No IntelliSense for regular expressions

[jkeech]

Issue

If you use re.compile to build a pattern, there is no IntelliSense for the pattern with the Microsoft Python Language server. You do see the IntelliSense with jedi enabled.

Example

import re
pattern = re.compile(r"(Mr|Ms|Mrs)\.?\s[A-Z]\w*")
pattern.

Current:

Expected:

Environment

VS Code

Version: 1.33.1 (user setup)
Commit: 51b0b28134d51361cf996d2f0a1c698247aeabd8
Date: 2019-04-11T08:27:14.102Z
Electron: 3.1.6
Chrome: 66.0.3359.181
Node.js: 10.2.0
V8: 6.6.346.32
OS: Windows_NT x64 10.0.17763

Python Extension

Version: 2019.4.11987

Python runtime

Version: 3.7.3 64-bit

[jakebailey]

Typeshed says those functions return typing.Pattern, and we implement the typing types directly; we appear to be missing that type.

[MikhailArkhipov]

Part of #535

[KongNan]

[MikhailArkhipov]

It boils down to _sre.compile which is compiled module and there is no typeshed stub. So we rely on scraper that uses Python means to look into the module but all it gets is

def compile(pattern, flags, code, groups, groupindex, indexgroup):
    pass

So basically _sre needs a good stub.