Hovering `_Float16`s displays the wrong value

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#13,395 opened on Mar 21, 2025 1 comment 1 reaction 0 assignees View on GitHub

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bug Language Service Visual Studio

Dominant language: TypeScript
Stars: 6.2k
Forks: 1.7k
Avg merge: 14h 46m
Merged PRs (30d): 61

Description

Type: Bug

Cast a double or a float to a _Float16.
Hover it.

VSCode will forget to promote the float, resulting in numbers like 1 being displayed as 2.1524E-41f16. Also, f16 isn't a literal.

Extension version: 1.23.6
VS Code version: Code 1.98.2 (ddc367ed5c8936efe395cffeec279b04ffd7db78, 2025-03-12T13:32:45.399Z)
OS version: Windows_NT x64 10.0.19045
Modes:

A/B Experiments

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First steps

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Research direction

No source file or test is named in the report. Reproduce the _Float16 hover after casting from double or float, then trace the C/C++ extension's hover path and its handling of promotion and f16 literals. Done means values such as 1 display correctly without the incorrect E-41f16 representation.

Written by the indexing model from the issue text.

Assessment

Tech stack: cpp, typescript, vscode
Domain: developer-experience, tooling
Issue type: Bug
Difficulty: 3/5
Estimated time: 1-2 days
Activity status: Stale
Clarity: Mostly clear
Newbie friendliness: 42/100