PTVS Analysis Engine: hovering symbols that do not have hover information results in an error

[patrys]

Environment data

• VS Code version: 1.22.0-insiders
• Extension version (available under the Extensions sidebar): 2018.4.0-alpha (nightly 11-46-46-464)
• OS and version: macOS High Sierra
• Python version (& distribution if applicable, e.g. Anaconda): 3.6
• Type of virtual environment used (N/A | venv | virtualenv | conda | ...): direnv
• Relevant/affected Python packages and their versions: n/a

Actual behavior

An error is reported:

Illegal argument, contents must be defined

Expected behavior

Nothing happens.

Steps to reproduce:

1. Make sure the new analysis engine is enabled
2. Hover a language keyword, a parenthesis, a bracket or a brace symbol.
3. Check the developer tools console for the error mentioned above.

Logs

Output for Python in the Output panel (View→Output, change the drop-down the upper-right of the Output panel to Python)

[Info  - 13:07:25] No hover info found in file:///Users/patrys/<redacted>/settings.py at (68, 5)

Output from Console under the Developer Tools panel (toggle Developer Tools on under Help)

ERR Illegal argument, contents must be defined: Error: Illegal argument, contents must be defined
	at new <anonymous> (/Applications/Visual Studio Code - Insiders.app/Contents/Resources/app/out/vs/workbench/node/extensionHostProcess.js:430:471)
	at asHover (/Users/patrys/.vscode-insiders/extensions/ms-python.python-2018.4.0-alpha/node_modules/vscode-languageclient/lib/protocolConverter.js:63:16)
	at <anonymous>

[MikhailArkhipov]

The engine is not fully integrated, there are still many issues there. Generally we capture engine issue in #1006, tracking issues opened in PTVS github.
I'll keep this one open, may be specific to VSC LS protocol implementation.

[MikhailArkhipov]

OK, fixes on PTVS side. Part of microsoft/PTVS#4065