Don't emit 'unused-variable' or 'unused-import' on names in string li…

…teral type annotations (pylint-dev#3299)

pylint/checkers/variables.py

@@ -2341,6 +2341,10 @@ def _check_is_unused(
         if name in comprehension_target_names:
             return
 
+        # Ignore names in string literal type annotation.
+        if name in self._type_annotation_names:
+            return
+
         argnames = node.argnames()
         # Care about functions with unknown argument (builtins)
         if name in argnames:
@@ -2904,6 +2908,20 @@ def _check_potential_index_error(
                 )
             return
 
+    @utils.only_required_for_messages(
+        "unused-import",
+        "unused-variable",
+    )
+    def visit_const(self, node: nodes.Const) -> None:
+        """Take note of names that appear inside string literal type annotations."""
+        if node.pytype() != "builtins.str":
+            return
+        if not utils.is_node_in_type_annotation_context(node):
+            return
+        if not node.value.isidentifier():
+            return
+        self._type_annotation_names.append(node.value)
+
 
 def register(linter: PyLinter) -> None:
     linter.register_checker(VariablesChecker(linter))

tests/functional/u/unused/unused_name_in_string_literal_type_annotation.py

@@ -0,0 +1,21 @@
+"""Test if pylint sees names inside string literal type annotations. #3299"""
+from argparse import ArgumentParser, Namespace
+from pathlib import Path
+from typing import TypeAlias
+
+def unused_variable_should_not_be_emitted():
+    """unused-variable shouldn't be emitted for Example1."""
+    Example1: TypeAlias = int
+    result: set["Example1"] = set()
+    return result
+
+# unused-import shouldn't be emitted for Path
+example2: set["Path"] = set()
+
+def example3(_: "ArgumentParser"):
+    """unused-import shouldn't be emitted for ArgumentParser"""
+
+# pylint: disable=too-few-public-methods
+class Class:
+    """unused-import shouldn't be emitted for Namespace"""
+    cls: "Namespace"