Allow nested C++ names after a module name (#5229)

Allow code like the following to compile:

cimport m

def my_func():
    cdef m.CppClass.NestedClass c

where m is a module, CppClass is a C++ class and NestedClass is a nested class inside CppClass.

4 files changed, 66 insertions, 0 deletions

diff --git a/Cython/Compiler/Nodes.py b/Cython/Compiler/Nodes.py
index 9c320cafa..3219768b7 100644
--- a/Cython/Compiler/Nodes.py
+++ b/Cython/Compiler/Nodes.py
@@ -1097,6 +1097,8 @@ class CSimpleBaseTypeNode(CBaseTypeNode):
                         entry.is_type and entry.type.is_cpp_class
                     ):
                         scope = entry.type.scope
+                    elif entry and entry.as_module:
+                        scope = entry.as_module
                     else:
                         scope = None
                         break
diff --git a/tests/run/cpp_nested_classes.pyx b/tests/run/cpp_nested_classes.pyx
index 8877c0440..50a453901 100644
--- a/tests/run/cpp_nested_classes.pyx
+++ b/tests/run/cpp_nested_classes.pyx
@@ -185,3 +185,30 @@ def test_nested_sub_struct(x):
     assert s.int_value == x
     s.typed_value = x
     return s.typed_value
+
+cimport cpp_nested_names
+cimport libcpp.string
+from cython.operator cimport dereference as deref, preincrement as inc
+
+def test_nested_names():
+    """
+    >>> test_nested_names()
+    Nested
+    NestedNested
+    C
+    y
+    t
+    h
+    o
+    n
+    """
+    cdef cpp_nested_names.Outer.Nested n = cpp_nested_names.Outer.get()
+    cdef cpp_nested_names.Outer.Nested.NestedNested nn = n.get()
+    print(n.get_str().decode('ascii'))
+    print(nn.get_str().decode('ascii'))
+
+    cdef libcpp.string.string s = "Cython"
+    cdef libcpp.string.string.iterator i = s.begin()
+    while i != s.end():
+        print(chr(deref(i)))
+        inc(i)
diff --git a/tests/run/cpp_nested_names.pxd b/tests/run/cpp_nested_names.pxd
new file mode 100644
index 000000000..04b5f8f97
--- /dev/null
+++ b/tests/run/cpp_nested_names.pxd
@@ -0,0 +1,17 @@
+# cython: language_level=3
+
+from libcpp.string cimport string
+
+cdef extern from "cpp_nested_names_helper.h":
+    cdef cppclass Outer:
+        cppclass Nested:
+            cppclass NestedNested:
+                string get_str()
+
+            string get_str()
+
+            @staticmethod
+            NestedNested get()
+
+        @staticmethod
+        Nested get()
diff --git a/tests/run/cpp_nested_names_helper.h b/tests/run/cpp_nested_names_helper.h
new file mode 100644
index 000000000..02aae485a
--- /dev/null
+++ b/tests/run/cpp_nested_names_helper.h
@@ -0,0 +1,20 @@
+#ifndef CPP_NESTED_NAMES_HELPER_H
+#define CPP_NESTED_NAMES_HELPER_H
+
+#include <string>
+
+struct Outer {
+  struct Nested {
+    struct NestedNested {
+      std::string get_str() { return "NestedNested"; }
+    };
+
+    std::string get_str() { return "Nested"; }
+
+    static NestedNested get() { return NestedNested(); }
+  };
+
+  static Nested get() { return Outer::Nested(); }
+};
+
+#endif