Nullness issue - static methods on struct do not report nullness warning

[T-Gro]

Issue description

Methods like:

DateTime.Parse Int32.Parse

require a non-nullable string. Yet, they do not a report a nullable warning when a possibly null string is passed in. They do report for the null literal

Choose one or more from the following categories of impact

• [ ] Unexpected nullness warning (false positive in nullness checking, code uses --checknulls and langversion:preview).
• [x] Missing nullness warning in a case which can produce nulls (false negative, code uses --checknulls and langversion:preview).
• [ ] Breaking change related to older null constructs in code not using the checknulls switch.
• [ ] Breaking change related to generic code and explicit type constraints (null, not null).
• [ ] Type inference issue (i.e. code worked without type annotations before, and applying the --checknulls enforces type annotations).
• [ ] C#/F# interop issue related to nullness metadata.
• [ ] Other (none of the categories above apply).

Operating System

Windows (Default)

What .NET runtime/SDK kind are you seeing the issue on

.NET SDK (.NET Core, .NET 5+)

.NET Runtime/SDK version

No response

Reproducible code snippet and actual behavior

No response

Possible workarounds

No response