Fix useless-type-doc false positive when args exist in the docstring

Closes #4117
Closes #4593

4 files changed, 74 insertions, 3 deletions

diff --git a/pylint/extensions/_check_docs_utils.py b/pylint/extensions/_check_docs_utils.py
index de2f427bf..5f1e8ea0b 100644
--- a/pylint/extensions/_check_docs_utils.py
+++ b/pylint/extensions/_check_docs_utils.py
@@ -25,6 +25,7 @@ import re
 from typing import List
 
 import astroid
+from astroid import AssignName
 
 from pylint.checkers import utils
 
@@ -206,6 +207,9 @@ class Docstring:
     def __repr__(self) -> str:
         return f"<{self.__class__.__name__}:'''{self.doc}'''>"
 
+    def arg_is_documented(self, arg_name: AssignName) -> bool:
+        return arg_name.name in self.doc
+
     def is_valid(self):
         return False
 
diff --git a/pylint/extensions/docparams.py b/pylint/extensions/docparams.py
index b53802bce..032e993a6 100644
--- a/pylint/extensions/docparams.py
+++ b/pylint/extensions/docparams.py
@@ -23,12 +23,14 @@
 """Pylint plugin for checking in Sphinx, Google, or Numpy style docstrings
 """
 import re
+from typing import Optional
 
 import astroid
 
 from pylint.checkers import BaseChecker
 from pylint.checkers import utils as checker_utils
 from pylint.extensions import _check_docs_utils as utils
+from pylint.extensions._check_docs_utils import Docstring
 from pylint.interfaces import IAstroidChecker
 from pylint.utils import get_global_option
 
@@ -460,7 +462,11 @@ class DocstringParameterChecker(BaseChecker):
             )
 
     def check_arguments_in_docstring(
-        self, doc, arguments_node, warning_node, accept_no_param_doc=None
+        self,
+        doc: Docstring,
+        arguments_node: astroid.Arguments,
+        warning_node: astroid.NodeNG,
+        accept_no_param_doc: Optional[bool] = None,
     ):
         """Check that all parameters in a function, method or class constructor
         on the one hand and the parameters mentioned in the parameter
@@ -541,10 +547,12 @@ class DocstringParameterChecker(BaseChecker):
             )
 
         for index, arg_name in enumerate(arguments_node.args):
-            if arguments_node.annotations[index]:
+            if arguments_node.annotations[index] and doc.arg_is_documented(arg_name):
                 params_with_type.add(arg_name.name)
         for index, arg_name in enumerate(arguments_node.kwonlyargs):
-            if arguments_node.kwonlyargs_annotations[index]:
+            if arguments_node.kwonlyargs_annotations[index] and doc.arg_is_documented(
+                arg_name
+            ):
                 params_with_type.add(arg_name.name)
 
         if not tolerate_missing_params:
diff --git a/tests/functional/u/useless/useless_type_doc.py b/tests/functional/u/useless/useless_type_doc.py
new file mode 100644
index 000000000..88dedb479
--- /dev/null
+++ b/tests/functional/u/useless/useless_type_doc.py
@@ -0,0 +1,51 @@
+"""demonstrate FP with useless-type-doc"""
+# line-too-long
+
+
+def function(public_param: int, _some_private_param: bool = False) -> None:
+    """does things
+
+    Args:
+        public_param: an ordinary parameter
+    """
+    for _ in range(public_param):
+        ...
+    if _some_private_param:
+        ...
+    else:
+        ...
+
+
+# +1: [useless-type-doc,useless-param-doc]
+def function_useless_doc(public_param: int, _some_private_param: bool = False) -> None:
+    """does things
+
+    Args:
+        public_param: an ordinary parameter
+        _some_private_param (bool): private param
+
+    """
+    for _ in range(public_param):
+        ...
+    if _some_private_param:
+        ...
+    else:
+        ...
+
+
+def test(_new: str) -> str:  # We don't expect useless-type-doc here
+    """foobar
+
+    :return: comment
+    """
+    return ""
+
+
+# +1: [useless-type-doc,useless-param-doc]
+def test_two(_new: str) -> str:  # We don't expect useless-type-doc here
+    """foobar
+
+    :param str _new:
+    :return: comment
+    """
+    return ""
diff --git a/tests/functional/u/useless/useless_type_doc.rc b/tests/functional/u/useless/useless_type_doc.rc
new file mode 100644
index 000000000..d4a6dc172
--- /dev/null
+++ b/tests/functional/u/useless/useless_type_doc.rc
@@ -0,0 +1,8 @@
+[MASTER]
+load-plugins=pylint.extensions.docparams,
+
+[PARAMETER_DOCUMENTATION]
+accept-no-param-doc=no
+accept-no-raise-doc=no
+accept-no-return-doc=no
+accept-no-yields-doc=no