From 026e3de9584ec60457222fcd97131dad8dac46ac Mon Sep 17 00:00:00 2001
From: Robert Bradshaw <robertwb@math.washington.edu>
Date: Sun, 21 Feb 2010 02:11:21 -0800
Subject: [PATCH] Reference type inference

---
 Cython/Compiler/TypeInference.py  |  4 ++++
 tests/wrappers/cpp_references.pyx | 16 ++++++++++++++++
 2 files changed, 20 insertions(+)

diff --git a/Cython/Compiler/TypeInference.py b/Cython/Compiler/TypeInference.py
index 8c10bcd3..6d33a7f8 100644
--- a/Cython/Compiler/TypeInference.py
+++ b/Cython/Compiler/TypeInference.py
@@ -276,10 +276,14 @@ def find_spanning_type(type1, type2):
 
 def aggressive_spanning_type(types, might_overflow):
     result_type = reduce(find_spanning_type, types)
+    if result_type.is_reference:
+        result_type = result_type.ref_base_type
     return result_type
 
 def safe_spanning_type(types, might_overflow):
     result_type = reduce(find_spanning_type, types)
+    if result_type.is_reference:
+        result_type = result_type.ref_base_type
     if result_type.is_pyobject:
         # any specific Python type is always safe to infer
         return result_type
diff --git a/tests/wrappers/cpp_references.pyx b/tests/wrappers/cpp_references.pyx
index bf53a2e2..a4c2edd2 100644
--- a/tests/wrappers/cpp_references.pyx
+++ b/tests/wrappers/cpp_references.pyx
@@ -1,9 +1,13 @@
+cimport cython
+
+
 cdef extern from "cpp_references_helper.h":
     cdef int& ref_func(int&)
     
     cdef int ref_var_value
     cdef int& ref_var
 
+
 def test_ref_func(int x):
     """
     >>> test_ref_func(2)
@@ -42,3 +46,15 @@ def test_ref_assign(int x):
     """
     cdef double d = ref_func(x)
     return d
+
+@cython.infer_types(True)
+def test_ref_inference(int x):
+    """
+    >>> test_ref_inference(23)
+    23
+    >>> test_ref_inference(29)
+    29
+    """
+    z = ref_func(x)
+    assert cython.typeof(z) == "int", cython.typeof(z)
+    return z
-- 
2.26.2