len(args))
+                    raise TypeError("Expected at least %d arguments" % len(<tuple>args))
                 {{endif}}
             """)
 
@@ -561,8 +561,9 @@ class FusedCFuncDefNode(StatListNode):
 
         pyx_code.put_chunk(
             u"""
-                def __pyx_fused_cpdef(dict signatures not None,
-                                      tuple args not None, dict kwargs, tuple defaults not None):
+                def __pyx_fused_cpdef(signatures, args, kwargs, defaults):
+                    # FIXME: use a typed signature - currently fails badly because
+                    #        default arguments inherit the types we specify here!
 
                     dest_sig = [{{for _ in range(n_fused)}}None,{{endfor}}]
 
@@ -617,7 +618,7 @@ class FusedCFuncDefNode(StatListNode):
         pyx_code.put_chunk(
             u"""
                 candidates = []
-                for sig in signatures:
+                for sig in <dict>signatures:
                     match_found = False
                     for src_type, dst_type in zip(sig.strip('()').split('|'), dest_sig):
                         if dst_type is not None:
@@ -635,7 +636,7 @@ class FusedCFuncDefNode(StatListNode):
                 elif len(candidates) > 1:
                     raise TypeError("Function call with ambiguous argument types")
                 else:
-                    return signatures[candidates[0]]
+                    return (<dict>signatures)[candidates[0]]
             """)
 
         fragment_code = pyx_code.getvalue()