fix declaration analysis (and type inference) for comprehensions

Cython/Compiler/ExprNodes.py

@@ -3631,14 +3631,13 @@ class ComprehensionNode(ExprNode):
     def infer_type(self, env):
         return self.target.infer_type(env)
 
+    def analyse_declarations(self, env):
+        self.append.target = self # this is used in the PyList_Append of the inner loop
+        self.loop.analyse_declarations(env)
+
     def analyse_types(self, env):
         self.target.analyse_expressions(env)
         self.type = self.target.type
-        self.append.target = self # this is a CloneNode used in the PyList_Append in the inner loop
-        # We are analysing declarations to late.
-        self.loop.target.analyse_target_declaration(env)
-        env.infer_types()
-        self.loop.analyse_declarations(env)
         self.loop.analyse_expressions(env)
 
     def calculate_result_code(self):

Cython/Compiler/ParseTreeTransforms.py

@@ -725,6 +725,11 @@ property NAME:
         self.seen_vars_stack.pop()
         return node
 
+    def visit_ComprehensionNode(self, node):
+        self.visitchildren(node)
+        node.analyse_declarations(self.env_stack[-1])
+        return node
+
     # Some nodes are no longer needed after declaration
     # analysis and can be dropped. The analysis was performed
     # on these nodes in a seperate recursive process from the

Cython/Compiler/TypeInference.py

@@ -25,7 +25,6 @@ class MarkAssignments(CythonTransform):
         if isinstance(lhs, (ExprNodes.NameNode, Nodes.PyArgDeclNode)):
             if lhs.entry is None:
                 # TODO: This shouldn't happen...
-                # It looks like comprehension loop targets are not declared soon enough.
                 return
             lhs.entry.assignments.append(rhs)
         elif isinstance(lhs, ExprNodes.SequenceNode):