Internal error while type checking

[goruck]

Environment data

• Language Server version: v2021.4.3
• OS and version: Ubuntu 20.04.2 LTS
• Python version (& distribution if applicable, e.g. Anaconda): 3.8.5

Expected behaviour

No internal error while type checking.

Actual behaviour

An internal error occurred while type checking file "/home/lindo/Develop/radar-ml/sgan.py": Error: Debug Failure. False expression.
at a.lock (/home/lindo/.vscode-server/extensions/ms-python.vscode-pylance-2021.4.3/dist/pyright-internal/src/analyzer/typeVarMap.ts:238:9)
at validateFunctionArgumentTypes (/home/lindo/.vscode-server/extensions/ms-python.vscode-pylance-2021.4.3/dist/pyright-internal/src/analyzer/typeEvaluator.ts:8080:24)
at callback (/home/lindo/.vscode-server/extensions/ms-python.vscode-pylance-2021.4.3/dist/pyright-internal/src/analyzer/typeEvaluator.ts:6349:28)
at useSpeculativeMode (/home/lindo/.vscode-server/extensions/ms-python.vscode-pylance-2021.4.3/dist/pyright-internal/src/analyzer/typeEvaluator.ts:17893:20)
at validateOverloadsWithExpandedTypes (/home/lindo/.vscode-server/extensions/ms-python.vscode-pylance-2021.4.3/dist/pyright-internal/src/analyzer/typeEvaluator.ts:6347:17)
at validateOverloadedFunctionArguments (/home/lindo/.vscode-server/extensions/ms-python.vscode-pylance-2021.4.3/dist/pyright-internal/src/analyzer/typeEvaluator.ts:6421:32)
at callback (/home/lindo/.vscode-server/extensions/ms-python.vscode-pylance-2021.4.3/dist/pyright-internal/src/analyzer/typeEvaluator.ts:7042:48)
at expandSubtype (/home/lindo/.vscode-server/extensions/ms-python.vscode-pylance-2021.4.3/dist/pyright-internal/src/analyzer/typeEvaluator.ts:3310:41)
at mapSubtypesExpandTypeVars (/home/lindo/.vscode-server/extensions/ms-python.vscode-pylance-2021.4.3/dist/pyright-internal/src/analyzer/typeEvaluator.ts:3326:13)
at ft (/home/lindo/.vscode-server/extensions/ms-python.vscode-pylance-2021.4.3/dist/pyright-internal/src/analyzer/typeEvaluator.ts:6960:28)

Logs

See problem message above from Visual Studio Code. 

Code Snippet / Additional information

XXX

[erictraut]

Thanks for the bug report. This appears to be a duplicate of #1218, which I've already fixed.

[jakebailey]

This issue has been fixed in version 2021.5.0, which we've just released. You can find the changelog here: https://github.com/microsoft/pylance-release/blob/main/CHANGELOG.md#202150-5-may-2021