Reproduction steps:
1. Open the attached project "JapaneseTypography.zip"
2. Open scene "Scene"
3. Open "Test.cs" script
4. Input certain Japanese typographic symbols in a preprocessor directive (Examples: "～", "仝", "…")
5. Add "Test.cs" script to any GameObject

Expected result: Script compiles without errors
Actual result: Unable to add the script as component

Reproducible with: 2020.1.0a7, 2020.3.14f1
Not reproducible with: 2018.4.36f1, 2019.4.39f1, 2020.1.0a6, 2021.1.0a1, 2021.1.14f1, 2021.2.0b3

Note: Some typography symbols work, but not all.
Error: "Can't add script component 'Test' because the script class cannot be found. Make sure that there are no compile errors and that the file name and class name match."