8381238: Remove tautological uses of checked_cast

[kimbarrett]

Please review this change that removes uses of checked_cast that are
unnecessary because they are tautological.

These were discovered by locally changing checked_cast to use the new
integer_cast for integral conversions, and noting which calls failed to
compile because of the anti-tautology check in the latter.

Testing: mach5 tier1

---

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Issue

• JDK-8381238: Remove tautological uses of checked_cast (Enhancement - P4)

Reviewers

• Manuel Hässig (@mhaessig - Committer)
• David Holmes (@dholmes-ora - Reviewer)
• Albert Mingkun Yang (@albertnetymk - Reviewer)

Reviewing

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[mlbridge]

Webrevs

• 00: Full (c7eff7fd)

[mhaessig]

Thank you for fixing these, @kimbarrett. This looks good.

[dholmes-ora]

Looks good to me. But one does have to wonder why such casts were used in the first place.

[dholmes-ora]

So this was put in by JDK-8309685 to apparently suppress a conversion warning (though I can't see how a function typed as int could possibly cause such a warning ???). Was that change in error or have the warnings changed since then?

[theRealAph]

Some of these checks make the code safe when the types of code elsewhere change. Just because something is a 32-bit type today doesn't tell us it always will be.

[kimbarrett]

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[dholmes-ora]

Hmm I was wrong above - it seems stream->write_int takes a juint so do we not need the cast for the signed-to-unsigned conversion?

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