From 1bb35c36df9e5504d092adb88b2475673c9954e5 Mon Sep 17 00:00:00 2001
From: Martin Krizek <martin.krizek@gmail.com>
Date: Tue, 9 Aug 2022 10:12:27 +0200
Subject: [PATCH] Use correct concat function for blocks evaluation

Fixes #1701
---
 CHANGES.rst               | 2 ++
 src/jinja2/runtime.py     | 4 ++--
 tests/test_nativetypes.py | 9 +++++++++
 3 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/CHANGES.rst b/CHANGES.rst
index 7ee75a6a7..6316cb637 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -5,6 +5,8 @@ Version 3.2.0
 
 Unreleased
 
+-   Use correct concat function for blocks evaluation. :issue:`1701`
+
 
 Version 3.1.2
 -------------
diff --git a/src/jinja2/runtime.py b/src/jinja2/runtime.py
index 985842b28..7496c7646 100644
--- a/src/jinja2/runtime.py
+++ b/src/jinja2/runtime.py
@@ -362,7 +362,7 @@ def super(self) -> t.Union["BlockReference", "Undefined"]:
 
     @internalcode
     async def _async_call(self) -> str:
-        rv = concat(
+        rv = self._context.environment.concat(  # type: ignore
             [x async for x in self._stack[self._depth](self._context)]  # type: ignore
         )
 
@@ -376,7 +376,7 @@ def __call__(self) -> str:
         if self._context.environment.is_async:
             return self._async_call()  # type: ignore
 
-        rv = concat(self._stack[self._depth](self._context))
+        rv = self._context.environment.concat(self._stack[self._depth](self._context))  # type: ignore
 
         if self._context.eval_ctx.autoescape:
             return Markup(rv)
diff --git a/tests/test_nativetypes.py b/tests/test_nativetypes.py
index 8c8525251..f78bf9131 100644
--- a/tests/test_nativetypes.py
+++ b/tests/test_nativetypes.py
@@ -160,3 +160,12 @@ def test_macro(env):
     result = t.render()
     assert result == 2
     assert isinstance(result, int)
+
+
+def test_block(env):
+    t = env.from_string(
+        "{% block b %}{% for i in range(1) %}{{ loop.index }}{% endfor %}{% endblock %}{{ self.b() }}"
+    )
+    result = t.render()
+    assert result == 11
+    assert isinstance(result, int)