Fix type declarations with template-dependent namespaces needing 'typename'

Cython/Compiler/PyrexTypes.py

@@ -433,7 +433,7 @@ class CTypedefType(BaseType):
         else:
             base_code = public_decl(self.typedef_cname, dll_linkage)
         if self.typedef_namespace is not None and not pyrex:
-            base_code = "%s::%s" % (self.typedef_namespace.empty_declaration_code(), base_code)
+            base_code = "%s::%s" % (namespace_declaration_code(self.typedef_namespace), base_code)
         return self.base_declaration_code(base_code, entity_code)
 
     def as_argument_type(self):
@@ -4017,10 +4017,7 @@ class CppClassType(CType):
         else:
             base_code = "%s%s" % (self.cname, templates)
             if self.namespace is not None:
-                base_code = "%s::%s" % (self.namespace.empty_declaration_code(), base_code)
-                if (self.namespace.templates is not None
-                    and any(isinstance(t, TemplatePlaceholderType) for t in self.namespace.templates)):
-                        base_code = "typename %s" % base_code
+                base_code = "%s::%s" % (namespace_declaration_code(self.namespace), base_code)
             base_code = public_decl(base_code, dll_linkage)
         return self.base_declaration_code(base_code, entity_code)
 
@@ -4443,7 +4440,7 @@ class CEnumType(CIntLike, CType):
         else:
             if self.namespace:
                 base_code = "%s::%s" % (
-                    self.namespace.empty_declaration_code(), self.cname)
+                    namespace_declaration_code(self.namespace), self.cname)
             elif self.typedef_flag:
                 base_code = self.cname
             else:
@@ -5294,3 +5291,14 @@ def cap_length(s, max_prefix=63, max_len=1024):
         return s
     else:
         return '%x__%s__etc' % (abs(hash(s)) % (1<<20), s[:max_len-17])
+
+def namespace_declaration_code(namespace):
+    """
+    Add 'typename' to the beginning of the declaration code when the namespace is template-dependent
+    """
+    base_code = namespace.empty_declaration_code()
+    if not base_code.startswith("typename "):
+        if hasattr(namespace, 'templates') and namespace.templates is not None:
+            if any(isinstance(t, TemplatePlaceholderType) for t in namespace.templates):
+                base_code = "typename %s" % base_code
+    return base_code