Allow type objects in utility code context.

This avoids issues of having to inject/name them
(and any conversions, see e.g. Issue #1737).

Cython/Compiler/UtilityCode.py

@@ -77,7 +77,13 @@ class CythonUtilityCode(Code.UtilityCodeBase):
         #    while the generated node trees can be altered in the compilation of a
         #    single file.
         # Hence, delay any processing until later.
+        context_types = {}
         if context is not None:
+            from .PyrexTypes import BaseType
+            for key, value in context.items():
+                if isinstance(value, BaseType):
+                    context[key] = key
+                    context_types[key] = value
             impl = Code.sub_tempita(impl, context, file, name)
         self.impl = impl
         self.name = name
@@ -87,6 +93,7 @@ class CythonUtilityCode(Code.UtilityCodeBase):
         self.from_scope = from_scope
         self.outer_module_scope = outer_module_scope
         self.compiler_directives = compiler_directives
+        self.context_types = context_types
 
     def __eq__(self, other):
         if isinstance(other, CythonUtilityCode):
@@ -163,6 +170,17 @@ class CythonUtilityCode(Code.UtilityCodeBase):
                 pipeline, scope_transform,
                 before=ParseTreeTransforms.AnalyseDeclarationsTransform)
 
+        if self.context_types:
+            # inject types into module scope
+            def scope_transform(module_node):
+                for name, type in self.context_types.items():
+                    module_node.scope.declare_type(name, type, None, visibility='extern')
+                return module_node
+
+            pipeline = Pipeline.insert_into_pipeline(
+                pipeline, scope_transform,
+                before=ParseTreeTransforms.AnalyseDeclarationsTransform)
+
         (err, tree) = Pipeline.run_pipeline(pipeline, tree, printtree=False)
         assert not err, err
         self.tree = tree