Pylance does not report expected error "Could not access item in TypedDict"

[jensmueller-com]

Environment data

• Language Server version: 2021.3.3
• OS and version: macOS 11.2.3
• Python version (& distribution if applicable, e.g. Anaconda): 3.9.2

Expected behaviour

Pylance reports the following error in func1, func2, and func3:

Could not access item in TypedDict
  "nonexistent_key" is not a defined key in "TestTypedDict"

Actual behaviour

Pylance reports the expected error in func1 and func2 but not in func3.

Logs

Background analysis message: ensurePartialStubPackages
Background analysis message: setFileOpened
[FG] parsing: test.py (37ms)
[FG] parsing: …/.vscode/extensions/ms-python.vscode-pylance-2021.3.3/dist/typeshed-fallback/stdlib/builtins.pyi [fs read 4ms] (107ms)
[FG] binding: …/.vscode/extensions/ms-python.vscode-pylance-2021.3.3/dist/typeshed-fallback/stdlib/builtins.pyi (38ms)
[FG] binding: test.py (1ms)
Background analysis message: getDiagnosticsForRange
Background analysis message: getDiagnosticsForRange
Background analysis message: getSemanticTokens full
[BG(1)] getSemanticTokens full at test.py ...
[BG(1)]   parsing: test.py (19ms)
[BG(1)]   parsing: …/.vscode/extensions/ms-python.vscode-pylance-2021.3.3/dist/typeshed-fallback/stdlib/builtins.pyi [fs read 3ms] (82ms)
[BG(1)]   binding: …/.vscode/extensions/ms-python.vscode-pylance-2021.3.3/dist/typeshed-fallback/stdlib/builtins.pyi (30ms)
[BG(1)]   binding: test.py (1ms)
[BG(1)]   parsing: …/.vscode/extensions/ms-python.vscode-pylance-2021.3.3/dist/typeshed-fallback/stdlib/typing.pyi [fs read 2ms] (22ms)
[BG(1)]   binding: …/.vscode/extensions/ms-python.vscode-pylance-2021.3.3/dist/typeshed-fallback/stdlib/typing.pyi (10ms)
[BG(1)]   parsing: …/.vscode/extensions/ms-python.vscode-pylance-2021.3.3/dist/typeshed-fallback/stdlib/_typeshed/__init__.pyi [fs read 2ms] (10ms)
[BG(1)]   binding: …/.vscode/extensions/ms-python.vscode-pylance-2021.3.3/dist/typeshed-fallback/stdlib/_typeshed/__init__.pyi (1ms)
[BG(1)]   parsing: …/.vscode/extensions/ms-python.vscode-pylance-2021.3.3/dist/typeshed-fallback/stubs/typing-extensions/typing_extensions.pyi [fs read 1ms] (3ms)
[BG(1)]   binding: …/.vscode/extensions/ms-python.vscode-pylance-2021.3.3/dist/typeshed-fallback/stubs/typing-extensions/typing_extensions.pyi (1ms)
[BG(1)]   parsing: …/.vscode/extensions/ms-python.vscode-pylance-2021.3.3/dist/typeshed-fallback/stdlib/abc.pyi [fs read 1ms] (1ms)
[BG(1)]   binding: …/.vscode/extensions/ms-python.vscode-pylance-2021.3.3/dist/typeshed-fallback/stdlib/abc.pyi (0ms)
[BG(1)] getSemanticTokens full at test.py (215ms)
Background analysis message: getSemanticTokens range
[BG(1)] getSemanticTokens range 0:0 - 29:0 at test.py (1ms)
Background analysis message: analyze
[BG(1)] analyzing: test.py ...
[BG(1)]   checking: test.py (7ms)
[BG(1)] analyzing: test.py (7ms)
Background analysis message: resumeAnalysis

Code Snippet / Additional information

from typing import TypedDict


class TestClass:
    def __init__(self, **kwargs) -> None:
        pass


class TestTypedDict(TypedDict):
    key: str


dictionary: TestTypedDict = {"key": "value"}


def func1() -> TestClass:
    nonexistent_key = dictionary["nonexistent_key"]

    return TestClass(dictionary=nonexistent_key)


def func2() -> TestClass:
    test_class = TestClass(dictionary=dictionary["nonexistent_key"])

    return test_class


def func3() -> TestClass:
    return TestClass(dictionary=dictionary["nonexistent_key"])

[erictraut]

Thanks for the bug report. This will be fixed in the next release.

[jakebailey]

This issue has been fixed in version 2021.3.4, which we've just released. You can find the changelog here: https://github.com/microsoft/pylance-release/blob/main/CHANGELOG.md#202134-31-march-2021