Ticket #3724: m4ri_hash2.patch

a/sage/matrix/matrix_mod2_dense.pyx

@@ -287 +287 @@
-
-        TEST:
-            sage: A = matrix(GF(2),2,0)
+            sage: hash(A)
+            Traceback (most recent call last):
+            ...
+            TypeError: mutable matrices are unhashable
-            sage: A.set_immutable()
-            sage: hash(A)
-            0
+            
-        """
+        if self.is_mutable():
+            raise TypeError("mutable matrices are unhashable")
-        cdef unsigned long _hash = 0xDEADBEEF
-        cdef unsigned long counter = 0
-        cdef unsigned long i, j, truerow