Reverse the order of decorators for infer_subscript

`path_wrapper` needs to come first, followed by `raise_if_nothing_inferred`,
otherwise we won't handle `StopIteration` correctly.

Close #762

ChangeLog

@@ -18,6 +18,13 @@ Release Date: TBA
 
   Close PyCQA/pylint#3209
 
+* Reverse the order of decorators for `infer_subscript`
+
+  `path_wrapper` needs to come first, followed by `raise_if_nothing_inferred`,
+  otherwise we won't handle `StopIteration` correctly.
+
+  Close #762
+
 * Numpy `datetime64.astype` return value is inferred as a `ndarray`.
 
   Close PyCQA/pylint#3332

astroid/inference.py

@@ -350,7 +350,6 @@ def infer_global(self, context=None):
 _SUBSCRIPT_SENTINEL = object()
 
 
-@decorators.raise_if_nothing_inferred
 def infer_subscript(self, context=None):
     """Inference for subscripts
 
@@ -407,8 +406,10 @@ def infer_subscript(self, context=None):
     return None
 
 
-nodes.Subscript._infer = decorators.path_wrapper(infer_subscript)
-nodes.Subscript.infer_lhs = infer_subscript
+nodes.Subscript._infer = decorators.raise_if_nothing_inferred(
+    decorators.path_wrapper(infer_subscript)
+)
+nodes.Subscript.infer_lhs = decorators.raise_if_nothing_inferred(infer_subscript)
 
 
 @decorators.raise_if_nothing_inferred

tests/unittest_inference.py

@@ -5646,5 +5646,26 @@ def test_custom_decorators_for_classmethod_and_staticmethods(code, obj, obj_type
     assert inferred.type == obj_type
 
 
+@pytest.mark.skipif(sys.version_info < (3, 8), reason="Needs dataclasses available")
+def test_dataclasses_subscript_inference_recursion_error():
+    code = """
+    from dataclasses import dataclass, replace
+
+    @dataclass
+    class ProxyConfig:
+        auth: str = "/auth"
+
+
+    a = ProxyConfig("")
+    test_dict = {"proxy" : {"auth" : "", "bla" : "f"}}
+
+    foo = test_dict['proxy']
+    replace(a, **test_dict['proxy']) # This fails
+    """
+    node = extract_node(code)
+    # Reproduces only with safe_infer()
+    assert helpers.safe_infer(node) is None
+
+
 if __name__ == "__main__":
     unittest.main()