diff --git a/src/etc/gdb_rust_pretty_printing.py b/src/etc/gdb_rust_pretty_printing.py
index 33f22e85796..554ab66bc56 100755
--- a/src/etc/gdb_rust_pretty_printing.py
+++ b/src/etc/gdb_rust_pretty_printing.py
@@ -10,8 +10,15 @@
 
 import gdb
 import re
+import sys
 import debugger_pretty_printers_common as rustpp
 
+# We want a version of `range` which doesn't allocate an intermediate list,
+# specifically it should use a lazy iterator. In Python 2 this was `xrange`, but
+# if we're running with Python 3 then we need to use `range` instead.
+if sys.version_info.major >= 3:
+    xrange = range
+
 #===============================================================================
 # GDB Pretty Printing Module for Rust
 #===============================================================================
@@ -215,7 +222,7 @@ class RustSlicePrinter:
         assert data_ptr.type.get_dwarf_type_kind() == rustpp.DWARF_TYPE_CODE_PTR
         raw_ptr = data_ptr.get_wrapped_value()
 
-        for index in range(0, length):
+        for index in xrange(0, length):
             yield (str(index), (raw_ptr + index).dereference())
 
 
@@ -244,7 +251,7 @@ class RustStdVecPrinter:
     def children(self):
         (length, data_ptr, cap) = rustpp.extract_length_ptr_and_cap_from_std_vec(self.__val)
         gdb_ptr = data_ptr.get_wrapped_value()
-        for index in range(0, length):
+        for index in xrange(0, length):
             yield (str(index), (gdb_ptr + index).dereference())